First-trimester maternal plasma cell-free fetal DNA and preeclampsia

OBJECTIVE: The purpose of this study was to determine whether, in pregnancies that experience preeclampsia, plasma cell-free fetal DNA (cffDNA) at 11-13 weeks of gestation is increased and whether this increase is related to the uterine artery pulsatility index ( PI). STUDY DESIGN: Plasma cffDNA and uterine artery PI were measured in 44 cases with preeclampsia, which included 11 cases that required delivery at <34 weeks of gestation and 176 normal control subjects. All fetuses were male, and cffDNA was assessed by amplification of the DYS14 gene. The association between cffDNA and uterine artery PI was assessed by regression analysis. RESULTS: Median cffDNA was higher in early preeclampsia ( median, 95.5 genome equivalents/mL; interquartile range, 72.7-140.9 genome equivalents/mL), but not late preeclampsia ( median, 50.8 genome equivalents/mL; interquartile range, 25.0-103.8 genome equivalents/mL), than control subjects ( median, 51.5 genome equivalents/mL; interquartile range, 31.1-84.9 genome equivalents/mL). There was a significant association between cffDNA and uterine artery PI ( P = .038) but not in the control subjects ( P = .174). CONCLUSION: The increase in plasma cffDNA in pregnancies that experience preeclampsia is associated with the degree of impairment in placental perfusion.