SOURCE: European Journal of Preventive Cardiology, news release, July 8, 2015
THURSDAY, July 9, 2015 (HealthDay News) -- Women who smoke and have had a premature baby are at significantly higher risk for heart disease, a new study finds.
Researchers examined data from more than 900,000 mothers and found that those who smoked and also had a preterm birth were nearly three-and-a-half times more likely to develop heart disease than nonsmokers who had full-term births.
That risk is 29 percent higher than the risk associated with either smoking or preterm birth alone, according to the study published July 9 in the European Journal of Preventive Cardiology.
The risk of heart disease was even higher among mothers who smoked and had multiple or extremely premature births.
"Fertility treatment is pushing up rates of preterm birth and smoking in pregnant women remains high, so knowledge of the impact of these conditions on [heart disease] is important for prevention efforts. Our research shows for the first time that smoking and preterm birth interact to create a greater [heart disease] risk than either risk factor on its own," lead author Dr. Anh Ngo, a research fellow at the University of Sydney at Royal North Shore Hospital in Australia, said in a journal news release.
One explanation, Ngo said, could be the stress of caring for a premature infant. That might prompt unhealthy behaviors such as smoking, which increases the likelihood of future preterm births. Ngo noted that stress itself causes metabolic disorders, hardening of the arteries and ultimately heart disease.
Ngo said smoking women who seek fertility treatment should be counseled about their risk for premature birth and heart disease later in life so they can make an informed decision.
Women who stop smoking when they plan to get pregnant will receive dual protection, Ngo added.
"They will avoid the increased risk of having a preterm birth, and they will avoid the elevated risk of getting cardiovascular disease when they reach an older age. Smoking mothers who have already had a preterm birth should quit smoking if they haven't already done so and go for periodic [heart disease] screening."
The U.S. National Heart, Lung, and Blood Institute has more about heart disease in women.