The first ultrasound examination during pregnancy is always an exciting and important event in the life of an expectant mother. This is the first "meeting" of a woman with her child, who is still very small.
This examination is awaited with a special feeling - impatience mixed with anxiety. How and when the first ultrasound scan is performed for women in an "interesting position", as well as what parameters are considered the norm, we will tell in this article.
Dates
The first scheduled ultrasound scan, which is recommended for all expectant mothers, is performed for a period from 10 to 13 weeks inclusive. This is an important and informative first prenatal screening for doctors and women. However, for many women, this mandatory examination will no longer be the first, since before 10 weeks, they may have already undergone such a diagnosis.
Theoretically, the first ultrasound can be informative during pregnancy. already in 2.5-3 weeks after the expected day of ovulation. This corresponds to approximately the fifth obstetric week.
At this time, for the first time, there is a technical opportunity to see the fetal egg on the monitor of the ultrasound scanner, which will indicate the onset of pregnancy. But before 10-11 weeks, ultrasound diagnostics is not officially recommended without good evidence.
Why is a routine ultrasound performed?
The purpose of a planned study within a specified time frame is to identify the so-called markers of possible fetal pathologies. Until 10-13 weeks according to obstetric calculation (this is approximately 12-15 weeks from conception), these markers cannot be evaluated.
The timing of the first prenatal screening was not chosen by chance, because in case anomalies are found, a woman will be able to have an abortion for medical reasons, without waiting for the deadlines to get big.
There are always more complications after long term abortion.
It is no coincidence that the first ultrasound scan takes place on the same day with the delivery of a venous blood sample for biochemical examination. Ultrasound results are not evaluated separately from blood counts. If markers are found both hormonal and protein balance in the blood are disturbed in a certain way, the risk of having a child with chromosomal abnormalities is higher.
A planned examination within the time frame established by the Ministry of Health is aimed at finding women who are at risk for the likelihood of giving birth to babies with severe total lesions caused by genetic "failure".
A person has 23 pairs of chromosomes. They are all the same, except for the last pair, in which the boys have XY and the girls have XX. An extra chromosome or a lack of one in one of the 23 pairs causes irreversible pathologies.
So, if the number of chromosomes in 21 pairs is violated, the child is diagnosed with Down syndrome, and if there is an incorrect number of chromosomes in 13 pairs, Patau syndrome develops.
It cannot be said that the first screening in general and ultrasound examination in its framework in particular are capable of revealing all possible variants of genetic disorders, but the most rude ones, for the most part, can be detected precisely at the first planned examination with subsequent additional diagnostics. Such pathologies include: Down, Edwards, Patau, Turner, Cornelia de Lange, Smith-Lemli-Opitz syndromes, as well as signs of non-molar triplodia.
Gross defects of the neural tube, such as a decrease or complete absence of the brain, anomalies in the development of the spinal cord, can be detected only at the second antenatal screening, which takes place according to the plan only in the second trimester of pregnancy.
Going to the first scheduled ultrasound scan, a woman should understand that no one will diagnose her baby only on the basis of the ultrasound scanner seen on the monitor.
If the diagnostician has suspicions of pathology and developmental anomalies, he will definitely indicate this in the conclusion, and the woman will be sent for a consultation with a geneticist, who will decide on the need for more accurate diagnostic methods than ultrasound - invasive, during which doctors take particles of fetal tissue , blood from the umbilical cord, amniotic fluid for genetic analysis. The accuracy of invasive methods is almost 99%.
An excellent analogue is the non-invasive analysis of fetal DNA, which is absolutely safe for both the mother and the baby, since the pregnant woman only needs to donate venous blood to carry it out.
Among other tasks of the first screening ultrasound is to clarify the gestational age according to the size of the baby, to determine the state of female reproductive health, and to assess the possible risks in the forthcoming birth in six months.
Unscheduled research - what is it for?
Today, ultrasound examination is more than affordable, and therefore a woman can go on it without the knowledge of the doctor and his direction. Many do this, and after a home test shows two strips, they go to the nearest clinic to confirm the fact of pregnancy using such a scan.
However, in addition to the woman's desire to know for sure whether conception has taken place, there may be medical indications for the first ultrasound scan ahead of schedule. It happens that before screening a woman has time to do several such examinations.
Medical indications for which the study can be recommended previously established according to the recommendations of the Ministry of Health, the timing is diverse:
- Miscarriage of pregnancy. If a woman previously had two or more miscarriages at the very early stages of gestation, it is recommended to undergo the first ultrasound scan when registering with a antenatal clinic to make sure that this time the fetus is developing.
- History of pregnancy stillness... If, before the current pregnancy, a woman had cases of non-developing pregnancy, anembryonia (absence of an embryo in the ovum), then an early ultrasound scan is strongly recommended to find out if there is a relapse.
- History of ectopic pregnancy or suspected ectopic pregnancy. In this case, the task of early examination is to identify possible ectopic anchorage of the ovum as early as possible, until it poses a serious threat to the woman's life. Suspicion arises if the level of hCG in the woman's blood is significantly lower than the prescribed level, if there are pains, discharge that does not resemble menstrual discharge, delayed menstruation, while the uterus is not enlarged.
- History of trauma and surgery on the uterus. If, before the onset of pregnancy, a woman underwent surgical interventions affecting the main female reproductive organ, then the task of the first ultrasound at the earliest possible date will be to assess the place of attachment of the ovum. The further from the postoperative scars the baby is fixed, the more favorable the prognosis for normal bearing and childbirth.
- Suspected multiple pregnancy. In this case, an ultrasound study before the screening time is necessary to confirm the very fact of bearing two or more babies. The doctor can guess about this by exceeding the level of hCG in the blood of a pregnant woman by two or more times.
- Chronic diseases tumors, fibroids. Existing pathologies of the reproductive system can affect not only the ability to conceive a child, but also the ability to carry him out. Therefore, women with such ailments are shown an early examination for ultrasound in order to assess the place of implantation and the growth rate of the ovum.
- Interruption threat. In the very early stages, there may also be a threat of miscarriage. Usually it is manifested by smearing discharge from the genitals, pulling (as with menstruation or slightly stronger) pain in the lower abdomen and in the lumbar region, deterioration of the general condition of the woman. With such symptoms, an ultrasound scan is recommended with the mark "cito", which means "urgently, urgently."
- Questionable test results. For a variety of reasons, there may be "disagreements" between the test strips, a blood test to determine the hCG hormone characteristic of pregnancy and the results of a "manual" gynecological examination. If the disagreements are such that the obstetrician-gynecologist cannot say with certainty whether a woman is pregnant at all, he will definitely refer her for an ultrasound scan.
First diagnosis after IVF
If for some reason a couple cannot conceive a baby on their own, doctors can do it for them. The entire process of in vitro fertilization, from preparation for it, and ending with embryo replanting - "three days" or "five days", is controlled by means of ultrasound diagnostics.
After embryo transfer, the woman is assigned hormone therapyso that babies have more chances to gain a foothold and start growing in the uterus.
The first ultrasound scan after IVF is recommended 12-14 days after the infusion, if menstruation has not begun, and the results of a blood test for chorionic gonadotropin indicate pregnancy.
At this stage, the task of diagnosis is to make sure that the pregnancy has taken place, and the efforts of the doctors and spouses are crowned with success.
If ultrasound diagnostics shows the presence of a fetal egg (or several fetal eggs) in the uterus, then the next ultrasound examination is scheduled after another two weeks to make sure that the embryos are growing and developing. Then the woman is assigned, like all other pregnant women, a scheduled screening examination at 10-13 weeks of gestation.
What can be seen on the first ultrasound?
The expectant mother, no matter how long she goes to the ultrasound office, is interested in what can be seen at one time or another. Modern types of ultrasound diagnostics significantly expand the prospects, especially for such innovative types as 3D and 4D ultrasound, as well as 5D ultrasound, which make it possible to obtain not two-dimensional, but three-dimensional and even color images in real time.
However, one should not think that the very next day after the start of the delay on any, even the most modern apparatus, you can see at least something. The earliest period at which it is possible (again, only theoretically) to consider a fertilized egg is considered 5 obstetric week (this is three weeks after ovulation or a week after the start of the delay).
There is no need to do an expensive "volumetric" three-dimensional ultrasound at such a short time, because so far you can see only a point, which is a fertilized egg. Going to the first ultrasound, a woman should know what exactly she can be shown.
At 5-9 weeks
An early ultrasound, according to or without indications, at the will of the future mother, will not be able to please a woman with impressive pictures and memorable pictures. At the earliest stages, only a rounded formation in the uterine cavity with a barely distinguishable inner nucleus - the embryo - is determined. In reality, there will not be such a beautiful detailed picture of a small embryo, as they are depicted using computer graphics.
Most women cannot really even consider the ovum itself, especially if the diagnosis is not accompanied by detailed comments from the doctor. But there is also one nice nuance - at five obstetric weeks, a tiny baby begins to pound a small heart, or rather, there is a characteristic pulsation where the chest will soon form.
If the apparatus on which the examination is carried out has a sufficiently good resolution and a modern sensor, then the mother will be able to see how this happens. The main characteristic of the development of the baby at the initial stage is the size of the ovum. This is what the doctor will measure if a woman comes for a scan at 5-9 weeks of pregnancy.
If the first ultrasound occurs at 7 weeks according to the obstetric calculation of the gestational age (approximately 5 weeks from the day of ovulation), then the woman will most likely be able to show her baby. The embryo at this time has a disproportionately large head and tail.
At 9 weeks old, the baby will already acquire human forms that are more understandable to the mother, although both the tail and the large head will still be observed. The heart of a child at 8-9 weeks can already be heard if the ultrasound machine is equipped with acoustic speakers.
At 10-13 weeks
By the time of the first screening, the baby is changing dramatically. At the first scheduled ultrasound scan, a woman will most likely show such a baby.
He already has clearly distinguishable pens, if you're lucky, you can even see the fingers on them. We can also distinguish the facial profile, tummy, chest. The heart of the crumbs beats rhythmically and loudly, they will let you listen to it.
In the baby at this time, the distance from the tailbone to the crown is measured (coccygeal-parietal size or CTE), the distance between the temporal bones is the biparietal head size (BPD), sometimes they continue to measure the size of the ovum, but this size is no longer of great diagnostic value.
The main goal is to detect, if any, the markers for the chromosomal abnormalities discussed above. These include two sizes - the length of the nasal bones and the distance from the inner surface of the baby's skin to the outer surface of the soft tissues of the neck.
Some pathologies tend to accumulate excess fluid in this area, due to which the TVP (collar space thickness) increases. Many chromosomal "malfunctions" are accompanied by various deformations of the facial bones, which is why the nasal bones are also trying to see, and, if possible, measure.
The external genitals are almost formed, and they can also theoretically be considered at 12-13 weeks, but doctors at this time cannot talk about the sex of the baby with certainty, because the differences so far look minimal. The diagnostician will be able to more accurately answer the mother's question about the gender of the child after the 18th week of pregnancy, when she comes for the second scheduled ultrasound.
Decoding and norms
A doctor should be involved in the interpretation of the ultrasound results. Everyone knows about this, but the understandable curiosity and anxiety inherent in expectant mothers force women to thoroughly approach the study of complex terminology in order to figure it out on their own. This is not unusual our task is to help pregnant women understand what is written in the conclusion.
SVD
This three-digit abbreviation hides the main indicator of a baby's development for up to 9-10 weeks. Since the embryo itself is still very small, and it is very difficult to measure the embryonic parts, the state, development and gestational age at the initial stage are determined by the size of the ovum.
The shape and size of the ovum can even tell about the baby's trouble, for example, deformation and some "compression" of the outlines of the fetal membrane may indicate that a woman has begun a miscarriage, and its simultaneous decrease in size indicates an undeveloped pregnancy and the death of the embryo.
Determining the gestational age by SVD in the early stages is considered quite reliable.
After all, so far, babies are not divided into large and small, thick and thin - all embryos in the first trimester grow at about the same rate, but they begin to show hereditary features of appearance somewhat later.
The average inner diameter of the ovum increases simultaneously with term, and the fetal membrane grows not even by week, but by day, therefore, it will not be difficult to establish the day of conception, provided that the pregnancy is developing normally.
SVD norms table (average)
CTE
The coccygeal-parietal size allows you to judge the growth rate of the child from about 7-8 weeks of pregnancy. This dimension is laid by the diagnostician from the highest point of the head (crown) to the lowest point - coccyx at maximum extension of the embryo.
Height is measured from head to foot. On an ultrasound scan, this size is considered an important indicator, especially if an early study is done prior to a planned one. According to the CTE, they not only determine how the baby is growing, whether he feels well, but also the gestational age in order to clarify the expected date of birth.
At a later date, when the woman enters the second trimester, the CTE is no longer determined, since the baby becomes large enough to measure it from the head to the coccyx as a whole.
KTR is a size that causes serious worries for expectant mothers. His hesitation causes a storm of emotions.
In fact, you should not look in tables for matches up to a millimeter. Not always minor deviations up or down may indicate anomalies, and not always deviations for 1-2 weeks have pathological reasons.
A decrease in CTE may be caused by the fact that the woman had late ovulation or the baby was "delayed" on the way to the uterine cavity after conception, that is, implantation occurred later than the woman thinks.
Among the possible adverse consequences of a decrease in CTE are infections, including intrauterine ones, as well as gross genetic pathologies that prevent the baby from developing at the physical level at a pace set by nature.
An increase in CTE can also indicate inaccuracies in determining the gestational age, that is, early ovulation, as well as a tendency to a large fetus.
CTE norm table (average)
TVP
This is the first indicator of possible chromosomal abnormalities. The thickness of the collar space is measured by the segment that is laid from the inner surface of the skin to the border of the dark anechoic area on the back of the baby's neck.
Some gross developmental anomalies associated with errors in the genetic code cause general edema in the child, but it can be determined during this period only by one study area - the collar space. After 13 weeks of pregnancy, this indicator is not measured, it is no longer considered diagnostically important.
About this size, expectant mothers undergoing the first prenatal screening worry the most.
You should not panic, because this size, like all the others determined on ultrasound scanning, does not speak with an accuracy of 100% about the presence of pathology. A slight deviation from the norms does not always indicate the presence of a disease.
Statistics show that disappointing diagnoses in children with increased TVP are confirmed only in 10% of cases. Among sick babies, TVP above 3.0 mm was found only in a few, usually an excess of 3-8 mm from the norm corresponds to true malformations.
TVP table (average)
Length of the bones of the nose
As in the case of the thickness of the collar space, the bones of the nose can also indicate the likelihood of pathology of chromosomal origin. In children with Down syndrome, for example, the nasal bones may not be detected at all, and in babies with Patau's syndrome, the nasal bone may be greatly shortened. But again, as with TVP, it all depends not only on the state of health of the baby.
Very often, doctors do not see the nasal bone due to the fact that the ultrasound machine in the consultation is outdated ten years ago. Sometimes the reason for the detection of an alarming marker is the lack of experience of the diagnostician. If the result of the examination of this marker is disappointing, then the woman is assigned a control ultrasound scan on an expert class apparatus and a consultation with a medical geneticist.
Table of norms for the length of the nasal bone (average)
Technique
Many women are interested in how the first ultrasound examination is performed. Most often, doctors use a vaginal probe for examination, which is inserted into the vagina in a condom. It is possible to examine the uterine cavity with this method through the vaginal wall. It is quite thin and the visualization is good. therefore intravaginal ultrasound is considered one of the most accurate.
It is theoretically possible during pregnancy in the first trimester to examine a woman transabdominally - with an external sensor, which is applied to the anterior abdominal wall, however, at a short time, a subcutaneous fat layer, which even fairly tiny girls have on the belly, can interfere with a tiny embryo.
The examination is carried out on a couch, on which the woman is asked to sit in a supine position with legs bent at the knees. Also, the doctor can examine the vaginal probe on the gynecological chair.
If a woman comes to an appointment at the ultrasound office before the scheduled screening, which happens when an examination is prescribed for possible complications of pregnancy, the doctor will scan exclusively with a vaginal sensor, since it allows a detailed study of the condition of the cervix and cervical canal, which is very important in suspicion of a threat of miscarriage, an ectopic pregnancy, an undeveloped pregnancy.
How to prepare for the examination?
Early ultrasound results can be affected by an insufficient amount of fluid through which the ultrasound waves pass better. That is why, before going to the doctor, the expectant mother it is recommended to drink about half a liter of water, thereby filling your bladder.
In the later stages of pregnancy, there will be enough amniotic fluid in the uterine cavity, which will serve as an ideal environment for conducting ultrasound waves.
While the embryo is very tiny, any factor can distort the real picture of what is happening. So, the intestines overflowing with feces, the intestines, the loops of which are swollen from gas, can squeeze the pelvic organs of a woman.
In order to better prepare for the first ultrasound scan, the expectant mother is advised not to eat foods that can cause fermentation and the formation of intestinal gases two to three days before visiting the diagnostic room.
It is better to exclude peas, white cabbage, baked goods, rye bread, sweets, carbonated drinks from the diet. On the day of the examination, the intestines should be emptied, and 2-3 hours before the ultrasound, take a drug that "collapses" the intestinal gas bubbles, preventing swelling. Such funds allowed for pregnant women include Espumisan or "Simethicone".
With you for the first ultrasound, you need to take an exchange card, if it has already been wound up, a passport, a policy of compulsory medical insurance, a clean diaper that can be placed on a couch or a gynecological chair, as well as replacement shoes. There is no need to starve, go for an ultrasound scan on an empty stomach.
Error probability
Errors of doctors of ultrasound diagnostics are a subject of wide discussion among expectant mothers. Indeed, ultrasound scanning is not considered a highly accurate method. Its accuracy is estimated at only 75-90%. Much in the veracity of the results depends on the quality of the apparatus, the qualifications of the doctor and the timeliness of the examination.
If a woman asks the doctor for an answer to the question of what gender is her child at 11-12 weeks of pregnancy, then the accuracy of such a "prediction" will not be higher than 70%, however after 18 weeks, the accuracy in determining gender will approach 90%.
The same pattern is observed with the confirmation of the pregnancy itself. If a woman came to do an ultrasound scan too early, then the doctor may not see anything and write in the conclusion that no signs of pregnancy were found.
If you resolve issues as they become available, within the recommended time frame, ultrasound can be considered a fairly accurate and informative way. And in cases where the results of an ultrasound scan cannot be unambiguously interpreted, if there are alarming markers or doubts at the doctor, he will certainly advise more accurate diagnostic methods - amniocentesis, chorionic biopsy, and a little later - cordocentesis.
If you wish, you can do non-invasive analysis of fetal DNA, which is an excellent alternative to invasive tests, and is absolutely safe for the baby.
In addition, in most cases, ultrasound again helps to dispel doubts, but of a different class - expert. Such devices are at the disposal of perinatal centers, medical genetic centers and clinics.
Does ultrasound harm a child?
There is no consensus on this score. Modern medicine has no evidence of the harm of this diagnostic procedure for the developing fetus in the womb. However, there is no evidence of the complete harmlessness of ultrasound. The point is that science cannot study the long-term consequences. No one knows how the effect of ultrasound in the embryonic period affects a person when he turns 30, 40, 50 years old.
It is the lack of information that is fertile food for pseudo-scientific reasoning about the influence of ultrasound waves on human DNA. Existing experience shows that children who were born to women who did not undergo ultrasound during pregnancy at all, and children who were born to women who underwent such diagnostics more than 6 times during the gestation period, did not differ in any way in health from each other.
To do an ultrasound or not is a woman's choice. The Ministry of Health only recommends three routine examinations for the entire pregnancy period, but they are not mandatory either. If a woman does not want, then no one will force her.
But before giving up screening or unscheduled ultrasound scanning, a woman should weigh all the risks well, because many pathologies during gestation and childbirth can be avoided if doctors are able to consider alarming symptoms in time.
