Contents
Pregnancy for many women is associated with a pleasant time in anticipation of replenishment of the family. But sometimes this period can be overshadowed by the gynecologist’s assumptions about possible deviations in the development of the fetus, which in the future can negatively affect the quality of life of the baby.
To eliminate risks of this kind, as well as to diagnose pathology at an early stage of its development, many doctors send their wards for duplex scanning of the uteroplacental blood flow. This is one of the most modern methods that allows you to safely evaluate certain conditions for both the expectant mother and the baby. Most of the similar ways to establish the current clinical picture have a whole string of contraindications, at the top of which is pregnancy.
Usually, the procedure is prescribed for those women who have been diagnosed with a suspected violation of the delivery of nutrients through the blood to the fetus. This is a common picture for those suffering from diabetes and a number of other chronic diseases. But even if the deviation is confirmed, this is not a reason to panic.
The doctor will simply adjust restorative therapy and refer to scans for regular monitoring of the condition more often than it happens in completely healthy women.
The essence of the study
The duplex testing format is a relatively new measure for establishing possible hemodynamic disorders. Also, with its help, it will be possible to consider the structure of internal organs and entire systems, which allows you to draw up a general clinical picture without involving traumatic instruments. Here, ultrasonic waves are used for this, which are much safer for humans than the same x-rays.
The technical side of the issue is based on the ability of tissues to transmit, and then reflect the waves of a high-frequency sample arriving at the viewed area. For medical use, devices are attracted, whose frequency range is more than 20 thousand Hz.
When involving duplex testing, a special sensor is used, which is designed to capture reflected signals. The result is displayed on the monitor, representing the usual two-dimensional image, which is transmitted in two modes.
The first mode is called “B” and is an indicator of the density of the tissue along with its uniformity. For the convenience of scanning, the studied areas are schematically divided into two camps:
- echo positive;
- echo negative.
They are dark and light in color, respectively.
To examine in detail the features of the movement of objects, doctors resort to the help of the “D” mode, which is sometimes also called simply doppleography. It is responsible for fixing the frequency offset of incoming signals, interpreting them depending on which direction the movement has.
To further simplify the subsequent reporting, the picture of the filling of the vessels along with the flow of blood flow is presented in two-dimensional parameters. Such a color image of a sufficiently high quality is called a cartogram.
The procedure for establishing deviations from the norms of the uteroplacental blood flow is evaluated by the doctor according to the state of the trio of vascular systems, which covers:
- both uterine arteries;
- the placenta in matters of uniformity of the vascular “network”;
- a pair of arteries and one vein of the umbilical cord.
If the gynecologist has indirect evidence that the fetus is suffering from hypoxia, then the pregnant woman is additionally prescribed to scan the blood flow of the aorta itself and the baby’s middle cerebral artery.
Also, an experienced expert will not stress the expectant mother once again and will definitely clarify the gestational age before scheduling a duplex examination. It is safest to carry it out for a period of approximately 20 to 24 weeks. This precautionary measure is explained by the fact that the power of the supplied signals will be slightly higher than it happens with traditional ultrasound for the pelvic organs and the abdominal cavity.
But even if the deadline does not fit into the generally accepted norms, this should not serve as a significant obstacle to the appointment of an examination in case of urgent need.
Advantages over analogues
In the normal course of the “interesting situation”, women are prescribed only a number of standard tests and traditional ultrasound. This progenitor of the modern duplex analogue is considered a safe method that has no significant contraindications and is designed to determine the exact gestational age.
Also, classical echography is designed to determine the simplest structural changes in the placenta, including difficulties with its location. If any suspicions arise at this stage, then just a scan is prescribed to examine the exact picture of the intrauterine development of the fetus.
Ultrasound, which helps to establish a possible multiple pregnancy, as well as the size of the crumbs and its possible entanglement with the umbilical cord, is unlikely to be able to provide more accurate information about any pathology. And if initially cardiotocography was used for a deeper analysis, today it has been replaced by a duplex study. It combines both conventional ultrasound and Doppler effect testing. The latter allows you to better study the reaction of the baby’s cardiovascular system to uterine contractions.
At this stage of the study, a girl can be diagnosed with fetoplacental insufficiency, as evidenced by:
- falling outside the basal heart rate (less than 100 beats or more than 170);
- rhythm deceleration;
- decreased heart rate variability.
Just such a non-invasive system, which is aimed at studying the dynamic blood circulation according to the “from mother to child” scheme, makes it possible to recognize the first alarming bells.
In addition to all of the above, scanning also allows you to establish deviations in the patency of the uterine, umbilical and small arteries with the fixation of blood flow velocity.
If the suspicions are not confirmed, then the previously scheduled amnioscopy may even be canceled. If the duplex technique identified causes for concern, but could not accurately determine the localization or nature of the disease, then the intervention of the amnioscope is indispensable. It is necessary to obtain an indirect assessment with the analysis of amniotic fluid. Deciphering the color of the liquid must be provided by the attending physician.
The main advantage of the procedure, which mixes the standards of ultrasound and the Doppler effect, is a fairly high accuracy, as well as the absence of undesirable consequences. Doctors themselves appreciate this analysis of uteroplacental blood flow due to the ease of execution and the ability to obtain results immediately after the test.
Indication for appointment
Since there are many reasons that become the primary source of abnormalities for blood flow in the placenta and uterus, experts sorted all of them according to three thematic groups. They cover the following categories:
- from the mother’s side;
- from the side of the placenta;
- from the side of the fetus.
In the first case, the most common cause is late toxicosis, which in medical terminology is called preeclampsia. The condition is caused by the natural reaction of the female body to the presence of foreign tissues in the body.
Less common are:
- arterial hypertension;
- obesity;
- anemia.
The first item belongs to the camp of chronic diseases and is a permanent high blood pressure. After a while, unnatural blood pressure indicators begin to affect the so-called target organs, which include not only the heart muscle, but also the brain, as well as the eyes.
An equally serious problem is obesity, which provokes unnecessary pressure on the uterus. Because of this, the inflow and outflow of blood do not occur as laid down by nature.
If, when deciphering the results of a duplex analysis, it turns out that the baby suffers from hypoxia, then the reason for this may be anemia of the mother. It is caused by a decrease in the level of hemoglobin, which is responsible for transporting oxygen throughout the body. If the disease detected by the scan is ignored, the risks of miscarriage, premature birth, or impaired development of the child increase.
Women who have previously been diagnosed with uterine fibroids can also be sent for testing. A benign formation from muscle tissue is considered not particularly dangerous, but not during pregnancy. In an interesting position, the neoplasm is able to compress the placenta and inhibit vascular patency.
Also, diseases on the part of the mother, after the detection of which she will be sent for a specific ultrasound, are:
- Chronical bronchitis;
- pneumonia;
- bronchial asthma;
- respiratory failure.
As soon as the supply of oxygen to a new family member is reduced, there is a risk of deviations in childhood development. By an identical principle, the danger is cardiovascular insufficiency. The disease may be the result of:
- ischemia;
- cardiomyopathy;
- valve defects.
As soon as the heart’s “pump” stops working at full capacity, it provokes a drop in pressure, which blocks the normal transport of blood.
In addition to problems on the part of the mother herself, there are also a number of prescriptions, which are explained by the pathologies of the placenta. Among them are separately distinguished:
- changes in tissue homogeneity, which may be a cyst, tumor, or a previous heart attack;
- premature aging;
- inconsistency with the gestational age;
- presentation
The latter option affects situations where the placenta is located in the lower part of the uterus, where the blood does not flow particularly actively. Such a scenario increases the risks of hypoxia several times.
A little less often, the reasons for sending ladies in a position for scanning are problems on the part of the fetus itself. Most often, they begin to be suspected after undergoing a primary classical ultrasound, which provides for the definition of developmental delay. This indicates a discrepancy between the growth dynamics of the crumbs and the established gestational age. Also, a large fetus weighing over 4 kilograms can become a problem.
Separately, young ladies with diabetes mellitus and those who had intrauterine infections during a laboratory test were included in the risk group.
Despite the stereotypes that any examination negatively affects the well-being of the future newborn, duplex scanning is not included in this list of risky procedures. The fact that the only significant contraindication for its implementation is only the serious condition of the woman confirms the truth. Then the victim needs first aid.
How is the manipulation going?
Diagnostics does not oblige the lady to specially prepare for the appointed date. The examination is carried out in the usual ultrasound room of the clinic. No special dietary requirements are put forward with the subject before direct analysis. It is also allowed to conduct it at any time of the day without the risk of getting a result with a high percentage of error.
The study is carried out in a supine position, for which a medical couch is provided in the office. First, the diagnostician applies a gel to the sensitive sensor so that contact with the skin is as tight as possible.
Next, the doctor slowly moves the sensor along the anterior part of the abdominal wall, which makes it possible to assess the blood flow in all the vessels present there. Usually, the procedure starts with checking the uterine arteries, and it doesn’t matter which one to start with – right or left. This allows you to identify problems with symmetry.
Having completed with the uterine part, the specialist switches to examining the structure of the placenta, which is necessary to exclude angiomas – vascular tumors. After that, the umbilical cord and certain problematic vessels, such as the fetal middle cerebral artery, are examined.
You also need to remember that before the 16th week of pregnancy, it is not advisable to use the presented technique. The reason for this is the incomplete formation of the placenta, which will not allow you to notice hemodynamic disorders.
An additional advantage of scanning is the possibility, along with the study of the clinical picture of the blood flow of the uteroplacental type, to also establish possible anomalies of the cardiovascular system of the crumbs. In total, the test lasts no more than twenty minutes.
Conclusions and decoding
The main consequence of impaired functioning of the blood flow of the uterus and placenta is called the syndrome of delayed development of the child. But not always the suspicions of gynecologists are justified.
To understand the conclusion made by the sonographer, you need to understand the features of three important aspects of the study:
- resistance index;
- systolic-diastolic ratio;
- pulse index.
The first nuance affects the indicators of the existing resistance, which occurs at pressure in the vessel. The higher this level, the less blood, and, accordingly, oxygen with nutrients, comes to the future child.
The systolic-diastolic ratio is responsible for the indicators of the ratio of blood flow velocity at various stages of cardiac activity.
And the pulsation index shows the amplitude of vascular filling. It is calculated by the difference between the maximum and minimum blood flow rates in relation to the average norms.
All versions of feto-placental insufficiency can be divided into three degrees of complexity. The first covers an isolated violation either in the segment of the uteroplacental nature, or fetal-placental. At the same time, the functionality of the system is still preserved, which is the easiest course of deviation.
The second degree is based on the defeat of both segments, but the study indicators are still outside the critical border.
The third degree is considered the most dangerous, as it involves blood flow disorders with a complete absence of blood flow. In a particularly sad scenario, a woman is even diagnosed with a reverse or retrograde flow format. But even here the functioning of the segments is still preserved.
Separately, situations are considered when false positive results are diagnosed. In this situation, the doctor writes down the diagnosis of “placental insufficiency” in the patient’s medical card. Such a strange state of affairs is explained by the fact that not all types of pathology are a direct consequence of a violation of the stability of blood flow.
It is not for nothing that gynecologists with experience in fixing an extraordinary pathology insist on conducting a comprehensive study. It includes an assessment of the morphological structure of the placenta and uterus, which occurs due to the conclusions after classical echography. Also, a comprehensive set is based on cardiotocography and dopplerometry.