Is it harmful to perform Doppler ultrasound diagnostics during pregnancy?

A third screening ultrasound for expectant mothers has recently become a recognized necessity. Thanks to the widespread introduction of prenatal screening, infant mortality has significantly decreased , and the number of congenital anomalies and fetal pathologies has decreased. Medical technologies are developing dynamically, and now ultrasound echography is often complemented by a special technique - Doppler ultrasound during pregnancy. What it is?

The essence of the method is to register and evaluate blood flow indicators:

• in the vessels of the umbilical cord;
• in the uterine arteries
• in the median artery of the child’s brain;
• in the ductus venosus;
• in some other vessels and arteries, according to indications.

The Doppler effect got its name thanks to an Austrian scientist who first noticed that ultrasonic waves are reflected from particles that move, including red blood cells.

Why do they do it?

Dopplerography successfully complements conventional ultrasound examination, because thanks to it you can:

1. Find out the state of the child’s heart, listen to the frequency with which his heart beats.
2. Determine whether there is a narrowing in the lumen of the umbilical cord vessels , Assess how passable they are.
3. Find out how well the fetal circulatory system functions.
4. Assess the condition of the placenta to identify oxygen starvation of the baby in its early stages.
5. Determine potential or actual umbilical cord entanglement around the baby's neck.
6. Identify pathologies of the placenta, low and polyhydramnios.
7. Clarify the information if the doctor suspects some developmental defects based on ultrasound.
8. Find out whether the fetus meets the expected development dates.
9. Find out if there are any umbilical cord abnormalities that are suspected based on ultrasound results.

An ultrasound with Doppler is necessary for an expectant mother who has the following problems:

• decrease in hemoglobin;
• “frozen” previous pregnancy or miscarriages;
• high blood pressure;
• uterine fibroids;
• genital tract infections;
• respiratory failure;
• diseases of the cardiovascular system.

But even a healthy woman may develop abnormalities during gestation or discover pathologies of the placenta, which require Doppler examination. Such pathologies include:

1. The likelihood of premature birth or sudden termination of pregnancy.
2. Ultrasound signs of structural changes in the placenta , or its discrepancy with the timing.
3. Placenta previa.
4. Intrauterine developmental delay of the child.
5. Rhesus conflict.
6. Ultrasound signs of intrauterine infection.
7. Large fruit.
8. Established heart failure or oxygen starvation in the baby .
9. Malformations of the heart, large vessels or internal organs of the child.
10. The umbilical cord entwines the baby's neck.

Video

When is ultrasound ultrasound prescribed (in what situations) during pregnancy? The video below will give you an idea of ​​the indications for the procedure.

What is Doppler testing during pregnancy?

Doppler ultrasound is a method for diagnosing pathologies in the early stages. It is considered a popular type of ultrasound. It is carried out during pregnancy, as planned, and is prescribed as an additional examination. Doppler testing involves assessing the frequency of sound, which is constantly changing due to the movement of blood flow. Also, this study allows the specialist to determine what kind of blood flow and at what speed it moves through the vessels, whether it is disturbed or not, and how it functions in the placenta. Thanks to Doppler ultrasound, the doctor can diagnose fetal diseases.

When do they do it?

After registering a pregnant woman, a gynecologist develops a specific plan for managing her pregnancy. This sample plan takes into account:

• general condition of the expectant mother;
• chronic diseases;
• compliance of fetal development with timing;
• bad habits;
• living conditions.

Reference! It is mandatory to perform an ultrasound examination with Doppler twice during the gestation period: at 22-24 weeks, at 30-34 weeks.

There are procedures common to all pregnant women. Such measures include triple screening , certain tests and ultrasound with Doppler .

Classification of blood flow disorders according to Medvedev

The magnitude of deviations of the ASC obtained during the Doppler study from existing norms allows us to judge the severity of the disturbance of the uteroplacental and fetal placental blood flow.

1st degree

A – violation of uteroplacental blood flow while maintaining fetal-placental blood flow;

B – violation of fetal-placental blood flow with preserved uteroplacental blood flow;

In this case, under strict medical supervision of the baby’s condition, a natural birth on time is possible, if there is no pathological deterioration in Dopplerography and CTG parameters.

2nd degree

Disruption of blood flow in the arteries of the uterus and the arteries of the umbilical cord simultaneously, in which, however, the rate of blood circulation does not reach zero even in the diastole phase.

This disorder requires frequent regular monitoring of the fetus’s condition using Dopplerography and CTG. The woman is sent to the hospital, where therapy is carried out to improve the functions of the placenta. Comprehensive treatment against hypoxia and intrauterine growth retardation is also prescribed.

3rd degree

Disturbance of fetal-placental blood flow, which has reached critical values, in which the blood flow velocity is “zero” or reverse (“reverse”) blood flow is noted in the diastolic phase.

If critical values ​​are detected indicating fetal suffering in late pregnancy (over 30 weeks), a decision is made on emergency delivery through cesarean section.

In the case of complex therapy aimed at supporting the placenta and fetus, under the control of Doppler and ultrasound, it is possible to carry the pregnancy to 30 weeks.

Evaluation of results to determine fetal hypoxia

For any indicator of disturbances in the utero-placental-fetal circulation, it is important to determine whether the baby began to suffer from hypoxia in the womb, and to what extent.

If this happens, then during a Doppler examination the ASC of the fetal aorta, middle cerebral and carotid arteries will show deviations of the current values ​​from normal:

If pathological changes in the speed of fetal blood flow are nevertheless recorded, then the medical tactics of pregnancy and childbirth also depend on the severity of circulatory disorders and their consequences.

1st degree

Changes in blood flow in the placenta-fetus system, with compensatory changes in the ASC in the fetal vessels.

This condition is not yet critical and with proper and timely treatment can be reversible. If the necessary measures are not taken on time or do not bring the desired effect, in a few weeks (about 3) the situation will worsen.

2nd degree

Blood flow in the vessels of the unborn baby is hampered, and intrauterine hypoxia develops. The deterioration progresses rapidly.

What are they watching?

Doppler ultrasound makes it possible to obtain information about the condition of the arteries and the entire vascular system of the expectant mother. On the monitor screen during a Doppler study, the doctor evaluates parameters such as:

• degree of vascular patency;
• the width of their lumens and the absence of stenosis;
• internal pressure;
• blood flow speed and its compliance with standards;
• the degree of blood supply to the child’s organs;
• possible oxygen starvation.

Decoding Doppler results

Only a highly qualified specialist can interpret the results of an ultrasound examination during pregnancy using Doppler.

When trying to understand the norms and deviations, the attending physician calculates the following data:

• resistance index (IR, or RI) - a parameter for assessing blood flow speed;
• pulsation index (PI) - average blood flow velocity during the cardiac cycle;
• systole-diastolic ratio (SDR) of arteries (uterine, umbilical, middle cerebral), fetal aorta. This indicator is calculated by establishing the proportion of contractions of the heart muscles and the intervals between them;
• indicators of venous function of the vessels of the mother and child, as well as the umbilical cord.

An increase in the above standards indicates disturbances in the development of the child associated with improper fetal-placental blood exchange.

What does it show?

Unlike traditional ultrasound, which gives a general idea of ​​the condition of mother and baby, Doppler ultrasound shows the speed and direction of blood flow .

It is this procedure that makes it possible to see areas where blood flow is blocked and begin correcting this condition in time, before the baby begins to experience hypoxia or the mother has health problems.

The latest ultrasound machines often provide the opportunity to choose one of two Doppler diagnostic options to get more complete and accurate results:

1. Ultrasound + Doppler is a duplex scan, which is also called Doppler ultrasound.
2. Triplex examination - supplemented with a colored image, where each section of the blood flow has its own color.

Indications for use during pregnancy

This examination of pregnant women is prescribed:

• When the age category of the pregnant woman is less than 21 and over 34 years.
• If there is oligohydramnios, polyhydramnios.
• If an ultrasound revealed that the umbilical cord loops are close or wrapped around the neck.
• The baby has a significant developmental delay.
• The pregnant woman suffers from diabetes, thyroiditis and hypertension.
• The pregnancy before this ended in a miscarriage, the birth of a fetus with abnormalities, and the death of the fetus inside the womb.
• If a specialist suspects malformations of internal organs.
• If a mother is pregnant with several babies.
• Mother's Rh factor is negative.

Decoding and norms

Normal Doppler readings are:

• uteroplacental blood flow - should be clearly visible in both uterine arteries;
• fetal-placental blood flow - should not have visual difficulties, otherwise the fetus will suffer;
• fetal blood flow - assessed in vessels such as the middle cerebral artery, aorta and internal carotid artery.

The device is designed in such a way that during operation, data on the maximum (S - systolic) and minimum (D - diastolic) blood flow velocity automatically appears on the screen. On their basis, vascular resistance indices (VRI) are calculated:

1. IR (resistance index) = (S-D)/S;
2. SDO (systodiastolic ratio) = S/D;
3. PI (pulsation index) = (S-D) / average speed shown on the screen.

The obtained values ​​are compared with normal values , which differ not only for each vessel, but also for each week of pregnancy:

Table 1. Normal values ​​by week.

Types of Doppler

When talking about what Doppler testing is, it is necessary to distinguish between the types of this study. Despite the fact that the methods of conducting the study do not differ from each other, how, to whom and at what time an ultrasound is performed can radically change the interpretation of its results. Therefore, when reading the results of the study yourself, you must remember that the information on a directory website or medical forum may also be unreliable.

Doppler examination makes it possible to:

• Determine the condition of different organs and parts of the body and the characteristics of blood flow in their vessels;
• Examine blood flow in microvessels:
• To study the vascular system of pregnant women, unborn children and the placenta.

Using Doppler ultrasound, the doctor can find out:

• About the causes of impaired blood circulation;
• About the peculiarities of the branching of veins and the condition of their walls;
• Does the patient have an aneurysm, atherosclerotic plaques, blood clots;
• About the speed of blood flow through veins and arteries;
• Does the patient have venous insufficiency?

The doctor prescribes an ultrasound with Doppler effect if the patient experiences the following symptoms:

• Increased cholesterol levels;
• Excess body weight;
• Constantly, occasionally, vision deteriorates;
• The head often hurts and feels dizzy;
• Speech suddenly becomes impaired, weakness occurs, and the upper and lower limbs go numb;
• Intermittent claudication appears;
• Brief loss of consciousness occurs;
• Arterial hypertension;
• Noisy in the ears and head;
• There are signs of a stroke.

Doppler testing reveals:

• Blockage and narrowing of blood vessels,
• Varicose veins and vein thrombosis of varying severity;
• Diabetes mellitus of all types;
• Ischemic and cerebrovascular diseases;
• Spasmodic conditions and brain strokes;
• Pathologies of the arteries of the upper and lower extremities;
• Occlusion of the carotid artery;
• Aneurysms of peripheral, central arteries and veins of the brain;
• Anomalies in fetal development.

Doppler ultrasound allows you to examine the vascular system of all parts of the patient’s body. What is Doppler, and what types of it are:

• Transcranial Doppler examines the blood supply to the brain. At the same time, the diagnostician identifies thrombosis, learns about the speed, volume, direction and quality of fluid movement, and the reasons for its violation. Most often, this diagnosis is performed to assess the quality of blood flow in the middle cerebral artery;
• Ultrasound of the hands and feet with the Doppler effect is used by phlebologists to identify pathologies of the vascular system of the upper and lower extremities. The study helps diagnose thrombosis, varicose veins and venous insufficiency. Doppler ultrasound is useful not only for thrombosis, but also for diseases of the heart, blood vessels and soft tissues of the extremities, for obesity and injuries of varying severity;
• Doppler ultrasound of the vascular system of the penis is used by andrologists to determine erectile dysfunction. With the help of ultrasound, neoplasms in the genital organs are also identified, the consequences of congenital and acquired anomalies and injuries are determined;
• Doppler testing in pregnant women is prescribed for alarming symptoms. This is an optional procedure if the fetus is developing normally and the expectant mother is in satisfactory health, but doctors recommend undergoing it after the 20th week of pregnancy;
• Doppler measurements can be performed separately for the vessels of the neck, kidneys, abdominal cavity, and aorta.

After the procedure is completed, the results of the study are assessed. High indices indicate increased resistance to blood flow. Low values ​​indicate a drop in resistance to fluid flow.

Normally, after the study, a healthy person should have the following Doppler measurements:

• The maximum intensity of blood movement through the vessels during systole is from 15 to 25 cm/sec;
• The final velocity of fluid flow through the veins during diastole is 0 cm/sec.
• The normal pulsation index is more than 4.
• The resistance index norm is about 0.8.

When the resulting systolic-diastolic ratio is greater than 4.5 and the resistance index is greater than 0.774, this indicates pathology.

How do they do it?

An ultrasound examination with Doppler takes about a quarter of an hour and does not harm either the expectant mother or the baby. The procedure is almost identical to a regular ultrasound. The patient lies down on the couch and frees her stomach from clothing, the doctor applies a conductive gel to the skin and turns to the screen.

After a detailed study of the uterus and placenta, it is the turn of the placental circulation and blood vessels. At the end of the examination, the expectant mother will be provided with a conclusion and commented on its results.

Is ultrasound dangerous for the fetus and mother?

Ultrasound is a non-invasive procedure that, when used correctly, has not been shown to have any negative effects on the fetus. However, the long-term effects of repeated exposure to ultrasound on the fetus have not been fully studied, so it is recommended to use ultrasound only when medically indicated.

Although ultrasound is considered safe when used judiciously by trained healthcare professionals, ultrasound energy has the potential to have biological effects on the body. The only thing that is harmful about ultrasound during pregnancy is that the ultrasound waves can slightly heat the tissue. In some cases, ultrasound can also create small pockets of gases in body fluids or tissues (cavitation). The long-term consequences of these effects are still unknown.

How to prepare?

Doppler testing does not require any special preparation.
However, those expectant mothers who were unable to quit smoking will have to give up cigarettes at least a few hours before the procedure. The fact is that nicotine causes vascular spasms and can distort the results of the study.

Preparation for ultrasound with Doppler does not require any special diets ; you can eat before the procedure or come on an empty stomach - this will not affect the quality of blood flow readings.

What can be found out with ultrasound

Ultrasound examination is a diagnostic procedure that detects or helps identify abnormalities and pathological conditions associated with pregnancy. To confirm the diagnosis, ultrasound is usually combined with other tests, such as triple tests, amniocentesis, or human chorionic villus testing.

From a medical point of view, ultrasound examination may be indicated throughout pregnancy for the following reasons:

1. First trimester:

• confirm a viable pregnancy;
• confirm pulse;
• determine the gestational age of the fetus;
• confirm molar or ectopic pregnancy;
• evaluate abnormal pregnancy.

1. Second trimester:

• identification of potential Down syndrome;
• determination of congenital malformations;
• structural abnormalities;
• multiple pregnancies;
• term and growth of the fetus;
• confirm intrauterine death;
• increased or decreased level of amniotic fluid.

1. Third trimester:

• determine the location of the placenta;
• confirm intrauterine death;
• determine fetal presentation;
• identify maternal uterine and pelvic anomalies.

Fetal Doppler at home

Recently, the use of fetal dopplers, portable devices for listening to the fetal heartbeat, has been growing in popularity.

Important! This device can be used at home; it makes it possible to monitor the baby’s condition in real time.

A stationary medical device uses ultrasound radiation 8 times stronger than fetal dopplers, so this device is considered safer.

Does Doppler ultrasound harm a baby?

Very often, medical devices and technologies use dangerous radiation and radiation for their work, so the question of the safety of each procedure is relevant for every expectant mother. However, specialists in the field of gynecology try to minimize all harmful effects so that the benefits of diagnosis outweigh the harm from it.

Doppler ultrasound is considered a modern and safe procedure. All possible consequences and harm must be reflected in the documentation attached to the equipment. Numerous reviews from mothers who have undergone this procedure statistically confirm that 10 minutes of exposure to ultrasonic waves does not affect the baby’s health in any way. Doppler ultrasound has made it possible to save many pregnancies and prevent an extraordinary number of childhood diseases thanks to their timely diagnosis.

Don’t be afraid to conduct additional examinations, and if you have questions that concern you, feel free to consult your doctor. Unfortunately, very often inaction becomes more detrimental to the fetus than conducting diagnostics every few months. Be sure to weigh all the pros and cons before refusing additional procedures.

Materials and methods

The retrospective study included 53 patients with signs of CKD who were under observation at the Clinic of Nephrology, Internal and Occupational Diseases named after. EAT. Tareev in the period from January 2003 to October 2013. Among them, 25 (47.2%) were women and 28 (52.8%) men; the average age was 44.4±13.6 years.

All patients were divided into two groups comparable in size: 26 with a predominance of glomerular pathology (chronic glomerulonephritis - CGN) and 27 with tubulointerstitial damage, in particular 9 patients suffered from tubulointerstitial nephritis (TIN), 4 from chronic pyelonephritis, 6 from kidney damage associated with hypertension, 5 - with antiphospholipid syndrome, the remaining - polycystic kidney disease. During the first hospitalization, clinical, instrumental and laboratory data of patients were analyzed: age, daily PU, GFR (calculated using the CKD-EPI formula), systolic and diastolic blood pressure, pulse pressure (PP), IR according to ultrasound data. To determine the rate of progression of renal failure over time, GFR was assessed. A decrease in GFR of 10 ml/min/1.73 m2 was regarded as a decrease in renal function. The observation period of the patients was 14±2.64 months.

Standard ultrasound and doppler ultrasound were performed on all 53 patients using an expert-class Sonoline Antares ultrasound device (Siemens Medical Solutions) using a sensor with a frequency of 1-5 MHz. The length and transverse size of the kidneys, the thickness of the renal parenchyma were measured, followed by calculation of the average values. The parenchymopyelic index (PPI) was calculated as the ratio of the size of the parenchyma to the size of the central echo complex, which includes the collecting system with adipose tissue, blood and lymphatic vessels [7]. IR is the ratio of the difference between maximum systolic velocity and end-diastolic velocity to maximum systolic velocity, determined for the renal artery (RA), interlobar arteries (IA), and renal arcuate arteries. For a comparative analysis of the correlation in independent samples between quantitative data, the Pearson criterion was used (where p

<0.05 was assessed as a statistically significant result). When calculating correlation coefficients, the average value of IR of the renal arteries was taken on the basis that this indicator varies slightly between organs [8].

To assess the prognostic significance of IR of the PA, segmental arteries (SA) and MA, their sensitivity and specificity, ROC analysis was used with the construction of curves of the same name.

Stepwise multivariate regression analysis was used to determine factors influencing intrarenal hemodynamics.

Indications

Doppler ultrasound during pregnancy is carried out within strictly defined periods:

• 18-21 weeks;
• 32-34 weeks.

The first time Doppler ultrasound is performed simultaneously with the second ultrasound screening. Conducting the study at an earlier date is not advisable. The final formation of the uterine arteries occurs only at the beginning of the second trimester. The process is completed at 16-18 weeks of pregnancy. After this, you can draw any conclusions about the state of blood flow in the uterine arteries and the performance of the placenta.

It is important to remember: in 30% of healthy women, the development of the uterine arteries is completed only at 22-25 weeks of pregnancy. In this regard, a single disturbance of blood flow at a period of 18-22 weeks should not be regarded as a serious threat to the development of the fetus. With moderate changes in the uterine arteries, the expectant mother is monitored. Blood flow is regularly monitored using Doppler ultrasound, and the condition of the fetus is assessed using ultrasound. In most women, blood flow returns to normal after 22 weeks without additional drug intervention.

Such tactics are not permissible in cases of severe blood flow disturbances, as well as in cases of identified pathology in the hemostasis system (hypercoagulable shifts). In this case, individual therapy is selected taking into account the duration of pregnancy and the severity of hemodynamic disorders. Blood flow monitoring is carried out every 2-3 weeks.