Scheduled pregnancy ultrasounds in what weeks. Why is an ultrasound performed during pregnancy? Myths about ultrasound diagnostics

Ultrasound examination is one of the most exact ways for diagnosing pregnancy and monitoring its development. All expectant mothers are concerned about the question - when to do the first ultrasound? According to the standards of the World Health Organization, this period is defined as 10-14 weeks. But almost every pregnant woman does her first ultrasound much earlier, wanting to make sure that her pregnancy is intrauterine and is developing correctly.

Is ultrasound harmful during pregnancy?

Very often on forums you can find the opinion that ultrasound during pregnancy, and especially in the first trimester, is very harmful. Examples are even given - “in last pregnancy I did an ultrasound and the fetus froze, but this time I didn’t do an ultrasound and everything was fine.” In fact, this is a subjective opinion based on random coincidence. A lot of research is being done on this topic, but so far no one has been able to prove the specific harm that ultrasonic waves bring to the baby in the womb; How, for example, is the harm proven? x-rays. Of course, you shouldn’t fanatically do an ultrasound every day, weekly, but you shouldn’t ignore this study because of its mythical harm either.

So you have a delay. The test shows the long-awaited two lines. I really want to do an ultrasound to make sure everything is fine. But there is no need to rush; at this time, even the most modern device will not be able to “see” anything. To reassure yourself, you can first take (hCG). In the future, this analysis will help the doctor to correlate the level hCG hormone and early ultrasound data.

The first ultrasound examinations during pregnancy are done with a vaginal sensor for greater accuracy. No special training not required.

Why is it necessary to do an ultrasound early?

Purpose Ultrasound in the first weeks of pregnancy is:

• establishment embryonic period pregnancy;
• diagnostics multiple pregnancy;
• establishing the uterine localization of the fertilized egg;
• diagnosis of pregnancy complications (tone, threatening and incipient miscarriage);
• assessment of the yolk sac, chorion;
• assessment of the vital activity of the embryo;
• study of the size and structure of the fertilized egg and embryo.

What will the ultrasound diagnostician see during the examination? At what stage is the embryo visible?

1. 4 obstetric weeks, or 2 weeks from conception
2. hCG is 30-170 units.
3. Ultrasound. A lush endometrium is determined in the ovary, which produces progesterone and other substances necessary for pregnancy until the placenta forms and takes on this role. It is very difficult to see the fertilized egg in the uterus; its size is no more than 1 mm.

1. 5 obstetric weeks, or 3 weeks from conception
2. hCG is 750-3100 units.
3. Ultrasound. At this time when using good device visible on ultrasound ovum , you can determine the number of fertilized eggs, their location, and the size of the uterus. You shouldn’t worry too much if you haven’t found a fertilized egg in the uterus at 5 obstetric weeks; you need to redo the ultrasound in a few days.

1. 8 obstetric weeks, or 6 weeks from conception
2. hCG is 28,000-128,000 units.
3. Ultrasound. The CTE of the embryo at this stage is 13-19 mm, weight is about 2.5-3 grams. The baby's heart beats almost twice as fast as the mother's heart, the heart rate is 130-160 beats per minute. The embryo becomes more and more like little man, he makes chaotic movements, but because... its size is still too small, mom doesn’t feel it yet

Ultrasound in the 3rd trimester is performed to assess fetal development and readiness reproductive organs mothers for childbirth. The procedure is included in the mandatory plan and is no different from previous studies.

The 3rd trimester ultrasound is the last ultrasound examination for the entire period of gestation and is prescribed at 30-34 weeks of pregnancy.

During ultrasound diagnostics, doctors look at:

• location of the fetus in the uterine cavity;
• volumes of the baby’s head and abdomen;
• presentation;
• length of the femurs;
• the size and weight of the child;
• location and maturity of the placenta;
• development internal organs fetus

In the third trimester ultrasonography– this is an additional examination of the mother and embryo to exclude serious congenital pathologies and developmental delay. It also allows you to find out, with an accuracy of up to a week, how far along a pregnant woman is.

How to prepare for your last ultrasound

The screening procedure in the third semester does not require special preparation, however, there are several general recommendations.

To prepare for the last ultrasound you need:

• bring with you wet wipes to wipe off excess gel from the skin;
• take a diaper with you if the examination takes place in a clinic;
• if necessary, take Activated carbon to reduce intestinal bloating;
• Do not drink too much water before the procedure - this may reduce the quality of the study.

In the video you can see how a baby’s fetus looks on an ultrasound at 32 weeks, as well as the degree of formation of its organs. The author of the video is Alena Ponomareva.

Norms of baby development and interpretation of results

The norms of baby development and interpretation of the results concern:

• weight and main dimensions of the fetus;
• umbilical cord blood flow;
• placenta;
• amount of amniotic fluid;
• frequencies heart rate.

Separately assessed general state the body of the expectant mother.

Fetal fetometry by week: table

Only a doctor can correctly decipher fetometry data, but there are standard norms that are worth paying attention to.

In the table you can see the standard sizes of the baby depending on the week of pregnancy:

Umbilical cord blood flow examination

Ultrasound Dopplerography, or Dopplerography, is one of the ultrasound diagnostic methods that allows you to effectively determine the speed of blood movement through the vessels of the umbilical cord. The doctor can make an opinion about the work of cardio-vascular system based on the results of analysis of the heart, umbilical cord and uterine artery.

IN last trimester During pregnancy, this is especially necessary because it allows you to find out how blood flows through the umbilical cord to the placenta and to the fetus.

Attention to the placenta!

The need to undergo an ultrasound in the third trimester of pregnancy is also due to the fact that it shows the condition of the placenta. The maturity of this organ determines the onset of labor: if the ultrasound protocol shows that its maturation has occurred earlier, the obstetrician makes a decision on premature birth.

During last ultrasound you can check the condition of the placenta late stages its development:

1. Stage one. Usually lasts from 30 to 34 weeks. In the normal state, compactions appear in the body of the organ; the average wall thickness ranges from 23.5 to 41.6 mm.
2. Stage two. Fixed at 34–39 weeks. Some depressions are permissible in the structure, and calcium deposits become noticeable. The placenta wall is up to 44 mm.

The length from the outlet of the small pelvis to the lower edge of the organ is no more than 70 mm. The degree of maturity of the placenta should be 1.

The amount of water surrounding the child

During an ultrasound, the doctor checks:

1. The amount of amniotic fluid. If there are not enough of them, the baby will become dehydrated.
2. Water quality Normally, they should be transparent, and only towards the end of pregnancy can they become cloudy.

During an ultrasound scan of the third trimester amniotic fluid Normally they occupy a volume of about 400 ml. Closer to week 37, their content in the uterus should be from a liter to one and a half.

Baby's heart rate

During an ultrasound, diagnosticians always listen to the baby’s heartbeat: this proves that the fetus is moving and actively moving in the womb.

Wherein:

• from the 11th week of pregnancy until the birth of the baby, its heartbeat should be from 140 to 160 beats per minute;
• An alarming symptom is a decrease in heart rate to 85–100 beats/min, or an increased value of up to 200 beats/min.
• In addition to the frequency of beats, the parameters of their rhythm and the peculiarity of the location of the heart in the chest are determined.

Condition of female reproductive organs

During the third trimester of pregnancy, ultrasound assesses the condition of the mother's uterus. Its length and tone are measured, and the general condition of the organ is determined.

An important indicator is the length of the cervix. Normally this figure is 30 mm. Outdoor and internal os organs must be closed.

Photo gallery

The photo shows screening images made using ultrasound examination.

Typically, three ultrasound examinations are performed during pregnancy. They are planned, that is, the sonologist cannot help but carry them out in order to judge proper development fetus Let's look at why and when routine ultrasounds are done and what they show.

The timing of ultrasound examinations during pregnancy is strictly regulated. And this schedule is approved by the Ministry of Health. Each medical institution may make certain adjustments to it, but in general all clinics adhere to a strict schedule of medical research.

First screening, 14 weeks

So, the first ultrasound examination during pregnancy is carried out at a period of 10 to 14 weeks.. On it, the doctor receives valuable information about the condition of the unborn child and the functioning of the mother’s organs that can support his life. If at this period the mother’s inability to bear a fetus is determined, then the question of medicinal interruption pregnancy.

in most cases it is done between 18 and 22 weeks. During this period, it is clearly visible whether the fetus has developmental anomalies, and whether there are pathological condition female genital organs. At this time, such pathologies can still be corrected. However, if the examination shows gross disturbances in the vital functions of the fetus, then the issue of terminating the pregnancy is also decided, this time by abortion.

The third examination is usually done at 30–34 weeks. The purpose of it is to find out the following important information:

• determining the method of delivery (during this period, for example, indications for caesarean section, which were not yet present, say, during the second examination);
• finally establish the time of birth;
• degree of development of the baby;
• determine whether the baby will need emergency help in the first minutes after birth.

You can’t ignore routine ultrasounds during pregnancy, as it sometimes the only way find out the level of development of the baby.

Ultrasound screening of the third trimester of pregnancy

When can you do the examination?

Usually the fetus can be seen in the uterine cavity from the fifth day of delay next cycle. That is, it is visible in the third week of the gestation period. For so much early stages Pregnancy, you should visit the ultrasound diagnostic room in the following cases:

• when discharge appears, regardless of its color and quantity;
• when a woman is bothered by pain in the abdomen (in its lower part);
• when severe weakness and dizziness appear.

Such signs most likely indicate that the fertilized egg is not implanted in the uterus, that is, an ectopic pregnancy is developing.

However, recently, more and more foreign clinics do not advise women to undergo their first ultrasound examination before the 10th week of pregnancy.

About the first ultrasound examination

As already noted, the most late date such examination – no more than 14 weeks. But at the same time, doing it earlier than the 10th week is also not recommended. Only if there are certain medical indications, then it can be carried out much earlier.

Not only if you suspect pathological pregnancy before the 10th week. There are approved indications for which it is necessary to do it earlier:

• if there is pain in the stomach (and not only below);
• if there is a history spontaneous abortion or ectopic pregnancy;
• in cases where pregnancy occurred through in vitro fertilization;
• if the woman has ever had fetal malformations;
• when pregnancy occurs during stimulation of ovulation.

The positive side of such an early ultrasound examination of the fetus is that it makes it possible to detect pathologies that will be incompatible with life in the future. In these cases it is done artificial interruption pregnancy.

Very rarely, invasive methods of diagnosing the fetus are required. To do this, amniotic fluid is usually examined. Much less often, a biopsy of future placental tissue is done.

When terminating a pregnancy due to the non-viability of the fetus, much less harm is done to the body of the mother than if an abortion is performed at a later date.

What will the second ultrasound show?

Usually the duration of such a study is 22, less often 24 weeks. Between the first and second ultrasound may be prescribed additional examination if a woman experiences changes in hormonal levels.

The objectives of such a survey at this time are as follows:

• accurately determine the size of the child;
• determine its gender;
• determine whether he has dangerous pathologies liver, kidneys, heart;
• This ultrasound makes it possible to determine possible violations in the condition of the placenta and based on its results, conduct a more detailed diagnosis;
• allows you to determine the presence of calcium deposits in the placenta;
• find out the volume of amniotic fluid in the uterus (both an increase and a decrease in the amount are equally dangerous).

At the same time, a Doppler examination may be performed. It makes it possible to see the condition of the vessels of the uterus and placenta.

Third ultrasound

If there are no deviations in the ultrasound readings (in the second examination), then at approximately 32–34 weeks the next, third examination is performed. During this interval, a repeat Doppler examination may be performed. This is necessary to more accurately trace the dynamics of the development of the baby’s circulatory system and the mother’s placenta. In the same interval, it is very important to do a blood test for clotting (again, to detect possible problems, which can complicate the course of labor).

A repeat ultrasound is done only when a lag in fetal growth is detected, as well as if there are any problems in the bloodstream. In this study, ultrasound shows:

• congenital malformations (their detection is no less important than in the second trimester);
• hydronephrosis of the kidney (that is, when fluid accumulates in the renal pelvis);
• position of the fetus (normal is cephalic presentation, and if the child is in an uncomfortable position, the issue of premature delivery can be decided to save his life);
• severe fetal malformations (artificial termination of pregnancy and childbirth);
• the size of the child (the doctor assesses how they compare with the age norm);
• location of the placenta;
• the position of the baby's head (sometimes it can turn as much as 180 degrees).

Diagnostic methods

There are two ways to conduct ultrasound diagnostics: transabdominal and by inserting a sensor into the vagina.

Performing transvaginal ultrasound during pregnancy

In the case of a vaginal examination, a condom is placed over the ultrasound probe. This is done mainly for hygienic reasons. Next, it is inserted into the woman’s vagina. Because the sensor is closer to the uterus, the doctor can better see the fetus, the uterus, its tissues and the placenta. This method of examination is most often used in the early stages. It is advisable that bladder was empty.

In the case of a transabdominal examination, no a large number of transparent gel. This is done to ensure that there are no air bubbles between the skin and the sensor, which impair visualization. The doctor moves an ultrasound probe over the abdomen to examine the fetus and uterine tissue.

There is no need to make any additional preparations before such studies.. The only requirement is to maintain hygiene of the skin and external genitalia. No need to diet and drinking regime before these types of examinations.

Why do a 3D study?

Currently, three-dimensional ultrasound is becoming increasingly widespread. Many parents believe that it is more accurate and correct. In fact, it's just an extra diagnostic examination. Sometimes a specialist who has a regular two-dimensional ultrasound machine, can examine the fetus and placenta and draw the necessary conclusions.

Such research attracts future parents primarily because it allows you to see the image in three projections. It will look on the screen as three-dimensional and very High Quality. It also allows you to record the child’s movements on electronic media. And they can be recorded on a disk or other electronic media.

Is such research harmful?

It is known that scheduled ultrasound It’s practically unavoidable, since all women go through it. Provided that the pregnant woman follows all the doctor’s instructions and advice and is registered on time, the number of such examinations is at least three. It happens that more such ultrasounds need to be done.

All studies performed using ultrasound are absolutely harmless. There is no evidence today that ultrasound is harmful and that it leads to any consequences for the female body.

Moreover, the woman does not feel any discomfort during the procedure. Ultrasound is completely harmless to the baby, as is touching the skin of the sensor (or placing it in the vagina). The intensity of such radiation is so low that it does not cause any chromosomal changes and does not affect living cells of the fetus.

However, pregnant women are not recommended to abuse such examinations on their own initiative. This means that you cannot do them whenever you want. For such a harmless examination as ultrasound, there are still deadlines and indications.

Should such research be neglected?

Of course, on different dates pregnancy, ultrasound examination helps to detect fetal pathologies, and at the most early stages. In many cases, it helps to avoid many adverse consequences for the woman. And you shouldn’t give it up. Moreover, it is harmless to the mother and her unborn child.

Every woman should undergo at least three ultrasound examinations. The doctor also decides when unscheduled diagnostics are needed. If he insists on conducting an unscheduled examination, there is no need to ignore it, since the child’s health may depend on it.

It is an ultrasound examination that helps the child to be born healthy and the mother to be happy.

Ultrasound diagnostics is a planned standard examination procedure during pregnancy. Ultrasound is considered one of the most reliable and safe procedures. It allows you to diagnose fetal defects during the period of intrauterine development, determine the condition of the child and the “uterus - placenta - fetus” system. Thanks to ultrasound diagnostics, the obstetrician-gynecologist leading the pregnancy has the opportunity to intervene in the processes occurring in the mother’s body, and thus preserve the life and health of her and the child.

However, the question of the safety of this type of research continues to haunt the minds of future parents. How safe is the procedure for the baby? How often should it be done? How many ultrasound procedures can be performed without health consequences? There is a lot of reliable information about ultrasound examination, but there is also a lot of speculation. It's time to figure out what is what.

What is the ultrasound research method based on?

The method is based on the analysis of the difference between the signals of the probing and reflected ultrasonic waves. Using a special ultrasound sensor (transducer), an ultrasonic wave of 3.5 MHz is sent to the organ under study. Reflecting from various media and changing its frequency, the ultrasound wave returns and is absorbed by the receiver of the ultrasound sensor. Next, the information goes to the computer, which is integral part ultrasound diagnostic device, which processes the received data. The ultrasound operator can see structures of different echogenicity on the monitor (amniotic fluid, fetal bones and tissues, etc.) and interpret the result. The reliability of the information depends on the accuracy of the ultrasound machine and the experience of its operator.

Frequency of ultrasound procedures during pregnancy

How many times can an ultrasound diagnostic procedure be prescribed during the period of pregnancy? According to the order of the Ministry of Health of the Russian Federation No. 457 dated December 28, 2000, the algorithm for examining a pregnant woman includes 3 scheduled screening ultrasounds:

• the first screening in the period from 12 to 14 weeks is carried out to clarify the duration of pregnancy, its fertility and to check whether the size of the child and the thickness of the nuchal region correspond to the standards;
• a second screening in the period from 20 to 24 weeks is carried out to diagnose possible pathological processes in the “uterus - fetus - placenta” system, the place of attachment of the placenta, the condition of the child in the womb and his gender are determined;
• the third screening in the period from 32 to 34 weeks is carried out to clarify the presentation of the fetus, confirm the placenta insertion, as well as to confirm or remove suspicions of pathology and abnormalities of the child’s development. A comparative analysis of the child’s size and normative data is carried out, and the quantitative characteristics of the amniotic fluid are assessed.

Reasons for prescribing additional ultrasound procedures

In addition to screenings, additional diagnostic ultrasound examinations may be prescribed, a referral for confirmation/clarification of previously identified pathology or by other methods, to monitor the condition of the mother and her baby and control the treatment process, if any, up to an ultrasound examination in the early stages. The reasons for ultrasound are quite compelling:

• burdened heredity;
• chronic diseases of the mother that can affect the development of the baby (diabetes, phenylketonuria, hypertension, etc.);
• when exposed to expectant mother pathological and harmful factors external environment (radiation, toxic substances, infections and intoxications);
• as a monitoring procedure for previously identified abnormalities during pregnancy.

Most expectant mothers wonder how long the ultrasound procedure takes, and how long will the fetus be exposed to ultrasound? The time required to complete the procedure depends on the type of study:

• standard ultrasound – 10 minutes;
• The duration of 3- and 4-dimensional ultrasound is from 30 to 50 minutes.

Ultrasound in the first weeks of pregnancy: benefits and harms

Reasons to prescribe an ultrasound early are:

• presence of bloody discharge;
• pain in the lower abdomen is sharp or nagging.

There is no reliable data about harmful influence Ultrasound in early pregnancy for the formation or development of the embryo, or any long-term consequences. However, it is worth remembering that ultrasound is a medical diagnostic procedure. And it is carried out strictly according to indications. During ultrasound, the fetus (its body and brain) is exposed to ultrasound radiation, once again this is not worth doing.

How harmful is it to frequently conduct ultrasound diagnostics?

The harm of ultrasound during pregnancy has not been proven. No effects on child development were found. Of course, no doctor or scientist will give a 100% guarantee. Because it is difficult to carry out a pure experiment, i.e. exclude the influence of other factors (examinations, treatment of the underlying disease, influence bad habits). It is also necessary to trace the effects of the ultrasound factor on several generations.

That is why they talk about relative safety or safety in comparison with other methods. Any medical procedure, any intervention should be carried out only if there is no other choice, especially in the early stages of pregnancy. Of course, the embryo is exposed to radiation directed at it, and although the effect of such exposure has not been identified, it is better not to experiment. In relation to any medical procedure need to come from next rule: when received from the procedure (with in this case Ultrasound) benefit, superior theoretically possible harm, then it needs to be carried out.

If you want to conduct an additional ultrasound, you should remember that no one, including ultrasound, provides one hundred percent reliable information about the child’s condition. The reliability of the information is quite high, but it is still a probabilistic indicator. Carrying out volumetric (3- and 4-dimensional) studies especially needs to be carried out strictly according to indications, because The time of exposure of the fetus to ultrasound waves during these procedures is significantly longer than with standard ultrasound. The desire to capture your not yet born child or specifying the sex of the baby is not a justification for additional procedure Ultrasound.

Myths about ultrasound diagnostics

Ultrasound examination is a breakthrough in non-invasive, painless diagnostic technology. How many ultrasounds are needed during pregnancy?

It is considered normal in Russia to carry out 3 screenings, but in some cases additional procedures may be prescribed.

You should not refuse a fairly accurate and informative study, listening to the following unproven considerations:

1. Ultrasound diagnostics negatively affects the genome. Ultrasound allegedly deforms the DNA structure, causing mutations and developmental abnormalities in future generations. There is no data to support this theory. Experiments on mice have led to the denial of this hypothesis.
2. It is believed that the baby experiences pain when exposed to ultrasound, because some children actively respond to exploration by waving their limbs. It is not known what the fetus reacts to: ultrasound, transducer pressure, maternal excitement or her discomfort caused by complete bladder. If you pat your belly, your baby will most likely respond and push you back. This does not mean that your actions caused him suffering.

The examination must be ordered by a specialist, and the diagnosis must be carried out by a master of his craft using high-quality equipment. This minimizes possible risks and maximizes undoubted benefit from ultrasound. Answer to the question: “How often can an ultrasound be done during pregnancy?” - comes down to a simple recommendation: no more often than prescribed by the obstetrician-gynecologist leading the pregnancy.