Original Article: PDF OnlyFetal Erythrocytes in Maternal Circulation of 155 Rh-Negative WomenBEER, ALAN E. MDAuthor Information From the Department of Obstetrics and Gynecology and the William Pepper Laboratory of Clinical Medicine, University of Pennsylvania School of Medicine, Philadelphia Obstetrics & Gynecology: August 1969 - Volume 34 - Issue 2 - p 143-150 Free Abstract One third of 144 Rh-negative unsensitized gravidas showed fetal erythrocytes during their third trimester of pregnancy. This was also true of more than half of 155 such women 1 hr after delivery of the placenta. Although manipulative removal of the placenta augments the occurrence of fetal-erythrocyte transfer, the number of such cells in the mother's circulation was not increased. Oxytocin-induced labor markedly increases transplacental passage of fetal red cells. Early postpartum injection of Rh-immune globulin clears Rh-incompatible fetal erythrocytes from the maternal blood and prevents primary isoimmunization. © 1969 The American College of Obstetricians and Gynecologists