Fetal hydrops and the risk of severe preeclampsia

Objective: To assess the incidence and severity of preeclampsia in pregnancies complicated by fetal hydrops. Methods: We performed a retrospective cohort study of singleton gestations from 2005 to 2008 in California. The primary predictor was fetal hydrops and the primary outcome was preeclampsia. Selected adverse maternal and neonatal events were assessed as secondary outcomes. Potential confounders examined included fetal anomalies, polyhydramnios, race/ethnicity, nulliparity, chronic hypertension, and gestational or pregestational diabetes mellitus. Results: We identified 337 pregnancies complicated by fetal hydrops, 70.0% had a concomitant fetal anomaly and 39.8% had polyhydramnios. Compared to the general population, hydrops was associated with an increased risk for severe preeclampsia (5.26 versus 0.91%, p < .001) but not mild preeclampsia (2.86 versus 2.02%, p = .29). In multivariable analysis, fetal hydrops remained an independent risk factor for severe preeclampsia (as adjusted odds ratios (aOR) 3.13, 1.91-5.14). Hydrops was also associated with increased rates of eclampsia, acute renal failure, pulmonary edema, postpartum hemorrhage, blood transfusion, preterm birth, and neonatal death. Conclusions: We find that fetal hydrops is an independent risk factor for severe preeclampsia. In light of serious concerns for maternal and neonatal health, heightened surveillance for signs and symptoms of severe preeclampsia is warranted in all pregnancies complicated by fetal hydrops.