Lindenberg (2012) reviewed long-term outcomes following intrauterine transfusion in a cohort of more than 450 alloimmunized pregnancies. Alloimmunization was secondary to anti-D in 80 percent, anti-Kell in 12 percent, and anti-c in 5 percent. Approximately a fourth of afected fetuses had hydrops, and more than half also required exchange transfusion in the neonatal period. Among nearly 300 children aged 2 to 17 years who participated in neurodevelopmental testing, fewer than 5 percent had severe impairments. hese included severe developmental delay in 3 percent, cerebral palsy in 2 percent, and deafness in 1 percent.
• Prevention of Anti-D Alloimmunization
Anti-D immune globulin is one of the success stories of modern obstetrics. It has been used for nearly five decades to prevent D alloimmunization. In countries without access to anti-D immune globulin, up to 10 percent of D-negative pregnancies are complicated by hemolytic disease of the fetus and newborn (Zipursky, 2015). With immunoprophylaxis, however, the alloimmunization risk is reduced to <0.2 percent. Despite long-standing and widespread use, its mechanism of action is not completely understood.
As many as 90 percent of alloimmunization cases occur from fetomaternal hemorrhage at delivery. Routine postpartum administration of anti-D immune globulin to at-risk pregnancies within 72 hours of delivery lowers the alloimmunization rate by 90 percent (Bowman, 1985). Additionally, provision of anti-D immune globulin at 28 weeks' gestation reduces the third-trimester alloimmunization rate from approximately 2 percent to 0.1 percent (Bowman, 1988). Whenever there is doubt whether to give anti-D immunoglobulin, it should be given.
If not needed, it will not cause harm, but failure to provide it when needed can have severe consequences.
Current preparations of anti-D immune globulin are derived from human plasma donated by individuals with hightiter anti-D immunoglobulin D antibodies. Formulations prepared by cold ethanol fractionation and ultrailtration must be administered intramuscularly because they contain plasma proteins that could result in anaphylaxis if given intravenously. However, formulations prepared using ion exchange chromatography may be administered either intramuscularly or intravenously. his is important for treatment of significant fetomaternal hemorrhage, which is discussed subsequently. Both preparation methods efectively remove viral particles, including hepatitis and human immunodeiciency viruses. Depending on the preparation, the half-life of anti-D immune globulin ranges from 16 to 24 days, which is why it is given both in the third trimester and following delivery. he standard intramuscular dose of anti-D immune globulin-300 I-Lg or 1500 IU-will protect the average-sized mother from a fetal hemorrhage of up to 30 mL of fetal whole blood or 15 mL of fetal red cells.