Relationship between severity of hyperemesis gravidarum and fetal DNA concentration in maternal plasma.

Abstract

Cell-free fetal DNA is present in maternal plasma (1), where its concentration increases during some abnormal conditions that can occur during pregnancy, including preterm delivery (2), preeclampsia (3)(4)(5), invasive placenta (6), and fetal trisomy 21 (7)(8). The origin of fetal DNA is not clear, but a body of evidence in the literature suggests that it comes mainly from the destruction of villous trophoblasts that border the intervillous space filled with maternal blood (5)(9). Although the pathogenesis of hyperemesis gravidarum (HG) is obscure, activation of natural killer and cytotoxic T cells is higher in the blood and uterine decidua of women with HG with respect to healthy pregnant women (10). Thus, if HG and DNA concentrations were correlated, one possible common pathway that could explain these conditions might be an overactivated maternal immune system that destroys trophoblasts, causing both HG and higher concentrations of cell-free fetal DNA. The aim of this study was to investigate a possible correlation between HG and fetal DNA concentrations. We also evaluated the relationship between the cell-free fetal DNA concentration and the severity of HG. A total of 202 pregnant women (gestational age, 6–16 weeks) bearing a single male fetus, who presented at Showa University Hospital between July 2000 and July 2002 were enrolled in this study. Forty-five consecutive pregnant women with HG were classified into three groups based on the severity of the condition and matched for gestational age with 157 controls. All samples were analyzed blindly without knowledge of case-control status. The three HG groups were generated according to the following criteria: mild HG (nausea and vomiting but no need for admission), moderate HG (admission for HG with dehydration that needed infusion therapy but lacking all of the criteria that define severe HG), and severe HG …