Increased fetal DNA in the maternal circulation in early pregnancy is associated with an increased risk of preeclampsia

Objective The aim of our study was to determine if fetal DNA is present in the maternal circulation in early pregnancy before the clinical manifestation of preeclampsia, and if this could be predictive of the development of preeclampsia. Study design Blood were obtained from patients attending for a first antenatal visit. Cases were asymptomatic women who subsequently developed preeclampsia matched to control women for parity and gestational age. Real-time polymerase chain reaction (PCR) using TaqMan primers and probes directed against SRY gene sequences quantified fetal DNA in the maternal circulation. Results There were 88 cases of women with preeclampsia and 176 control women, both sampled at a mean gestation (±SD) of 15.7 ± 3.6 weeks. The presence of fetal DNA in the maternal circulation in early pregnancy is associated with an 8-fold increased risk of developing preeclampsia. Conclusion Increased fetal DNA is present in the maternal circulation in early pregnancy in women who subsequently develop pre-eclampsia and there appears to be a graded response between the quantity of fetal DNA and the risk of developing pre-eclampsia.