Fetal-maternal hemorrhage after amniocentesis: incidence, degree and ramifications.

A review of the literature indicates a small but significant incidence of fetal-maternal hemorrhage following amniocentesis. In these studies, consideration has not been given to the frequency with which erythrocytes containing hemoglobin F are to be found in the maternal circulation in the absence of amniocentesis. In this investigation, Kleihauer-Betke analysis was carried out before and after amniocentesis. This study confirms previous reports that spontaneous fetal maternal hemorrhage is not uncommon during normal intrauterine gestation and that amniocentesis is probably only an occasional cause of fetal-maternal hemorrhage. This impression is based on the findings that most Kleihauer-positive maternal blood samples after amniocentesis were also positive before amniocentesis. In spite of these findings, and since Rh-immune serum globulin is apparently harmless to the fetus and mother, its use is still advocated in nonsensitized Rh-negative mothers after amniocentesis.