Risk of Recurrent Severe Preeclampsia, HELLP (Hemolysis, Elevated Liver Enzymes, and Low Platelet Count) Syndrome, and Eclampsia in a Subsequent Pregnancy.

OBJECTIVE: To assess the recurrence risk of severe hypertensive disorders of pregnancy (HDP) in a U.S. cohort because prior studies report inconsistent recurrence rates for severe HDP. METHODS: This is a retrospective cohort study using the Premier Inpatient database. Individuals with two or more observed pregnancies between October 2015 and December 2020 were identified. Clinical characteristics were identified with International Classification of Diseases, Tenth Revision codes. The risk and relative risk (RR) of developing a severe HDP, defined as preeclampsia with severe features, superimposed preeclampsia, HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, or eclampsia, in a subsequent pregnancy were estimated with multivariable risk regression. Risk was stratified according to the presence and severity of HDP in the first observed (index) pregnancy and gestational age at delivery. RESULTS: During the study period, 560,295 patients had two or more pregnancies. Of the included patients 57,584 (10.3%) had HDP and 11,433 (2.0%) had severe HDP during the index pregnancy. Of these patients, 1,703 individuals (14.9%) experienced recurrent HDP in a subsequent pregnancy. Compared with patients with no HDP in the index pregnancy, those with severe HDP at any gestational age had an increased risk of severe HDP in a subsequent pregnancy (14.9%, RR 16.0, 95% CI, 15.2-17.0); those with a history of a severe HDP before 28 weeks of gestation had the highest risk (22.9%, RR 23.1, 95% CI, 19.1-27.9). Having a severe HDP before 28 weeks of gestation conferred the highest risk of HDP before 28 weeks in a subsequent pregnancy (4.7%, RR 184.9, 95% CI, 107.2-318.9). Patients with a history of HELLP syndrome or eclampsia also had elevated risk of severe HDP in a subsequent pregnancy (11.5%, RR 9.7, 95% CI, 8.3-11.3; and 11.0%, RR 9.2, 95% CI, 7.2-11.8 respectively), including recurrent HELLP syndrome (4.6%, RR 61.0, 95% CI, 46.2-80.6) and eclampsia (1.1%, RR 40.1, 95% CI, 16.3-98.3), but these phenotypes occurred infrequently. CONCLUSION: The risk of recurrent severe HDP was 14.9% and was influenced by the severity and timing of HDP in the index pregnancy, with the highest risk of recurrence in patients with early-onset severe HDP. These results inform counseling about risk of future HDP to inform patient decision making.