Preterm delivery and implications for maternal hypertension in later life

OBJECTIVE:

We examine the relationship between preterm delivery and later risk of hypertension for the mother, and whether this association varies by race/ethnicity.

BACKGROUND:

Complications during pregnancy can reveal a mother's risk for chronic disease in later life. Preterm delivery and chronic hypertension may share common genetic susceptibilities and predisease pathways, such that women who had an early preterm birth may be at increased risk for hypertension in later life.

METHODS:

This study analyzes a sample of 3,151 women from the National Longitudinal Study of Youth 1979 who are 40 years or older and had not been diagnosed with hypertension before or during pregnancy. Cox proportional hazards models predicting the time to hypertension diagnosis are performed. Interaction effects of race/ethnicity and gestation are also tested. Survival curves are conducted based on the hazards models.

RESULTS:

Results suggest that women with a history of very preterm birth had a two-fold increased risk of hypertension (HR=2.03, 95% CI=1.22, 3.37), while women with moderate preterm birth had a 50% higher risk (HR=1.50, 95%=CI 1.09, 2.05), controlling for sociodemographic and health behavior variables. Survival curves by race and gestation indicated that White women with term births had the highest probability of not reporting hypertension; Black women with very preterm births had the lowest survival probabilities over time.

DISCUSSION:

Women with a history of preterm delivery are at increased risk for hypertension in later life. Our findings reframe preterm birth as a women's health problem and as an opportunity for primary prevention.