Maternal Plasma Cell-Free DNA in the Prediction of Pre-Eclampsia

Abstract

Objectives To examine whether maternal plasma concentrations of total cell-free (cf)DNA and fetal fraction at 11–13 and 20–24 weeks' gestation in pregnancies that subsequently develop pre-eclampsia (PE) are different from those without this complication. Methods Total cfDNA and fetal fraction were measured in 20 cases of early PE requiring delivery at < 34 weeks, in 20 cases of late PE with delivery at ≥ 34 weeks and in 200 normotensive controls, at 11–13 and 20–24 weeks' gestation. Total cfDNA and fetal fraction measured at 11–13 weeks were converted to multiples of the median (MoM), corrected for maternal characteristics and gestational age. The distributions of total cfDNA and fetal fraction at 20–24 weeks were expressed as MoM of values at 11–13 weeks. The Mann–Whitney U-test was used to determine the significance of differences in the median values in each outcome group relative to that in the controls. Results In the early-PE group at 11–13 weeks, compared with controls, there was a significant increase in median total cfDNA (2104 genome equivalents (GE)/mL vs 1590 GE/mL) and a decrease in median fetal fraction (6.8% vs 8.7%). In the late-PE group at 20–24 weeks, compared with controls, there was a significant decrease in median fetal fraction (8.2% vs 9.6%). These significant differences between groups were not observed when the values were converted to MoM. Conclusion Measurements of total cfDNA and fetal fraction in maternal plasma at 11–13 and 20–24 weeks are not predictive of PE. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.