Preterm Delivery and Maternal Cardiovascular Disease Risk Factors: The Nurses' Health Study II.

Abstract

Background: Preterm delivery has been linked to future maternal cardiovascular disease (CVD); however, research investigating clinical CVD risk factors is limited. We evaluated whether women who have delivered an infant preterm are at higher risk of developing CVD risk factors after adjustment for prepregnancy confounders. Materials and Methods: We examined the association between preterm delivery and incident chronic hypertension, type 2 diabetes mellitus (T2DM), and hypercholesterolemia among 57,904 parous women in the Nurses' Health Study II. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between preterm delivery in first pregnancy and each CVD risk factor; adjusted cumulative incidence curves were computed using the Breslow estimator. Results: Preterm delivery (<37 weeks) was associated with HRs of 1.11 (95% CI: 1.06-1.17) for chronic hypertension, 1.17 (95% CI: 1.03-1.33) for T2DM, and 1.07 (95% CI: 1.03-1.11) for hypercholesterolemia, adjusting for age, race/ethnicity, parental education, and prepregnancy confounders (e.g., body mass index, smoking, and family history). HRs were higher in women who delivered very preterm (<32 weeks) and in the first 10 years after first birth. The cumulative incidence of each risk factor was highest in women who delivered very preterm. Conclusions: Women with a history of preterm delivery are at higher risk of developing chronic hypertension, T2DM, and hypercholesterolemia in the years after pregnancy. This increased risk was particularly pronounced in the first 10 years after a preterm delivery, indicating that it may be an important time period to implement lifestyle interventions.