Exercise during pregnancy among US women.

This report describes the prevalence and pattern of exercise during pregnancy among US women. It is based on 9953 randomly selected women who gave birth to live infants in 1988 and participated in the National Maternal and Infant Health Survey, a cross-sectional survey with a stratified systematic sampling in 48 states, the District of Columbia, and New York City. Self-reported exercise before and during pregnancy, specific activities, and number of months of exercise were examined in relation to maternal demographic characteristics, reproductive history, and prenatal care. Forty-two percent of all women reported exercising during pregnancy, half of whom exercised longer than 6 months. Walking was the leading activity (43% of all activities reported), followed by swimming (12%) and aerobics (12%). Older mothers and women who had multiple gestations, previous children, or an unfavorable reproductive history were less likely to exercise during pregnancy. Given this high prevalence of exercise in pregnancy, more research is warranted on both the beneficial and adverse maternal and fetal effects of exercise in pregnancy.