If you are Rh-negative
Unless you are given Rh immune globulin just before or after a high-risk event, such as , , abortion, , or childbirth, you have a chance of becoming sensitized to an Rh-positive fetus's blood.
If you have been Rh-sensitized in the past
If you have been Rh-sensitized in the past, you must be closely monitored during any pregnancy with an Rh-positive partner because your fetus is more likely to have Rh-positive blood. In response to an Rh-positive fetus, your immune system may quickly develop IgG antibodies, which can cross the placenta and destroy fetal red blood cells. Each subsequent pregnancy with an Rh-positive fetus may produce more serious problems for the fetus. The resulting fetal disease (called Rh disease, , or erythroblastosis fetalis) can be mild to severe.
- Mild Rh disease involves limited destructionof fetal red blood cells, possibly resulting in mild fetal. The fetus can usually be carried to term andrequires no special treatment but may have problems with after birth. Mild Rh disease is more likelyto develop in the first pregnancy after sensitization hasoccurred.
- Moderate Rh disease involves the destruction of largernumbers of fetal red blood cells. The fetus may develop an enlarged and may become moderately anemic. The fetus mayneed to be delivered before term and may require a blood transfusion before(while in the uterus) or after birth. A newborn with moderate Rh disease iswatched closely for jaundice.
- Severe Rh disease () involves widespread destruction offetal red blood cells. The fetus develops severe anemia, liver and enlargement, increased levels, and fluid retention (edema). Thefetus may need one or more blood transfusions before birth. A fetus with severeRh disease who survives the pregnancy may need a blood exchange. This procedurereplaces most of the infant's blood with donor blood (usually type O,Rh-negative).
- A history of pregnancy with Rh disease is a sign thatyou will need special treatment when you are pregnant with an Rh-positivefetus.
If you have been Rh-sensitized in the past, an Rh-negative fetus cannot trigger an immune reaction.