Pregnancy. Signs and course of pregnancy. The body of a pregnant woman. How many weeks does pregnancy last for women: obstetric calculations and the correct timing

18.09.2019

We are used to thinking that bearing a fetus lasts 9 months. Where does the 40-42 gestational week come from? How to calculate the estimated date of birth of a baby? How many weeks does pregnancy actually last? Why does the timing of the birth of a baby not always coincide with the estimated date?

Several factors affect the correctness of the calculation:

knowledge of the time when the last one was;
knowledge of the rate of advancement of sperm and the time of fusion of gametes (two germ cells);
knowledge of the speed of movement of the zygote through the fallopian tubes;
determining the time of implantation;
information about how many times a woman carries a baby.

Most pregnant women can unequivocally determine only the last point. Some may know the day of conception or ovulation. But the rest of the aspects will remain a mystery both for the future mother herself and for the doctors. Therefore, doctors use the calculated obstetric method for determining the date of birth, which can give an error, but this error is not so significant for practical purposes.

How long does a pregnancy last?

The gestational period is 10 obstetric months. An obstetric month is 28 calendar days or 4 weeks. A normal full-term pregnancy lasts 38-42 weeks. This is an average figure.

According to scientists, in 70% of 100% from conception to childbirth, 266 days or less pass. But since almost no one knows the day of conception, doctors count the period from the last day of the menstrual cycle, and not from the moment the gametes merge.

On average, the ovulation period occurs 14 days after the last day of menstruation. These 14 days are included in the obstetric period, according to which gestation is 40-42 weeks 280-294 days. This period is usually called gestational or menstrual.

In reality, the embryo and then the fetus will be 14 days younger. And the real period, which is usually called embryonic, will be 266-280 days or 38-40 weeks from the day of conception.

If you recalculate the 40-week period in calendar months, you get the same cherished 9 months. According to some reports, according to modern trends, 37-43 obstetric weeks are considered the norm. If the woman in labor is relieved of the burden in this time range, the pregnancy will not be considered premature or delayed.

It should be remembered that all these calculations are correct if the menstrual cycle is 28 days.

Factors affecting the duration of gestation?

Within certain limits, the duration of normal gestation is variable, and depends on a number of points:

the state of the expectant mother;
fetal development;
hereditary factors;
psycho-emotional state of the mother.

Sometimes expectant mothers set themselves up so much for the birth of a child by a certain date that during this period they begin labor activity. There are other examples, for example, the expectant mother went to the maternity hospital ahead of time for some reason, and the screams of the comrades in the ward, who had contractions, stimulated her labor activity.

It is believed that during the first pregnancy, especially late, women are more likely to postpone children than with repeated gestations. According to doctors, second births come faster only if very little time has passed between gestation periods. That is, a woman conceived before she could breastfeed her first child.

In other cases, the number of successful conceptions does not play a big role for the gestation period.

Mothers with multiple pregnancies carry their babies a little less. Two-fetal pregnancies in most cases end at, three and four fetal - at 32-34 weeks.

Some expectant mothers believe that the sex of the child affects the duration of gestation. There is no medical evidence to support this opinion.

Premature birth

Labor activity that began earlier than 37 weeks of gestation is considered premature. The fetus is viable starting at 28 weeks of gestation, and the closer to full-term pregnancy begins labor, the less effort will be required from doctors to keep the baby alive.

A child born prematurely requires special conditions to support his life. The baby is placed in an incubator, which maintains the desired body temperature, is supplied with humidified oxygen, and other measures are taken to maintain its life. Premature labor can start for a variety of reasons:

ICI (cervical insufficiency);
STIs that provoke inflammatory processes in the tissues of the uterus;
endocrine pathologies;
trauma (physical and psychological).

There may be other reasons for fetal undermaturity. For example, taking certain medications.

Postterm pregnancy

If the mother carries a child for more than 294-301 days, in weeks more than 42-43 weeks, such a pregnancy is defined as post-term. Overburdening also occurs for various reasons:

delayed fetal development;
hormonal perturbations;
endocrine pathologies;
some gynecological problems;
unpreparedness of the psyche for childbirth.

In this case, labor will be artificially stimulated. Oversight of the fetus is just as bad for its condition as early childbirth. The placenta begins to age, the child does not receive the required amount of nutrients and oxygen. His bones harden and he continues to grow in a very confined space. This threatens the woman in labor with serious ruptures, and the baby with birth injuries.

If the estimated date has come, and there are no harbingers of an early resolution from the burden, there is no need to panic. The main criterion in this case is the condition of the baby and mother. If the child stops physical activity, the mother does not feel well, it is imperative to contact a gynecologist.

If the child is active enough, the mother feels good, but she is very nervous about the delay in labor, you can consult a specialist. He may order CTG of the fetus to assess his heart rate and activity. And if necessary, he will be sent to the hospital.

To speed up the onset of labor in the last weeks before the estimated date, experts advise taking 1 tablespoon of sunflower oil, to stimulate peristalsis and reflex stimulation of the myometrium, walk more, climb stairs and have sex, if there are no contraindications and there is a desire.

Every woman, having learned about pregnancy, begins to count the weeks and days in order to determine the likely date of birth. The doctor who leads her pregnancy helps her in this. Naturally, no one can guarantee that a pregnant woman will have a baby on a specific day, since even when you know exactly the time of conception of a child, the duration of pregnancy is absolutely unknown, how much the baby in mother's belly will develop and grow before decides to be born.

The estimated due date (PDD) will depend on many different factors, and in each case, the calculation of the duration of pregnancy for women is made on an individual basis.

How many weeks do pregnant women go from the day of conception?

As is known, pregnancy lasts 9 months... But when this period is compared with the calculation of the PDD in weeks, it turns out that they differ, since 9 months is only 36 weeks, and not 40 or 42, as doctors believe. How can this difference be explained?

There is such a thing as obstetric gestational age or "gold obstetric standard". This period is determined taking into account the duration of ovulation and the monthly cycle.

The average cycle time is taken into account - 28 days with ovulation in the middle or maturation of the egg (by the way, the obstetric month also lasts 28 days, as opposed to the calendar, lasting 30 or 31 days).

Before childbirth, from the moment of conception, the conditional number of days, taking into account this method of calculation, will be 280, that is, full 40 weeks.

Doctors talk about the conventionality of these numbers, since it is almost certainly impossible to predict, even during the exact time of ovulation, how quickly the sperm reached the goal, and when exactly the fertilization of the egg took place. Remember also that the time of passage of the fertilized already the oocyte before implantation into the wall of the uterus through the fallopian tubes can also be different.

How long does pregnancy last in women: The main ways of determining

There are several ways that help determine how long a pregnant woman has to walk with a fetus inside and determine the estimated date of birth.

Obstetric method

The most popular way to determine how long the pregnancy lasts is obstetric. The main date from which the countdown begins in a pregnant woman is the start date of the last menstrual cycle. For which the Negele formula is applied, taking into account which, a full 9 months and 7 days are added to the date of the last menstruation.

Even simpler calculations can be performed when subtract the full 3 months from this very date and also add one week.

Thus, the age of pregnancy can be calculated, but not conception. ... Since at the time of the onset of menstruation pregnancy has not yet occurred, that is, actual conception with a 40-week calendar occurs only at 3 weeks (since on average ovulation occurs 14-15 days after the menstrual cycle has ended), and, accordingly, the gestational age of the baby will be less for about 2-3 weeks.

Embryonic way

When you know exactly both the time and day of conception, and the time and day of the maturation of the egg, you can use the embryonic method of calculating the time of birth and determine the duration of the process in a pregnant woman.

Most often, the approximate figure is approximately thirty-eight weeks or two hundred and sixty-six days. ... However, this method of application is practically not used, since not many expectant mothers can tell the doctor this data.

When calculating the obstetric gestational age, as a rule, only the average duration of menstruation with ovulation in the middle (at 14-15 days) is taken into account.

Therefore, when you suffer from disruptions in the cycle, irregular periods, or the cycle lasts less or more than 28 days, then you will need to take into account all these nuances (when your cycle is less, then subtract the required number of days from the proposed calculation, and when more, then add).

Besides, at a later time, the estimated date of birth is also determined:

But all this is most of all additional and auxiliary methods, except for the two main ones.

Rates and duration of pregnancy

Naturally, the possible date of birth is called possible, since the baby should not and cannot be exactly born by day in the time period you calculated.

Natural and normal childbirth, most often, go away for a period of 30-42 weeks. It is at this time that the pregnancy is full-term, since all the main systems and organs of the fetus have matured and developed, so he is ready to be born. At the moment, by the way, this length of time has been increased from 37 to 43 weeks.

When gestation lasts longer than these terms, the doctors will begin to prepare you for artificial stimulation of labor, since we are already talking about a post-term pregnancy.

This condition is quite dangerous. rather than premature birth, since after 42 weeks the placenta begins to age, this can lead to significant problems with the baby's breathing and nutrition, and other processes are also disrupted.

There are many reasons for this:

in some cases - metabolism or heredity;
in some cases, hormones are the culprit;
certain diseases in a woman of an endocrine or gynecological nature;
delayed development of the fetus is also possible;
psychological unpreparedness for childbirth and other factors.

However, under the supervision of a doctor, you will be able to control the situation.

The situation is much more complicated with premature pregnancy or premature birth. Thus, the birth of a child before 37 weeks is determined. Most often in premature babies all parameters (developmental norms, weight, height) are lower than necessary, therefore they need either emergency medical care, or special care and observation, taking into account the time frame.

Premature birth occurs for various reasons:

during physical injuries, falls, injuries;
with hormonal disorders;
when the cervix is weak and cannot hold the fetus;
during the processes of inflammation in the cervix or vagina;
during a strong nervous shock, emotional stress.

It is not in vain that Mother Nature has determined a certain period of time that is required in the mother's womb for a baby for full development and growth, and when the gestation lasts less or more than it should be, this creates some risks and is a danger for both the mother and the fetus.

What factors affect the duration of pregnancy?

For the duration of bearing a baby many nuances and different factors will influence.

Number of pregnancies

There is an opinion that the first pregnancy may be the longest, and further pregnancies may be shorter than the previous ones. It is also believed that women who give birth to their first child have an increased likelihood of overmaturity. Naturally, this is quite likely during the period of psychological unpreparedness directly to the mother.

And what about the relationship between the number of pregnancies and their duration, the doctors refute this opinion, leaving the possibility for the next earlier birth only in the case when the second pregnancy occurred immediately after the previous one. Since if a couple of years pass, then the woman's body will perceive the pregnancy again as the first.

Number of fruits

When a woman has multiple pregnancies (triplets or twins), most often childbirth can begin 7-14 days earlier than with a singleton pregnancy.

Most twins are born at or before 37 weeks, and pregnancies for triplets are approximately 34-35 weeks pregnant.

Baby gender

Another affirming opinion is that the duration of gestation can be influenced by who you are waiting for - a girl or a boy. Some doctors claim that boys like to be late, some, on the contrary, are convinced that girls are in no hurry to be born. But experts say that the sex of the baby does not really affect the duration of pregnancy.

Complications

During the presence of certain pathologies or diseases, both prolongation of pregnancy and premature birth are likely - among them infectious and inflammatory processes, strong hormonal disruptions or other diseases of a chronic and acute nature, and disruption of work in the main systems (endocrine, cardiovascular, central nervous system ), and ischemic-cervical insufficiency, and placenta previa, etc.

Monthly cycle

For a starting point, this is a kind of reference point. As mentioned above, during an average monthly cycle of 28 days, the duration of pregnancy should be approximately 40 weeks.

And when a woman's cycle is longer, for example, 35 days? Then ovulation will occur at about 17-18 days. When the cycle is less, then in this case ovulation will occur earlier (10-20 days). Accordingly, to determine the estimated date of delivery in the first case, the doctor will add the difference in days to the countdown date, and in the latter case, subtract it.

Lifestyle

Any bad habits (drugs, smoking, alcoholic beverages) have a rather negative effect on the intrauterine growth of the fetus and directly on pregnancy. Induce premature labor can also be excessive stress, excitement, negative emotions, experiences. And a very amorphous life image will, on the contrary, be the cause of prolongation.

Lack of useful elements and vitamins, malnutrition, non-compliance with the regimen, lack of physical activity and many other factors - all this also creates a certain influence on the duration of bearing a child.

Statistics indicate that only 5% of women give birth to children on a well-defined date. In all other situations, the real time of childbirth does not coincide with the estimated calculated time, thus, the children independently decide when they need to be born. See your doctor periodically, follow all his appointments, so that your pregnancy was pleasant and easy period of time, and the birth took place exactly at the time when it is necessary.

The question is both simple and complex at the same time. Everyone knows that pregnancy lasts about 9 months. But for the expectant mother, such an answer is not enough. I would like to calculate exactly in what numbers the baby will be born, who he will be according to the sign of the zodiac, when the prenatal sick leave begins. Situations are not uncommon when childbirth occurs earlier or, conversely, later than the intended date. What factors affect the duration of pregnancy, from what gestational age the child is already viable, how dangerous is prolongation - we will tell about all this in our article.

Within the framework of the norm:

It is difficult to say exactly how long a pregnancy lasts. It is impossible to establish the true date of ovulation, the time of movement of the sperm to the egg and their fusion. Therefore, in the medical literature there are contradictory data on this issue. A fully mature, healthy child can be born in 230-240 days after fertilization ... At the same time, there are cases when the gestation period is significantly lengthened - over 300 days or more. But most often it is 10 obstetric months (28 days each), or 280 days (if counted from the first day of the last menstrual bleeding).

The entire gestation period is conventionally divided into 3 trimesters. The first trimester of pregnancy lasts up to 12-14 weeks, the second - from 14 to 24-28 weeks, and the third - from 24-28 weeks before delivery. If the fetus is born before 24 weeks, it is considered a late miscarriage. A baby born between 24 and 27 weeks is premature. A pregnancy that lasts longer than 42 weeks is considered to be post-term and a newborn is considered to be post-term.

When to give birth ?:

It is practically impossible to predict this for sure, since pregnancy does not always occur on the day of sexual intercourse, but it can occur in 48-72 hours. However, with the help of anamnesis, internal obstetric examination and ultrasound, the estimated date of birth is determined for each pregnant woman.

For example, knowing the date of the first day of the last menstruation, and assuming that the pregnancy will last 280 days: add 7 days to this date and subtract 3 months. So, if the date of the beginning of the last menstruation is January 10, then the birth will presumably take place on October 17. If the date of ovulation is known (you measured basal temperature or performed special tests), then 266 days are added to it. & Nbsp & nbsp

When the cycle is not regular, it is difficult to remember the date of the last menstruation or it was not at all, since you are breastfeeding, how long the pregnancy will last is judged by the ultrasound data. The earlier it takes place, the smaller the error. Usually it is 7-8%, in the first trimester - 1 week, in the II - 2 weeks, in the III - 3. To reduce the error to 3-5 days, during ultrasound screening of the first trimester, they are guided by the vertical size of the embryo (from the coccyx to crown).
The duration of the current pregnancy can be judged by fixing the date of the onset of sensations of fetal movement. For women who are carrying a child for the first time, 22 weeks are added to this date, again - 24 weeks. Determining the size of the uterus at the first visit to the antenatal clinic also helps in this (the error will be smaller if this is done before 12 weeks). These techniques are optional, as well as external obstetric changes. & Nbsp & nbsp

All these data complement each other. But remember that they are geared towards the average pregnancy of 40 weeks (280 days). With this in mind, shortening or prolonging pregnancy by 2 weeks is not considered a pathology.

About overburdening:

It is legal to talk about prolonged pregnancy when it lasts more than 42 weeks, or 294 days, from the date of the beginning of the last menstruation. This is a fairly common occurrence, occurring in 4-9% of cases. Why is this condition dangerous? Fetal macrosomia, oligohydramnios, swallowing of meconium, antenatal fetal death, and the development of a newborn's "overmaturity" syndrome are likely. For the mother, this is fraught with an increase in the frequency of operative abdominal delivery. In practice, it is confirmed that the risk of these complications is much higher even at a period of more than 40-41 weeks.

In establishing this diagnosis, the main role is played by the precise determination of the gestational age. If this is not done correctly, then the fact of prolongation is questioned. What factors can prolong pregnancy? Nobody knows for sure. The most likely are: a decrease in the level of estrogen in a woman, on the part of the fetus - underdevelopment of the adrenal glands, anhypophysia, anencephaly. Medical tactics: hospitalization, monitoring the reaction to a non-stress test, assessing the condition of the fetus, the amount of amniotic fluid, stimulation of labor at 41-42 weeks.

Prematurity: causes and prognosis:

When regular contractions occur in the period from 24 (28) to 37 weeks, which lead to the onset of cervical dilatation, they speak of premature birth. Frequency - up to 15% of cases. We hasten to reassure you: many women experience periodic contractions of the uterus, but only those that cause smoothing of the cervix and opening are capable of provoking childbirth. It happens that the painless gradual opening is not accompanied by contractions - this is isthmic-cervical insufficiency.
Premature birth is a major factor in losing a child. The cause of death is immaturity of lung tissue, intraventricular hemorrhage, necrotizing colitis, etc. The survival rate is directly proportional to gestational age. At birth, 50% of babies survive at 24 weeks, and 99% at 36 weeks.

Why can the duration of pregnancy decrease? There are many reasons: rupture of the fetal bladder or detachment of the placenta, multiple pregnancy, chorioamnionitis, bicornuate uterus, genetic predisposition. Smoking, low body weight, history of abortion, frequent childbirth are a premorbid background for this pathology.

Medical tactics: hospitalization, bed rest, full examination, monitoring of the fetal heart rate and contractions, laboratory and ultrasound examination, the possibility of tocolysis is assessed. Determination of fetal fibronectin in cervical mucus "speaks" of a high probability of the onset of labor in the next week. To accelerate the maturation of the child's lungs, a woman is urgently prescribed glucocorticosteroids. This increases his chances of survival.

How long does pregnancy last for a boy and a girl ?:

It is very common among expectant mothers that pregnancy with a boy lasts longer. We consider it necessary to debunk this myth. The gestation period does not depend at all on the sex of the fetus. The formation of the genitals begins from the 4th week of embryonic development, they become clearly distinguishable from 12-16 weeks, at 20 weeks they are already clearly marked. The further development of a boy and a girl is exactly the same. & Nbsp & nbsp

How long does the second pregnancy last ?:

The theory that the second pregnancy is shorter than the first is also not confirmed in practice. There are no physiological prerequisites for the second child to require less time for intrauterine development. But the fact that the period of contractions during the second birth is shorter, and the opening of the cervix is faster, is true. In a woman who has given birth, the birth canal is more elastic and malleable, so it takes less time to form the lower segment of the uterus and open its cervix. The period of contractions is on average reduced to 6-8 hours.

American scientists from the University of North Carolina questioned the "traditional" duration of a woman's pregnancy

The most recent studies have shown that a normal pregnancy should be 10 months. To come to this conclusion, scientists observed 125 pregnant women. According to their research, only 4% of pregnant women became mothers on time. About 70 percent of women give birth to children only a decade after the date of birth set using ultrasound, American experts say. All this means that a pregnancy lasting 10 months should be considered the norm, and not the usual 9 months.

Traditionally, according to the Negale Rule, which is used to calculate the date of birth, a person's pregnancy lasts about 40 weeks, or 280 days, from the last menstrual period. A baby born before 37 weeks is considered premature, when after 43 weeks it is premature. However, scientists questioned this.

Experts ruled out six cases of premature birth. But even so, the duration of pregnancies differed by 37 days, according to novostiua.net.

Every year a woman carries a baby 1 day longer. That is, the older the woman in labor, the longer her pregnancy lasts. In addition, it turned out that a woman who herself was born with a lot of weight will carry her child longer. For every 100 grams of excess weight at birth, you should add 1 day of pregnancy when carrying your own child, reports MyJane.ru.

MK Help The Naegele Rule -

the method used to calculate the likely due date of labor: nine months and seven days are added to the date of the first day of the last menstrual period. If a woman's menstrual cycle is different from 28 days, then an amendment is required when using this rule. ("Medical Dictionary").

The average duration of pregnancy from the beginning of the last menstrual period until delivery is 40 weeks (the so-called "obstetric period"). The use of the obstetric term is more common in medicine, since the date of fertilization is usually difficult to determine.

In obstetrics, physiological and pathological pregnancies are distinguished. Normally, any pregnancy ends with a generic act - a child is born, and in the case of multiple pregnancies - twins (homo - identical or heterozygous - different).

It is customary to divide a woman's pregnancy into so-called "trimesters" (periods of three months), informs wikipedia.org. Accordingly, they talk about the first, second and third trimesters of pregnancy. Each of the trimesters is characterized by certain obstetric characteristics and risks.

Human development begins with the fertilization of a woman's egg with a man's sperm. Fertilization is possible during ovulation, when a mature egg leaves the ovary. The period of ovulation usually falls on the 10-16th day of the menstrual cycle, but can be greatly shifted. After ovulation, the egg enters the fallopian tube and remains viable for about one day. Sperm cells are capable of fertilization within 2-3 days after ejaculation.

Pregnancy is at the same time the most wonderful, exciting and responsible time. It is pregnancy that teaches a woman to wait. Wait for the most wonderful and magical moment - the moment of meeting your baby. I would like to “be fully armed” and prepare for it in advance. Therefore, the question is: "How many days from conception to childbirth?" - every future mom is interested. Some pregnant women bother doctors with this question, but in response even the most experienced gynecologists just shrug their shoulders. They are doctors, not fortune-tellers. And they are responsible for their words. And no one can name the exact date of birth.

PDR - estimated due date

You can calculate it yourself. Just remember that any forecast in this case will only be indicative. Be prepared for the fact that your main date with your son or daughter (or maybe twins) will happen a couple of days or even weeks earlier or later than the date received during the calculation.

Pregnancy and its stages

Before calculating the PDR, it is worthwhile to understand and understand how the child develops from conception to childbirth and how long the pregnancy lasts on average.

According to statistics, in 80% of cases, the duration of a healthy pregnancy is about 38 weeks. This is about 266 days. It would seem that this is it! The time from conception to childbirth is 38 weeks. What is there to count? But the main problem is that very few people can accurately name this very date of conception.

Each week of pregnancy is a new stage in your baby's life. Let us briefly consider what a woman expects from conception to childbirth by week.

Pregnancy from the first to the twelfth week

A woman learns about what is expecting a child after a delay in menstruation. But by this time, changes had already taken place in her body. The fertilized egg has found its place and is attached to the walls of the uterus.

In the third week of pregnancy, the zygote (fertilized egg) already has 32 cells and begins its movement along the fallopian tube into the uterus. The placenta is formed - a link between mom and baby. With its help, the baby will receive food throughout the pregnancy.

From 4 to 7 weeks, an increased growth of the embryo occurs. This is the time to "lay the foundation" for a new person - the nervous and circulatory systems, skeleton, heart and brain are being formed. The growth of the crumbs by the beginning of the 8th week is up to 13 mm. On ultrasound, you can distinguish his facial features. The process of formation of genitals, hair and nails begins. The embryo starts to move.

Pregnancy from thirteenth to twenty-sixth weeks

A characteristic feature of the second trimester is the active growth of the embryo. The reproductive system begins to form - girls develop ovaries, and boys develop a prostate gland.

The movements of the embryo become clear and coordinated. From the 17th week, a fatty layer develops on the body of the fetus, which is involved in metabolic processes. By week 20, the baby has a fully formed brain, limbs and sensory organs. The skin of the embryo begins to thicken, and a lubricant appears on it to protect the delicate skin of the newborn.

At 25-26 weeks, the growth of the crumbs increases so much that it becomes cramped. During this period, the expectant mother begins to feel the active shocks and movements of the baby in the stomach.

Pregnancy from the twenty-seventh to the fortieth week

From week 27, the third, final stage of pregnancy starts. How many days of pregnancy are still left and what is the baby doing in the mother's stomach? How does one prepare for a meeting with mommy and the world? All these thoughts are spinning incessantly in the head of every expectant mother.

The kid doesn't think about it. At this time, he is actively gaining weight, begins to open his eyes and distinguish sounds outside his "house". The active growth of the fetal brain continues. The subcutaneous fat layer in the crumbs is already fully formed.

From 31 to 33 weeks, the proportions of the fetus change - the head ceases to exceed the body, the facial features become more pretty. She no longer feels such active movements as in mommy. This is due to the fact that the baby sleeps more often and can even dream. The epithelium of the fetus is smoothed and becomes pinkish.

The main task of the mother's body at the final stage of pregnancy is to help the child gain weight. In his lungs, the production of surfactant begins - a substance that will help the lungs of a newborn to open up and take the first breath in his life. Thus, by the 40th week, the baby is ready for life outside the mother's tummy.

In the table below, expectant mothers can determine which tests and studies, as well as new sensations from communicating with the baby, await them at each stage of pregnancy.

Gestational age	Stage characteristics	Research Needed
Tenth to Thirteenth Weeks	The end of the embryonic period, the formation of the central nervous system.	Double test (free and PAPP-A). Screening for the risks of developing Down syndrome and Edwards syndrome.
Sixteenth to eighteenth week	Formation of the reproductive system of the fetus, fatty layer.	Triple testing (alpha-feto protein, human chorionic gonadotropin and biochemical screening for Down and Edwards syndromes, as well as fetal neural tube defects.
Eighteenth week	Feeling of the first tremors of the embryo in women who have already given birth.
Twentieth week	Feelings of fetal movement in primiparous mothers.
Twenty-second week	The formation of the brain and sense organs comes to an end.	Second ultrasound to measure fetal organs.
Twenty-fourth week	Thickening of the endometrial layer, the formation of primordial lubricant.	Dopplemetric analysis - determination of blood flow in the placenta.
Twenty sixth week	The baby has noticeably increased in size and is a bit cramped for him. Therefore, mommy increasingly hears his jolts and twirling.	Test O "Sullivan or glucose tolerance testing (to exclude the development of diabetes in the fetus)."
Twenty-eighth week	The second trimester ends. There is a risk of gestosis or late toxicosis in pregnant women.	Registration of prenatal leave
Thirty week	There are fewer and fewer jerks of the crumbs, since he spends most of the day in a dream.	Mommy goes on vacation
Thirty second week	The development of a surfactant - a substance that helps the baby take the first breath	Third ultrasound to determine the state of the placenta and baby
Thirty-eighth week	Full-term pregnancy	Mom prepares to meet the baby

Now that we have got acquainted with the stages of pregnancy from conception to childbirth, and we know what happens to the baby inside the mother's belly, we will try to predict the date of meeting with him.

Option one: date of birth by day of conception

The effectiveness of this method is controversial. This is due to the fact that women rarely know the day of conception. But doctors reliably know how many days pass from conception to childbirth on average. This is 280 calendar days. Therefore, if you can name the day of fertilization, then it is not difficult to calculate the date of birth. We add 280 days to the date of conception and get the desired result.

A possible error in calculating the PDD by the day of conception arises due to the fact that pregnancy does not necessarily occur on the day when intercourse took place. After all, the sperm, being in the vagina, retains its ability to fertilize for several days. The discrepancy is possible in two to three days. Therefore, the calculated due date is indicative.

Option two: due date of ovulation

Many people use the method of calculating the date of birth by ovulation. The calculator is not for everyone. After all, ovulation is monitored using tests or only those women who are trying to get pregnant for a long time.

The estimated ovulation date falls in the middle of the cycle. For example, if the menstrual cycle is 28 days, then ovulation should be 14. To this date, the middle of the cycle, and add 280 days, getting the estimated day of birth.

The accuracy of this technique is possible only if there is an ovulation diary and its confirmation by tests.

Option three: due date of last menstruation

There are two options for calculating the due date based on the date of your last period:

Using the Negel formula. To do this, subtract 3 months from the start date of the last critical days, and then add another 7 days.
40 weeks (or 280 days) are added to the start date of the last menstruation. This practice is resorted to by many practicing gynecologists.

Despite the popularity of this technique among obstetricians and gynecologists, its accuracy leaves much to be desired. Especially if a woman's menstrual cycle does not meet the average standard (less than 28 days or more than 30). How many days a pregnancy will last depends on how long her menstrual cycle is the standard 28 days. Each additional day of the cycle lengthens the pregnancy by 1 day. But no more than 5 days in total.

For women with menstrual irregularities, this technique is not suitable at all. The popularization of the method among professionals is due to the fact that much more women can name the day of the beginning of the last menstruation than those who can report the day of ovulation or conception.

Often, calculations of the date of birth by the date of the last menstruation are erroneous due to profuse implantation bleeding, indicating that a fertilized egg is attached to the wall of the uterus. Many women mistake it for critical days, and the due date starts from the wrong date.

An experienced obstetrician-gynecologist can determine the estimated date of birth based on the date of attendance at the antenatal clinic. You can confirm pregnancy with a doctor as early as 4 weeks. The full 36 weeks are conditionally added to this date. The use of such calculations is now becoming irrelevant due to the development of the pharmacy industry, which offers to establish the presence of pregnancy at home using tests. An increasing number of women prefer this method of establishing pregnancy. And they get registered with the ZhK (antenatal clinic) for pregnancy later.

Option four: date of birth by wiggle

Another option allows you to calculate the date of birth by the movement of the fetus, that is, based on the date when it happened for the first time. Usually, primiparous mothers feel this movement starting from the 20th week of pregnancy. And for women who are preparing to become a mom a second time or more - from 18 weeks. Adding the same number of weeks to the original date, we get the desired date of birth of the baby.

This is perhaps one of the most ancient ways of calculating the date of birth of a baby. In the absence of an ultrasound machine, it was considered not only the most reliable, but also practically the only one. When using this calculation method, it is worth remembering the following:

The first movements of the embryo in the uterine cavity are recorded at 12 weeks of pregnancy, but they are so weak that the expectant mother does not notice them.
Thin mothers, leading a sedentary lifestyle, are much more "sensitive" to the jolts and movements of the fetus. Such women are able to feel the movement of the baby, similar to a slight tickling, even at 14 weeks of pregnancy. And overweight women are less sensitive in this matter.
A woman who is carrying a pregnancy for the first time simply has no idea how exactly the movements of the embryo manifest themselves. As a result, they often do not attach importance to the slight turns of the crumbs in their tummy. Women who already have children are more experienced and therefore notice them earlier.
The noticeability of the first movements of the embryo is also due to the thickness of the walls of the uterus. And this is a purely individual parameter.

If a woman is registered in the antenatal clinic, her gynecologist will definitely ask and enter into the card information about the first fetal movement.

Option five: date of birth by ultrasound

The most truthful answer to the question: "How many days from conception to childbirth?" - will give an ultrasound examination. With the help of an ultrasound machine, a specialist can determine the size of the ovum, in accordance with which the gestational age is calculated.

From the 12th week of pregnancy, using an ultrasound scan, the dimensions of the baby's body parts are measured. But it also happens that the date of birth by ultrasound does not coincide with the embryonic gestational age. Sometimes the difference between these values is up to two weeks. Such inconsistencies confuse the expectant mother and make her nervous. She fears abnormal development of the fetus or a frozen pregnancy.

However, there is no cause for concern. It is rather difficult to interpret the results of ultrasound. Often an old ultrasound machine or an inexperienced doctor can "lubricate" the picture. In addition, the development of a crumb is an individual matter and does not always exactly coincide with the generally accepted standard. But in case mommy hears from the doctor that the fetal head corresponds to 23 weeks, and the heart is 26, it is better to seek advice from another specialist and conduct a new ultrasound procedure.

According to doctors, the most accurate picture of pregnancy on an ultrasound machine can be seen up to 12 weeks. This is due to the fact that the stages of fetal development during this period are most obvious. And from the 13th week, the development of each crumb goes according to its own scenario. Someone is developing slowly and gradually catching up with standards. Another is in a hurry to meet with mommy and is ahead of schedule.

When decoding ultrasound screening, specialists correlate the data obtained with tables of fetal parameters. Do not get depressed if obstetric and do not match. This is not a pathology, but a kind of norm.

The most truthful will be the forecast of the date of birth with the greatest amount of known data. But if you can't name any for sure, it's okay. After all, all the best things in life happen suddenly! And the birth of a long-awaited baby is no exception! What does a couple of days of waiting mean in comparison with the joy of meeting your baby and the opportunity to show him this world ?!