Significant fetal-maternal hemorrhage after termination of pregnancy: Implications for development of fetal cell microchimerism

OBJECTIVE: Recent reports that an association exists between fetal cell mic rochimerism and autoimmune disease has increased interest in the postpartum persistence of fetal cells. The purpose of this study was to determine, by means of quantitative polymerase chain reaction amplification, whether a s ignificant fetal-maternal hemorrhage occurs after elective termination of p regnancy. STUDY DESIGN: Blood samples were obtained from 23 women who underwent termi nation of pregnancy immediately before venipuncture; these samples were sub jected to analysis by quantitative polymerase chain reaction amplification with the use of Y-chromosome primers. There were 21 male and 2 female fetus es. Results were equilibrated to 16 mL and analyzed by a weighted linear re gression analysis to evaluate the correlation between detected fetal nuclea ted cell equivalents and gestational weeks. RESULTS: Among the 21 known male fetuses, the median number of detected fet al nucleated cell equivalents was 1552 (range, 50-37,618). The female fetus es had no fetal nucleated cell equivalents detected. A positive dependence of male fetal nucleated cell equivalents on gestational age was shown (P<.0 01). CONCLUSION: Analysis by quantitative polymerase chain reaction amplificatio n demonstrated a large fetal-maternal transfusion after elective abortion. Consideration of the biologic consequences of pregnancy and the potential f or future development of fetal cell microchimerism must now extend to a lar ger population of women.