Ultrasound of the cervix during pregnancy: a necessary examination. Determination of the reproductive tract at the beginning of gestation

The most important view diagnosis when carrying a child is an ultrasound examination (ultrasound). Pregnant women are required to undergo three examinations with this device for the entire period of gestation. An examination is prescribed by a gynecologist and is carried out once in each trimester (often prescribed during the second trimester). Including we are talking about ultrasound of the cervix during pregnancy.

After the study, a specialist gynecologist, based on the data obtained, determines the characteristics of the development of the fetus, the state of the placenta and amniotic fluid. Ultrasound will reveal abnormalities in the genital organs of the patient, if any.

When ultrasound examination of the cervix also pay attention to the following indicators:

For determining normal state measure its length. It should correspond to the period of development of the fetus. At normal process development, the cervix is not shortened, the external and internal os are closed. The visualization of the smoothness of the organ is determined in the third trimester.
Determine the state of the myometrium.
Identification of pathologies in the reproductive organs of a woman. Thanks to this procedure, the early stages of inflammatory processes are detected, oncological diseases, predisposition to possible development severe forms of illness.

In the management of pregnancy, ultrasound of the cervix plays a key role. The detection of a condition such as isthmic-cervical insufficiency makes it possible to prevent many dangerous situations both for the unborn baby and for the expectant mother. The nature of the state of such insufficiency is determined by a decrease in the length of the organ and the opening of the cervical canal. Accordingly, there is a threat to the life of the fetus and a deterioration in the condition of the woman in labor.

Signs of isthmic-cervical insufficiency, which can be detected before 37 weeks, and in connection with which an appropriate diagnosis is made:

opening of the cervical passage;
reduction in the length of the neck of the uterine node to a size of less than 25 mm;
expansion of the pharynx (internal).

The process of measuring the length of the cervix during ultrasound examination called cervicometry.

Preparation and how to do it?

A woman does not need special preparation for an ultrasound of the uterus and its appendages during pregnancy.

Reference! In the first trimester, the procedure is usually performed first transvaginally, and then, if necessary, transabdominally.

The presence of amniotic fluid serves as an echogenic cavity, so the bladder can't fill up.

A completely different approach to ultrasound for non-pregnant women. Considering a number of factors, choose a method:

Transabdominal. The picture on the monitor shows neighboring areas, including the organ under study. receive big picture pelvis, which makes it possible to make a more accurate diagnosis.
Transvaginal. A probe is used that is inserted very slowly into the vagina. The examination takes no more than 10 minutes. If the hymen is not broken, this method should be abandoned.
Transrectal. The method of conducting an ultrasound examination and inserting a sensor through the rectum.
Transperineal. This method is used through the perineum for women with rare disease- atresia.

Photo 1. Ultrasound of the cervix.

Decoding and norm

Conducting an ultrasound early dates pregnancy most often indicates the following indicators:

The uterine canal is closed.
The inner and outer pharynx of the neck are closed. The length of the neck is 3-5 centimeters, which is the norm.

Reference! In women who have given birth, the cervix is generally shorter than in women who have not given birth.

At the earliest stages of gestation, these indicators are not much paid attention.

At the end of the second trimester, most pregnant women are scheduled for a re-examination of the uterus. This period characterizes the following changes:

Zev (internal) has a closed position.
Zev (external) is in an ajar position if the woman has already given birth to a child. When carrying the first child in the family, the external os is closed tightly.
The length of the cervical canal is normally about 3 cm.

Reference! The third trimester makes it possible to determine the date of birth of the baby.

When conducting an ultrasound examination for the third time, the following parameters are evaluated:

Zero degree. Childbirth will begin soon. The organs have a dense structure, the length of the cervix does not exceed 2 centimeters, the pharynx (external) has a closed appearance or has the ability to pass one finger. The cervix has a tilt back, which makes it possible to hold the fetal head firmly.
First degree. Childbirth will begin soon. Ultrasound determines a compacted structure, the size of the neck is from one to two centimeters with the axis directed forward. The inner pharynx is tightly closed, the outer one has the ability to skip one finger.
Second degree. The birth will start soon. The length of the canal is up to one centimeter, the cervix has signs of softness, smoothed, its inclination along the axis of the pelvis.

Difficulties during the study

Problems that arise during the examination of ultrasound may be associated with the structural features of the patient:

On the mucous membrane of the cervical canal there is a polyp, due to which the detection of the cervix is not possible or difficult.
The cervix is curved, which is one of the frequent moments during pregnancy. It is fraught with obtaining not entirely reliable data. Therefore, the length of the cervix is measured using mathematical formulas or tracing, measuring the length along a curved line.

Where to do it and how much does it cost?

In paid clinics and medical centers, the price of the procedure, depending on the gestational age, will be from 2500 to 6500 rubles. IN public institutions a referral for an ultrasound scan will be obtained from a doctor and the examination will be performed free of charge.

Conclusion

An examination using ultrasound equipment is a very important point during pregnancy. It helps to determine hidden forms threats to the unborn child and the health of his mother.

By refusing, a pregnant woman puts herself and the fetus in danger, because. makes it impossible to diagnose dangerous diseases and heal them in time.

The screening of the first trimester of pregnancy is over, time passes, the tummy grows, and new worries appear.
Have you heard or read somewhere about isthmic-cervical insufficiency (ICI), premature birth, ultrasound of the cervix and now you don’t know if this threatens you and whether you need such a study, and if necessary, when?
In this article I will try to talk about such a pathology as ICI, about modern methods of its diagnosis, the formation of a high-risk group premature birth and methods of treatment.

Premature births are those that occur between 22 and 37 weeks (259 days) of pregnancy, starting from the first day of the last normal menstruation with a regular menstrual cycle, while the body weight of the fetus is from 500 to 2500 g.

The frequency of preterm births in the world in last years is 5 - 10% and, despite the emergence of new technologies, does not decrease. And in developed countries, it increases, first of all, as a result of the use of new reproductive technologies.

Approximately 15% of pregnant women fall into the high risk group for preterm birth even at the stage of anamnesis. These are women who have a history of late miscarriages or spontaneous preterm births. In the population of such pregnant women, about 3%. In these women, the risk of recurrence is inversely related to the gestational age of the previous preterm birth, i.e. the earlier the preterm birth occurred in past pregnancy the higher the risk of recurrence. In addition, this group can include women with uterine anomalies, such as a unicornuate uterus, a septum in the uterine cavity, or injuries, surgical treatment cervix.

The problem is that 85% of preterm births occur in 97% of women in the population who have this first pregnancy or previous pregnancies ended in full-term birth. Therefore, any strategy aimed at reducing the number of preterm births that targets only a group of women with a history of preterm birth will have very little effect on the overall rate of preterm birth.

The cervix plays a very important role in maintaining pregnancy and the normal course of childbirth. Its main task is to serve as a barrier that prevents the fetus from being pushed out of the uterine cavity. In addition, the glands of the endocervix secrete special mucus, which, when accumulated, forms a mucous plug - a reliable biochemical barrier for microorganisms.

"Maturation of the cervix" is a term that is used to describe the rather complex changes that occur in the cervix, related to the properties of the extracellular matrix and the amount of collagen. The result of these changes is the softening of the cervix, its shortening up to smoothing and expansion of the cervical canal. All these processes are the norm at full-term pregnancy and are necessary for the normal course of childbirth.

Some pregnant women have various reasons"cervical ripening" occurs ahead of time. The barrier function of the cervix is sharply reduced, which can lead to premature birth. It should be noted that this process does not clinical manifestations, is not accompanied by pain or bloody discharge from the genital tract.

What is an ICN?

proposed by various authors whole line definitions for this state. The most common is this: ICI is an insufficiency of the isthmus and cervix, leading to premature birth in the II or III trimester of pregnancy.
or such : CCI is a painless dilatation of the cervix in the absence of
uterine contractions leading to spontaneous interruption
pregnancy.

But after all, the diagnosis should be made even before the termination of pregnancy occurred, and we don’t know whether it will happen. Moreover, most pregnant women diagnosed with CI will deliver at term.
In my opinion, ICI is a condition of the cervix, in which the risk of preterm birth in this pregnant woman is higher than the general population.

IN modern medicine, the most reliable way to assess the cervix is transvaginal ultrasound with cervicometry - measurement of the length of the closed part of the cervix.

Who is shown an ultrasound of the cervix and how many times?

Here are the recommendations from https://www.fetalmedicine.org/ The Fetal Medicine Foundation:
If a pregnant woman belongs to those 15% with a high risk of preterm birth, then such women are shown an ultrasound of the cervix every 2 weeks from the 14th to the 24th week of pregnancy.
For all other pregnant women, a single ultrasound of the cervix is recommended for a period of 20-24 weeks of pregnancy.

Cervicometry technique

The woman empties her bladder and lies on her back with her knees bent (lithotomy position).
The ultrasound transducer is carefully inserted into the vagina towards the anterior fornix so as not to exert excessive pressure on the cervix, which can artificially increase the length.
Obtain a sagittal view of the cervix. The mucosa of the endocervix (which can be either elevated or reduced echogenicity compared to the cervix) serves as a good guide to determine the true position internal os and helps avoid confusion with the lower uterine segment.
The closed part of the cervix is measured from the external os to the V-shaped notch of the internal os.
The cervix is often curved and in these cases the length of the cervix, considered as a straight line between the internal and external os, is inevitably shorter than the measurement taken along the cervical canal. From a clinical point of view, the measurement method is not important, because when the cervix is short, it is always straight.

Each study should be completed within 2-3 minutes. In about 1% of cases, the length of the cervix can change depending on the contractions of the uterus. In such cases, the lowest values should be recorded. In addition, the length of the cervix in the II trimester may vary depending on the position of the fetus - closer to the bottom of the uterus or in the lower segment, in a transverse position.

You can evaluate the cervix and transabdominally (through the abdomen), but this is a visual assessment, not cervicometry. The length of the cervix with transabdominal and transvaginal access significantly differs by more than 0.5 cm, both up and down.

Interpretation of research results

If the length of the cervix is more than 30 mm, then the risk of preterm birth is less than 1% and does not exceed the general population. Hospitalization is not indicated for such women, even in the presence of subjective clinical data: pain in the uterus and minor changes in the cervix, copious discharge from the vagina.

In case of detecting a shortening of the cervix less than 15 mm in a singleton pregnancy or 25 mm in a multiple pregnancy, urgent hospitalization and further management of pregnancy in a hospital with the possibility of intensive care for newborns. The probability of delivery within 7 days in this case is 30%, and the probability of preterm birth before 32 weeks of pregnancy is 50%.

Shortening of the cervix to 30-25 mm in a singleton pregnancy is an indication for consultation with an obstetrician-gynecologist and weekly ultrasound monitoring.

If the length of the cervix is less than 25 mm, the conclusion is made: “ECHO-signs of CI” in the 2nd trimester, or: “Considering the length of the closed part of the cervix, the risk of preterm birth is high” in the 3rd trimester, and it is recommended to consult an obstetrician gynecologist with the aim deciding whether to prescribe micronized progesterone, perform a cervical cerclage, or install an obstetric pessary.

Once again, I want to emphasize that the detection of a shortened cervix during cervicometry does not mean that you will definitely give birth prematurely. It's exactly about high risk.

A few words about the opening and shape of the internal os. When conducting an ultrasound of the cervix, you can find various forms internal os: T, U, V, Y - figurative, moreover, it changes in the same woman during pregnancy.
With ICI, along with shortening and softening of the cervix, it dilates, i.e. expansion of the cervical canal, opening and changing the shape of the internal pharynx is one process.
A large multicenter study conducted by FMF showed that the shape of the internal os, without shortening the cervix, does not increase the statistical likelihood of preterm birth.

Methods of treatment

The effectiveness of two methods of preventing preterm birth has been proven:

Cervical cerclage (suturing the cervix) reduces the risk of delivery before the 34th week by about 25% in women with a history of preterm birth. There are two approaches in the treatment of patients with previous preterm births. The first is to cerclage all such women shortly after 11-13 weeks. The second is to measure the length of the cervix every two weeks from weeks 14 to 24, and suturing only if the length of the cervix becomes less than 25 mm. The overall preterm birth rate is similar for both approaches, but the second approach is preferred as it reduces the need for cerclage by about 50%.

In case of detection short neck uterus (less than 15 mm) at 20-24 weeks in women with an uncomplicated obstetric history, cerclage can reduce the risk of preterm birth by 15%.
Randomized studies have shown that in the case of multiple pregnancy, with a shortening of the neck to 25 mm, cervical cerclage doubles the risk of preterm birth.

Prescribing Progesterone from 20 to 34 weeks reduces the risk of delivery before 34 weeks by about 25% in women with a history of preterm birth, and by 45% in women with an uncomplicated anamnesis, but a shortening of the cervix up to 15 mm is detected. Recently, a study was completed that showed that the only progesterone that can be used for a short cervix is micronized vaginal progesterone at a dose of 200 mg per day.

Currently, multicenter studies of the effectiveness of the use of a vaginal pessary are ongoing. A pessary, which is made of flexible silicone, is used to support the cervix and change its direction towards the sacrum. This reduces the load on the cervix due to a decrease in the pressure of the fetal egg. More details about the obstetric pessary, as well as the results latest research in this area you can read

The combination of cervical sutures and a pessary does not increase efficiency. Although opinions on this matter various authors diverge.

After suturing the cervix or with an obstetric pessary installed, ultrasound of the cervix is impractical.

See you in two weeks!

A woman during the period of bearing a child undergoes a number of research procedures, among which ultrasound examinations are necessarily present.

They are prescribed in order to monitor the condition of the fetus, diagnose the condition of the mother and, if necessary, prescribe appropriate treatment. Ultrasound of the cervix is considered an indispensable procedure for detecting pathologies.

Why is an ultrasound of the cervix performed during pregnancy

The cervix (cervix) is an organ located at the bottom of the uterus. During pregnancy, it keeps the fetus in the uterine cavity and prevents infections from entering the uterus.

During this period, the uterus, depending on the duration of pregnancy, undergoes certain changes that are signs of maturation of the organ. At the beginning of fruiting, the neck is hard, which allows it not to stretch and not release the fetus, but by childbirth, on the contrary, it becomes soft and elastic.

The main goal of ultrasound of the cervix is to prevent pathologies that can interfere with the normal bearing and birth of a child. The state of the organ is checked and diagnosed in terms of the length of the CMM.

Ultrasonography, which allows you to measure the length, is called cervicometry.

In which case the doctor prescribes the procedure

The length of the CMM must be measured during screening ultrasound procedures. If the pregnancy proceeds without deviations, then cervicometry is not prescribed separately. But there are women who are at risk for certain reasons.

For those who are included in these groups, ultrasound of the CMM is assigned unscheduled:

Suspicion of ICI (isthmic-cervical insufficiency - a condition in which the body can not cope with the increasing load).
Screening ultrasound indications.
There were threats of abortion, miscarriages or premature births.
Pregnancy with twins or more.
Past abortions, operations and the presence of stitches in the pelvic organs.
Inflammation and infection.

Also, the small size of the uterine organs can be due to the individual characteristics of the female body.

Timing of ultrasound of the cervix

For the entire period of bearing a child, a woman with a normal pregnancy is assigned an ultrasound scan three times, every trimester.

The due dates for the procedure are:

11-16 weeks;
17-24;
32-34.

Each screening is aimed at identifying certain features of the woman's condition, determining the length of the cervix and the degree of its maturation.

Length indicators in different trimesters:

up to 24 weeks - 35 - 45 mm .;
at 25-28 weeks - at least 35 mm;
at 32-36 weeks - at least 30 mm;
in the prenatal period - at least 10 mm.

What pathologies does the examination show?

status of the cervix the most important source information about the course of pregnancy. If the process of bearing the fetus proceeds normally, the cervix has a dense texture, the cervical canal is smaller than a finger in diameter.

The gynecologist reveals these indicators to the touch during examination. If the channel opens easily, and the neck itself is short and soft, the question is about diagnosing the threat of spontaneous abortion. If the channel expands to last dates, there is a threat of preterm labor.

CMM ultrasound during pathology reveals the following pathologies:

Possible pathology during fruiting- immaturity of the neck, leading to the fact that the organ loses its elasticity and cannot be stretched. The cervix usually reaches a mature state by 37 weeks. If this does not happen, complications may occur during childbirth and the only optimal solution to save the fetus will be a caesarean section.
ICI - isthmic-cervical insufficiency. This pathology is the inability of the muscles of the pelvic organs to contract. Thus, the uterus cannot withstand the load of the fetus, and it descends to the internal os earlier than expected. In the early stages, this leads to a miscarriage, in the later stages - to premature birth. Basic symptom of CCI – stabbing pains in the genital area, a feeling of heaviness in the lower abdomen. But most of the women who have encountered this diagnosis claim that the disease has no symptoms and is detected during a gynecological examination.
Endocervitis- This inflammatory process occurring in the cervical canal. Inflammations are caused by infections that have entered the canal cavity sexually. Diagnosis of pathology helps characteristic scarlet inflammation. Symptoms of endocervitis are abundant discharge in the form of a liquid with an unpleasant specific odor.

Preparing for diagnostics

The ultrasound procedure is performed transabdominally and transvaginally. A study with a transvaginal sensor is prescribed more often, since this is the maximum exact method diagnosis of pathologies. Many women worry about whether it is harmful to the fetus. BUT the procedure does not pose any danger to the child and mother.

Prepare for cervicometry:

the vagina should be washed with ordinary soap;
on this day you can’t drink water, since the bladder filled with liquid will prevent you from correctly diagnosing the condition of the cervical canal;
the day before, you do not need to eat food that is poorly digested and contributes to increased gas formation.

How is an ultrasound of the cervix done?

The transvaginal examination procedure takes place in a conventional ultrasound room and lasts an average of 2-3 minutes. The patient lies on the couch, spreads her legs and bends them at the knees. The gynecologist inserts a sensor into the vagina, previously lubricated with a special sound-conducting gel, looks and reads information on the computer monitor.

There you can see the image of the median uterine section and its lower segment. Also, internal and external openings, the mucous membrane of the cervical canal become visible.

There may be a situation where the image is artificially lengthened due to excessive pressure on the sensor. To avoid incorrect readings, the sensor is removed until the image is blurred on the screen, and reintroduced. Possible measurement inaccuracy due to uterine contractions. In this case, the smallest numbers are fixed. Also, the length of the neck depends on the location of the fetus.

Difficulties in the study arise in the case of a curvature of the organ or the presence of a polyp on the wall of the cervical canal.

Survey results

Thanks to the results of cervicometry, the gynecologist finds out the condition of the organs of the pregnant woman.

Deciphering normal indicators:

First trimester. The cervical canal is closed, does not pass a finger. The inner and outer pharynx of the neck are closed. The length is approximately 3-5 centimeters. It is worth considering that in women who have given birth, the figures are slightly lower.
Second trimester. The internal os is closed. The external pharynx in women who have given birth is ajar, in primiparas it is tightly closed. The normal length is 3 cm.
Third trimester. The results of this procedure are evaluated by degrees of maturity. A zero degree of maturity indicates that childbirth will not begin in the near future. The neck has a dense texture, the length is not more than 2 cm, the external pharynx is either tightly closed or ajar at a distance that passes a finger. The uterine organ has a backward slope. Signs of the first degree of maturity: the consistency is compacted, the length is 1-2 cm, the slope is forward, the opening of the external pharynx increases by a finger. These signs indicate the approach of delivery. Maturity of the second degree warns of early delivery. The length of the cervical canal is not more than 1 cm, the uterus is relaxed, loose, with an inclination along the axis of the pelvis.

If the neck length is more than 3 cm, this is a normal indicator and the risk of preterm birth is very low - only 1%. A length of less than 15 mm in 30% indicates childbirth within a week, and in 50% of preterm birth for up to 32 weeks. With multiple pregnancies, such risks arise at sizes of 25 millimeters.

Indicators of 30-25 mm indicate the need for consultations with an observing gynecologist and weekly cervicometry. 25 mm or less is a reason for a medical opinion about a high risk of preterm birth.

In this case, the patient is placed under full medical supervision, after which she is prescribed either progesterone or wearing an obstetric pessary - a special silicone ring. IN extreme cases cervical cerclage is performed - suturing. After surgery, transvaginal examination is no longer done.

You can do cervicometry free of charge in the direction of the observing gynecologist in antenatal clinic at the place of residence or in any private institution where ultrasound is done. average price for the service - 2500 rubles.

Details about normal the gynecologist will tell you the length in this video:

Conclusion

Remember that the period of bearing a child for each woman has individual characteristics.

Pathology of the cervix does not mean a 100% risk of miscarriage or premature birth. Timely diagnosis will reduce these risks and ensure normal course the entire period of pregnancy.

How the process of bearing a baby proceeds, doctors are watching very carefully. To do this, they assign future mother whole complex various studies. One such examination performed during pregnancy is cervicometry.

What it is?

By cervicometry, specialists mean the method of ultrasound examination of the cervix. By using this method doctors can evaluate both the length and other parameters of this organ. Also, with the help of ultrasound, you can estimate the size of the external and internal os of the cervix.

The examination is carried out using a transvaginal probe. Thanks to this method, it is much easier for a specialist to evaluate the necessary parameters. As a rule, this diagnostic procedure is painless and well tolerated by a pregnant woman.

This method is widely used. It is based on the reflection of ultrasonic waves from various biological structures of the body. This study is widely used in various countries. It is important to note that it can be carried out not only in a hospital, but also in a regular clinic.

Often to detect various pathologies other research methods are also needed. One of them is doppler. This helper method study allows you to evaluate the blood flow according to the main blood vessels uterus.

The use of this examination is necessary in order to identify pathologies of the blood supply. reproductive organs on the most early stages their formation. Dopplerography allows you to easily determine the heart rate of the fetus.

If the doctor reveals any significant changes in the performance of the diagnostic procedure, then in this case a mandatory set of recommendations will be required. This is necessary so that a pregnant woman can bear and give birth to a healthy baby.

Indications for carrying out

This research method is carried out according to certain medical indications. The decision on the need for his appointment is made by the gynecologist who observes the woman during pregnancy. In some cases, a specialist may prescribe a future mother to undergo cervicometry even several times.

This study is indicated for women who carry several babies at once.. In this case, more careful medical supervision for the condition of the cervix and the width of its canal.

If a pregnant woman has recently undergone some kind of surgery on the reproductive organs, then in this case she will also need to perform cervicometry. This examination is especially important for women who have had surgical intervention or underwent laser treatment of the cervix a few months before the onset of conception.

If future mother there is isthmic-cervical insufficiency, then in this case she will also need to conduct this research method. In this situation, the risk of spontaneous miscarriage in the first half of pregnancy is very high. In order to prevent this dangerous condition, it is necessary to determine the main investigated parameters.

Too short length of the cervical canal of the uterus - another clinical indication for this research method. Typically, this condition is individual feature and is present in women from birth. However, various pathologies, as well as surgical operations performed on this organ, can also lead to a shortening of the cervix.

In some cases, it is possible to conduct an examination with the omission of the cervix. In this situation, the need for an obstetrician-gynecologist establishes. Usually, this pathology requires fairly careful monitoring by doctors over the health of the reproductive organs of the expectant mother.

If a woman experiences pain in the abdomen, or she constantly has uterine hypertonicity, then she may also need to undergo this study. In this case, it is very important for the doctor to exclude dangerous pathologies, which can become a threat of premature birth.

How is the procedure carried out?

Research can be done different methods. As a rule, the most commonly used transvaginal probe. Many expectant mothers prefer to undergo a transabdominal examination. However, it should be remembered that the choice necessary way diagnosis remains with the attending physician.

The examination should be entrusted to an experienced and qualified specialist. It is especially important to do this if the expectant mother has any pathologies of the reproductive organs. In this case, the reliability of the results is very important.

The study is carried out in a conventional ultrasound room. The duration of the diagnostic procedure may be different. This largely depends on the experience of the specialist who conducts the study. The examination usually takes 20-30 minutes.

The doctor, examining the organs using a transvaginal or transabdominal sensor, sees the result on a special monitor. The resolution of modern devices makes it possible to detect various pathologies quite easily.

Special training not required for the examination. If the study is carried out in a antenatal clinic, then in this case, the expectant mother should bring a towel with her. It will be required in order to put it on the couch before the examination.

If the study is carried out using a transvaginal sensor, then it is not necessary to pre-fill the bladder. Before the procedure, the expectant mother should go to the toilet and urinate. This will help her to more easily transfer this study.

Many women are afraid that during the study, the doctor may introduce an infection with a transvaginal sensor. It should be said right away that this is out of the question. All medical instruments and devices are carefully processed using special disinfectants.

In this case, the risk of infection of the expectant mother and fetus is negligible. Also, before each diagnostic procedure, an individual condom must be put on the ultrasonic sensor.

The norms of the studied indicators

Estimated parameters may be different. There are quite a few reasons for this. So, during the first pregnancy, as a rule, all the estimated indicators are much less. If a woman gave birth several times, or she had a previous pregnancy with twins, then in this case the norms of the studied indicators also differ.

Also, when conducting a study, it is very important to remember which week it is conducted. The indicators of the survey at 16-17 weeks will differ from those at 20-22 weeks.

Cervical length

The norm of this estimated parameter is 30 mm. If at a period of 17 weeks of pregnancy the length of the cervix in a pregnant woman is 25-29 mm, then in this case you should not panic. In this situation it is very important to carry out dynamic surveillance for the further course of pregnancy.

It often happens that in miniature women, the cervix has a small length.

Also small size reproductive organ may also be in expectant mothers who have a small body mass index before pregnancy.

Too dilated cervical canal already at 24-25 weeks of gestation is a rather dangerous condition. According to statistics, if a pregnant woman's cervix is less than 25 mm, then the risk of premature birth is 15-18%.

With a cervical length of less than 20 mm, this figure is already 25-28%. And only 50% of pregnant women will be able to bear the baby until the due date of delivery if their cervix is less than 15 mm long.

If, against the background of a shortening of the uterus, the expectant mother develops pain in the lower abdomen, then this condition can be dangerous. The likelihood of spontaneous miscarriage increases many times over. In such situation required medical intervention.

In this case, before the 20th week of pregnancy, the doctor may put stitches on the cervix. They stay for several months. In some cases, the sutures from the cervix are removed only at 37-38 weeks of pregnancy. If the pathology manifested itself after the 20th week, then the doctor will install a special medical ring. It's called obstetric pessary.

The shape of the internal os

The clinical parameter can also be determined during cervicometry. Normally, the internal os resembles the letter "T". In this state, the cervix is completely closed.

If it ripens too early, then the shape changes. It becomes like the letter "Y", then "V", and later on "U". It is also extremely unfavorable if the shape of the internal pharynx resembles an hourglass.

This happens due to the fact that amniotic sac starts to slide down.

Internal os