Self-rated physical activity level during the second trimester and pregnancy outcome.

To examine the relationship between level of physical activity during pregnancy and subsequent pregnancy outcome, we asked women enrolling for maternal serum alpha-fetoprotein (MSAFP) screening in Maine during the years 1984-1988 to rate their usual physical activity level as light, moderate, or vigorous. Overall, 23,091 women were approached and 21,342 (92%) responded. Ten percent rated their physical activity level as light, 84% as moderate, and 6% as vigorous. Those who identified their physical activity level as vigorous were, on average, slightly older and more educated, and weighted less than women in the other two categories. However, there were no significant differences in the rates of low birth weight or fetal or neonatal death.