Rh-conflict during pregnancy: how to diagnose and treat

A woman’s immunity collides with the Rh antigen in two cases: after a blood transfusion with a positive Rh factor or mixing the erythrocytes of a pregnant woman and a fetus.

As a rule, the placenta does not allow maternal and infant blood to mix – this is called the hematoplacental barrier.

But the barrier function of the placenta is disrupted:

• during childbirth;
• during placental abruption;
• due to ectopic pregnancy;
• due to abortion or miscarriage;
• due to uterine bleeding.

After a positive Rh factor of the child enters the mother’s bloodstream, the immune system perceives the Rh antigen as foreign and produces antibodies that destroy the fetal erythrocytes.

In the normal physiological course of pregnancy, sensitization of the mother’s body with the Rh antigen does not occur. Therefore, the birth of the first child occurs with a minimal risk of Rh-conflict.

After the destruction of red blood cells by antibodies, bilirubin is released, which accumulates in the body and causes the development of fetal brain hypoxia.

For the processing of accumulated bilirubin and the formation of new erythrocytes, the liver and spleen are enlarged.

The abnormal concentration of bilirubin causes hemolytic disease of the fetus.

In terms of severity, the disease is divided into three types:

• anemic;
• icteric;
• hydropic.

The first option is manifested by mild anemia, increased concentration of bilirubin in the blood, but jaundice is not observed. The newborn will recover even without medication.

Hemolytic disease in moderate severity is manifested by an icteric form. The newborn has anemia, yellowing of the skin, enlarged liver and spleen, so resuscitation therapy is prescribed.

Pregnancy with Rh-conflict in an edematous form in the early stages ends in spontaneous miscarriage.

The baby is born in a serious condition: severe anemia, hypoxic encephalopathy occurs, tissues swell, fluid accumulates in the chest and abdominal cavities.

In the antenatal clinic, every pregnant woman is examined for the Rh factor.

If her partner has an Rh antigen, then the first antibody test in a Rh-negative woman is done between weeks 18 and 20. Up to 32 weeks of pregnancy, a study of antibodies in the blood is done monthly.

The allowable concentration of antibodies is 1: 4. From the 32nd to the 35th week of the term, the antibody titer is examined twice a month, and from the 35th week to the delivery, the analysis is done every 7 days.

An increase in antibody titer over 1: 4 confirms Rh-conflict during pregnancy. Titles 1:64, 1: 128 and more are considered critical.

For prophylactic purposes, at the 28th week of the term, a woman is given an injection of anti-rash serum, which counteracts the formation of antibodies to fetal erythrocytes.

Within 48 hours after the birth of a child with a positive Rh factor, abortion, miscarriage or ectopic pregnancy, a woman is injected with anti-rhesus serum, which prevents the appearance of a Rh conflict in the future.

For the treatment of a newborn, use:

• hemosorption;
• blood transfusion;
• phototherapy;
• hyperbaric oxygenation.

With the help of hemosorption, the baby’s blood is purified by passing it through filters. To replace the disintegrated red blood cells in utero or after birth, replacement blood transfusion is performed.

Phototherapy for a child with jaundice is done under special blue lamps. Ultraviolet light acts through the skin and accelerates the breakdown of bilirubin.

Treatment with hyperbaric oxygenation is placing the newborn in a hyperbaric chamber with increased oxygen pressure to combat cerebral hypoxia.