Is there a link between CVD and preterm birth?
Preterm delivery may put women at increased risk of cardiovascular disease (CVD) later in lifem according to a study in Circulation.
Researchers looked at the 70,182 parous women in Nurses’ Health Study II to examine the link between delivering an infant preterm (< 37 weeks) and CVD. They used multivariable Cox proportional-hazards to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for cardiovascular events (myocardial infarction and stroke, n = 949).
Following adjustment for age, race, parental education, and prepregnancy lifestyle and cardiovascular risk factors, a preterm delivery in a woman’s first pregnancy was linked with an increased risk of CVD (HR, 1.42; 95% CI, 1.16–1.72) when compared to women who had a term delivery (≥ 37 weeks) in their first pregnancy. When split into moderate preterm (≥ 32 to < 37 weeks) and very preterm (< 32 weeks), the HRs were 1.22 (95% CI, 0.96–1.54) and 2.01 (95% CI, 1.47–2.75), respectively.
Even among women who had first pregnancies uncomplicated by hypertensive disorders of pregnancy, the increased rate of CVD persisted in the very preterm group (HR, 2.01; 95% CI, 1.38–2.93). When compared to women with at least 2 pregnancies all delivered at term, women with a preterm first birth and at least 1 more later preterm birth had an HR for CVD of 1.65 (95% CI, 1.20–2.28). The link between moderate preterm first birth and CVD was accounted for in part by the development of changes in body mass index, type 2 diabetes, postpartum chronic hypertension, and hypercholesterolemia (proportion accounted for, 14.5%; 95% CI, 4.0–41.1), as was the very-preterm-CVD relationship (13.1%; 95% CI, 9.0–18.7).
The researchers concluded that preterm delivery was independently predictive of CVD and could prove useful in CVD efforts. Because only a relatively modest proportion of the association between preterm birth and CVD was accounted for with development of convention CVD risk factors, the researchers say that further research could help identify other pathways.