Embryogenesis stages. Critical periods in the development of the embryo and fetus. Critical periods of pregnancy

22.06.2019

Critical periods are periods in which there are common and specific features in the nature of the responses of the embryo and fetus to pathogenic effects. They are characterized by the predominance of processes of active cellular and tissue differentiation and a significant increase in metabolic processes.

1st critical period from 0 to 8 days. It is considered from the moment of fertilization of the egg until the introduction of the blatocyst into the decidua. During this period, there is no connection between the embryo and the mother's body. Damaging factors either do not cause the death of the fetus, or the embryo dies (the principle of "all or nothing"). A characteristic feature of the period is the absence of malformations even under the influence of environmental factors that have a pronounced teratogenic effect. The nutrition of the embryo is autotropic - due to the substances contained in the egg, and then due to the liquid secretion of the trophoblast in the blastocyst cavity.

2nd critical period from 8 days to 8 weeks. During this period, the formation of organs and systems occurs, as a result of which the occurrence of multiple malformations is characteristic. The most sensitive phase is the first 6 weeks: defects of the central nervous system, hearing, eyes are possible. Under the influence of damaging factors, inhibition and arrest of development initially occur, then random proliferation of some and dystrophy of other rudiments of organs and tissues. The value in damage is not so much the gestational age, but the duration of exposure to an adverse factor.

3rd critical period - 3-8 weeks of development. Along with organogenesis, the formation of the placenta and chorion occurs. When exposed to a damaging factor, the development of allantois is disrupted, which is very sensitive to damage: vascular death occurs, as a result of which chorion vascularization stops with the onset of primary placental insufficiency.

4th critical period - 12-14. Refers to fetal development. The danger is associated with the formation of the external genitalia in female fetuses with the formation of false male hermaphroditism.

5th critical period - 18-22 weeks. During this period, the formation of the nervous system is completed, the bioelectric activity of the brain, changes in hematopoiesis, and the production of certain hormones are noted.

Bleeding in the afterbirth and early postpartum periods. Causes. emergency obstetric care

Bleeding afterbirth and postpartum periods.

The result of a violation of the separation and allocation of the placenta: violations of the expulsion of the placenta; violations of the contractility of the uterus; coagulation change. Postpartum hemostasis is a complex system consisting of 2 components:

Mechanical hemostasis - is provided by a strong retraction of the myometrium, as a result of twisting and clamping of the spiral vessels of the uterus. Its effectiveness depends on the contractility of the uterus, which cannot exist indefinitely.

Coagulation hemostasis - under conditions of vascular clamping, blood flow in them slows down, cell aggregates are formed, blood thromboplastin is released, the blood coagulation system is activated, and thrombosis occurs in the area of the placental site. In the formation of a stable thrombus, the tone of the uterus does not play a decisive role, but it takes 2-3 hours to stabilize the thrombus. If during this time the uterus relaxes, then the blood clots loosely bind to the vascular wall, can be washed out, and bleeding resumes.

Thus, mechanical coagulation hemostasis are supported by each other and provide a stop of bleeding. Normal contraction of the uterus is possible after the complete expulsion of all elements of the fetal egg. The normal postpartum period provides adequate postpartum hemostasis.

2nd complication of the postpartum period:

a) tight attachment of the placenta

b) true increment of the placenta

a) this pathology is associated with morphological changes in the spongy layer of the basal part of the decidua, which is the endometrium, is formed during pregnancy. The basal layer (adjacent to the placenta) + capsular section (covers the fetal egg) + parietal section (covers the part of the uterine cavity not occupied by the fetal egg) is isolated in it. In the decidua - 2 layers: spongy - forms sects on the placenta, the basal plate is the maternal part of the placenta. In the region of the basal plate, the vessels of the uterus are opened and lacunae are formed, in which chorionic villi float (exchange of mother and fetus). In the placenta, 2 groups of villi are distinguished: some provide metabolism and are immersed in maternal blood, others grow deep into the basal plate (provide fixation of the plate - "" anchor villi "").

With thinning of the basal layer of the decidua, more than a quarter of the villi grow into the basal plate without reaching the myometrium> a dense attachment of the placenta is formed. Morphological changes in the basal plate are the result of a large number of pregnancies, intrauterine interventions, and inflammatory changes in the myometrium.

Attachment.

Complete - in the afterbirth period, there is no independent separation of the placenta within 30 minutes.

Partial - some part of the placenta is separated, part of the vessels of the placental site is opened, which leads to bleeding. The remaining unseparated part of the placenta prevents mechanical hemostasis. Signs of separation of the placenta are negative.

Prevention of postpartum hemorrhage (PPK) - in the 2nd stage of labor, a powerful stimulant drug is administered. Now they don't even wait 30 minutes.

In all cases, regardless of bleeding, a manual separation and removal of the placenta is performed.

b) it is observed with severe changes in the morphology of the spongy layer of the basal decidua. When the chorionic villi completely sprout the basal lamina and come into contact with the myometrium, the placenta is "acreta". If the chorionic villi grow into the thickness of the muscle - the placenta "increte". The villi can grow through the entire thickness of the myometrium up to the peritoneum - the placenta "per creta".

Similarly, depends on full or partial increment. The final diagnosis and differential diagnosis between tight attachment and true increment is made during manual separation of the placenta. If, with a tight attachment, the placenta is separated with difficulty, but completely, then with an increment, it comes off in pieces, with increased attempts to separate the placenta, the hand plunges into the myometrium until the uterus is perforated. The consequence of placenta accreta is increased bleeding during surgery, since the myometrium is damaged.

Bleeding in the early postpartum period. Causes, diagnosis, treatment and prevention.

Bleeding from the genital tract in the first 4 hours after childbirth is called bleeding in the early postpartum period.

Delay in the uterine cavity of parts of the child's place.

Atony and hypotension of the uterus.

Injury of the soft tissues of the birth canal.

Violation of the coagulation system (coagulopathy).

Hypotension of the uterus is a condition in which the tone and contractility of the uterus is sharply reduced. Under the influence of measures and means that stimulate the contractile activity of the uterus, the uterine muscle contracts, although often the strength of the contractile reaction does not correspond to the strength of the impact.

Uterine atony is a condition in which uterine stimulants do not have any effect on it. The neuromuscular apparatus of the uterus is in a state of paralysis. Atony of the uterus is rare, but causes massive bleeding.

The clinic of hypotonic bleeding is expressed by the main symptom - massive bleeding from the postpartum uterus, and hence the appearance of other symptoms associated with hemodynamic disorders and acute anemia. A picture of hemorrhagic shock develops.

The condition of the puerperal depends on the intensity and duration of bleeding and the general condition of the woman. Physiological blood loss during childbirth should not exceed 0.5% of a woman's body weight (but not more than 450 ml). If the forces of the body of the puerperal are exhausted, the reactivity of the body is reduced, then even a slight excess of the physiological norm of blood loss can cause a severe clinical picture in those who already have a low BCC (anemia, preeclampsia, diseases of the cardiovascular system, obesity).

The severity of the clinical picture depends on the intensity of bleeding. So, with a large blood loss (1000 ml or more), for a long time, the symptoms of acute anemia are less pronounced, and a woman copes with this condition better than with rapid blood loss in the same or even less quantity, when collapse can develop faster and death occurs. .

DIAGNOSTICS

The diagnosis of hypotension is established on the basis of a symptom of bleeding from the uterus and objective data on the state of the uterus: on palpation, the uterus is large, relaxed, sometimes poorly contoured through the anterior abdominal wall, with external massage it may shrink slightly, and then relax again, and bleeding resumes.

The differential diagnosis of hypotonic bleeding is carried out with traumatic injuries of the birth canal. In contrast to hypotonic bleeding in trauma of the birth canal, the uterus is dense, well reduced. Examination of the cervix and vagina with the help of mirrors, manual examination of the walls of the uterine cavity confirm the diagnosis of soft tissue ruptures of the birth canal and bleeding from them.

Emptying the bladder with a catheter.

External uterine massage

Manual examination of the uterine cavity and massage of the uterus on the fist.

Simultaneously with the massage of the uterus on the fist, agents that reduce the uterus (oxytocin, prostaglandins) are injected. To consolidate the effect of stopping bleeding, you can apply a suture according to V.A. Lositskaya (on the posterior lip of the cervix, a thick catgut is sutured through all layers), insert a swab moistened with ether (cold irritant) into the posterior fornix of the vagina, introduce ice into the rectum, and an ice pack on the lower abdomen.

The lack of effect from a manual examination of the uterine cavity and uterine massage on the fist, continued bleeding makes it possible to diagnose atonic bleeding and proceed with surgical intervention.

After opening the abdominal cavity, catgut ligatures are applied to the uterine and ovarian vessels on both sides, waiting for some time. In 50% of cases, the uterus contracts (myometrial hypoxia sets in and the uterine muscle contracts reflexively), bleeding stops, and the uterus is preserved. However, in half of the cases this does not happen, especially if there are signs of coagulopathy, then the bleeding cannot be stopped. In such a situation, the only method of saving the life of the puerperal is amputation or extirpation of the uterus. The volume of the operation is determined by the state of hemostasis, with signs of coagulopathy, the uterus is extirpated.

maternal mortality. Structure. Prevention.

Maternal mortality according to WHO - due to pregnancy, regardless of duration and location, the death of a woman occurring during pregnancy or within 42 days after its termination from any cause associated with pregnancy, aggravated by it or its management, but not from an accident or an accidental cause.

This is the most important indicator of the quality and level of organization of the work of obstetric institutions, the effectiveness of the introduction of scientific achievements in healthcare practice. This indicator allows you to evaluate all losses of pregnant women (from abortions, ectopic pregnancy, obstetric and extragenital pathology during the entire gestation period), women in labor and puerperas (within 42 days after termination of pregnancy).

All cases of MS are divided into two groups:

a) Death directly related to obstetric causes: death due to obstetric complications of pregnancy, childbirth, the postpartum period, as well as as a result of improper treatment tactics.

b) Death indirectly attributable to obstetric causes: death resulting from a pre-existing disease or disease that developed during pregnancy, not due to a direct obstetric cause, but the clinical course of which was exacerbated by the physiological effects of pregnancy.

Maternal mortality:

number of dead pregnant women, puerperas in tech 42 after childbirth / number of live births * 100000

Structure of maternal mortality:

number of women who died from a given cause/total number of wives who died from all causes*100

The structure of the causes of MS: most (about 80%) - obstetric (most common: ectopic pregnancy, bleeding, abortion in non-medical institutions), 20% - causes indirectly related to pregnancy and childbirth (extragenital diseases).

Directions for the prevention of MS: improving the quality of medical care for pregnant women, women in labor and puerperas; re-equipment of maternity hospitals and antenatal clinics with all necessary equipment; prevention of prenatal and postnatal complications, etc.

Uteroplacental insufficiency. Diagnosis, treatment. Prevention

Placental insufficiency is a clinical syndrome caused by morphological and functional changes in the placenta and violations of compensatory-adaptive mechanisms that ensure the functional usefulness of the fetus.

Classification. Allocate primary and secondary placental insufficiency.

Primary placental insufficiency develops during the formation of the placenta and is most common in pregnant women with a history of recurrent miscarriage or infertility.

Secondary placental insufficiency occurs after the formation of the placenta and is due to exogenous influences transferred during pregnancy by diseases.

The course of both primary and secondary placental insufficiency can be acute and chronic. Acute placental insufficiency occurs due to extensive infarcts and premature detachment of a normally located placenta.

In the development of chronic placental insufficiency, the gradual deterioration of decidual perfusion as a result of a decrease in compensatory-adaptive reactions of the placenta in response to pathological conditions of the maternal organism is of primary importance.

In clinical terms, it is customary to distinguish between relative and absolute placental insufficiency. Relative insufficiency is characterized by persistent hyperfunction of the placenta and is compensated. This type of placental insufficiency develops with the threat of miscarriage, moderate manifestations of late preeclampsia (edema, stage I nephropathy) and, as a rule, responds well to therapy.

Absolute (decompensated) placental insufficiency is characterized by a breakdown of compensatory-adaptive mechanisms and develops with hypertensive forms of preeclampsia, ultimately leading to developmental delay and fetal death.

Clinical picture and diagnosis. The diagnosis of placental insufficiency is established on the basis of anamnesis data, the course of pregnancy, and clinical and laboratory examination. To assess the course of pregnancy, the function of the placenta and the condition of the fetus, the following are performed:

regular general obstetric supervision;

dynamic ultrasound examination in I, II, III trimesters;

dopplerometry;

study of hemostasis;

determination of estradiol, progesterone, chronic gonadotropin, a-fetoprotein in the blood;

colpocytological examination;

fetal CTG;

determination of the height of the fundus of the uterus.

The clinical picture of the threat of termination of pregnancy in women with placental insufficiency is characterized by uterine tension in the absence of structural changes in the cervix. The course of this pregnancy in women with emerging primary placental insufficiency due to the threat of interruption is often accompanied by blood discharge, autoimmune hormonal disorders, and dysbacteriosis.

Treatment and prevention. The success of preventive measures and treatment for placental insufficiency is determined by the timely diagnosis and treatment of concomitant diseases and complications of pregnancy. With the threat of termination of pregnancy in the early stages, due to a low level of estrogen, signs of chorionic detachment, spotting, it is recommended to treat with small doses of estrogen.

1. With a low basal level of human chorionic gonadotropin, the appropriate drugs (pregnil, profazi) are administered up to 12 weeks. pregnancy. To maintain the function of the corpus luteum, progesterone, duphaston, and utrotestan are used (up to 16-20 weeks).

2. Therapeutic and preventive measures include diet therapy, vitamins, physiotherapy, sleep aids.

3. It is advisable to use antioxidants (a-tocopherol acetate), hepatoprotectors, nootropics, adaptogens.

4. The main drugs used to maintain pregnancy after 20 weeks are b-blockers, magnesium sulfate, metacin.

5. Upon receipt of data on infection (exacerbation of pyelonephritis, polyhydramnios, detection of urogenital infection), etiotropic antibiotic therapy and vaginal sanitation are performed. Eubiotics are widely used, acting by the method of competitive displacement of pathogenic and opportunistic flora.

6. In the complex therapy of late gestosis, agents that improve uteroplacental blood flow (glucose-novocaine mixture, rheopolyglucin, trental) must be included, sessions of abdominal decompression, hyperbaric oxygenation are performed.

7. In the presence of antiphospholipid syndrome, antiplatelet agents (aspirin, chimes), low molecular weight heparins (fraxiparin), immunoglobulins are used. High titer of antiphospholipids can be reduced by a course of plasmapheresis

Methods of research of pregnant women and women in childbirth.

1. Anamnesis

2. Inspection.

3. Gynecological examination

3.1. External gynecological examination - when examining the external genital organs, the degree and nature of the hairline are taken into account

3.2. A study using gynecological mirrors is performed after examining the external genitalia.

3.3. Vaginal examination

3.4. Bimanual (vaginal-abdominal, bimanual) examination is the main method for recognizing diseases of the uterus, appendages, pelvic peritoneum and tissue.

3.5. Rectal (rectal) and rectal-abdominal examination

3.6. Rectovaginal examination - is used in the presence of pathological processes in the wall of the vagina, rectum, in the surrounding tissue.

4. Instrumental methods of research (probing of the uterus, separate diagnostic curettage, biopsy, aspiration curettage, puncture of the abdominal cavity, blowing out the fallopian tubes, catheterization of the bladder).

4.1. Biopsy of the cervix: targeted, cone

a) diathermoexcision (diathermo or electroconization) of the cervix - cone-shaped excision of the cervix with a Rogovenko electrode.

b) targeted biopsy

4.2. Puncture of the abdominal cavity through the posterior fornix of the vagina

4.3. Separate diagnostic curettage is an instrumental removal of the mucous membrane of the cervical canal, and then the mucous membrane of the body of the uterus.

5. X-ray methods

5. 1. Metrosalpingography (MSG, hysterosalpingography) - an x-ray method for examining the uterine tubular cavity using contrast agents

5.2. Bicontrast gynecography (pneumopelviography, pneumopelviography, roentgenopelviography) is an x-ray examination based on the introduction of gas (nitrous oxide, carbon dioxide, oxygen) into the abdominal cavity in combination with hysterosalpingography.

6. Hormonal studies

6.1. Functional diagnostic tests are used to determine the activity of the ovaries and characterize the estrogen saturation of the body:

a) the study of cervical mucus - the method is based on the fact that during the normal menstrual cycle, the physico-chemical properties of mucus are subject to changes

b) colpocytological examination of the cellular composition of vaginal smears - based on cyclic changes in the vaginal epithelium.

c) measurement of basal temperature - the test is based on the hyperthermic effect of progesterone.

d) histological examination of endometrial scrapings. The method is based on the appearance of characteristic changes in the endometrium under the influence of ovarian steroid hormones.

e) blood test. It is based on the fact that the composition of the formed elements changes in accordance with the phases of the menstrual cycle.

e) skin-allergic test. Based on the appearance of an allergic reaction in response to the introduction of hormonal drugs

6.2. Hormonal-functional tests are used for topical and differential diagnosis of endocrine diseases

a) progesterone test - used for amenorrhea of any etiology to exclude the uterine form;

b) a test with estrogens and progesterone - is carried out to exclude (confirm) the uterine or ovarian form of amenorrhea.

c) test with dexamethasone - used to determine the nature of hyperandrogenism in women with signs of virilization, based on the inhibition of ACTH secretion.

d) a test with clomiphene - is indicated for a disease accompanied by anovulation, more often against the background of oligo- or amenorrhea.

e) test with luliberin - carried out with a negative test with clomiphene.

7. Endoscopic methods

7.1. Colposcopy: simple and advanced. Microcolposcopy.

Colposcopy (vaginoscopy, vulvoscopy) is a diagnostic method for determining the pathological conditions of the vaginal part of the cervix, cervical canal, vagina and external genitalia by examining them using special optical instruments (colposcopes).

Microcolposcopy is an intravital histological examination of the vaginal part of the cervix.

7.2. Hysteroscopy - examination with optical systems

7.3. Laparoscopy - examination of the organs of the abdominal cavity and small pelvis with the help of optical instruments through the anterior abdominal wall.

Culdoscopy is a similar procedure, but the examination is through the posterior fornix of the vagina.

8. Ultrasound diagnostics

Ultrasound options in gynecology:

1) pin

2) transvaginal

Methods for assessing the state of the intrauterine fetus.

Biophysical profile of the fetus - a set of studies, including physical activity, respiratory movements, heart rate, fetal tone and the amount of amniotic fluid, which allows you to objectify the condition of the fetus.

Test methodology: a) a non-stress test is performed (see question non-stress test)

b) the fetus is observed with real-time ultrasound for 30 minutes in order to identify criteria (fetal respiratory movements, fetal motor activity, fetal tone, amniotic fluid volume) It is better to conduct a study after a meal.

Interpretation of the test: a) normal test - score 10-8 (out of 10 possible)

b) suspicious - 6-7 points, i.e. chronic asphyxia is possible and the test must be repeated within 24 hours

c) less than 6 points - a serious risk of chronic hypoxia, which requires a repetition of the non-stress test immediately and if the result is the same, then an emergency delivery is necessary

d) any number of points less than 10 with the presence of oligohydramnios - an indication for immediate delivery (if oligohydramnios is not associated with rupture of the membranes).

Benefits of the test:

a) can be performed on an outpatient basis

b) low false positive rate (compared to non-stress test)

c) no contraindications

d) can be used at the beginning of the third trimester of pregnancy

Disadvantages of the test:

a) requires the skill of an ultrasound specialist

b) requires more time (45-90 minutes).

Multiple pregnancy, features of the course and management of childbirth.

Multiple pregnancy: clinical picture and diagnosis, management of pregnancy and childbirth.

A multiple pregnancy is a pregnancy in which two or more fetuses develop simultaneously in the uterus. Children born in multiple pregnancies are called twins. Boys predominate among born twins.

Factors contributing to the development of multiple pregnancy:

a) heredity - more common in families where the mother, father or both parents are twins.

b) age and number of births - the probability increases with increasing age and number of births.

c) stimulation of ovulation.

d) taking oral contraceptives for a long time (more than 6 months) and conception within one month after their cancellation

Diagnostics.

1. Clinical signs: rapid growth of the uterus and discrepancy between its size (exceeding them) and the gestational age; small size of the presenting head with a significant volume of the pregnant uterus and high standing of its bottom; early sensation of fetal movement (from 15-16 weeks of pregnancy); determination in the uterus by palpation of three or more large parts of the fetus; determination during auscultation of two or more autonomous zones of the fetal heartbeat; palpation of small parts of the fetus in different parts of the uterus; definition of a saddle uterus, a longitudinal or horizontal groove between the fruits; identification of factors predisposing to multiple pregnancy.

2. Phono- and electrocardiography of fetuses, radiography, ultrasound (from 6 weeks - 100%) - allow you to identify reliable signs of pregnancy.

The course of childbirth.

Most often, the course of childbirth is normal. After the opening of the cervix, the first fetus is born first, and then the next one is expelled. After the birth of children, the placenta of each fetus is separated from the wall of the uterus and afterbirths are born.

Complications: premature birth; premature and early rupture of amniotic fluid; anomalies of labor activity; premature detachment of the placenta of the second fetus; hypotonic bleeding in the afterbirth and early postpartum periods; fetal hypoxia.

Birth management.

Delivery. The question of choosing a method of delivery is taken before childbirth or with their onset.

1. Cesarean section. It is produced after 36 weeks of pregnancy, when the viability of the fetus is more likely.

Indications: intrauterine suffering of one of the fetuses with an unprepared birth canal in a woman in labor; breech presentation of fetuses and burdened obstetric history; transverse position of the first fetus; premature detachment of the monochorionic placenta; the presence of a diagnosed one fetal bladder (monoamnial pregnancy), which can lead to entanglement of the umbilical cord and its prolapse when the membranes rupture; the absence of the effect of labor induction or stimulation of labor within three hours. The issue of caesarean section for a period of less than 36 weeks is decided individually, taking into account the indications and the availability of conditions for nursing premature babies.

2. Childbirth through the natural birth canal. Premature pregnancies are carried out without perineal protection. To prevent injury to the advancing head of the first fetus, paracervical and pudendal anesthesia with a 0.25% solution of novocaine, as well as perineal dissection, are performed. In the case of a breech presentation of the first fetus, manual assistance is provided, as gently as possible. The weakness of labor activity in the second stage of labor is corrected by fractional administration of oxytocin.

In pregnancy over 36 weeks or full-term, there is often a weakness of exertive activity. For its prevention during the period of exile, intravenous drip administration of oxytocin at a low rate is necessary. At the same time, measures are taken to prevent fetal hypoxia. If there are complications from the mother or fetus, then the period of expulsion of the first fetus should be accelerated by surgical methods (vacuum extraction, obstetric forceps, extraction of the fetus by the pelvic end). After the birth of the first fetus, the fetal and maternal ends of the umbilical cord are carefully tied up - with identical twins, the second fetus may die from blood loss through the umbilical cord of the first fetus if it is not bandaged. After the birth of the first fetus, an external examination is performed, the position of the second fetus and the nature of its heartbeat are ascertained. In a good condition of the woman in labor, the longitudinal position of the second fetus, 10-15 minutes after the birth of the first child, the fetal bladder is opened, under the control of the hand, the water is slowly released and the birth is given to the natural course. If uterine contractions are insufficient, labor is stimulated with oxytocin or prostaglandins. When intrauterine hypoxia of the second fetus is detected, bleeding due to placental abruption immediately opens the fetal bladder and proceeds to operative delivery, taking into account the preparedness of the birth canal and the possibility of rapid delivery. In the transverse position of the second fetus, an external obstetric turn and opening of the fetal bladder is performed, which leads to the independent birth of the second fetus. In exceptional cases, a combined rotation of the fetus on the leg is performed, followed by its extraction by the pelvic end.

Sometimes in such a situation, they resort to a caesarean section. When pregnant with three fetuses or more, delivery by caesarean section is preferable. A caesarean section is also performed when twins are fused.

The third stage of labor requires special attention, careful monitoring of the condition of the woman in labor and the amount of blood she loses. Continued intravenous administration of oxytocin. If bleeding occurs, immediately take measures to remove the placenta from the uterine cavity. The born afterbirth (afterbirths) is carefully examined to make sure that it is intact and to establish the identical or dizygotic origin of the twins.

In the first hours after childbirth, they carefully monitor the condition of the puerperal, contraction of the uterus and the amount of blood released from the genital tract. If necessary, strengthen the contraction of the uterus with uterotonics and other means.

The fact that the expectant mother should take care of herself is perceived as a common truth. But few people know that during pregnancy there are periods when the risk of all kinds of health troubles increases significantly. Observing increased caution at “critical moments”, a woman will be able to “insure” in time and avoid unnecessary problems.

Pregnancy lasts 9 calendar or 10 obstetric months (its average duration is 280 days from the first day of the last menstruation to childbirth). During this time, the most complex process of transformation of a fertilized egg into a mature fetus, capable of independent existence outside the mother's womb, takes place. For 9 months, there is a rapid division of cells, the formation of organs and tissues of the fetus, the maturation of functional systems, the establishment of a connection between them, thanks to which the newborn will be able to adapt in the external environment, live an independent life, separate from the mother's body.

It is difficult to overestimate the role of any period of intrauterine life of the fetus. But during pregnancy there are several critical periods when the risk of its spontaneous interruption (miscarriage or premature birth), the occurrence of complications during pregnancy, anomalies in the development of the embryo and fetus are highest. It is these terms that will be discussed.

There are the following periods of fetal development during pregnancy:

pre-implantation (from the moment of fertilization of the egg with sperm until the introduction of the fertilized egg into the uterine wall mucosa);

implantation (attachment of a fertilized egg to the wall of the uterus);

organogenesis and placentation (the period of formation of all organs and tissues of the fetus, as well as the placenta);

fetal - a period of growth and development of formed organs and tissues.

Pre-implantation period

contraction of the smooth muscles of the wall of the fallopian tube. These contractions normally occur in a unilateral direction - towards the uterine cavity from the end of the tube facing the abdominal cavity;

movement of the cilia of the mucous membrane, which covers the fallopian tube from the inside. The fluid in the tube begins to move, and with the flow of this fluid, the fertilized egg enters the uterus;

relaxation of the sphincter (circular muscle) in the junction of the fallopian tube with the uterus. This sphincter is designed to prevent a fertilized egg from entering the uterine cavity prematurely, before the uterus is ready to receive a fertilized egg.

The movement of the egg through the fallopian tube occurs under the influence of the female sex hormones estrogen and progesterone. Progesterone is a pregnancy hormone that is produced in the ovary in the early stages of pregnancy (a corpus luteum forms at the site of a burst follicle, which produces this hormone in large quantities and contributes to the onset and maintenance of pregnancy). If progesterone is not produced enough, the egg from the fallopian tube will enter the uterine cavity late. With increased peristalsis of the fallopian tube, the fertilized egg will enter the uterine cavity before it can penetrate the mucous membrane, as a result of which the egg may die. Since pregnancy will not take place, there will be no delay in the next menstruation, the pregnancy remains undiagnosed, unrecognized. The period of advancement of a fertilized egg through the fallopian tube is considered the first critical period of pregnancy (from 12-14 to 10-8 days before the next menstruation). As a result of a violation of the complex mechanisms of regulation of the fallopian tube, the egg after fertilization can also be introduced into the wall of the tube (ectopic pregnancy).

Implantation period

This period also passes even before the expected menstruation, most often when the woman is still unaware of her pregnancy. Once in the uterine cavity, the embryo already consists of 16-32 cells, but it does not immediately penetrate into the uterine mucosa, and is in a free state for another two days. These two days from the moment the fertilized egg enters the uterine cavity to its attachment to the uterine wall constitute the implantation period. The place of implementation depends on a number of circumstances, but most often it is the anterior or posterior wall of the uterus.

The nutrition of the fetal egg during this period occurs due to the local dissolution of the mucous membrane of the uterine wall with the help of enzymes secreted by the fetal egg. After 2 days, the fetal egg is introduced into the uterine mucosa, which contains a large amount of enzymes, glycogen, fats, trace elements, protective antibodies and other biologically active substances necessary for the further growth of the embryo.

The second critical period of pregnancy is implantation, that is, the attachment of the fetal egg to the wall of the uterus. If implantation fails, then the pregnancy ends under the guise of menstruation (in fact, this is an undiagnosed miscarriage at a very short time). Since there is no delay in menstruation. the woman does not even assume that she is pregnant.

The process of implantation is greatly influenced by hormonal factors: the concentration of hormones such as progesterone, estrogens, prolactin (a pituitary hormone - a gland located in the brain). glucocorticoids (adrenal hormones), etc.

If the fetal egg is not active enough, does not release the required amount of enzymes that destroy the uterine mucosa in a timely manner, then it can penetrate the uterine wall in the lower segment or in the cervix, resulting in pregnancy or an abnormal placenta (the placenta blocks the exit from the uterus partially or completely) .

The presence of adhesions (synechia) in the uterine cavity after inflammatory processes, curettage, as well as uterine fibroids, can also interfere with normal implantation.

Each embryonic germ and the organ developing from it has its own critical periods of sensitivity, when the action of various factors selectively disrupts organogenesis. So, for the brain, the 23-28th day, the 30-42nd day, the 45th day, the fifth month of intrauterine life are critical; for the lens of the eye - 23-45 days, for the limbs - 28-56 days, for the cardiovascular system - 23-51 days of intrauterine development (in this case, the days are counted from conception)

Period of organogenesis and placentation

What should be cause for concern?

If the action of adverse factors at a critical time has led to the threat of termination of pregnancy, women complain of pain in the lower abdomen, in the lower back - pulling or cramping. Pain may be accompanied by bloody discharge from the genital tract. Such symptoms should not be left without due attention, because. following them, massive bleeding may occur due to incomplete spontaneous miscarriage, in which the pregnancy cannot be saved.

It is very important at the first symptoms of a threatened miscarriage to immediately contact a gynecologist, undergo the necessary studies, including an examination on a chair, ultrasound, hormonal blood tests for female sex hormones, male sex hormones, thyroid hormones.

This period lasts from the moment of introduction of the fetal egg into the uterine mucosa until 10-12 weeks of pregnancy, when all organs and tissues of the fetus, as well as the placenta, are fully formed. The placenta is a child's place - a link between the fetus and the mother's body, with the help of which the processes of nutrition, metabolism and respiration of the fetus in the womb take place. This is a very important period of intrauterine life, because. at this time, all the organs and tissues of the fetus are laid. Already on the 7th day after the fertilization of the egg, the mother's body receives a signal of pregnancy due to the hormone - chorionic gonadotropin (CG), which is secreted by the fetal egg. CG, in turn, supports the development of the corpus luteum in the ovary. The corpus luteum secretes progesterone and estrogens in sufficient quantities to maintain pregnancy. At the initial stage of pregnancy, before the formation of the placenta, the corpus luteum takes on the function of hormonal support for pregnancy, and if for one reason or another the corpus luteum does not work properly, then there may be a threat of miscarriage, miscarriage or non-developing pregnancy.

The entire period of organogenesis and placentation is also a critical period of intrauterine life of the fetus, because the fetus is highly sensitive to the damaging effects of the environment, especially in the first 3-6 weeks of organogenesis. This critical period in the development of pregnancy is especially important, because. under the influence of adverse environmental factors, the embryo may die or develop abnormalities.

During these periods, the influence of environmental factors on the embryo is especially dangerous, including:

physical (ionizing radiation, mechanical effects); this can be the action of ionizing radiation, for example, in the conditions of a man-made disaster at nuclear facilities, mechanical effects in the form of vibration, and so on. in the relevant industries or at the time of sports training;

chemical: phenols, nitric oxide, pesticides, heavy metals, etc. - these substances can also enter the body of a pregnant woman if she works in the relevant industries or during repairs in a room where a woman stays for a long time. Chemicals include nicotine, alcohol, and some drugs. For example, used for the treatment of cancer, etc.;

biological (for example, herpes virus, cytomegalovirus, rubella virus, etc.).

It must be emphasized that during critical periods, harmful effects lead to the most severe consequences - the death of the embryo or the formation of gross malformations.

According to French researchers, if a pregnant woman for the first time in her life encountered cytomegalovirus, a pathogen that causes a disease that in adults can occur as a banal acute respiratory disease during pregnancy (as can be seen from a blood test for CMV immunoglobulins), especially in the early stages, then in In 1/3 of cases, fetal malformations may occur. If, before pregnancy, she was already infected, the body turns on the protective mechanisms to fight the virus in time, and this probability decreases to 1%. The same can be said about the herpes simplex virus.

Of particular danger is the rubella virus when infected with it in the early stages of pregnancy. In this case, a woman is recommended artificial termination of pregnancy, tk. there is a high risk of having a child with malformations such as microphthalmia - a malformation of the eyes, microcephaly - a serious malformation of the brain, deafness, congenital heart defects, etc.

Of the chemical compounds, lead, mercury, benzene, nicotine, carbon oxides and other substances that can cause malformations have a particularly adverse effect on the state of the embryo.

Some drugs are especially contraindicated during pregnancy (eg anticancer antibiotics); if they were taken, early termination of pregnancy is recommended. When taking certain medicines, it is necessary to consult a geneticist, carefully monitor the condition of the embryo and fetus during pregnancy (ultrasound, blood test for chorionic gonadotropin, alpha-fetoprotein, estriol, which make it possible to suspect the presence of fetal malformations - the analysis is carried out at 16-20 weeks of pregnancy ).

Women working in the chemical industry during pregnancy must be transferred to other, less dangerous workshops. As for the effect of radiation, if it affects a woman before the implantation of the embryo (during the pre-implantation period), in 2/3 of the cases the embryo dies. During the period of organogenesis and placentation, malformations often occur or intrauterine death of the embryo or fetus occurs.

At 7-8 weeks of pregnancy, the reverse development of the corpus luteum in the ovary usually begins: figuratively speaking, the ovaries transfer the function of hormonal support for pregnancy to the chorion (future placenta), and if the chorion is not sufficiently developed, not active, then there is a threat of termination of pregnancy.

7-8 weeks is also a critical period for the development of pregnancy. Very often, a miscarriage, an undeveloped pregnancy or a threat of miscarriage (bloody discharge from the genital tract, pain in the lower abdomen and lower back) appear precisely at this time. If this happens, the woman needs hospitalization. The hospital uses various medications to help keep the pregnancy, if possible.

So, as we have seen, the first trimester of pregnancy consists almost entirely of critical periods, so at this time it is especially important:

if possible, eliminate the negative impact of harmful production;

change the complex of physical exercises during active training in the period before pregnancy, postpone extreme sports for the postpartum period;

spend enough time outdoors;

enough time (8-10 hours) to sleep;

do not take an active part in the repair of premises;

give up bad habits, especially such as drinking alcohol, drugs, smoking.

fertile period

From 12 weeks of pregnancy, the fetal period of intrauterine life begins, which lasts up to 40 weeks. At this time, the fetus is already fully formed, but physically immature.

Pregnancy periods of 13, 20-24 and 28 weeks are critical for patients with hyperandrogenism - an increased content of male sex hormones - due to the onset of fetal hormone production. During these periods, it is necessary to check the level of hormones and adjust the dose of drugs that are prescribed to reduce the amount of male sex hormones (DEXAMETHA3ONE, METIP-RED, etc.). At the same time, the doctor monitors the condition of the cervix, since an increase in the amount of male sex hormones can lead to its premature opening.

At 13 weeks of pregnancy, the male fetus begins to produce its own testosterone - the male sex hormone, at 20-24 weeks the production of cortisol and male sex hormones by the adrenal cortex of the fetus begins, as a result of which a woman with hyperandrogenism may have another rise in male sex hormones, which will lead to termination of pregnancy.

At 28 weeks, the fetal pituitary gland begins to synthesize a hormone that stimulates the adrenal glands. - - adrenocorticotropic hormone, resulting in increased production of male sex hormones, which can also lead to abortion. If necessary, the doctor will adjust the dose of medications at this time.

So, the action of adverse factors during critical periods of pregnancy can lead to the most adverse consequences. Therefore, a woman during the entire period of expectation of a child, and especially during critical periods, should avoid the action of adverse factors and consult a doctor in case of any “malfunctions”. I would like to advise expectant mothers to take care of themselves, especially since pregnancy lasts only 9 months, and the health and life of your baby depends on its course.

Kriticheskie_periody_beremennosti.txt Last modified: 2014/11/28 00:16 (external edit)

Separate tissues and organs are formed during different periods of embryonic and fetal growth. At the same time, the tissues of the body at the moment of maximum intensity of the processes of differentiation become highly sensitive to the damaging effects of the external environment (ionizing radiation, infections, chemical agents).

Such periods, which are characterized by increased sensitivity to the effects of damaging factors, are called "critical periods of embryogenesis". The probability of formation of deviations in development during critical periods is the highest.

Period of blastogenesis

According to WHO, the first critical period of development falls on the first - the period of blastogenesis. The response during this period is realized according to the “all or nothing” principle, that is, the embryo either dies, or, due to its increased stability and ability to recover, continues to develop normally. Morphological disorders that occur at this time are called "blastopathies". These include anembryony, which is formed as a result of early death and resorption of the embryoblast, aplasia of the yolk sac, etc. Some researchers refer ectopic pregnancy and violations of the depth of implantation of the developing embryo to blastopathies. Most of the embryos damaged during blastogenesis, as well as those formed from defective germ cells carrying mutations, are eliminated during this period by spontaneous abortions. According to the scientific literature, the frequency of termination of pregnancy at this time is about 40% of all pregnancies that have taken place. Most often, a woman does not even have time to find out about her onset and regards the episode as a delay.

Embryonic period

The second critical period of intrauterine development lasts from the 20th to the 70th for after fertilization - this is the time of maximum vulnerability of the embryo. The entire embryonic period - from the moment of implantation to 12 weeks - is a very important period in human development. This is the time when the laying and formation of all vital organs takes place, the placental circle of blood circulation is formed, the embryo acquires a “human appearance”.

Fetal (fetal) period

The significance of the genetic component of the developing organism can be demonstrated using the example of thalidomide syndrome and alcoholic fetopathy. Thalidomide syndrome was formed only in 20% of children whose mothers during pregnancy at the same terms took the same doses of thalidomide.

The influence of teratogenic factors is most often realized in the form of the development of multiple malformations and developmental anomalies, the formation of which depends on the dose of the damaging agent, the duration of its exposure and the gestational age at which the adverse effect occurred.

Article provided by the "EMBRIOTOKS" service

Comment on the article "Critical periods of embryo development"

Critical periods of embryonic development. Weeks of pregnancy, especially important for the development of the child. Print version. Does early child development begin at conception?

Discussion

Finally, in the TV programs "Best of All" (First Channel) and "Amazing People" (Russia-1) they showed interesting results, early development according to the MIR system, set out in the books: "How to accelerate the intellectual development of a child" (1995), "Reading - before walking" and other books by P.V. Tyulenev (see: [link-1] teaching reading, sciences, foreign languages, chess, phenomenal physical development, musical development and other results, which began in 1988, see: - [link-2] and on this site on this call.
Honor and praise to Maxim Galkin, the wonderful host of the TV channel, the husband of the great Alla Pugacheva, who dared to show the excellent results of early development on the First not only to the whole country, but, I think, to the whole world.
Watch and admire, raise your children to be outstanding people and geniuses! :)

03.03.2017 06:55:46, remember well

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"Elevit Pronatal" is a complex of vitamins, minerals and trace elements intended for women at the stage of pregnancy planning, during pregnancy and after childbirth during breastfeeding. To date, "Elevit Pronatal" is the only vitamin-mineral complex (VMC), the effectiveness of which in relation to the prevention of congenital malformations has been clinically proven 1 . One tablet of "Elevit Pronatal" (which is the daily dose) contains 800...

According to the international study of Fetal Alcohol Syndrome, every third woman does not stop drinking alcohol during pregnancy, which often leads to irreversible changes in the developing fetus. Many women are still not aware of the extreme dangers of even small doses of alcohol. The term Fetal Alcohol Syndrome, or FAS, describes a set of disorders that develop in children whose mothers drank alcohol during pregnancy. Before...

At 9 weeks of pregnancy, organs, muscles and nerves develop with might and main. The most critical embryonic stage has been passed and the fetal period of development begins. And so on... Is it worth the risk?

Discussion

Find a good polish and don't cover yourself. I am a native in repair, and last year they varnished in the presence of a very small child. A good varnish does not smell for a long time, it disappears almost completely in 2-3 hours.

Of course, this will not harm a healthy pregnancy, but I would categorically NOT recommend doing this.

I meant that ALL women have 3 critical periods during pregnancy, when all sorts of problems are most likely: these are 8-12 weeks in the 1st trimester, 18-22 in the 2nd, 28-32 in the 3rd. Retardation of intrauterine development of the fetus.

Discussion

I canceled at 16-18 weeks

Canceled after 14 weeks. The medicine is needed to support pregnancy from the 8th to the 12th week, this is a critical period (there are only 3 such terms for pregnancy, IVF women for these periods are generally kept for preservation, regardless of well-being) - if there is not enough own progesterone, then it is during this period that the probability of miscarriage is high or frozen. After 12 weeks, there is no such threat, so they slowly begin to reduce the dose, and at 14 weeks they cancel it altogether. The placenta still continues to form until 14 weeks, and then it is completely ready to take care of the baby.
My own hormones fail, the third pregnancy in the morning in the first trimester - after the abolition, no problems.

And yet, when the fetus stops developing, what happens to the uterus? The uterus grows until the pregnancy is still developing, while the trophoblast is alive (and it can stretch a little without a live embryo).

Discussion

Tanya, as I understand it, it’s you, really, go for an ultrasound scan, at your time this is the most informative and will disperse the cockroaches.
Keeping my fingers crossed for the best this time!

The essence of the question is not very clear. What did you see on the ultrasound? Are you an ultrasound doctor who can interpret the picture? If not, forget about that Uzi. If you want to ask with all this post whether the uterus can grow during a frozen pregnancy, then no, it grows during a developing pregnancy. Determining the size of the uterus during manual examination is a very subjective matter and cannot be accurate, so all these discrepancies per week .....

05/19/2009 11:05:33 AM, yes

R.S. - in history - large fetus (4100), extrusion, 7-8 apgars, nimble physical development. Under his leadership, correction of existing violations is carried out, especially during the child's adaptation in kindergarten and school, as well as during critical periods of growth.

Discussion

onr, IMHO, nonsense. when there is dysarthria
The other day I got my school card. speech is the norm. and how much they fought! Yes, actually from the age of 2, despite the fact that he began to speak at the age of 4 - ((
it is not true that in the speech therapy garden "they pick up mistakes from each other." elementary, we went to an ordinary kindergarten, where no one monitors the speech of children, and the speech of those children is an order of magnitude lower than in a specialized one. again, in an ordinary garden, they are sent to a speech therapist closer to five years, and there is a year less time to correct, while speech therapy groups of temporary stay exist in a speech therapist. gardens from the age of two.
We are current graduates of a speech therapy kindergarten. as I said, we are leaving with "speech N"
dysarthria is also no longer diagnosed, although of course I still see it - and salinization still remains a little, and the tongue, if you do not support gymnastics, relaxes. work, work, and work again.
By the way, I am an opponent of trust in speech therapy groups. it's an excuse for the poor. if it is not possible to get to a speech therapy garden, it is better to give it to a regular garden, pick it up after dinner and take it to a normal speech therapist. and to the defectologist (tree-trees-trees, one ball-many balls, etc., etc., in terms of ONR, own).
in general, be healthy, and do not relax. School is just around the corner and there's a lot to do ;)

With OHP grade 3, within the same diagnosis, children are different in terms of problems. There is sound pronunciation, and the ability to tell, and the grammatical structure of speech ... We suffered from the first two points.
Removable diagnosis, of course. They took it off for us too. I started reading early. He already speaks very well. He only writes badly. They even put dysgraphia, although I already see only disgusting handwriting and omissions of letters sometimes. Grade 2 regular school: 4 and 5.
A neighbor on the desk (the same garden) reads very averagely, and does not tell much, but writes better. A lot of triplets.
There was also dysarthria. Classes greatly improved the situation, but not completely.
"A lot of gestures, suffocating, in a hurry and generally breaks out of the story" - are they engaged in speech breathing? Have us went deterioration then in 1 class to ser. of the year. Make sure that it does not grow into logoneurosis. Hesitations, hesitation, pauses in the middle of a sentence, words, repetition of a syllable, pulling uh, well, how to say ... Is there such a thing?
And the neurology in general is normal? Often MMD is attached ...

04/13/2007 5:34:23 PM, LaMure

Time to be careful (critical periods of pregnancy). Weeks of pregnancy, especially important for the development of the child. Let's discuss the timing ... When is the best time to conceive a child?

Discussion

There was a strong confidence in success. Unusual. Appeared somewhere 5-4 days before the delay. And there were no signs. Unless she went to the toilet more often, due to changes in hormonal status.

I slept, slept, slept, even slept at work, my chest ached, got better (I determined it by the trousers, they were fastened at the waist, so I noticed) in general, everything !!!

Herpes (herpes) was first described in ancient Greece, the name of this virus The most typical viral diseases of the embryo and fetus. Waiting for the miracle of conception. Time to be careful (critical periods of pregnancy).

Discussion

Serezha, please don't worry! I'll try to somehow clarify the situation.
By the age of 30, up to 100% of the population is infected with CMV and herpes and remains carriers for the rest of their lives.
Any woman planning a pregnancy is recommended to be screened for CMV and herpes.
I don't know if your wife was examined? If it was examined, then most likely Ig G was already found in the blood and there was no Ig M, since doctors do not recommend getting pregnant in such situations. The fact that your wife carried the baby to 14 weeks is a very good sign that everything is going well so far.
Because most often the problems are in the early stages, when immunity drops so much that a secondary relapse of the disease begins. This did not happen with the herpes virus. But the CMV raised its head. I have an antibody titer of CMV infection of 1:3200 (strongly positive). I can't plan a pregnancy yet. But no one is listening. They said that many have such a situation that you just need to keep the situation under control. I think the doctor who observes your wife is doing just that, keeping the situation under control. He will definitely take appropriate measures, and at a certain time he will prescribe examinations for you to make sure that the fetus develops normally!
In any case, the norms in different laboratories are different and in brackets it should be indicated how strong the infection is (weakly positive, strongly positive ...)
I recommend that you read the question-answer information on the website http://www.mama.ru/gynecolog/ (2.2. Pregnancy against the background of diseases (infectious))
people have the same problems
And here I will give a short reference to cheer you up. Let's hope for the best!
CMV IgM, IgG Cytomegalovirus - present in most adults. It is of clinical significance only during pregnancy (danger of primary infection of the fetus and newborn) and in people with immunodeficiency. In other situations, research and even more so treatment is not required. IgG antibodies, as with other infections, mean the presence of long-term immunity to the virus, they guarantee that the body has already met the virus, which means that there will be no primary infection, which is most dangerous during pregnancy. Against the background of chronic carriage of CMV-IgG, an exacerbation may occur, then IgM appears, and there is a risk of infection of the fetus, so treatment is required. For the fetus, the risk in a secondary exacerbation is much lower than in the primary. The absence of IgG means a lack of immunity, and requires frequent screening for timely detection of primary infection and treatment.
IgM-, IgG- Lack of immunity to the virus. A potentially dangerous situation during planning and during pregnancy is the risk of primary infection.

HSV I, II, IgM, IgG Herpes occurs in two localizations (on the face and on the genitals) and is caused by two types of the virus - I and II. There is no strict association: genital herpes is type II, and facial herpes is type I. Both localizations can be caused by any type of virus. Herpes is a chronic infection; after the initial infection, the virus lives permanently in nerve cells, causing periodic exacerbations. Treatment requires not the presence of the virus, but its clinical manifestations. During pregnancy, an exacerbation of herpes (of any type and localization) can pose a threat of infection to the fetus, therefore, they are guided not only by clinical signs, but also by the level of antibodies in the blood.
IgM-, IgG- Lack of immunity to the virus. A potentially dangerous situation during planning and during pregnancy is the risk of primary infection. Especially dangerous is the absence of antibodies to all types of the virus.
IgM-, IgG+ The most favorable situation. The presence of immunity, there is no risk of primary infection, the risk of secondary exacerbation depends on the state of the immune system, is preventable, and does not pose a great danger to the fetus.
IgM+, IgG- Primary infection. During pregnancy and the newborn requires urgent treatment. During pregnancy planning, it requires a delay in conception until immunity is formed and IgM disappears.
IgM+, IgG+ Secondary exacerbation. It does not create such a threat to the fetus as the primary one, but it still requires treatment.

I already posted this here about a year ago, I'll repeat it a little: o))).

God knows how much information, but I am so illiterate in terms of psychology that for me it was just a discovery.

I quote here:

"The crisis of 3 years is among the acute ones. ... The symptoms are called the seven-star crisis of 3 years.

1. Negativism is a reaction not to the content of the adult proposal, but to the fact that it comes from adults.
The desire to do the opposite, even against their own will.

2. Stubbornness. The child insists on something, not because he wants to, but because he demanded it, he is bound
their original decision.

3. Obstinacy. It is impersonal, directed against the norms of upbringing, the way of life that has developed up to 3
years.

4. Willfulness. Strives to do everything himself.

5. Protest riot. The child is in conflict with others.

6. A symptom of devaluation is manifested in the fact that the child begins to swear, tease and call names to parents.

7. Despotism. The child forces the parents to do whatever he requires. towards younger sisters and
to the brothers, despotism manifests itself as jealousy.

The crisis proceeds as a crisis of social relations and is associated with the formation of the child's self-awareness.
The position "I myself" appears. The child learns the difference between "should" and "want".

If the crisis proceeds sluggishly, this indicates a delay in the development of the affective and volitional sides of the personality. At
children begins to form a will, which E. Erickson called autonomy (independence,
independence). Children no longer need care from adults and tend to do things themselves.
choice. Feelings of shame and insecurity instead of autonomy arise when parents restrict
manifestations of independence of the child, punish or ridicule all attempts at independence.
..............

The child develops unevenly. There are periods of relatively calm, or stable, and there are
called critical.

critical periods. Crises are discovered empirically, and not in turn, but in random order:
7 years old, 3 years old, 13 years old, 1 year old, 0.
in general, in the main personality traits. This is a revolutionary, stormy, impetuous course of events, both in terms of pace,
as well as in terms of the changes that are taking place. Critical periods are characterized by the following features:

1. The boundaries separating the beginning and end of the crisis from adjacent periods are extremely indistinct. Crisis arises
imperceptibly, it is very difficult to determine the moment of its onset and end. Sharp aggravation (climax)
seen in the middle of a crisis. At this time, the crisis reaches its climax.

2. The difficulty of educating children during critical periods at one time served as the starting point for their
empirical study. There is obstinacy, a drop in academic performance and working capacity, an increase
the number of conflicts with others. The inner life of the child at this time is associated with painful
experiences.

3. Negative period of development. It is noted that during crises, in contrast to stable periods,
destructive rather than constructive work is done. The child does not acquire so much as
loses from what was previously acquired. However, the emergence of something new in development necessarily means the death of
old. At the same time, during critical periods, constructive processes of development are also observed. Vygotsky
called these acquisitions neoplasms. Neoplasms of critical periods are transitional
character, that is, they are not preserved in the form in which they arise, for example, autonomous speech in
one year old children.

stable periods. During stable periods, the child accumulates quantitative changes rather than
high-quality, as during critical. These changes accumulate slowly and imperceptibly.
The sequence of development is determined by the alternation of stable and critical periods.

Dynamics of development.

1. By the beginning of each period, a unique relationship of the child with the environment develops.
reality - the social situation of development.

2. It naturally determines his lifestyle, which leads to the emergence of neoplasms.

3. Neoplasms entail a new structure of the child's consciousness, a change in relationships.

4. Consequently, the social situation of development is changing. An associated critical
period.

(R.P. Efimkina "Child Psychology", Novosibirsk State University, Scientific and Educational Center of Psychology)

And if you get pregnant in winter, there are no special pluses, but there are many minuses: 1. the first trimester falls at the peak of epidemic trouble in terms of influenza and acute respiratory infections (and at this time, as mentioned earlier, the embryo goes through a critical period of development ...

For antenatal protection of the fetus, it is important to know the critical periods of its development, when a high percentage of embryonic death and damage to individual organs and systems are observed. Under the action of damaging factors on the body of a pregnant woman, those organs and systems are the first to be affected, which at the time of exposure are in a state of increased differentiation and increased metabolism. In this regard, the rudiments of the nervous and cardiovascular systems are especially sensitive.

There are three stages of intrauterine development - the period of progenesis (the first 3 weeks), the period of embryogenesis (from the 3rd week to the 12th week), the period of fetal development (from the 4th month to birth.

The first critical period of development is the pre-implantation stage and implantation. The pre-implantation stage begins from the moment of fertilization and continues until the introduction of the blastocyst into the decidua of the uterus. Implantation in humans occurs on average on the 7-8th day after fertilization.

The action of damaging factors during this period (radiation, overheating, hypoxia, etc.) causes the highest death of embryos.

The second critical period - the period of organogenesis and placentation - begins with the moment of vascularization of the villi, which occurs at the 3rd week and ends by the 12th-13th week of intrauterine development.

The action of damaging factors during this period causes disturbances in the formation of the brain, cardiovascular system and other organs.

In addition to critical periods in the early stages of pregnancy, V. I. Bodyazhina draws attention to the average terms of intrauterine development of the fetus, which can also be considered as a kind of critical period of development. In fetuses at the 18-22nd week of ontogenesis, qualitative changes are observed in the bioelectrical activity of the brain, reflex reactions, hematopoiesis, hormone production, which, in their nature, are close to the structures and processes characteristic of the body of a newborn.

In the second half of pregnancy, there is a decrease in the sensitivity of the fetus to the effects of damaging factors. This is due to the maturation and formation of the most important organs and systems - the nervous, cardiovascular, hematopoietic, etc., in connection with which the fetus acquires the ability to respond differently to the action of the environment.

It has been established that in the process of embryogenesis there is a multi-temporal maturation of the functional systems of the fetus, depending on their significance for the development of the organism at different stages of the prenatal period. First of all, the systems and organs that are necessary to ensure the viability of the fetus are laid down and differentiated. This uneven prenatal development of the fetus is the basis of the theory of systemogenesis developed by P. K. Anokhin. According to this theory, the various components of any vitally important functional system, depending on the complexity of their organization, are laid down at different speeds, but by the time of birth they all turn out to be mature and begin to function as a single whole. One of the main regularities of the life of an organism is the continuous development and change of functional systems that provide it with adequate adaptation at various stages of postnatal life.

Nerve centers are grouped and begin to mature before the substrates innervated by them are formed and mature.

There are the following periods of fetal development during pregnancy:
pre-implantation(from the moment of fertilization of the egg with sperm until the introduction of the fertilized egg into the mucosa of the uterine wall);
implantation(attachment of a fertilized egg to the wall of the uterus);
organogenesis and placentation(the period of formation of all organs and tissues of the fetus, as well as the placenta);
fetal- the period of growth and development of formed organs and tissues.

Pre-implantation period

Normally, 12-14 days before the expected menstruation, ovulation occurs, that is, an egg that has reached a large size leaves the ovary, enters the fallopian tube, where fertilization most often occurs. From this point on, pregnancy begins. A fertilized egg continues its journey through the fallopian tube for 4 days towards the uterine cavity, which is facilitated by:
contraction of the smooth muscles of the wall of the fallopian tube. These contractions normally occur in a unilateral direction - towards the uterine cavity from the end of the tube facing the abdominal cavity;
movement of the cilia of the mucous membrane, which covers the fallopian tube from the inside. The fluid in the tube begins to move, and with the flow of this fluid, the fertilized egg enters the uterus;
relaxation of the sphincter (circular muscle) in the junction of the fallopian tube with the uterus. This sphincter is designed to prevent a fertilized egg from entering the uterine cavity prematurely, before the uterus is ready to receive a fertilized egg.

The period of advancement of a fertilized egg through the fallopian tube is considered the first critical period of pregnancy (from 12-14 to 10-8 days before the next menstruation). As a result of a violation of the complex mechanisms of regulation of the fallopian tube, the egg after fertilization can also be introduced into the wall of the tube (ectopic pregnancy).

Implantation period

The second critical period of pregnancy is implantation, that is, the attachment of the fetal egg to the wall of the uterus. If implantation fails, then the pregnancy ends under the guise of menstruation (in fact, this is an undiagnosed miscarriage at a very short time). Since there is no delay in menstruation, the woman does not even assume that she is pregnant.

Of great importance is the preparedness of the uterine mucosa for implantation, its readiness to accept a fetal egg. After abortion, curettage, long-term wearing of an intrauterine device, infections, inflammatory processes, the receptor (perceiving) apparatus of the endometrium may be disrupted, that is, hormone-sensitive cells located in the uterine mucosa do not respond correctly to hormones, due to which the uterine mucosa is not sufficiently prepared for upcoming pregnancy. If the fetal egg is not active enough, does not release the required amount of enzymes that destroy the uterine mucosa in a timely manner, then it can penetrate the uterine wall in the lower segment or in the cervix, resulting in cervical pregnancy or abnormal placentation (the placenta blocks the exit from the uterus partially or completely ).

The presence of adhesions (synechia) in the uterine cavity after inflammatory processes, curettage, as well as uterine fibroids, can also interfere with normal implantation.

Period of organogenesis and placentation

This period lasts from the moment the fetal egg is introduced into the uterine mucosa until 10-12 weeks of pregnancy, when all the organs and tissues of the fetus, as well as the placenta, are fully formed (children's place is the link between the fetus and the mother's body, through which nutrition processes take place, metabolism and respiration of the fetus in the womb). This is a very important period of intrauterine life, because. at this time, all the organs and tissues of the fetus are laid. Already on the 7th day after the fertilization of the egg, the mother's body receives a signal of pregnancy due to the hormone - chorionic gonadotropin (CG), which is secreted by the fetal egg. CG, in turn, supports the development of the corpus luteum in the ovary. The corpus luteum secretes progesterone and estrogens in sufficient quantities to maintain pregnancy. At the initial stage of pregnancy, before the formation of the placenta, the corpus luteum takes on the function of hormonal support for pregnancy, and if for one reason or another the corpus luteum does not work properly, then there may be a threat of miscarriage, miscarriage or non-developing pregnancy.

During these periods, the influence of environmental factors on the embryo is especially dangerous, including:
physical (ionizing radiation, mechanical effects); this can be the action of ionizing radiation, for example, in the conditions of a man-made disaster at nuclear facilities, mechanical effects in the form of vibration, and so on. in the relevant industries or at the time of sports training;
chemical: phenols, nitric oxide, pesticides, heavy metals, etc. - these substances can also enter the body of a pregnant woman if she works in the relevant industries or during repairs in a room where a woman stays for a long time. Chemicals include nicotine, alcohol, certain drugs such as those used to treat cancer, etc.;
biological (for example, herpes virus, cytomegalovirus, rubella virus, etc.).

It must be emphasized that during critical periods, harmful effects lead to the most severe consequences - the death of the embryo or the formation of gross malformations.

According to French researchers, if a pregnant woman for the first time in her life encountered cytomegalovirus, a pathogen that causes a disease that in adults can occur as a banal acute respiratory disease (acute respiratory disease) during pregnancy (as seen from a blood test for CMV immunoglobulins), especially on early terms, then in 1/3 of cases fetal malformations may occur. If, before pregnancy, she was already infected, the body turns on defense mechanisms to fight the virus in time, this probability decreases to 1%. The same can be said about the herpes simplex virus.

Of particular danger is the rubella virus when infected with it in the early stages of pregnancy. In such cases, a woman is recommended artificial termination of pregnancy, tk. there is a high risk of having a child with such malformations as microphthalmia - a malformation of the eyes, microcephaly - a serious malformation of the brain; deafness, congenital heart defects, etc.

Of the chemical compounds, lead, mercury, benzene, nicotine, carbon oxides and other substances that can cause malformations have a particularly adverse effect on the state of the embryo.

So, as we have seen, the first trimester of pregnancy consists almost entirely of critical periods, so at this time it is especially important:
if possible, eliminate the negative impact of harmful production;
change the complex of physical exercises during active training in the period before pregnancy, postpone extreme sports for the postpartum period;
spend enough time outdoors;
enough time (8-10 hours) to sleep;
do not take an active part in the repair of premises;
give up bad habits, especially such as drinking alcohol, drugs, smoking.

fertile period

From 12 weeks of pregnancy, the fetal period of intrauterine life begins, which lasts up to 40 weeks. At this time, the fetus is already fully formed, but physically immature.

Pregnancy periods of 13, 20-24 and 28 weeks are critical for patients with hyperandrogenism - an increased content of male sex hormones - due to the onset of fetal hormone production. During these periods, it is necessary to check the level of hormones and adjust the dose of drugs that are prescribed to reduce the amount of male sex hormones (dexametlezone, metip-red, etc.). At the same time, the doctor monitors the condition of the cervix, since an increase in the amount of male sex hormones can lead to its premature opening.

At 28 weeks, the fetal pituitary gland begins to synthesize a hormone that stimulates the adrenal glands - adrenocorticotropic hormone, resulting in increased production of male sex hormones, which can also lead to termination of pregnancy. If necessary, the doctor will adjust the dose of medications at this time.

So, the action of adverse factors during critical periods of pregnancy can lead to the most adverse consequences. Therefore, a woman during the entire time of waiting for a child, and especially during critical periods, should avoid the action of adverse factors and consult a doctor in case of any “malfunctions”. I would like to advise future mothers to take care of themselves, especially since pregnancy lasts only 9 months, and the health and life of your baby depends on its course.

What should be cause for concern?

Jasmina Mirzoyan
Obstetrician-gynecologist,
cand. honey. Sciences, Moscow
Article provided by the journal
"9 months", 2006