PREVENTION OF RH ISOIMMUNIZATION AFTER SPONTANEOUS, MASSIVE FETOMATERNAL HEMORRHAGE

Massive fetomaternal hemorrhage has been associated with numerous risk factors and can occur spontaneously. The risk is probably greater whe n a woman who is Rh negative has an ABO-compatible fetus. We report th e case of a gravid, A-negative unsensitized patient who came to the ho spital at term complaining of decreased fetal movement over the previo us 24 hours. During evaluation, the fetal heart rate was found to have decreased beat-to-beat variability and repetitive late decelerations, and the mother was delivered of a 3,005 g A-positive neonate (by cesa rean section) with a hemoglobin level of 2.9 g/dL. An acid elution tes t showed 400 mt of fetal blood in the maternal circulation, and the pa tient received 23 ampules (6,900 mu g) of Rh immune globulin postpartu m. The patient's condition was observed for 156 days after delivery; s he did not become sensitized to the Rh factor. A massive fetomaternal hemorrhage can occur without any antecedent risk factors, with a risk of subsequent morbidity to the neonate. Sensitization can be prevented by prompt administration of adequate amounts of Rh immune globulin.