incompatibilidade de Rh

Why is Rh disease a concern?

When an Rh negative mother has a baby that is Rh positive, problems can develop if the baby's red blood cells cross to the Rh negative mother. This usually happens at delivery when the placenta detaches. It may also happen, however, anytime blood cells of the two circulations mix such as during a miscarriage or abortion, with a fall, or during an invasive prenatal testing procedure such as an amniocentesis or chorionic villus sampling.

The mother's immune system sees the baby's Rh positive red blood cells as foreign. Just as when bacteria invade the body, the immune system responds by developing antibodies to fight and destroy these foreign cells. The mother's immune system keeps the antibodies in case the foreign cells appear again, even in a future pregnancy. The mother is now Rh sensitized.

Prevention of Rh disease:

Fortunately, HDN is a very preventable disease. Because of the advances in prenatal care, nearly all women with Rh negative blood are identified in early pregnancy by blood testing. If a mother is Rh negative, she will be tested for Rh antibody titers. If she has not been sensitized, she is usually given a drug called Rh immunoglobulin (RhIg), also known as RhoGAM. This is a specially-developed blood product that can prevent an Rh negative mother's antibodies from being able to react to Rh positive cells. Many women are also given RhIg around the 28th week of pregnancy. After the baby is born, a woman should receive a second dose of the drug within 72 hours.

RhIg destroys any anti-Rh antibodies that enter in the mother's circulation before her immune system becomes sensitized. This helps protect a future Rh positive baby.

source: http://uuhsc.utah.edu/healthinfo/pediatric/hrpregnant/rhdiseas.htm