Premature birth raises future heart disease risk in mothers

Mother with baby in the NICU

Women who deliver prematurely before the 37th week of their pregnancy face a heightened risk of heart disease over the course of their life, finds a new NHLBI-funded study in the Journal of the American College of Cardiology.

The researchers say the findings suggest that cardiovascular risk assessments in women should take into account whether they have had a premature birth. If they have, they may want to carefully monitor their risk and address other factors that can lead to heart disease, including obesity, low levels of physical activity, and smoking.

In the U.S., 1 in 10 infants is born prematurely. Previous research has found that women who have premature birth face an increased risk of high blood pressure, diabetes, and high cholesterol levels, but it was unclear how early delivery affected their heart disease risk over the course of their life. 

Researchers used data from the Swedish Medical Birth Registry to look at more than 2 million women who gave birth in Sweden from 1973-2015. Their analysis showed that in the 10 years after delivery, women who delivered preterm (before 37 weeks) had 2.5 times the risk of developing heart disease compared with women with full-term births (39-41 weeks). Those who delivered extremely early (22-27 weeks) had four-fold the risk of heart disease.

The risk was not affected by other factors, including preeclampsia, diabetes, obesity, or smoking. The analysis also compared women with their sisters who had given birth and found no genetic or environmental factors in families that explained the increased risk.