Research conducted by exercise science assistant professor Dr. Abbi Lane-Cordova, at the University of South Carolina, Arnold School of Public Health, provides preliminary evidence for the connection between cardiovascular responses to exercise and adverse pregnancy outcomes. The study, published in BJOG: An International Journal of Obstetrics and Gynaecology, found that exercise testing may be useful in identifying women who are more likely to have preterm birth or small-for-gestational-age deliveries.
[Photo: Dr. Lane-Cordova]
The connection between adverse pregnancy outcomes and heart disease for women has already been well established by previous research. The American Heart Association lists outcomes, such as preterm birth and small-for-gestational age deliveries, as risk factors for heart disease in women.
“The challenge of pregnancy serves as a ‘stress test’ for future heart disease in women because the blood vessels must undergo lots of changes to support a pregnancy,” explains Dr. Lane-Cordova. “Adverse pregnancy outcomes sometimes occur because the blood vessels of the placenta, the flat organ that is formed to deliver blood and nutrients to the baby, didn’t develop quite as they should have.”
Cardiorespiratory fitness (i.e., how long you can run or walk on a treadmill), blood pressure responses to exercise, and heart rate recovery (i.e., how quickly heart rate returns to resting levels) after maximal exercise have been linked to heart disease risk factors in the general population. Higher cardiorespiratory fitness levels are linked to less heart disease, fewer heart disease risk factors, and better blood vessel function.
In the present study, Dr. Lane-Cordova and her team looked at over 20 years of follow-up in black and white women — testing whether fitness, blood pressure during submaximal exercise, and heart rate recovery were associated with preterm birth and small-for-gestational age deliveries. They found that women who had preterm birth or small-for-gestational age deliveries were less fit than women who did not have adverse pregnancy outcomes; however, the association was no longer significant after adjusting for maternal age, race, smoking, and history of high blood pressure or diabetes.
The authors also looked at the data collected closer to pregnancy. For women who completed the exercise test less than five years before their first birth, the association between submaximal exercise blood pressure and heart rate recovery approached significance.
“We concluded that hemodynamic responses to exercise testing might be useful for identifying women who are more likely to have preterm birth or small-for-gestational-age deliveries if the test is conducted closer to the onset of pregnancy,” says Dr. Lane-Cordova. “We believe our findings support the inclusion of an exercise test for women who are planning to become pregnant to identify women who may be more likely to have an adverse pregnancy outcome.”