Precautions for pregnancy in women with RH-negative blood, this article focuses on RH-negative blood antibody potency testing.
First, pre-pregnancy preparation.
Before a Rh-negative woman gets pregnant, she needs to go to a blood center or designated hospital for ABO and Rh blood group identification and to have a preconception blood immunology prenatal test (blood group antibody test). Women with rare blood types should not abort easily, as abortion may lead to the production of antibodies. Other eugenics tests are no different from those for people with popular blood types, so basically, just do what the maternity hospital asks.
①If it is your first pregnancy, there is generally no need to be overly nervous. You should have a blood immunology prenatal test (blood group antibody test) from the 5th month of pregnancy, then have an antibody test at the 7th month of pregnancy and at the 9th month of pregnancy, and then have a repeat antibody test about 6 months after delivery. Anti-D immunoglobulin can be injected within 72 hours after delivery if antibodies are rarely produced during the first pregnancy. The anti-D immunoglobulin is a preventive shot to prevent the development of anti-D antibodies, that is to protect their reproductive rights and future blood transfusion to protect the right to donate blood, so before the development of antibodies to play and not wait until there are antibodies and then consider playing, anti-D antibodies once developed is difficult to eliminate, prevention is the key.
If antibodies are detected during pregnancy, see the following pregnancy monitoring
② If you have a history of miscarriage or childbirth, you need to check your blood type for antibodies from 16 weeks, and then test for antibodies once a month thereafter (especially after 28 weeks, which is a critical period for antibody production), and then have a follow-up antibody test about six months after delivery. If no anti-D antibodies are produced during this period, anti-D immunoglobulin will be injected between 26 and 28 weeks of pregnancy as a preventive measure, and again within 72 hours after delivery. (If antibody production is detected during pregnancy see pregnancy monitoring below)
It is best to get pregnant when the anti-D potency is zero in Rh-negative women, and generally not more than 1:8 if antibodies are already present.
The mother-to-be who has given birth to a newborn with hemolytic disease is not suitable to get pregnant immediately when the antibodies in her body are still at a high value, because the fetus may develop severe intrauterine anemia in the middle and late stages of pregnancy, causing fetal edema and stillbirth. In this case, it is necessary to take drugs with antibody immunosuppressant effect beforehand, and if necessary, to carry out plasma exchange or plasma removal treatment to make the antibody potency in the body drop to a low value before conceiving, and the current methods to reduce the antibody, whether they are traditional Chinese medicine or plasma exchange, are not 100% effective, so it is important to prevent antibody production.
Secondly, monitoring during pregnancy.
① Regular immunohematological prenatal checkups (blood group antibody testing) for pregnant women: Once the presence of antibodies is confirmed, it is important to immediately go to an advanced hospital that has specialized research on rare blood group fertility for treatment.
If there are cases where antibodies are found to be produced during pregnancy, it is important to check once every 2 weeks to observe if the antibodies are elevated.
If there is an elevation when the antibody potency is greater than 1:16 then there is an effect on the fetus, which can be combined with ultrasound to check for edema, effusion and arterial anemia. When the antibody is elevated above 1:64, amniotic fluid examination can be done: measurement of high optical density value at 450nm wavelength, umbilical vein puncture, fetal blood group, hemoglobin, red blood cell count, bilirubin level and anti-human globulin test.
If the antibody potency is >128, plasma exchange can be performed as appropriate. If the fetus is severely anemic, intrauterine blood transfusion and postpartum blood exchange can be considered.
In order to correct severe anemia and save the fetus, intrauterine transfusion should be combined with early fetal intrauterine transfusion in addition to maternal plasma exchange. All these need to be carried out in an advanced hospital with these hardware facilities and related operational experience, a professional and responsible hospital is quite important.
Third, post-delivery treatment.
①If the mother did not produce Rh antibodies during pregnancy and the fetus is in good condition, it can be treated as a general neonatal routine, but should be closely observed for the possibility of progressive jaundice.
②If the maternal Rh antibodies are too high, the newborn is often already damaged in the fetal period and can be delivered by early cesarean section.
③After birth, a direct anti-human globulin test should be performed on the affected red blood cells to clarify whether the newborn has RhD, RhE or other Rh hemolytic disease. Pay attention to the time of appearance of jaundice, the rate of bilirubin elevation and the severity of anemia in the child, and pay attention to high bilirubin causing nuclear jaundice. If there is an aggravation of progressive jaundice, neonatal blood exchange should be used, and light and medication should be given at the same time. Improve fetal edema, reduce bilirubin concentration, correct anemia to improve hypoxia and prevent heart failure.
If the mother’s prenatal antibodies are known to be high before the pregnancy or before the birth, you should not hesitate to go to a hospital that specializes in maternal plasma exchange, intrauterine transfusion and postpartum neonatal blood exchange for rare blood groups.
The blood type of the newborn should be checked early after the delivery of a negative blood type woman and the red blood cell anti-human globulin test should be done to determine whether the newborn has hemolysis, RhD, RhE or other Rh hemolytic diseases.