Cardiovascular mortality in women in their forties after hypertensive disorders of pregnancy in the Netherlands: a national cohort study.

Background: Hypertensive disorders of pregnancy are associated with cardiovascular disease later in life. Given that hypertensive disorders of pregnancy often occur at a relatively young age, there might be an opportunity to use preventive measures to reduce the risk of early cardiovascular disease and mortality. The aim of this study was to assess the risk of cardiovascular mortality in women after a hypertensive disorder of pregnancy.

Methods: In this population-based cohort study, the Netherlands Perinatal Registry (PRN) and the national death registry at the Dutch Central Bureau for Statistics were linked. We analysed women in the Netherlands with a first birth during 1995-2015 to determine the association between cardiovascular mortality and hypertensive disorders of pregnancy (based on recorded diastolic blood pressure or proteinuria, or both). We analysed the association between the highest diastolic blood pressure measured in pregnancy and cardiovascular mortality and constructed survival curves to assess cardiovascular mortality after hypertensive disorders of pregnancy, specifically pre-eclampsia and gestational hypertension. To differentiate between the severity of hypertensive disorders of pregnancy, cardiovascular mortality was assessed in women with a combination of hypertensive disorders of pregnancy with preterm birth (gestational age <37 weeks) and growth restriction (birthweight in the 10th percentile or less). All hazard ratios (HRs)were adjusted for maternal age.

Findings: Between Jan 1, 1995, and Dec 31, 2015, the PRN contained 2 462 931 deliveries and 1 625 246 women. In 1 243 890 women data on their first pregnancy were available and were included in this analysis after linkage, with a median follow-up time of 11·2 years (IQR 6·1-16·3). 259 177 (20·8%) women had hypertensive disorders of pregnancy, and of these 45 482 (3·7%) women had pre-eclampsia and 213 695 (17·2%) women had gestational hypertension; 984 713 (79·2%) women did not develop hypertension in their first pregnancy. Compared with women without hypertensive disorders of pregnancy, the risk of death from any cause was higher in women who had hypertensive disorders (HR 1·30 [95% CI 1·23-1·37], p<0·001), pre-eclampsia (1·65 [1·48-1·83]; p<0·0001), and gestational hypertension (1·23 [1·16-1·30]; p<0·0001). Those women with pre-eclampsia had a higher risk of cardiovascular mortality compared with those without any hypertensive disorders of pregnancy (adjusted HR 3·39 [95% CI 2·67-4·29]), as did those with gestational hypertension (2·22 [1·91-2·57]). For women with a history of hypertensive disorders of pregnancy combined with preterm birth (gestational age <37 weeks) and birthweight in the 10th percentile or less, the adjusted HR for cardiovascular mortality was 6·43 (95% CI 4·36-9·47), compared with women without a hypertensive disorder of pregnancy. The highest diastolic blood pressure measured during pregnancy was the strongest risk factor for cardiovascular mortality (for 80-89 mm Hg: adjusted HR 1·47 [95% CI 1·00-2·17]; for 130 mm Hg and higher: 14·70 [7·31-29·52]).

Interpretation: Women with a history of hypertensive disorders of pregnancy have a risk of cardiovascular mortality that is 2-3 times higher than that of women with normal blood pressure during pregnancy. The highest measured diastolic blood pressure during pregnancy is an important predictor for cardiovascular mortality later in life; therefore, women who have hypertensive disorders of pregnancy should be given personalised cardiovascular follow-up plans to reduce their risk of cardiovascular mortality.

Funding: None.