21.01.2021

Rhesus conflict. How dangerous is it during pregnancy

Few people know what the Rh factor is (Rh). This is due to the fact that during ordinary life, its absence or the presence of any painful way does not affect a person. However, if a man and woman have an incompatible combination of Rh, then during pregnancy this can lead to a phenomenon called rhesus conflict.

What is the Rhesus factor? It refers to a protein or antigen located on the surface of red blood cells. Positive rhesus (Rh (+)) refers to the presence of this antigen, and negative (Rh (-)) refers to its absence. Most people are Rh-positive, and only 15% are negative.

This phenomenon occurs only in two cases. Firstly, with a blood transfusion that is incompatible in rhesus. Secondly, if a pregnant woman with Rh (-) has a fetus with Rh (+).

Rhesus conflict development mechanism

Production of antibodies by the body (isoimmunization) becomes a reaction to the receipt in the blood of a pregnant Rh-negative woman of fetal antigens with Rh (+). Their main mass penetrates the fetus through the placenta. Thus, in the body of an unborn baby, red blood cells stick together (hemolysis), and this, in turn, provokes damage to various organs. Hemolysis most affects the brain, liver. This condition is called hemolytic disease of the newborn (GBN).

It is encouraging that during the first pregnancy of a woman with no antigen bearing a child with his presence, the Rh conflict between the mother and the child will not occur. At this stage, antibody production occurs, but it is extremely difficult to avoid it during the second pregnancy.  If a mother who does not have antigen carries a fetus with a similar Rhesus, then there will be no conflict. The same is the case if the mother has a positive rhesus and the fetus is negative, since the blood of the father he inherited does not have antigens.

Symptoms

There are no external signs of isoimmunization on the part of the mother. Symptoms of malaise in a pregnant woman are not observed. Her body is not in danger, but the same cannot be said for the baby inside the womb.

Symptoms of the development of the process in the fetus are noticeable when examined by ultrasound. Water will accumulate in its cavities, resulting in swelling. The position of the baby is usually unnatural, it is also called the pose of Buddha. The mother’s belly may increase due to accumulated fluid, and the baby will be forced to raise its legs. The contour of the head may become double, and the diameter of the vein in the umbilical cord and the size of the placenta will be subject to change.

As a result, a newborn can develop one of three forms of HDN disease: edematous, icteric, or anemic. The edematous form is considered the most dangerous for the baby. Typically, these babies are sent to the intensive care unit or intensive care unit. The degree of complexity of the icteric shape is determined by analyzing amniotic fluid for the amount of bilirubin. The anemic form depends on the severity of the anemia, but is most easily tolerated.

What causes can cause rhesus conflict?

Isoimmunization (Rh-sensitization), which occurs when a woman carries Rh (-), is due to the ingress of Rh incompatible blood of the child into her bloodstream. In many ways, this process depends on the outcome of the primary pregnancy. Sometimes the occurrence of Rh sensitization occurs during the first pregnancy. This is possible if a woman has been given a blood transfusion before, without considering the Rh compatibility. Also, the risk increases if a pregnancy was previously terminated spontaneously or artificially.

Most often, umbilical cord blood enters the bloodstream of the mother during childbirth. So, the female body becomes susceptible to the baby antigen, and there is a risk of Rh sensitization during the second pregnancy. In addition, the risk increases after cesarean section. At risk are also women who suffer from bleeding due to damage or detachment of the placenta, manual separation, and those who underwent prenatal diagnosis – cordocentesis, chorionic biopsy, amniocentesis. In 2% of women with a lack of antigen, the cause of the Rh conflict may be the intrauterine sensitization of a pregnant Rh (-), which once occurred at her birth from an Rh (+) mother. If a Rh (-) pregnant woman suffers from diabetes, preeclampsia, or has suffered acute respiratory infections, influenza, then synthesis of anti-Rhesus antibodies can be activated in her body due to a violation of the integrity of chorionic villi.

Rhesus conflict can even lead to a miscarriage. In view of this, Rh negative moms should be very careful about their position. They need to follow all the recommendations of a leading pregnancy specialist.

Diagnosis

The first thing that doctors do in order to determine whether a Rhesus conflict develops is an analysis for the presence of antibodies. To determine whether women are at risk, an analysis is made in the first trimester of pregnancy that determines the Rh factor. This procedure is also the father of the baby. If there is a danger, then once a month the pregnant woman will re-take such an analysis.

If there is a threat, starting from the 20th week, the mother carrying the fetus passes from the antenatal clinic to a specialized center. From 32 weeks she will be tested twice a month, and after 35 weeks and before delivery – weekly. From 28 weeks, the blood exchange between the fetus and the mother increases, which means that the amount of antibodies in the body of the child is the same. Starting from this time, the expectant mother will be closely monitored.

The first ultrasound is prescribed somewhere at 18-20 weeks, after – at 24-26, another – at 30-32, the penultimate – at 34-36 and the final – before childbirth. If the condition of the fetus worsens, then an additional examination can be performed. To assess the speed of blood flow and heart function, Dopplerometry is performed. To determine the reactivity of the cardiovascular system, the possible presence of hypoxia, CTG is performed.

To assess the condition of the unborn baby, you may need invasive methods of examination. Amniocentesis is sometimes prescribed, for which the fetal bladder is punctured and amniotic fluid is taken, then their analysis is carried out. The procedure provides an opportunity to establish the amount of bilirubin, and this helps to determine the true condition of the fetus. Such a puncture is indicated only if the titers of antibodies are 1:16 or the woman has children with any form of GBN. Amniocentesis can lead to dangerous consequences. For example, infection of amniotic fluid, their leakage, bleeding, may start the process of premature detachment of the placenta, as well as other pathologies.

Cordocetosis is carried out if the antibody titer is 1:32, the rhesus conflict has caused the death of children, there are those born with severe form of HDN. Like the previous study, the procedure is very dangerous, as it can lead to the same consequences. To conduct it, the umbilical cord is pierced and blood is taken for analysis. Cordocetosis more accurately determines the content of bilirubin than amniocentesis. In the same way, a blood transfusion is carried out to the fetus. Examination can lead to the development of a hematoma on the umbilical cord, which interferes with the metabolism between the mother and the fetus.

Isoimmunization Treatment

To weaken the effect of antibodies, all mothers with Rh (-) undergo desensitizing therapy for a period of 10 to 12 weeks, 22 to 24, 32 to 34. For this, women are prescribed vitamins, iron and calcium preparations, metabolic and antihistamines, oxygen therapy. After 37 weeks, in the normal condition of the baby, the pregnant woman can give birth on her own. In order to prolong pregnancy, intrauterine blood transfusion can be performed, which helps to compensate for anemia, hypoxia, prolong the process of gestation. To reduce the titer of antibodies, mothers can prescribe plasmapheresis.

Most often, a pregnancy that proceeds along with the development of a Rhesus conflict ends with a planned preterm birth. Using all available methods, doctors monitor the condition of the baby. So, they can make an immediate decision regarding the continuation of gestation or premature birth. It depends on what will be safer for the baby. Practice shows that with the development of such a phenomenon, natural childbirth is rarely allowed, and then if the condition of the fetus is satisfactory, and there are no other contraindications. But even if childbirth is allowed, then specialists continue to actively monitor the condition of the fetus. If complications arise, they can prescribe an immediate caesarean section.

Even if Rh sensitization does not occur in a Rh negative mother during gestation, a blood test should be performed immediately after birth. If the baby has Rh (+), then during the first 72 hours after giving birth, the woman is given an anti-Rhesus immunoglobulin. The drug very quickly destroys the red blood cells of the newborn that got into the mother’s body. Thanks to this, the mother’s body does not have time to develop antibodies. This minimizes the fact that the Rhesus conflict will develop during subsequent pregnancy. The same drug is administered to a Rh-negative woman during the first 72 hours after a miscarriage, abortion, in some other cases. At the moment, immunoglobulin is recommended to be administered to all women carrying babies with Rh (-). It is administered at 28 and 34 weeks of gestation.

Mother Responsibility

A woman, first of all, must herself understand the measure of her responsibility. So, after conception, she must carefully comply with all the doctor’s prescriptions, the timing of the control. In addition, to determine the presence of antibodies, she needs to be tested regularly – at least once a month. The absence of antibodies indicates that the child is developing normally at this stage. But, the expectant mother must understand that the risk of their formation will be before the birth itself and even in their process.

An increase in antibody levels means that the activity of the immune system against Rh (+) is enhanced. If all analyzes indicate that the Rhesus conflict develops, then the mother carrying the child should immediately go to the perinatal center for preservation. Here she will be prescribed and given the necessary treatment, and the woman and the fetus will be constantly under close medical supervision. The future mother cannot be resisted by the offered help, otherwise she risks giving birth to a child in serious condition or losing him altogether.

In severe forms of the lesion immediately after birth, the newborn begins to be treated for HDN. In order not to worsen the condition of the baby during the first two weeks, breastfeeding is prohibited. If the baby develops normally, without symptoms, then the mother is just given an injection of anti-Rhesus immunoglobulin, after which breastfeeding can begin. But in this case, the doctors did not come to a consensus regarding feeding.

Some experts evaluate the condition of the newborn and, to ensure its safety, may prohibit feeding for several days. Others argue that there is no need to limit breastfeeding. But, since these studies do not have any confirmation, and the equipment of the clinics leaves much to be desired, it is better not to dispute the decisions made by the doctors. They focus on their capabilities and the condition of the newborn. The main thing is that specialists are interested in the well-being of the baby and its mother.

So, the Rhesus conflict is not a sentence, and it is quite possible to bear a baby with such a diagnosis. The absence of antigens in the mother does not always mean that pregnancy will lead to isoimmunization. It is indisputable that this diagnosis can end in failure, but this is not a reason for despair. Only 0.8% of Rh-negative pregnant women experience this problem.

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