Rh Sensitization During Pregnancy
If you are Rh-negative
Unless you are given Reference Rh immune globulin just before or after a high-risk event, such as miscarriage, amniocentesis, abortion, ectopic pregnancy, 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 watched 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, Reference hemolytic disease of the newborn Opens New Window, or erythroblastosis fetalis) can be mild to severe.
- Mild Rh disease involves limited destruction of fetal red blood cells, possibly resulting in mild fetal Reference anemia Opens New Window. The fetus can usually be carried to term and requires no special treatment but may have problems with Reference jaundice Opens New Window after birth. Mild Rh disease is more likely to develop in the first pregnancy after sensitization has occurred.
- Moderate Rh disease involves the destruction of larger numbers of fetal red blood cells. The fetus may develop an enlarged liver and may become moderately anemic. The fetus may need 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 is watched closely for jaundice.
- Severe Rh disease (Reference fetal hydrops Opens New Window) involves widespread destruction of fetal red blood cells. The fetus develops severe anemia, liver and spleen enlargement, increased Reference bilirubin Opens New Window levels, and fluid retention (edema). The fetus may need one or more blood transfusions before birth. A fetus with severe Rh disease who survives the pregnancy may need a blood exchange. This procedure replaces most of the infant's blood with donor blood (usually type O, Rh-negative).
- A history of pregnancy with Rh disease is a sign that you will need special treatment when you are pregnant with an Rh-positive fetus.
If you have been Rh-sensitized in the past, an Rh-negative fetus cannot trigger an immune reaction.
|By:||Reference Healthwise Staff||Last Revised: Reference October 20, 2011|
|Medical Review:||Reference Sarah Marshall, MD - Family Medicine
Reference William Gilbert, MD - Maternal and Fetal Medicine