Secular Trends in Preeclampsia Incidence and Outcomes in a Large Canada Database: A Longitudinal Study Over 24 Years.

BACKGROUND: The incidence of preeclampsia is increasing, but effects on women and infants are unclear. We measured the incidence of preeclampsia over time in a large Canadian population, and assessed trends in maternal and infant morbidity and mortality.

METHODS: We carried out a population-based study of 1,901,376 linked hospital discharge abstracts for all deliveries in the province of Quebec, Canada from 1989 through 2012. We computed the annual incidence of preeclampsia, and used log binomial models to determine associations with severe morbidity and mortality for preeclamptic vs nonpreeclamptic pregnancies. Main outcomes included maternal, fetal, and infant mortality, admission to intensive care, intubation, preterm delivery, growth restriction, cesarean delivery, transfusion, and severe medical complications.

RESULTS: The incidence of preeclampsia increased from 26.4 per 1000 deliveries in 1989 to 50.6 in 2012. Maternal, fetal, and infant mortality decreased with time for preeclamptic but not for nonpreeclamptic pregnancies. By 2007-2012, risk for women with preeclampsia had declined for most maternal morbidities, except acute renal failure, which increased relative to no preeclampsia (risk ratio, 21.5; 95% confidence interval, 16.9-27.3). Risk of infant morbidity also decreased, but this coincided with an increase in the excess number of intubations and admissions for intensive care for preeclampsia relative to no preeclampsia.

CONCLUSIONS: The incidence of preeclampsia increased during the study, but with little effect on the risk of maternal and infant morbidity and mortality. For most outcomes, the risk decreased relative to no preeclampsia, with more aggressive medical management over time.