Today, in the diagnosis of fetal malformations and abnormalities in the course of normal pregnancy, modern equipment is increasingly being used, which allows you to look at the problem from the inside. The ultrasonic device is widely used in the diagnosis and analysis of diseases and conditions of the human body. Such studies have firmly entered medical practice and are practically indispensable in the process of observation and treatment. For pregnant women, in addition to the usual study, a fetal ultrasound with dopplerometry is prescribed. This is a common practice for any medical center.
Dopplerometry
Throughout the entire period of bearing a baby, a woman is prescribed ultrasound examinations. At different stages of pregnancy, fetal Doppler is prescribed to conduct research and prevent developmental disorders. Dopplerometry is a type of ultrasound that is usually done in the last months of pregnancy, usually in the third trimester.
The study of blood flow inthe central arteries of the fetus, uterus, placenta allows you to assess the blood flow rate and the state of the main vessels, as well as the umbilical cord arteries, which ensure the life and nutrition of the fetus. To carry out such a study, a special nozzle is needed. As a rule, Doppler ultrasound is performed in conjunction with the main one or can be prescribed as a separate, additional study by the attending physician.
Doppler ultrasound appointment
Dopplerometry allows you to determine the exact size, diameter and location of the main arteries not only of the fetus, but also of the placenta, umbilical cord, uterus of a woman, the speed of blood flow through the vessels, and also makes it possible to timely detect the presence of any violations or extinction of the function of the placenta, which can be a harbinger of various complications both during pregnancy and during childbirth. Therefore, the importance of such a study should not be underestimated. So, timely fetal dopplerometry, deciphering its indicators allow timely prevention, alleviate the condition and prevent possible risks.
Indications for dopplerometry
Dopplerometry as an additional study must be prescribed if the following diseases are found in a pregnant woman:
- Preeclampsia.
- Hypertension.
- Kidney disease.
- Diabetes mellitus.
And also fetal Doppler can be prescribed for early detection of developmental disorders, congenital malformations, developmental delays,oligohydramnios, the possibility of premature maturation of the placenta, anomalies in the structure of the umbilical cord or congenital chromosomal pathologies, severe forms of heart defects, etc.
Study of uterine arteries by Doppler method
Dopplerometry of the uterine arteries allows you to assess the state of the vascular system of the uterus, placenta, interciliary space. The formation of the interciliary space occurs even during the implantation of the embryo, approximately a week after conception. Blood circulation in the uterus of a 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. Thanks to this process, the uteroplacental blood flow is formed to the full formation of the placenta and increases 10 times.
Uterine artery Doppler allows you to evaluate the functioning of the spiral arteries, the formation of which ends by the beginning of the 3rd trimester. When complications arise during pregnancy, not all arteries undergo physiological changes, thus, they do not expand and do not grow during the growth of the placenta. Thus, the arteries become unable to provide sufficient blood circulation and blood supply to the placenta, which can lead to its death or deficiency of nutrients and oxygen. This, in turn, can lead to placental abruption, miscarriage and miscarriage.
Doppler: decoding
When conductingDoppler study on the screen of the ultrasound machine displays a graphical image of the speed of blood flow through the arteries during each cardiac cycle, which differ in systolic and diastolic. To understand in the future what is at stake, we will decrypt:
- Systol is the pressure that occurs when the heart muscle contracts.
- Diastole is the pressure that occurs when the heart muscle relaxes.
So, for one heart beat, there are indications of systolic and diastolic pressure in the arteries. Each of the studied vessels has its own norms and characteristic typical curves of blood flow velocity.
The following indices are used to assess the norms and indicators of blood flow:
- Systole-diastolic ratio.
- Pulse index.
- Resistance index.
The systolic-diastolic ratio, pulse index and resistance index reflect the state of the main arteries and aortas and blood flow in them, which is the purpose of such a study as Doppler. Norms and deviations from them reflect different types of fetal developmental disorders, determine pathologies associated with the influence of blood flow on pregnancy. So, the doctor can evaluate the functioning of the placenta, its viability, providing the fetus with oxygen reserves through the umbilical cord, as well as possible malformations in the development of the fetus associated with circulatory disorders and diseases of the heart muscle.
Doppler: norms
For evaluationDoppler study results use special tables of values. They indicate all the permissible norms of fetal Doppler for three indicators:
- Systole-diastolic ratio.
- Resistance index.
- Pulse index.
Such studies should be carried out in all pregnant women, but this 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 for a 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 termination of pregnancy. But such studies can be carried out from 13 weeks until the end of pregnancy. Each week has its own Doppler indicators. All these studies are conducted to study the three main arteries: umbilical artery, uterine artery, fetal aorta.
The systolic-diastolic ratio should be 2, 4 or less from the 20th week of pregnancy.
The resistance index is calculated for the umbilical cord, uterine, and middle 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 fetal middle cerebral artery, the index must be less than or equal to 0.77.
Already in the second half of pregnancy, these figures are practicallyare unchanged. And by the end of the gestation period, the systolic-diastolic ratio should not exceed two units.
Display values
Fetal Doppler in the 3rd trimester studies the blood flow and contributes to the implementation of early diagnosis, the appointment of the prevention of placental insufficiency, the treatment of preeclampsia with characteristic changes in arterial blood flow in the uterine vessels. When a decrease in the average diastolic value is detected, the systolic-diastolic ratio increases significantly, and, accordingly, the other indices calculated on its basis also increase.
When dopplerometry in the second and third semester of pregnancy, specialists pay special attention to the umbilical artery. The study of blood flow curves of the central umbilical artery becomes important after the tenth week of pregnancy. In this case, the diastolic aspect of the blood flow may not be detected until 14 weeks. In a fetus that has chromosomal anomalies, reverse diastolic blood flow is usually recorded for a period of 10-13 weeks.
In an uncomplicated pregnancy, the systolic-diastolic ratio does not exceed three units on the curve showing blood flow. The pathology of fetal development is characterized by a decrease in end-diastolic velocity up to complete disappearance.
By the fifth and further months of pregnancy, the most significant diagnostic indicators are studies of fetal blood flow. First of all, the aorta is examined, as well asmiddle cerebral artery. The values of these blood flows are characterized by high systolic pressure thresholds in the aorta, often accompanied by a decrease in diastolic values. The smaller 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 blood flow may be accompanied, on the contrary, by an increase in the diastolic component, which, in turn, is a manifestation of cerebral hyperperfusion or indicates the development of fetal hypoxia.
When examining blood flow velocity in the venous ducts, systolic peaks occupy most of the percentage area of the curve and are at the same level without sharp drops, dips to the diastolic component of a short duration periodically appear. Thus, the entire curve is almost uniform with no prominent sharp peaks. If high peaks of the systolic component or the disappearance of diastolic pressure are indicated, then this may indicate a chromosomal pathology of the fetus, as well as the onset of fetal hypoxia.
The Doppler ultrasound is about 70% accurate. The most effective is the study of uteroplacental and fetal-placental blood flow, which can almost one hundred percent diagnose various disorders.
Research Evaluation
According to the assessment of different indices, the indicators of blood flow disorders are divided into differentdegrees:
- 1 degree is a violation in the uteroplacental blood flow with unchanged fetal-placental blood flow or a violation of the fetal-placental with unchanged uteroplacental.
- 2 degree - this is a one-time change and violation in both types of blood flow, the indicators of which do not reach any critical values, but take place.
- 3 degree is the presence of critical disorders in terms of fetal-placental blood flow, regardless of the presence of changes or even a slight violation of the uteroplacental blood flow.
Indications for Doppler appointment
Fetal Doppler may be administered once or twice during the entire pregnancy as a routine procedure. Sometimes it is prescribed more often. This happens if there are risks or pathologies for the development of the fetus, or if the condition of the uterus and placenta requires it. There is a list of indications for which it is simply necessary and mandatory to undergo a Doppler study:
- If the mother's age is over 35 or under 20 (early or late pregnancy).
- Polyhydramnios and oligohydramnios.
- An entanglement of the umbilical cord was revealed on a previous examination with an ultrasound machine.
- Fetal development lags behind established norms.
- Mother has a chronic severe illness.
- When previous pregnancies ended in miscarriages or children were born with severe defects or stillbirths.
- If there is a suspicion of malformations.
- When multiplepregnancy.
- If the mother has a negative Rh factor, which can cause fetal rejection if the circulation is disturbed.
- When CTG parameters are unsatisfactory.
- If there was a trauma to the abdomen of a pregnant woman.
If there is a threat of sudden termination of pregnancy, a Doppler study is required to determine the reasons for such fears. In this case, the woman goes to the day hospital, where the first thing she does is undergo a Doppler ultrasound examination and take hormonal therapy in order to maintain the pregnancy until the terms at which it is possible to carry out a safe delivery with minimal risks.
Preparing for the study
To prepare for a Doppler study, it is advisable for a pregnant woman to take food a couple of hours before visiting the ultrasound room and then limit herself to only water. To start the study, you will need to lie down on the couch near the apparatus on your back, while opening your stomach from the chest to the groin. One or more drops of a special conductive gel is applied to the surface of the pregnant woman's abdomen, which helps the penetration of the ultrasound signal, and a special sensor is applied, which is smoothly driven over the surface of the abdomen.
Fetal Dopplerometry can be performed both on black and white equipment, and on modern color equipment, on which an ultrasound specialist will see curves with peaks indicating the intensity and norm or deviation from it of blood flow in the arteries. After the study, the doctor will enter the data obtained duringexamination, and write a transcript to them, after which he will give the conclusion of the Doppler ultrasound to the hands of the pregnant woman.
Fetal Doppler, indicators and their interpretation will be a good help for an obstetrician-gynecologist in managing a woman's pregnancy, preparing for a safe delivery and monitoring complications. Observation of the state of the internal organs and the fetus with the help of Doppler studies is greatly simplified and has been proving its effectiveness and reliability for many years. More and more studies in recent years confirm the safety of examination using ultrasound technology, eliminating the possibility of harm to the he alth of both the expectant mother and the unborn baby.
