Expectant management of mild preeclampsia versus superimposed preeclampsia up to 37 weeks

OBJECTIVE: We sought to compare maternal and neonatal outcomes of expectantly managed pregnancies complicated by chronic hypertension with superimposed preeclampsia vs mild preeclampsia up to 37 weeks of gestation. STUDY DESIGN: This was a multicenter retrospective cohort study of all pregnancies complicated by chronic hypertension with superimposed preeclampsia or mild preeclampsia expectantly managed in the hospital from January 2008 through December 2011. The primary outcomes, adverse maternal and neonatal composite morbidities, were compared between these 2 groups. Frequency differences of maternal adverse outcomes were stratified by gestational age at delivery of <34 and 34-36(6/7) weeks of gestation. RESULTS: We found no significant differences in rates of neonatal composite morbidity or latency periods between women with superimposed preeclampsia and mild preeclampsia. Adverse neonatal outcomes were significantly higher at <34 compared to 34-36(6/7) weeks of gestation (97-98% vs 48-50%) in both cohorts. Maternal adverse composite outcome occurred more frequently in women with superimposed preeclampsia compared to mild preeclampsia (15% vs 5%; P = .003; relative risk, 3.0; 95% confidence interval, 1.45-6.29). CONCLUSION: Women with superimposed preeclampsia have similar neonatal outcomes but more maternal complications than women with preeclampsia without severe features who are expectantly managed <37 weeks.