Fetal egg 0 8. Fetal egg, yolk sac: normal size by week

10.09.2019

Immediately after the joyful news of an interesting situation, a woman begins to worry and take care of the developing baby. Doctors come to her aid - at the end of the first month of bearing a child, an ultrasound can already see a fetal egg. Changing its size by weeks allows you to draw conclusions about whether the pregnancy is proceeding correctly.

Fertilized egg: what is it and why follow it?

A fertilized egg is a fertilized egg surrounded by membranes. It is constantly dividing - first into 2 parts, then into 4, etc. As a result of this process, the size of the embryo is constantly increasing. Before fixation in the uterus, which occurs 7 days after conception, the fetal egg receives the necessary substances from the yolk sac. The term "gestational sac" is replaced by "fetus" at the end of 12-14 weeks of pregnancy.

Tracking the size of the fetal egg by weeks is not a whim and not a reinsurance of scrupulous physicians and their patients. This information helps:

determine the duration of pregnancy;
name the expected date of birth;
make sure that the growth of the embryo is normal;
detect the appearance of pathologies;
prevent involuntary termination of pregnancy, that is, miscarriage.

Do not put off an ultrasound examination until later. After all, the woman herself, who is preparing for imminent motherhood, is interested in obtaining the above information, first of all.

What numbers create a "portrait" of a tiny embryo?

Medical science has long known the norms of various indicators of the development of the fetal egg in the first 3 months of expecting a child. Examining the embryo, visualized on the monitor, the doctor will first of all pay attention to its shape - at the minimum time it resembles a circle. Next, you need to measure the inner diameter of the fetal egg and tell the woman how long the long-awaited "resident" is inside her. But this diameter is not the same for everyone, as it depends on the individual characteristics of the organism. Therefore, if, when establishing the time elapsed after conception, rely only on this indicator, an error of 1.5 weeks is possible.

Thanks to modern transvaginal ultrasound devices, it is possible to detect a fetal egg measuring 2-4 mm. What period confirms this measurement? No more than 2-3 weeks after the onset of development and 5-6 weeks from the day of the last menstruation.

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How will this figure change in the future? We offer a small "cheat sheet", which indicates the period of development, and in brackets - the period since the last menstruation:

5 (8) weeks - 6 mm;
6 (9) weeks - 11-18 mm;
7 (10) weeks - 19-26 mm;
8 (11) weeks - 27-34 mm;
9 (12) weeks - 35-43 mm;
10 (13) weeks - 50 mm.

But what women hear during an ultrasound scan is not always found in the standard list of sizes. Therefore, expectant mothers often have questions - for example, if the fetal egg is 5 mm, what is the gestational age? It's about 5 weeks. And what is the period if the fetal egg is not 5 mm, but 8 mm? Then pregnancy 5 weeks and a few days. During the day, the egg cell surrounded by a membrane will grow by an average of 1 mm, and after crossing the line at 15 weeks, the fetus increases daily by 2-2.5 mm.

To make sure that everything is fine with the future baby, in addition to these data, the area and volume of the fetal egg, as well as the diameter of the yolk sac, are measured. The norm of these indicators for weeks is different.

No less important information is KTR and BPR. How to decipher these abbreviations?

The coccyx-parietal size (KTR) is the length of the embryo from its top to the coccyx. Such measurements make it possible to determine the time of pregnancy as accurately as possible, because the indicator is almost identical in all patients.

The biparietal size of the fetal head (BDP) is the area from the surface of the upper border on the outside to the surface of the lower border on the inside between the parietal bones. BDP is measured starting at 6 weeks after conception.

To understand how the results of ultrasound correspond to the norm, the following table will help.

Weeks since last menstrual bleeding	weeks after conception	Yolk sac diameter

When is women's excitement justified?

A woman who has recently learned about her new position does not always hear good news on ultrasound. What can overshadow her hope for a prosperous motherhood?

wrong shape

Before the onset of 5-6 weeks of pregnancy, the doctor sees the fetal egg in the form of a rounded figure. But when the baby's gestation period approaches 2 months, with a longitudinal scan, the embryo will look oval, although it will remain rounded with a transverse one. Other deviations from the normal form are also possible. This pathology most often develops in the presence of neoplasms in the uterus or partial detachment of the placenta.

Placement violations

The fetal egg should be fixed in the bottom of the uterus or on its back wall, less often in the internal pharynx or in the upper part of the organ. If the embryo is located differently, the doctor assesses how dangerous it is, and decides on the future fate of the crumbs.

size pathologies

If the egg in the shell is smaller or larger than the above values, this indicates possible developmental disorders. But since these indicators can fluctuate even during the normal course of pregnancy, only a specialist concludes how significant the deviations are.

False fertilized egg

In the case of an ectopic pregnancy, the doctor can still see a fetal egg in the uterine cavity. But in fact, this formation consists of an accumulation of mucus and the secretion of the glands of the fallopian tubes. You can recognize the “deception of the body”: from a normal fertilized egg, this egg will differ in wall thickness and shape.

Empty fertilized egg

At 1-2 weeks, the fetus is not yet noticeable, so it will not work to understand whether it is developing. But an empty egg at a later date is a warning sign. Most likely, a medical termination of pregnancy will be required. Among the reasons for such a sad situation are the woman's age, genetic disorders, medications that are contraindicated for pregnant women.

When conducting the very first ultrasound, which is done with a delay in menstruation and in order to accurately diagnose a uterine pregnancy, you can see the fetal egg. It was at this time, having seen this tiny formation on the monitor, the doctor already informs you that you will soon become a mother. In the photo you can see a fetal egg - a small oval formation. At an early stage, the embryo that will develop in the fetal egg is not yet visualized, but soon it will grow up and be clearly visible. An empty ovum is an egg without an embryo when pregnancy does not develop. The embryo is usually visible from the fifth week of pregnancy, but sometimes there are situations when the ultrasound doctor does not see the embryo even at this time, in which case a repeat ultrasound is prescribed. Very often, a repeated ultrasound shows both the embryo and the heartbeat. If after six to seven weeks the embryo is not visible, then, unfortunately, there is a high probability that the pregnancy does not develop.

Diameter of the fetal egg

Ultrasound assesses the average internal diameter of the fetal egg -SVD. Our table showsSVDin mm, typical gestational age for this sizeSVD(50 percentile), as well as possible normal fluctuations (terms of pregnancy for which such an indicator may be possibleSVD, 5th and 95th percentile). The diameter of the fetal egg is considered a variable value, which is why there is an error in determining the gestational age only by this fetometric indicator. The average error is 1.5 weeks. Only by the size of the fetal egg, they usually do not determine the gestational age, they always look in additionKTRdue to the smaller variability of this size. Please note that after 16 weeksKTRusually not measured, and when determining the gestational age, other indicators are guided.

The diagnosis of an empty fetal egg without an embryo is not uncommon, it is made in 5-10% of cases. The most unpleasant thing is that the chances of identifying its causes are minimal. In order for a planned pregnancy to be successful, experts recommend taking multivitamin complexes and leading a healthy lifestyle.

This is what an empty fetal egg looks like on an ultrasound.

An empty fetal egg is essentially a pregnancy that has not begun to develop. The development process stopped even before the stage of embryo formation. There are many reasons for this violation. Any negative changes in a woman's body can provoke it. When making a diagnosis of anembryony, the necessary measures should be taken immediately, as this entails the inevitable death of the fetus.

Among the main causes of an empty fetal egg are:

Genetic disorders.
Infectious diseases.
External factors (state of the environment).
Wrong diet.
Lack of vitamins.

That is, in each specific situation, it is extremely difficult to determine the cause of the formation of an empty fetal egg. Genetic disorders begin at the initial stage of cell division and entail subsequent errors. This may be the formation of extra chromosomes, or vice versa, their incomplete set. In this case, the transformation of the egg into an embryo does not occur, the woman's body understands this and begins to reject it.

According to statistics, out of 100 women, 5-10 do not have an embryo in the ovum.

How does anembryony manifest itself?

At the initial stage, an empty pregnancy will not be noticeable. It cannot be determined even with the help of a gynecological examination. Violations become visible already at the most extreme stage, when the body begins to reject the fetus. At this stage, there are pains in the lower abdomen, brown discharge from the vagina and a pungent odor - and these are already signs of a fetal egg without an embryo that the body began to reject.

How does hCG change with an empty fetal egg?

Monitoring the dynamics of the hCG indicator is one of the ways to determine an empty fetal egg. HCG values will change, but much less than during the normal course of pregnancy. It is also possible that the values of the hCG indicator stand still - this is the main sign of the existence of problems with the development of the fetus.

Be sure to watch this helpful video:

The symptoms of an empty pregnancy do not differ from the usual one: this is a delay in menstruation, manifestations of toxicosis, a constant feeling of fatigue.

In the early stages, it is extremely difficult to identify an empty fetal egg. Since the size of the embryo is very small and you can simply not notice it. Only after 5 weeks, it becomes possible to determine the absence of the fetus.

ultrasound diagnostics

Only at the sixth week of pregnancy, an empty fetal egg can be diagnosed using ultrasound. It is carried out in any case to determine the location of the fetus, as well as to exclude an ectopic pregnancy. A woman can hear such a terrible diagnosis as anembryony even if she feels well and has no symptoms. The first trimester of pregnancy is the most important time for the formation of the fetus, at this stage, the expectant mother should carefully monitor her health, as the risk of miscarriage is very high.

This video shows an ultrasound of an empty gestational sac:

If a woman has an empty fetal egg without an embryo, a medical correction (cleansing the uterus) will be required.

What to do with anembryos?

If such a disappointing diagnosis was made, a correction will need to be made. Medical correction is possible in two ways.

Surgical method

This is the most common correction option. This method allows you to clean the uterine cavity without consequences. During surgery, general anesthesia is used. The operation is very fast from 10 to 25 minutes. The doctor must scrape out the uterine layer and an empty fetal egg. After a couple of hours, the woman can go home.

medical abortion

Abortion with the use of special drugs can be used if the gestational age is less than 6 weeks. The woman takes the medicine and waits for the contractions to start. It hurts. The whole procedure takes place in the hospital under the supervision of a doctor. After everything superfluous comes out of the uterus, the woman must spend a couple of days in the hospital before the bleeding stops.

To clarify the cause of the violation of the development of pregnancy, the material obtained from the uterus during the cleaning process is sent for histological examination. Such a study should find out the reasons for the termination of the development of the embryo and when exactly it stopped its development.

After an abortion, you need to do an ultrasound.

At the completion of either of the two methods of abortion, an ultrasound should be done. Thus, you can make sure that the uterus is clean and no particles of the fetal egg remain in it.

Prevention

It is better to prevent a problem than to deal with its consequences. If an empty fetal egg is found, then extreme measures are taken. But if you follow some recommendations when planning a pregnancy, you can reduce the likelihood of developing pathologies.

You can reduce the risk of developing an empty ovum in the following ways:

both spouses undergo a full medical examination (do tests, ultrasound, consult a gynecologist and therapist to exclude chronic diseases, it is also recommended to visit narrow specialists);
on the recommendation of a specialist, start taking multivitamins, including folic acid. The course of vitamins should be started 2-3 months before conception;
in preparation for pregnancy, you should give up bad habits: drinking alcohol, smoking. Review your diet, diet: fill it with foods rich in vitamins and minerals.

Summary

It is worthwhile to agree in advance with an obstetrician-gynecologist who will advise you throughout the pregnancy. It is important to understand that a single case of an empty fetal egg is not yet a sentence. This absolutely does not mean that one of the partners has violations in the reproductive system. The main thing is not to get upset and keep trying to get pregnant ( after anembryony, continuation of the genus can be taken after six months), then everything will work out.

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The connection of a male cell with a female cell is considered the first stage in the development of pregnancy. The resulting embryo and its shell, as a result of the connection, are called in medicine a fetal egg. The spermatozoon that has fallen on the egg fertilizes it, and it begins to multiply by division. With an increase in the number of cells in the fetal egg, the size of the embryo itself also increases. In addition to division, there is an internal movement of the embryo through the fallopian tube. Ultimately, the fertilized egg attaches to the walls of the uterus.

It takes about seven days for a fertilized egg to reach the uterus. The nutrients of the egg itself do not allow it to die before it enters the uterus. The woman's uterus is also preparing to receive the fertilized egg. The mucous membrane of the uterus becomes thicker, and it is she who will feed on the egg before the formation of the placenta. The process of placental formation begins immediately after the attachment of the egg to the walls of the uterus. The surface of the fetal egg is covered with villi, which liquefy the mucous membrane and are introduced into the right place. At the site of attachment, the walls of the vessels burst, and the mucosal area is filled with blood.

The appearance of a fetal egg in the uterus can be seen on ultrasound 2 weeks after a delay in the woman's menstrual cycle, and means the normal course of pregnancy. The appearance of the embryo on ultrasound can be expected by the fifth week. If the embryo is not visible on the ultrasound by this time, most likely the fetal egg is empty. Usually, doctors prescribe a re-examination after some time to confirm the results of the absence of an embryo.

Photo of the fetal egg on ultrasound

For a period of about 6-7 weeks from the moment of delay of menstruation, the embryo has a heartbeat. By this time, various complications are possible. In the absence of an embryo, doctors state that the pregnancy is not developing, i.e. empty ovum. An ultrasound examination checks the correct location, correct shape, attachment of the embryo to the walls of the uterus. Ultrasounds in the early stages of pregnancy are extremely important. Many pathologies can be avoided or corrected with timely diagnosis. It is in the initial stages (first trimester) that miscarriages most often occur.

With ultrasound examination in the early stages, the fetal egg has an oval shape. The main characteristic during the first examinations is the inner diameter of the fetal egg. It is possible to determine the actual gestational age according to the SVD of the ovum only in a rounded manner, since there is a range of sizes at the same time. The size of the egg diameter allows you to determine the period with an accuracy of 1.5 weeks. For a more accurate determination of the gestational age, in addition to the diameter of the fetal egg, the coccygeal-parietal size is looked at. The CTE of the embryo and several other parameters make it possible to calculate the term much more accurately.

Fertilized egg and its size by week

The sizes of the fetal egg according to the term are listed in the table. According to the table, you can see that with an egg diameter of 4 mm, the gestation period is up to six weeks. With this size, experts set a deadline of 4 weeks. With an increase in the ovum to 6 mm, a period of 5 weeks is set, then the increase becomes more noticeable, for example, at 5 weeks 3 days, the size of the egg is usually 7 mm in diameter.

Fetal egg size chart

After 6 weeks, the egg reaches a size of 18 mm. At the sixth week, the inner diameter of the fetal egg is measured, which is 16 mm - and usually with this value they set a period of 6 weeks and 5 days. At the seventh week, the size of the SVD fluctuates 19-26 mm. At the end of the eighth week, the size of the egg reaches 34 mm, and at the ninth week, the size ranges from 35 to 43 mm. On average, the growth rate of the fruiting egg is 1 mm per day until 16 weeks, 2.5 mm after.

Table of pathologies of the development of the fetal egg

The specific cause and degree of risk for deviations in the development of the fetal egg can only be said by a qualified doctor after an ultrasound scan.

When a woman has a serious delay in critical days, the gynecologist sends the patient for an ultrasound diagnosis to confirm or deny the presence of pregnancy. First of all, the doctor looks at the contents of the uterus, whether there is a fertilized egg in it.

Why is it important to have a fertilized egg?

A fetal egg found by ultrasound in the uterine cavity is the first confirmation of a healthy uterine pregnancy. At the same time, the thoroughly studied sizes of the fetal egg by weeks make it possible to find out the exact terms of pregnancy, as well as to predict the further course of pregnancy.

From the beginning to the middle of the first trimester, the fetal egg is one of the main indicators of the good development of the embryo. Since the size of the fetal egg grows by weeks of pregnancy, its size and filling can indicate a successful pregnancy, possible problems, and even a missed pregnancy.

How is the presence of a fertilized egg determined?

A gynecologist, by examination on a chair and palpation, can only assume the presence of a fetal egg in the uterus, based on an increase in the size of the organ. Namely, the doctor can see the fetal egg only with the help of an ultrasound machine.

As a rule, transvaginal ultrasound is performed in the early stages, and it gives the most accurate results, since with this method of diagnosis, the ultrasound can get as close as possible to the object under study.

Fertilized egg - what is it?

A fertilized egg is an accumulation of a mass of cells resulting from the fusion of an egg and sperm and further division

The shape of the cell mass can be round or oval, but cases of deformation are not excluded. As a rule, diagnosticians look at unusual forms more carefully; in such situations, more frequent observations of the development of the embryo are not excluded. But it’s not worth talking about any problems due to the unusual shape of the egg, since the matter may be in the tone caused by the ultrasound machine itself. By removing the apparatus for a while or by reducing the pressure, the uzist can see that the shape has changed and returned to normal.

How does a fertilized egg appear

A mass of cells travels through the fallopian tube for some time, heading towards the uterus and the place of their future implantation. A week after fertilization has occurred, the fetal egg is attached to any wall of the uterus convenient for this, using the villi located on the outer shell of the egg, destroying a micro-part of the uterine mucosa and vascular walls during implantation. All the time of the journey and the formation of the fetal egg, the cells feed on substances from the egg, after which the nutrients will begin to come from the placenta.

At 3 weeks from conception, the size of the fetal egg seriously increases, since a “baby place”, in other words, the placenta, begins to grow from a set of cells embedded in the wall of the uterus. In it, the fetus will live, eat and develop until the very birth.

The size of the fetal egg will increase again at 5 weeks of pregnancy. At this time, the embryo can already be seen inside the egg. It is worth noting that if at this time the uzist did not see the embryo in the fetal egg, then there is still no talk of a missed pregnancy and cannot be, since the discrepancy in the timing of the growth of the fetal egg is quite large and can reach two weeks.

The thing is that it is impossible to determine the exact timing of pregnancy during natural conception due to the fact that a woman can ovulate on different days of the cycle, fertilization can also be delayed, attachment can be faster or slower. Therefore, the gestational age is set on the basis of the beginning of the last critical days, which is an obstetric period, and not an embryonic one, and if an embryo is not visible inside the egg at the 5th week of pregnancy, the ultrasound is repeated again after two weeks. Most often, on a repeated ultrasound, the embryo is already visible.

Weekly sizes

It is not necessary that the size of the fetal egg by week coincide exactly with the standards. Possible error reaches two weeks. In some cases, for example, with late ovulation, the error may be even greater, the fetal egg may have a larger or smaller diameter, and this will be the norm, but only if the embryo develops normally.

Here are the sizes of the fetal egg by week on ultrasound:

Until the 5th week of pregnancy, the fetal egg is very small, by the end of the fifth week it reaches 18 millimeters, and the volume is 2187 millimeters cubed, but even in the fourth week it has a diameter of only 7 millimeters. If the egg has a small diameter, then this also indicates a short period that has elapsed since conception.
Already on the 6th week, the size reaches 22 millimeters.
At 7 weeks, the size of the fetal egg is already 24 millimeters.
In the following weeks, the growth of the fetal egg takes place spasmodically, at the eighth week of pregnancy it will be already 30 millimeters, in the future the egg will grow by an average of 6-8 millimeters weekly.
By the 13th week, the diameter will already reach 65 millimeters, and the volume will be 131,070 millimeters cubed.

The growth of the fetal egg

The size of the fetal egg by week also gives an idea of what size the embryo is hiding in the egg. Each week, the embryo develops as rapidly as its house, while the dimensions of the embryo and egg correspond to:

At 5 weeks, the coccyx-parietal size is 3 millimeters.
At 6 weeks already 6 millimeters.
On the 7th week, it grows to 10 millimeters.
At 8 weeks, not only ktr is estimated, but also the biparietal size, namely the estimated width of the head of the embryo, ktr at this time is 16 millimeters, and bpr is already 6.
From 9 to 13 weeks, the fetus grows an average of 10-13 millimeters weekly, and by the end of the first trimester, its growth reaches 66 millimeters. The width of the head also grows all this time, at 9 weeks - 8.5 millimeters, at 10 - 11, at 11 - 15 millimeters, at 12 - 20 and at 13 already reaches 24 millimeters.

It is also worth paying attention to the fact that in the weeks between the main screenings, the size of the egg and the indicators of the embryo may not be so perfectly adjusted, therefore, for screening demonstration studies, weeks are allocated when the fetus approaches the average in all its indicators, in the first trimester, for example , this is 11-14 weeks of pregnancy. Before the first screening, at about the 9th week of pregnancy, the uzist and gynecologist check the ratio of the size and the presence of a heartbeat in the fetus, in accordance with these data, adjustments can be made to the estimated gestational age.

How many fertilized eggs can there be

Depending on how many eggs are fertilized at the same time or in a short period of time, one or more fertilized eggs appear.

As a rule, if we are talking about twins, that is, about the fertilization of one egg in which two embryos were born, then the fetal egg is one and it is divided into two parts closer to the moment of attachment to the uterine wall or is not divided at all. In all other cases, in a multiple pregnancy, there will be as many fetal eggs as there are fertilized eggs, that is, two or more. In conditions of multiple pregnancy, the size of the fetal egg by weeks will differ slightly from the standards, since the development of the pregnancy itself is a little more complicated, the distribution of nutrients and space in the uterus also goes differently.

Fertilized egg and artificial insemination

The fact that with the advent of such methods for fertilization as IVF, multiple pregnancies, with the development of several fetal bladders at once, has become much more worthy of special attention.

With artificial insemination, everything happens a little differently, since an already fertilized fetal egg with an age known to doctors is inserted into the uterus, therefore the size of each fetal egg usually exactly corresponds to the embryonic period and may not correspond to the gestational age.

All ultrasound transcripts regarding the size of the fetal egg and embryo should be obtained directly from the ultrasound specialist who performed the diagnosis, as well as from a personal gynecologist, since only they will be able to correctly assess absolutely all indicators, taking into account the specific features of pregnancy.