Rh Sensitization Following Induced Abortion

In this multicenter, observational, prospective cohort study, flow cytometry was used to detect circulating fetal red blood cells (fRBCs) in maternal blood among 506 participants before and after induced abortion up to 12 weeks’ gestation. Only three participants had elevated fRBCs at baseline, and only one of these had elevated fRBC counts following the abortion, which indicates that first trimester abortion is not a risk factor for Rh sensitization.