8% of African-American women, and Mexican women are RhD negative.
Fewer than 1% of native American and Asian women are RhD negative.
Fetal anemia may lead to fetal death as early as 17 weeks gestation.
Survival rates exceed 90% if anemia diagnosed and treated with intrauterine blood transfusions.
Anemia severity identified by mother’s obstetrical history and serum antibody levels.
Standard test to evaluate need for transfusion is serial amniocentesis to determine amniotic fluid bilirubin.
Amniotic bilirubin correlates with severity of hemolysis.
Bilirubin in amniotic fluid is quantified by spectrophotometry and expressed associated the change in optical density at a wavelength of 450 nm.
Peak serum bilirubin higher than 20 mg per deciliter usually predicts a poor outcome in infants with Rh hemolytic disease.
Postpartum Rh immune globulin administration to Rh negative women who have RhD positive infants is the standard of care.
The administration of Rh immune globulin to Rh negative pregnant women in the postpartum period results in a 10 fold reduction in sensitization rates compared with untreated controls.
When IgG is administered together with xenogenic erythrocytes, this combination causes almost complete suppression of the erythrocyte-specific antibody response.
This effect is used clinically to prevent Rh-negative mothers from becoming immunized against fetal Rh-positive erythrocytes, and its use has dramatically decreased the incidence of hemolytic disease in newborns.
The administration Rh immune globulin at 28 weeks 10% third trimester sensitization in RhD antigen negative women.
Antibody screens for Rh disease should be performed in all pregnant women and anti-RhD titers of greater than four indicate sensitization.
Anti-RhD antibody titers of greater than 16 or the birth of the previously affected child requires appropriate fetal surveillance, and in patients with a titer of less than 16 the test should repeated monthly.