A Swedish study of more than 2 million women has suggested that preterm delivery is associated with high risk of future hypertension. The study published in JAMA Cardiology found that delivering the child before 37 weeks of gestation was associated with a 1.67-fold increased risk of developing hypertension in the next decade of life. This association was strong for recurrent preterm delivery.

All 2,195,989 women in the Swedish Medical Birth Register with a singleton delivery from 1973 to 2015 were included in this study to assess the risk of new-onset hypertension in women who had a preterm delivery.

In this study, 351,189 of 2,195,989 women (16%) were diagnosed with new-onset hypertension in 46.1 million person-years of follow-up. The mean age of women who developed hypertension was 55.4 years.

Compared to women who delivered full-term infants at 39-41 weeks of gestation, those who delivered before 37 weeks of gestation had 1.67 times higher risk of becoming hypertensive in the next decade.

When risk was stratified according to gestational age, the risk was found to be 2.23 times higher in women who delivered before 22-27 weeks of gestation (extremely preterm), 1.85 higher for moderately preterm (28-33 weeks of gestation), 1.55 for late preterm (34-36 weeks of gestation) and 1.26 for early-term (37-38 weeks of gestation).

Although the risk declined, it persisted after delivery over the next four decades; 10 to 19 years (HR 1.40), 20 to 29 years (HR 1.20) and 30 to 43 years (HR 1.12) after delivery. This association was independent of family history of preterm births and hypertension.

Based on their findings, the study authors therefore suggest that “preterm delivery should be recognized as a lifelong risk factor for hypertension in women”. When evaluating cardiovascular risk in women, a history of preterm delivery and other relevant aspects of reproductive history should be elicited. At-risk women should be advised lifestyle changes to keep the modifiable risk factors such as sedentary lifestyle, overweight and obesity, smoking, alcohol use and diet under control.

Reference

1. Crump C, et al. Preterm delivery and long-term risk of hypertension in women. JAMA Cardiol. 2021 Oct 13. doi: 10.1001/jamacardio.2021.4127.