Quantitative abnormalities of fetal DNA in maternal serum in preeclampsia

Background: There is much recent interest in the biologic and diagnostic im plication of cell-free non-host DNA in the plasma and serum of human subjec ts. To determine if quantitative abnormalities of circulating non-host DNA may be associated with certain pathologic processes, we used circulating fe tal DNA in preeclampsia as a model system. Methods: We studied 20 preeclamptic women and 20 control subjects of compar able gestational age (means, 32 and 33 weeks, respectively). Male fetal DNA in maternal serum was measured using real-time quantitative PCR for the SR Y gene on the Y chromosome. Results: The imprecision (CV) of the assay was 2.7%. The median circulating fetal DNA was increased fivefold in 20 preeclamptic women compared with 20 control pregnant women (381 vs 76 genome-equivalents/mL, P <0.001). Conclusions: These observations suggest that preeclampsia is associated wit h disturbances in the liberation and/or clearance mechanisms of circulating DNA. These results also raise the possibility that measurement of circulat ing DNA may prove useful as a marker for the diagnosis and/or monitoring of preeclampsia.