Can Exercise Lower Baby's Blood Pressure?

Regular exercise during pregnancy reduces the chances that low-birth weight babies will have high blood pressure later in life, new research shows.

High blood pressure, or hypertension, is a key factor in cardiovascular health. The new findings are a start in getting at the issue of genetic preprogramming of a child’s health characteristics while in the womb, researchers say.

“We looked at a range of normal birth weight babies, some falling at the lower end of the scale, and surprisingly we found that this lower birth weight and higher blood pressure relationship in these offspring is not supported if the women were physically active,” says James Pivarnik, professor of kinesiology at Michigan State University.

“The connection was disrupted, indicating that exercise may in some way alter cardiovascular risk that occurs in utero.”

This phenomenon is linked to what’s known as the fetal origins hypothesis. The theory suggests if something strenuous happens to a mother and her unborn child during critical growth periods in the pregnancy, permanent changes can occur that can affect the health of the baby.

In an earlier study, researchers evaluated 51 women over a five-year period based on physical activity such as running or walking throughout pregnancy and post-pregnancy.

The follow-up study, published in the Journal of Sports Medicine and Physical Fitness, shows that regular exercise in a subset of these women, particularly during the third trimester, is associated with lower blood pressure in their children.

“This told us that exercise during critical developmental periods may have more of a direct effect on the baby,” Pivarnik says.

The finding was evident when the researchers also discovered that the children of mothers who exercised at recommended or higher levels of activity displayed significantly lower systolic blood pressures at 8 to 10 years old, Pivarnik says.

“This is a good thing as it suggests that the regular exercise habits of the mother are good for heart health later in a child’s life.”

Other researchers from Michigan State and from Iowa State University, Winona State University, and Saginaw State University contributed to the study.