Rh Incompatiblity
Rh Incompatibility
 |
| Rhesus Factor (Rh Factor) Incompatibility |
Introduction
Each cell in the body has numerous antenna like structures, called antigens on its surface. One such antigen often present on the surface of red blood cells is the Rh factor. Most people inherit the Rh factor (making from Rh positive), while other people lack it (making then Rh negative)- and whether you 're Rh positive or Rh negative doesn't much matter except when it comes to pregnancy.
When an Rh negative mom is carrying a baby who's Rh positive (having inherited the Rh factor from an Rh positive dad) mom's red blood cells don't match up with baby's. If Rh positive fetal blood cell enter a Rh negative mom's circulation her immune system may view them as "foreign" and may mobilize armies of antibodies to attack the foreigner who;s generating those cells (her baby) in a normal immune response. This is known as Rh incompatibility.
All pregnant women are tested for the Rh factor early in pregnancy usually in the first prenatal visit. If a mom to be turns out to be Rh positive, as 85% of population is. the issue of incompatibility isn't an issue at all. That's because whether the baby is Rh positive or Rh negative, there are no foreign antigens on the fetal blood cells to cause mom's immune system to mobilize against them.
When the mother is Rh negative and the baby's father is tested to determine whether he is Rh positive or negative. If you are Rh negative and your spouse also turn out to be Rh negative, you baby will be Rh negative. too ( make a positive baby) which means that your red blood cells and baby's are compatible and there is no potential for a problem
But if your spouse is Rh positive, there is a significant possibility that the baby will inherit the Rh factor from him, creating an incompatibility between you and your little one. This compatibility is usually not a problem in a first pregnancy because there aren't very antibodies to the baby's Rh Factor. But once a mom's natural protective immune response kicks in and produces antibodies during her first pregnancy of delivery, or abortion or miscarriage) they stay in her system. Which it isn't a concern until she becomes pregnant again with another Rh positive baby. During the subsequent pregnancy, these antibodies could potentially cross the placenta into the baby's circulation and attack the fetal red blood cells, causing very mild (if maternal antibody levels are low) to very serious (if they are high (anemia in the fetus).
Prevention
Prevention of the development of Rh antibodies is a key to protecting the baby when there is Rh incompatibility. Most Practioner use a two pronged strategy. At 28 weeks, a Rh negative expectant mom is given a vaccine like injection of Rh immune globulin known as RhGAM to prevent the development of antibodies.
Another dose is administered within 72 hours after delivery ( if blood test shows her baby is Rh positive. If the baby is Rh negative no treatment is required
Rhogam should also be administered after a miscarriage, an ectopic pregnancy, an abortion. CVS (chorionic villus sampling), amniocentesis, vaginal bleeding or physical trauma during pregnancy. Giving RhGAM as needed at these times can head off problems in future pregnancies.
What if an Rh negative mom to be has already developed levels of Rh antibodies capable of causing anemia in an Rh positive fetus ? First the baby's father will be tested for the Rh factor, if he hasn't been. If he is Rh positive than baby's blood type will be checked.. This can be done through amniocentesis or non-invasive blood test (though not all insurance companies will cover the blood test since its pricey). If the fetus is Rh negative, mother and baby have compatible blood types and there is no cause for concerns for treatment..
If the fetus ifs found to be Rh positive, and the mothers antibody levels have reached a critical levels, a special ultrasound has to be performed every week or two to assess the baby's condition and rule out anemia. If at any point anemia has developed, a transfusion of Rh negative blood to the fetus is neccessary. This is done through a small needle placed in a fetal umbilical cord under ultrasound guidance. Such fetal transfusions are very effective and associated with excellent outcomes
Fortunately the use of RhGAM has greatly reduced the need for transfusion in Rh incompatibility pregnancies to less than 1%.
A similar incompatibility can arise with other factors in blood, such as the KELL antigen, though these are less common than Rh incompatibility. If the mother doesn't have the antigen and the father does there is again potential for problems. A standard screening part of the first routine blood test, looks for the presence of the circulating antibodies in the mother's blood. If these antibodies in the mother's blood. If these antibodies are found in babies father is tested to see if he is positive in which case the management is the same as with Rh incompatibility.
https://madhuchhandacdmo.blogspot.com/2023/08/rh-incompatiblity.html
Comments
Post a Comment