Together, smoking and having a preterm birth more than triples a woman’s risk for heart disease, according to a study published in the European Journal of Preventive Cardiology.
Smoking and preterm birth are both established risk factors for heart disease—the No. 1 killer of men and women in the United States. Independently, each of these risk factors increases a woman’s risk of developing heart disease later in life, but experts wondered about the combined impact of smoking and preterm birth on heart disease risk.
Despite the serious risks associated with smoking and pregnancy, such as increased risk for preterm birth, smoking among pregnant women remains high. Increased use of fertility treatments has further driven preterm birth rates in recent years.
To learn more about the impact of smoking and preterm birth on heart risks, Australian researchers analyzed the health records of more than 900,000 women giving birth between 1994 and 2011. Using information contained in the health records, researchers determined whether women smoked during pregnancy and/or had a preterm birth. Investigators also analyzed subsequent admission records to see which women were ever hospitalized or died from heart disease.
After analysis, researchers found that both smoking and preterm birth were significantly associated with risk of heart disease. Furthermore, mothers who smoked and had a preterm birth had three times the risk of heart disease than women without either factor.
Interestingly, researchers also found that the more severe the preterm birth, the greater a woman’s risk for heart disease later in life. Having multiple preterm births further increased risk for heart disease compared to non-smoking mothers with full-term births.
Authors believe that the stress of caring for a preterm infant may explain some of this relationship, as stress can lead to unhealthy behaviors that increase risk for heart disease. The stress itself may also contribute.
The take-home message, authors explain, is about prevention. Lead author Dr. Anh Ngo highlights the importance of counseling women about quitting smoking, especially if they’re considering getting pregnant.
“Smoking women who stop smoking when planning to get pregnant will receive dual protection,” says Dr. Ngo. “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 CVD screening.” Together, these efforts can help women avoid complications during pregnancy and reduce risk for heart disease later in life.