The effect of physical activity during pregnancy on preterm delivery and birth weight

The effects of physical activity during pregnancy on premature birth and birth weight has been a subject of considerable investigation; however, results have been conflicting. To learn more about this issue, 7,101 women who were part of a multicenter study were interviewed concerning their physical activity during a typical day in the first five months of pregnancy. The interviews took place between 23 and 26 weeks' gestation, and results were analyzed after pregnancy ended. Demographic differences were found for different activity levels; thus, prolonged heavy work and standing were more common among Hispanic women and women interviewed at the San Antonio center. Women with more education were less likely to participate in such work. These differences are discussed in detail. Women who spent more time standing had a slightly increased risk of premature birth; with eight or more hours per day spent standing, the risk of delivery before 37 weeks' gestation was 28 percent higher than with no standing. Premature delivery was more common among women who were black, smokers, or lived in Texas. Heavy work, though, was not associated with preterm birth. Women who performed light work or exercise were less likely than those who did not work to deliver preterm. No trend was seen that related birth weight to activity level. The dilemma faced by employed women who may be required to work to retain their salaries and medical benefits, when the work itself may threaten the pregnancy, is noted. (Consumer Summary produced by Reliance Medical Information, Inc.)