A national surveillance approach to monitor incidence of eclampsia: The Netherlands Obstetric Surveillance System

Introduction: There have been many efforts in the last decade to decrease the incidence of eclampsia and its related complications in the Netherlands, such as lowering thresholds for treatment of hypertension and mandatory professional training. To determine the impact of these policy changes on incidence and outcomes, we performed a nationwide registration of eclampsia, 10 years after the previous registration. Material and methods: Cases of eclampsia were prospectively collected using the Netherlands Obstetric Surveillance System (NethOSS; 2013-2016) in all hospitals with a maternity unit in the Netherlands. Complete case file copies were obtained for comparative analysis of individual level data with the previous cohort (2004-2006). Primary outcome measure was incidence of eclampsia; main secondary outcomes were antihypertensive and magnesium sulfate use, and maternal and perinatal mortality. Results: NethOSS identified 88 women with eclampsia. The incidence decreased from 6.2/10 000 in 2004-2006 to 1.8/10 000 births (relative risk [RR] 0.28, 95% confidence interval [CI] 0.22-0.36). Increases in the use of antihypertensive medication (61/82 vs 35/216; RR 18.4, 95% CI 9.74-34.70) and magnesium sulfate treatment (82/82 vs 201/216; RR 1.08, 95% CI 1.04-1.12) were observed. There was one intrauterine death following termination of pregnancy. No cases of neonatal mortality were reported in NethOSS compared with 11 in the LEMMoN. Maternal death occurred in one woman compared vs three in the previous registration. Conclusions: There has been a strong reduction of eclampsia and associated perinatal mortality in the Netherlands over the last decade. Management changes and increased awareness may have contributed to this reduction.