Pregnancy‐associated mortality due to cardiovascular disease: Impact of hypertensive disorders of pregnancy

Abstract

Background

Reported rates of maternal mortality in the United States have been staggeringly high and increasing, and cardiovascular disease (CVD) is a chief contributor to such deaths. However, the impact of hypertensive disorders of pregnancy (HDP) on the short‐term risk of cardiovascular death is not well understood.

Objectives

To evaluate the association between HDP (chronic hypertension, gestational hypertension, preeclampsia, eclampsia, and superimposed preeclampsia) and pregnancy‐associated mortality rates (PMR) from all causes, CVD‐related causes both at delivery and within 1 year following delivery.

Methods

We used the Nationwide Readmissions Database (2010–2018) to examine PMRs for females 15–54 years old. International Classification of Disease 9 and 10 diagnosis codes were used to identify pregnancy‐associated deaths due to HDP and CVD. Discrete‐time Cox proportional hazards regression models were used to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for mortality at delivery (0 days) and at <30, <60, <90, <180, and <365 days after delivery in relation to HDP.

Results

Of 33,417,736 hospital deliveries, the rate of HDP was 11.0% ( n = 3,688,967), and the PMR from CVD was 6.4 per 100,000 delivery hospitalisations ( n = 2141). Compared with normotensive patients, HRs for CVD‐related PMRs increased with HDP severity, reaching over 58‐fold for eclampsia patients. HRs were higher for stroke‐related (1.2 to 170.9) than heart disease (HD)‐related (0.99 to 39.8) mortality across all HDPs. Except for gestational hypertension, the increased risks of CVD mortality were evident at delivery and persisted 1 year postpartum for all HDPs.

Conclusions

HDPs are strong risk factors for pregnancy‐associated mortality due to CVD at delivery and within 1 year postpartum; the risks are stronger for stroke than HD‐related PMR. While absolute PMRs are low, this study supports the importance of extending postpartum care beyond the traditional 42‐day postpartum visit for people whose pregnancies are complicated by hypertension.