Fetal DNA in uterine vein blood

Objective: To investigate whether the ratio of fetal cells in the maternal circulation differs before and after the blood passes through the maternal lung. Methods: We performed polymerase chain reaction-based Y-sequence analysis of DNA derived from antecubital vein blood obtained before and 2 hours after cesarean delivery, and from uterine vein blood obtained during cesarean of 14 women carrying male fetuses. Results: Fetal DNA was detected in 17 tested specimens and, as estimated by comparison with parallel dilution series, the fetal-maternal DNA ratio was 1:10 5 to 1:10 6