Is Rh testing and treatment necessary after an induced first-trimester abortion?
This study found that an induced abortion in the first trimester, whether by medication or by procedure, is not a risk factor for Rh sensitization. Blood Rh typing and/or immunoglobulin administration are not clinically important parts of first-trimester abortion care.
Reliable evidence to determine the necessity of testing and treating Rh sensitization after an induced first-trimester (before 12 weeks' gestation) abortion remains uncertain. These investigators identified consenting patients (n = 644) who were undergoing medication or procedural abortions at less than 12 week's gestation. The primary outcome was the number of patients with fetal red blood cell (fRBC) counts above the predetermined sensitization threshold. Complete data including both pre-abortion and post-abortion blood samples were available for 506 patients (78.9%). Of these, 3 individuals had elevated fRBC counts at baseline; 1 individual also had an elevated fRBC count post-abortion. None of the other participants had fRBC counts above the clinically significant sensitization threshold after either a medical or procedural first-trimester induced abortion. No significant differences in fRBC counts occurred between the medical and procedural abortions, nor between patients reporting or not reporting bleeding prior to presenting for abortion care.
David C. Slawson, MD
Professor and Vice Chair of Family Medicine for Education and Scholarship
Professor of Family Medicine, UNC Chapel Hill