Examining the Association Between Vigorous Physical Activity and Pregnancy-related Outcomes

Abstract

Pregnancy is an ideal time for positive lifestyle modifications, including sustaining physical activity behavior. However, medical association guidelines specifically avoid giving recommendations on the optimal frequency or amount of vigorous physical activity (VPA) for women planning or carrying a pregnancy. Due to limited literature, little is known about the risks and benefits of VPA on pregnancy-related outcomes, including time to pregnancy, miscarriage, and infant birthweight. Furthermore, the effects of various modes of VPA on pregnancy-related outcomes cannot be evaluated.

This work examines the influence of cumulative VPA across modes using Right from the Start, a community-recruited cohort with over five thousand pregnant women from Southern United States. I found that VPA prior to conception, estimated using VPA during the first trimester, has no effect on time to pregnancy, regardless of women’s body mass index. I also found that cumulative VPA frequency and amount have no effect on miscarriage risk, adjusting for nausea and vomiting symptoms. While VPA frequency is not associated with infant birthweight, higher VPA amounts may be associated with increased birthweight. In summary, this work suggests women may continue levels of activity that are vigorous and contributes data on the safe upper limit for frequency and amount of physical activity immediately prior to and during early pregnancy.