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Fetal dopplerometry: indices and transcript

Today, in the diagnosis of malformations of the fetus and violations of the course of normal pregnancy, more and more modern equipment is used to look at the problem from within. The ultrasonic device is widely used in diagnosing and analyzing diseases and conditions of the human body. Such studies are closely integrated into medical practice and are almost indispensable in the process of observation and treatment. For pregnant women, in addition to the usual study, ultrasound of the fetus with dopplerometry is prescribed. This is a common practice for any medical center.

Doppler

Throughout the entire period of gestation of a baby, a woman is prescribed a US ultrasound examination. At different stages of pregnancy, fetal dopplerometry is prescribed for research and prevention of developmental disorders. Doppler is one of the types of ultrasound that is usually done in the last months of pregnancy, usually in the third trimester.

The study of blood flow in the central arteries of the fetus, uterus, placenta allows you to assess the speed of blood flow and the state of the main vessels, as well as the umbilical arteries, providing vital activity and nutrition of the fetus. To carry out such a study, a special nozzle is needed. As a rule, ultrasound with dopplerometry is performed in conjunction with the primary or can be prescribed as a separate, additional study by the attending physician.

The appointment of an ultrasound with a doppler

Doppler can determine the exact size, diameter and location of the main arteries not only of the fetus, but also of the placenta, the umbilical cord, the womb of the woman, the rate of blood flow through the vessels, and also makes it possible to detect any abnormalities or fading of the placenta, which may be a harbinger Various complications both during pregnancy and during childbirth. Therefore, the importance of conducting such a study should not be underestimated. Thus, the timely dopplerometry of the fetus, the interpretation of its indicators allow timely to carry out prevention, to alleviate the condition and to prevent possible risks.

Indications for Doppler

Dopplerometry as an additional study is necessarily prescribed if the following diseases are found in the pregnant woman:

  • Gestosis.
  • Hypertonic disease.
  • Kidney disease.
  • Diabetes.

And fetal dopplerometry can be prescribed for early detection of developmental disorders, congenital malformations, developmental delays, lack of hydration, the possibility of premature ripening of the placenta, abnormalities in the structure of the umbilical cord or congenital chromosomal pathologies, severe forms of heart disease, etc.

The study of uterine arteries by Dopplerometry

Dopplerometry of the uterine arteries allows to assess the state of the vascular system of the uterus, placenta, intermittent space. Formation of the intermittent space occurs even during implantation of the embryo, approximately a week after conception. Circulation in the womb of the woman is carried out with the participation of two arteries: ovarian and uterine. Even during the formation of the placenta, some changes occur in the walls of these arteries, which subsequently lead to their growth and expansion in parallel with the growth of the placenta. Due to this process, uteroplacental blood flow is formed to complete formation of the placenta and increases by 10 times.

Dopplerometry of uterine arteries allows to evaluate the functioning of spiral arteries, the formation of which ends at the beginning of the 3rd trimester. When complications arise during pregnancy, physiological changes do not occur in all arteries, so they do not expand and grow during placenta growth. Thus, the arteries become unable to provide sufficient blood circulation and blood supply to the placenta, which can lead to its withering away or a deficiency of nutrients and oxygen. This, in turn, can entail the detachment of the placenta, miscarriage and miscarriage.

Doppler

When carrying out a Doppler study, a graphical representation of blood flow rates along the arteries is displayed on the ultrasound screen during each cardiac cycle, which differ in systolic and diastolic. In order to understand what is going on in the future, we will make a decoding:

  • Systole is the pressure that occurs when the heart muscle contracts.
  • Diastole is the pressure that occurs when the heart muscle relaxes.

So, for one cardiac stroke there are indications of systolic and diastolic pressure in the arteries. For each of the vessels under study, there are norms and typical typical blood flow velocity curves.

To assess the norms and indices of blood flow, the following indices are used:

  • Systolic-diastolic ratio.
  • Pulse index.
  • Resistance index.

Systolic-diastolic ratio, pulse index and resistance index reflect the state of the main arteries and aorta and blood streams in them, which is the purpose of such a study as dopplerometry. Norms and deviations from them reflect different types of violations of fetal development, determine pathologies associated with the effect of blood flow on gestation. So, the doctor can give an assessment of the functioning of the placenta, its viability, providing the fetus with oxygen stores through the umbilical cord, as well as possible defects in the development of the fetus associated with circulatory disorders and heart muscle diseases.

Dopplerometry: standards

To evaluate the results of the Doppler study, special tables of values are used. They indicate all the permissible dopplerometry of the fetus for the three indicators:

  • Systolic-diastolic ratio.
  • The index of resistance.
  • Pulse index.

Similar studies should be conducted in all pregnant women, but it is especially important for those who are at risk and have problems with blood circulation or hereditary defects.

Dopplerometry of the fetal vessels and ultrasound examination is prescribed at the period of 23 weeks of pregnancy. During this period, this procedure is very relevant for assessing the risk of complications and malformations of the placenta, which can lead to abortion. But such studies can be conducted, starting from 13 weeks and until the end of pregnancy. For each week there are indicators of Doppler. All these studies are conducted to study the three main arteries: the arteries of the umbilical cord, the uterine, the aorta of the fetus.

The systolic-diastolic ratio, already from the 20th week of pregnancy, should be 2.4 or less.

The resistance index is calculated for the arteries of the umbilical cord, uterine, and medium cerebral arteries. The norm is:

  • For uterine - less than or equal to 0.58;
  • For the umbilical artery - less than or equal to 0.62;
  • For the average cerebral artery of the fetus, the index should be less than or equal to 0.77.

Already in the second half of pregnancy, these indicators are almost unchanged. And by the end of the gestation period, the systolic-diastolic ratio should not exceed two units.

Displaying Values

Doppler examination of the fetus in the 3rd trimester studies blood flow and promotes early diagnosis, prevention of placental insufficiency, treatment of gestosis with characteristic changes for arterial blood flow in the uterine vessels. When a decrease in the average diastolic value is detected, the systolic-diastolic ratio is significantly increased, and, respectively, the remaining indices calculated on its basis also increase.

With dopplerometry in the second and third semesters of pregnancy, specialists pay particular attention to the artery of the umbilical cord. The study of blood flow curves of the central artery of the umbilical cord is important after the tenth week of pregnancy. At the same time, the diastolic aspect of the blood flow can not be detected until 14 weeks. In a fetus that has chromosomal abnormalities, at a period of 10-13 weeks, the reverse diastolic blood flow is usually recorded.

In uncomplicated pregnancy, the systolic-diastolic ratio does not exceed three units on the curve representing the blood flow. For the pathology of fetal development, a decrease in the final diastolic rate is characteristic, up to complete disappearance.

By the fifth and forthcoming months of pregnancy, the most significant diagnostic indicators are the studies of fetal blood flow. First of all, the aorta, as well as the middle cerebral artery, are examined. Values of these blood streams are characterized by high systolic thresholds of pressure changes in the aorta, often accompanied by a decrease in diastolic parameters. The less they are, the higher the risk of pathologies. The most unfavorable situation is the zero value of the diastolic component.

For the middle cerebral artery, clinical changes in the blood flow may be accompanied, on the contrary, by an increase in the diastolic component, which in turn serves as a manifestation of hyperperfusion of the brain or indicative of the development of fetal hypoxia.

When examining the blood flow velocity in the venous ducts, the systolic peaks occupy most of the percentage of the curve and are at the same level without sudden changes, periodically failures occur to the diastolic component of a short duration. Thus, the entire curve is practically homogeneous without isolated acute peaks. If high peaks of the systolic component are indicated or diastolic pressure is lost, this may indicate a chromosomal pathology of the fetus, as well as the onset of hypoxia of the fetus.

The accuracy of ultrasonic examination by the Doppler method is about 70%. The most effective is the study of utero-placental and fetoplacental blood flow, which can almost 100 percent diagnose various disorders.

Evaluation of research results

According to different indices, the indices of blood flow disturbance are divided into different degrees:

  • 1 degree - a violation in the utero-placental blood flow with constant fruit-placental blood flow or a violation of the placenta with unchanged utero-placental.
  • 2 degree - a one-time change and a violation in both types of blood streams, the indices of which do not reach any critical values, but they have a place to be.
  • The third degree is the presence of critical disturbances in the parameters of the fetoplacental blood flow, regardless of the presence of changes or even a slight disturbance of uteroplacental blood flow.

Indications for doppler administration

Fetal doppler can be administered once or twice during the course of the entire pregnancy as a routine procedure. Sometimes it is prescribed more often. This occurs if there are risks or pathologies of fetal development or whether the condition of the uterus and the placenta requires it. There is a list of indications in which it is simply necessary and necessary to pass the Doppler study:

  • If the mother's age is more than 35 or less than 20 years (early or late pregnancy).
  • Polyhydramnios and waterlessness.
  • On a previous study, a umbilical cord was identified by the ultrasound apparatus.
  • Fetal development lags behind established norms.
  • The mother has chronic serious illnesses.
  • When previous pregnancies ended in miscarriages or children were born with severe vices or stillbirths.
  • If there is a suspicion of malformations.
  • With multiple pregnancies.
  • If the mother has a negative Rh factor, which can lead to rejection of the fetus in case of circulatory disturbance.
  • At unsatisfactory parameters of CTG.
  • If there was a trauma to the abdomen of a pregnant woman.

If there is a threat of sudden termination of pregnancy, it is necessary to appoint a Doppler study to find out the reasons for such fears. In this case, the woman lies in the day hospital, where the first step is the examination on Doppler ultrasound and takes hormonal therapy to keep the pregnancy until the time at which it is possible to conduct safe delivery with minimal risks.

Preparation for research

To prepare for a Doppler study of a pregnant woman, it is advisable to take food for a couple of hours before going to the ultrasound examination room and then just water. To start the study, you need to lie down on the couch near the apparatus on your back, while opening the stomach from the chest to the groin. One or several drops of a special conductive gel that helps penetrate the ultrasound signal are applied to the pregnant abdomen surface and a special sensor is applied, which is smoothly guided along the abdominal surface.

Fetal dopplerometry can be performed both on black-and-white equipment and on a modern color one, at which the ultrasound specialist will see curves with peaks indicating the intensity and rate or the deviation from it of blood flows in the arteries. After the examination, the doctor will record the data obtained during the examination and write a transcript to them, after which he will give the conclusion of a Doppler ultrasound in the hands of a pregnant woman.

Fetal dopplerometry, indices and their interpretation will be a great help for an obstetrician-gynecologist in the conduct of a woman's pregnancy, preparing for a successful delivery and monitoring complications. Monitoring the condition of internal organs and fetus with the help of Doppler research is much simpler and has proved its effectiveness and reliability for many years already. More and more studies conducted in recent years confirm the safety of examination using ultrasound technology, excluding the possibility of harm to the health of both the future mother and the unborn baby.

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