The most common question that future parents ask the doctor during the first ultrasound screening is: “Doctor, can I find out who we are having – a boy or a girl?”, but they do not always receive a definite answer to this. So, from what stage of pregnancy, how reliably and by what signs is the sex of the fetus determined by ultrasound?
Not long ago, Russia introduced mandatory ultrasound screenings for all pregnant women. at 11 weeks – 13 weeks 6 days. During this period, the fetus is assessed for:
- anatomy in order to exclude gross congenital defects that can be detected in the first trimester;
- ultrasound markers of chromosomal abnormalities (in particular for);
- condition of the placenta, amniotic fluid, uterus, ovaries.
In addition, at this time it is possible to reliably determine the number of fetuses, if this has not been done before, to determine the term of the fetus, and to assess the viability of the unborn baby.
What determines the sex of the unborn child?
Many people already know well from their school biology course that all female reproductive cells contain an X chromosome, and male reproductive cells contain either an X or a Y chromosome. During conception, only one sperm can penetrate the egg. And the sex of the unborn child depends on which chromosome set it ends up with: if it is a sperm carrying an X chromosome, then it is a boy, if it is a sperm carrying a Y chromosome, then it is a girl.
Different sperm have their own characteristics. So Y-sperm are more mobile, faster, but live no more than 48 hours. X-sperm are larger and therefore, on the contrary, slower, but they remain viable for up to 5 days.
Thus, the possibility of fusion of an egg with sperm carrying a Y chromosome and the birth of a boy is higher during sexual intercourse the day before or in the next 12 hours after it. If sexual intercourse was several days earlier or later than ovulation, then there is a greater chance of a sperm with an X chromosome penetrating the egg and giving birth to a female child.
Diagnosis of the baby's gender by ultrasound at 12 weeks
Establishing the sex of the unborn child is important not only for the parents themselves, but also for the doctor for the differential diagnosis of some congenital and hereditary diseases that can be transmitted only through the maternal or only through the paternal line (for example, hemophilia). But, despite this, sex determination is currently not included in the mandatory scope of echographic examination in obstetrics and is carried out only on the initiative of a doctor or at the request of parents.
The external genitalia of the fetus begin to form from. First, the genital tubercle is formed, which contains the rudiments of the clitoris of a girl or the penis of a boy, and the genital folds, from which the labia or scrotum are later formed. Differentiation of the genitals occurs under the influence of hormones and visual differences in the structure of the external genitalia appear only at the end of the 1st trimester of pregnancy.
With the modern level of ultrasound diagnostics using expert high-resolution devices, a qualified doctor can with a high degree of probability determine the sex of the child starting from the 12th week of pregnancy. According to the results of various studies in different clinics around the world, the accuracy of diagnosing the sex of an unborn child at 11 weeks of gestation using ultrasound varies from 45% to 92%, at 12 weeks - 54-100%, at 13 weeks - 56-100%.
Simply put, at this stage the sex of the child can most often be determined with a probability of 50:50. This can be done more accurately when the external genitalia become clearly visible on the screen.
In the second half of pregnancy, when the fetus reaches a sufficiently large size, sex determination usually does not cause any difficulties for the ultrasound doctor. The male gender is assigned when the penis and scrotum are clearly identified, and the female gender is assigned when the labia are identified.
What determines the accuracy of sex determination?
For up to 12 weeks, the external genitalia of males and females have a similar structure, which makes their diagnosis most difficult.
Most often, one of the reasons why it is impossible to diagnose the sex of the fetus is its inconvenient position for examination. The baby may squeeze or cross his legs, press them to his stomach - all this prevents the doctor from examining and assessing the fetal perineal area.
In some situations, umbilical cord loops, fingers or swollen labia can imitate the image of the penis and scrotum.
When scanning in a transverse plane, a girl’s external genitalia can be represented by one of two types:
- Type 1 - in the form of four parallel hyperechoic lines with hypoechoic spaces between them. This type of image is typical for fetuses with a small clitoris relative to the labia;
- Type 2 - in the form of a rounded cone with hyperechoic sides and a hypoechoic space between them. This type of image is characteristic of an enlarged clitoris and small labia in female fetuses.
Expectant parents should not take the results of determining the sex of the fetus too seriously at the 12th week of pregnancy and even later, since there are many reasons why an ultrasound doctor cannot give an answer to this with an absolute guarantee. And the love of parents for their future baby should in no way depend on whether it is a boy or a girl - all children are good!
1
- Anus
2
- Labioscrotal tubercles
3
- Legs
4
- Genital tubercle
7
- Deepening of the urethra
8
- Genital folds
Embryo size - 45 mm.
At the 9th week there are no noticeable differences between the genitals of a boy and a girl. The genital tubercle and genital folds are surrounded externally by labioscrotal tubercles. The pictures confirm that the boy and the girl are no different in appearance.
Boy (11 weeks post fertilization, 13 obstetric weeks)
Boy, 11 weeks
Embryo size - 64 mm.
The development of male external genitalia depends on dihydrotestosterone, which is produced by the testes. The genital tubercle lengthens and grows, forming into the penis, and the urogenital folds on both sides of the urogenital membrane begin to fuse, forming the urethra. The labial-scrotal tubercles grow rapidly and turn into the scrotum, fused along the midline.
In boys, the genital tubercle forms the penis (4) . The body of the penis is formed from the genital folds; at this stage of development, the formation of the penis is not yet complete (7) . Scrotum (6) formed from labioscrotal tubercles (2) . Scrotal fusion line (5) formed by the connection of the labial-scrotal tubercles.
At this stage of development, the testicles are located in the abdomen. They do not descend into the scrotum (6) up to 7-8 months of pregnancy.
The foreskin at the 12th week of embryo development is already formed.
Changes in the development of the genital organs of girls at 13-20 weeks after fertilization
Girls have very little testosterone in their blood. Therefore, after the formation of the external genitalia in the 8th week, in the future they practically do not change in appearance.
The genital tubercle turns into the clitoris; it can increase not only while it is in the mother’s stomach, but also after the birth of the girl.
The genitourinary folds form the labia minora. The labioscrotal tubercles enlarge and become the labia majora, while the urogenital groove remains open, forming the entrance to the vagina.
The position of the external opening of the urethra is determined by the 14th week of embryo development.
13 week embryo size - 90 mm, 17 weeks - 150 mm, 20 weeks - 185 mm.
Girl, ultrasound 13-20 weeks
1
- Anus
2
- Buttocks
3
- Clitoris
4
- Labia majora
6
- Legs
7
- Labia minora
Girls' genitals are formed from the same folds and tubercles as boys' genitals.
By the 20th week, the labial-scrotal tubercles and genital folds in girls do not fuse and form small (7) and big (4) labia The clitoris is formed from the genital tubercle (3) .
The ovaries are not identified until the 10th week.
Gender determination during the second planned ultrasound at 20-22 weeks
At week 20, all external changes in the genitals have already occurred and you can “see” everything quite accurately. But if you come across a qualified specialist and high-quality equipment, then an ultrasound can determine the sex of the child starting from the 12th week.
In boys, you can see a lump between the legs, which is the scrotum and penis. may show a round, raised area within the genital area, which is the scrotum and penis. On the ultrasound machine screen, the boys' genitals in profile look like a small snail.
Some babies turn around during an ultrasound so that their genitals are not visible even at the third screening ultrasound at 32-34 weeks.
Determination of the sex of the fetus is influenced by factors such as the position of the fetus, the amount of amniotic fluid and the thickness of the abdominal wall.
Three-dimensional (3D) ultrasound makes it easier for specialists to determine the sex of the fetus.
Answers to the most frequently asked questions
Question: Can the sex of the baby be determined at the first screening ultrasound at 12 weeks?
Answer: At 12 weeks, the ultrasound doctor can make a guess regarding gender, sometimes it is a little more accurate than 50/50.
Correct visualization of any part of the fetus depends on many factors, including:
- fetal position,
- amount of amniotic fluid,
- thickness of the abdominal wall, etc.
So, if you are very interested in who will be born, then here are several possibilities assume about the field based on the results of early ultrasound examination.
Such successful pictures as in the photo on the right are extremely rare.
If the child turns so “comfortably”, the sex can be determined 12 weeks after conception (14 obstetric weeks).
3 ways to determine sex by ultrasound in the early stages
1. Determination by analysis the angle between the genital tubercle and the baby's back.
In the ultrasound screenshots below you can see what it looks like. All screens are of embryos at the 12th (14th obstetric) week of pregnancy, the size of the embryos is about 75 mm.
U boys the genital tubercle forms an angle of approximately 30 degrees or more with a back (left column in the photo).
U girls the genital tubercle forms an angle less than 30 degrees(right column of examples in the picture).
2. According to the location of the placenta
If the placenta is located on the right side of the uterus, is more likely to be born boy.
If the placenta is located on the left side of the uterus- wait girl.
This method bears the name of its discoverer and is known as . (Follow the link you will find a description of the research, as well as a vote by site readers on whether the method of determining gender by the location of the placenta was confirmed in their case).
3. According to the shape of the skull
If the skull and jaw are square, it is a boy; if it's round, it's a girl.
Question: How accurate are the results of determining the sex of a child in the first trimester of pregnancy?
Answer: Experienced sonographers can determine gender by measuring the angle of the genital tubercle.
At the 11th week, the percentage of error is approximately 50% (out of 100 boys, 14 of them have an accurate sex determination); at the 14th week, the sex determination is more accurate.
If a woman has not performed an ultrasound examination of the fetus at an earlier stage, then an ultrasound scan at the 12th week of pregnancy becomes the first and takes on special significance.
The deadline already allows the mother to see the baby in its entirety, albeit only on the equipment monitor. And the doctor has the opportunity to evaluate the anatomical features of the fetus and tell the expectant mother about them. From a medical point of view, ultrasound screening at 12 weeks (1st trimester) is of considerable value for determining measures for further management of pregnancy and maintaining the health of the baby.
There are several reasons why an ultrasound examination of a pregnant woman at 12 weeks is of great importance:
- At this time, the age of the unborn child can be determined with high accuracy, and later he will gain weight, and the error in the date of conception will be significant (up to a week).
- At that time it is important to determine the size of the collar area(this is the name given to the soft tissues of the back of the head and neck). This indicator is key in the early diagnosis of chromosomal diseases, including Down, Patau, and Edwards syndromes. The examination must be carried out before 12 weeks, because after the 14th week, chromosomal pathologies can no longer be detected, and some fetal malformations too.
- Assessing the placenta insertion site, the presence of abruption, the quality and quantity of amniotic fluid are significant indicators of pregnancy that affect the health of the child and the management of pregnancy - they are also important to find out at 12 weeks.
- The doctor assesses the condition of the uterus - there should be no increased tone (that is, tension) or isthmic-cervical insufficiency. All these conditions require timely treatment, so high-quality and timely diagnosis during pregnancy plays a key role.
How does the baby develop?
Modern ultrasound examination allows the expectant mother to observe what is happening on the screen of the ultrasound machine along with the doctor. And the first examination becomes the first meeting between mother and son (or daughter).
Reference! Although it is still difficult to see the child in the usual sense on the monitor, women are excitedly waiting for this moment.
The most important thing at this stage is to make sure that everything is going as it should. And, of course, when the doctor says: “Listen to how the child’s heart beats. Here is the head, here are the legs, and here are the arms, all the fingers have already formed. Everything is fine with you,” – Mom feels a surge of happiness.
By 12 weeks of pregnancy, all the baby’s organs and body systems are fully formed.
Reference! The baby’s weight now is no more than 19 grams, and his body length is about 9 cm.
Despite its tiny parameters, a child’s brain is no different from the brain of an adult in anything except its size.
Often, on an ultrasound, a woman sees how the baby sucks his finger, and his nails are already formed. The chaotic movements of the baby are thought out by nature - during them he trains his muscular system.
Video
The ultrasound video below contains footage of the baby's activity in the womb at 12 weeks of pregnancy.
What will the study show?
What is an ultrasound at the 12th week of pregnancy in terms of information content, and what is looked at with its help? Ultrasound screening at 12 weeks of gestation allows the doctor to see and evaluate:
- the size of the unborn baby (the length of certain bones, body length and head parameters are recorded);
- symmetry of the brain hemispheres;
- location of the kidneys, stomach, heart and other important organs;
- possible developmental abnormalities, including heart defects, tumors, congenital anomalies;
- signs of genetic disorders;
- the place where the placenta is attached (normally it should be located along the anterior or posterior walls of the uterus);
- the condition of the umbilical cord, the presence and functioning of 2 arteries and a vein in it;
- the length of the cervix, which depends on the duration of pregnancy and the individual characteristics of the expectant mother;
- the exact date from the conception of the child.
How is it done?
The ultrasound examination procedure is performed transvaginally (by inserting a vaginal sensor) or transabdominally (through the abdominal wall).
And if the first method is common only at the beginning of pregnancy, when it is still difficult to obtain the necessary information through the abdominal wall, then the second method is used more widely.
However, there are indications for transvaginal ultrasound at a later date.
The study is performed transvaginally, If:
- low position of the placenta or chorion is diagnosed;
- Isthmic-cervical insufficiency has been identified, the severity of which needs to be assessed;
- there are myomatous nodes;
- there are suspicions of inflammatory processes in cysts or appendages;
- There is a large layer of fatty tissue on the abdomen, through which it is not possible to see the necessary parameters.
Preparation
Preparation for the procedure depends on its type:
- During a transvaginal ultrasound, you should drink 500 ml. water immediately before the study.
- During transabdominal examination, increased gas formation should be avoided. For this purpose, on the eve of the study, it is not recommended to eat foods that cause fermentation (raw cabbage, grapes, white bread, legumes). You can take medications containing simethicone to eliminate accumulated gas.
Who is it prescribed to?
In our country, three times mandatory examination of all expectant mothers is regulated. It is carried out for preventive purposes and is called screening. A screening study makes it possible for early detection of perinatal pathology even in those pregnant women who are not worried about anything.
There are three such studies in total; they are prescribed at different stages of pregnancy and include ultrasound examination and determination of the biochemical composition of the blood. So an ultrasound at 12 weeks is indicated for all pregnant women, without exception.
Will a woman find out the gender of her baby at 12 weeks?
It happens that already at the first screening, the mother finds out who is worth waiting for - a boy or a girl. The child’s genitals are already fully formed, but only a very experienced diagnostician can discern the baby’s gender. It often happens that the baby turns sideways or backwards and does not want to open up to the doctor. Do not worry if the first ultrasound does not clarify the sex of the unborn child - it will be determined at the next examination.
Functional diagnostic doctors have their own secrets for early recognition of the baby’s gender, because this information is very important for the mother. For example, when the child is positioned facing the sensor, the specialist can measure the angle formed by the baby’s back and the genital tubercle. If it is less than 30 degrees, there is a high probability that it will be a girl. An angle above the specified value indicates that a boy is expected.
What is KTR?
One of the central indicators determined by ultrasound at 12 weeks is the coccygeal-parietal size of the embryo. During the first screening, normally it should be about 5.1-5.3 cm, fluctuations of a few tenths of a centimeter are acceptable. The doctor will clarify that the size of the KTP greatly depends on the exact stage of pregnancy. For example, at 11 weeks the CTE indicator will be approximately 4.2 cm (acceptable figures are from 3.4 to 5.0 cm).
The coccygeal-parietal size is a key factor in highly accurate determination of gestational age, but only for a period of 7 to 16 weeks.
Important! Determining the gestational age using KTP is unique in that the error when using this method is no more than 3 days.
But after 16 weeks, the method loses its relevance and completely different parameters come to the fore.
The resulting indicators must correspond to the standard, which is determined using a special table. Based on a comparison of two indicators, the doctor draws conclusions about the well-being of the embryo and the compliance of its development with the established period.
3D and 4D ultrasound – three-dimensional images for memory
More and more expectant mothers today prefer to replace conventional echography with 3D or 4D ultrasound. How are these methods better than traditional research? What is the difference between each other and what is given to future parents?
3D ultrasound allows you to get a three-dimensional image (photo), in which you can accurately see the baby’s face and examine the details of his appearance, find out the gender of the child and count his tiny fingers. The difference between a 3D examination and a traditional procedure is that it can only be carried out within a certain period of time - from 20 to 33 weeks and it is done only at the request of the parents, since from a medical point of view it is no different from a regular ultrasound, but costs several times more once.
4D differs from 3D only in the ability to see how a child lives in the womb in real time. Three-dimensional ultrasound shows only static frames, but four-dimensional, thanks to the rotation of the picture, allows you to see the baby’s movements and facial expressions.
Where to do it and how much does it cost?
Ultrasound examination at 12 weeks has no contraindications. As a rule, the doctor prescribes a planned procedure in a clinic at the place of residence or a large (regional) perinatal center, or a regional hospital with extensive experience in examining pregnant women. Routine screening is free, but if parents want to see an image of the baby in volume or real time, they will have to pay from 2,500 rubles. for a 3D ultrasound and about 4,000 rubles for a 4D procedure.
Conclusion
All ultrasound examinations during pregnancy are measures that should not be ignored. Ultimately, they are the key to successful monitoring of the health of both the baby and the mother.
Pregnancy at 12 weeks involves undergoing an ultrasound to monitor fetal growth in order to avoid the development of anomalies and gross defects of the fetus. At this stage, the formation of the child’s organs and systems occurs, which makes it possible to study their growth and development in more detail. An ultrasound at 12 weeks of pregnancy will provide the first screening of the embryo to determine genetic abnormalities of the fetus. In this way, the pregnant woman will be aware of the current state of health of the unborn baby, which is very important in case of some serious pathologies.
The 12th obstetric week of pregnancy is the final stage of the first trimester. The period when a woman’s health improves, toxicosis and insomnia go away. This occurs due to the functionality of the placenta, which has taken over all the vital functions of the fetus.
If the pregnancy is multiple, toxicosis is possible along with emotional lability, fatigue, and anemia. A woman’s weight begins to increase at 12 weeks, as nausea and vomiting no longer bother the expectant mother. The norm for weight gain is 500 g every week.
Compared to the first trimester of pregnancy, the function of the adrenal glands decreases, the urge to go to the toilet becomes less frequent. As the uterus grows, pressure on the intestines occurs, its work slows down, which can cause constipation and discomfort inside the abdomen.
The fetus and its development at 12 weeks
During this period, the growth of the abdomen is felt, but a change of clothes is not yet required. If a woman has a second pregnancy, then the belly can increase significantly, then changing her usual clothes to spacious ones is inevitable.
As the 12th week begins, the size of the woman's uterus increases, putting pressure on the pelvis. Its width becomes 10 cm larger. The uterus, as it grows, enlarges the woman’s abdomen at 12 weeks. At this time, an important measurement of the fetal CTE reading at 12 weeks is taken.
It is necessary to measure the size of the embryo and establish the gestation period in conjunction with the weight and its norms. The baby's CTE at 12 weeks looks 5.3 cm. If the embryo develops without pathologies, at week 12 growth accelerates and reaches 1.5-2 mm per day.
Indicators of the coccygeal-parietal size change based on the duration of pregnancy. It indicates the exact duration of pregnancy, the margin of error is allowed within 3-4 days. The average CTE value, which corresponds to the 12-week fetal size, is 51 mm. If there are deviations within 42-59 mm, there is no need to worry - this is the norm.
The fetus at 12 weeks of gestation weighs around 14 grams. In order for the child to be comfortable inside the womb, the uterus tends to stretch, performing all the nutritional functions coming from mother to child.
The collar zone is an area located in the interspace of the first section of the fetal spine and the epithelium connecting the neck and spine. In this area, subcutaneous fluid accumulates, which will subsequently resolve. The thickness of the nuchal translucency is determined through ultrasound screening. If the collar area is enlarged, this is a signal of the possible development of Down syndrome.
The development of individual phases of embryonic growth is determined by patterns, where the main parameter is the length of the nasal bone. The nasal bone at 12 weeks measures about 3 mm. If the nasal bones are not identified during the scan, Edwards or Down syndrome is likely occurring. The normal nasal bone size for a baby at 12 weeks is 3.1 mm.
Deviations from the norm in the structure of the cardiac system may indicate a heart defect, and hyperechogenicity of the kidneys indicates dysplasia or polycystic disease. However, you should not panic if the results are not entirely positive, as congenital defects are unlikely in most cases. Further screening will help either confirm or refute the risk of a congenital fetal anomaly.
Determining the sex of the baby at 12 weeks by ultrasound
Is it possible to see the sexual characteristics of a child if it is the twelfth week of pregnancy? You can determine the sex of the baby at a given gestation period using an ultrasound device. An embryo at 12 weeks already has a genital tubercle, which will fully indicate the gender of the unborn child. At 12 weeks of pregnancy, the genitals are sufficiently formed and different from each other. However, few diagnosticians can say with complete confidence whether the baby will be a boy or a girl. To accurately determine the sex of the fetus at 12 weeks, the ultrasound image must be very clear, and the fetus itself must be positioned so that its genitals are visible as much as possible.
Ultrasound results of 12 weeks pregnancy
The ultrasound examination procedure at 12 weeks of pregnancy is carried out using a transvaginal sensor. The procedure is carried out in a supine position, with the legs pulled up to the stomach. An ultrasound device, covered with a condom, is inserted into the vagina; the woman does not feel any sensations in the form of pain.
A transabdominal examination consists of the following: a sensor is passed along the abdomen, selecting the best position for displaying the results of the fetal condition on the screen. The ultrasound photo will clearly display the size of the body, which has disproportionate shapes: the head of the embryo is much larger than the body.
Prenatal screening is prescribed to assess fetal development. The procedure is possible after undergoing an ultrasound. Its use is recommended for the study of women aged 35 years and older who have previously had stillbirths. Screening is done in special medical centers for women who are 12 weeks pregnant.
The ultrasound image and its results are issued by a geneticist. Particular attention is paid to the collar zone and the levels of free β-hCG and PAPP-A after blood donation. Ultrasound during pregnancy does not have any negative effects on both the mother and the child.
The price of an ultrasound scan during pregnancy ranges from 1,000 to 3,000 rubles.
What can you see on an ultrasound?
- Child sizes.
- Cerebral hemispheres and their symmetry.
- Location of the internal organs of the embryo.
- Brain structure.
- Heart pathologies.
- Symptoms of genetic disorders.
- The place where the embryo is attached to the placenta.
- Condition of the umbilical cord (normally, 2 arteries and one vein should be visible).
- Indicators of the walls of the uterus and its cervix.
- Exact gestational age.
The average fetal ultrasound findings are as follows:
- baby weight - 9-13 g;
- fruit length - 6-9 cm;
- KTR - 51-63 mm;
- biparietal head size - 21 mm;
- chest volume - 24 mm;
- thigh length - 9 mm;
- thickness of the collar space - 1.6-2.5 mm;
- nasal bone size - at least 3 mm;
- heart rate - 150-175 beats/min.
Preparing for an ultrasound
Preparation for a transvaginal ultrasound involves avoiding foods that cause fermentation in the intestines a few days before the procedure. It is recommended to consume foods that have a beneficial effect on the intestines, leading to its complete emptying. This is necessary to clearly obtain the result of the study.
During a transabdominal ultrasound of the fetus at 12 weeks, an hour before the procedure, it is necessary to drink as much fluid as possible in order to fill the bladder. The requirement is important for an adequate assessment of the condition and development of the embryo.
In addition to the size of the fetus and its anatomical features, ultrasound shows:
- Number of embryos. If more than one is indicated, the woman is expected to have twins, and in rare cases, triplets or more.
- Fetal presentation - indicates the part of the fetus located closest to the birth canal.
- A pregnant woman's diet during this period should include healthy foods with portion control. You should not overeat, eat fats, or sweets that cause constipation, which will be difficult to overcome due to decreased intestinal motility.
- Folic acid is the main beneficial mineral for women in the 12th week of pregnancy. It prevents defective development of the fetal neural tube, which is responsible for the entire process of formation of the nervous system. The recommended dose is 800 micrograms per day. For the healthy condition and development of the child inside the pregnant womb, a woman needs to eat fresh foods, paying attention to their expiration date, storage period, composition and quality.
- During this period, you need to be active, it is better to replace a sitting position with a lying one, rest more often, and walk in the air.
- It is important to follow the rules of hygiene; you should avoid using aromatic products, soaps, and gels. For intimate hygiene, laundry soap is best.
- Special exercises for pregnant women are recommended to maintain a healthy physical condition.
- Temporary abstinence from sex will be required if the previous pregnancy ended in miscarriage or there is a threat of miscarriage.
A woman must come for a consultation with her gynecologist within the time frame that he sets, take all tests, and undergo an ultrasound examination. And since at 12 weeks there is still a risk of pregnancy failure, self-medication and procedures without consulting a gynecologist at this period are strictly contraindicated!