Cassandra N. Spracklen, Kelli K. Ryckman, Elizabeth W. Triche, Audrey F. Saftlas

Physical activity (PA) is hypothesized to reduce the risk of preeclampsia, but few epidemiologic studies have simultaneously evaluated leisure time PA (LTPA), sedentary activity, occupational activity, and non-occupational, non-leisure time PA. Thus, we assessed the independent and combined effects of these different types of PA during pregnancy on preeclampsia and gestational hypertension risk. Preeclamptic (n = 258), gestational hypertensive (n = 233), and normotensive (n = 182) women identified from Iowa live birth records (2002-2005) were participants in Study of Pregnancy Hypertension in Iowa. Disease status was verified by medical chart review. All PA exposures were self-reported. Multinomial logistic regression was used to test for associations between various PA types and risk for preeclampsia or gestational hypertension. After adjusting for prepregnancy BMI, increasing levels of LTPA were associated with a reduced risk of preeclampsia (trend, p = 0.02). Additionally, increasing amount of time spent active each day was associated with decreasing risks for preeclampsia (adjusted, trend; p = 0.03). Increasing amount of time spent sitting per day was associated with an increasing risk of preeclampsia (adjusted, trend; p = 0.10). Women whose activity averaged >8.25 h per day were at a significantly reduced risk of preeclampsia relative to women active <4.2 h per day (adjusted OR 0.58, 95 % CI 0.36, 0.95). Most analyses evaluating the risk of gestational hypertension yielded null results or results that trended in the direction opposite of the preeclampsia results. Consistent with previous studies, these data suggest increasing PA during pregnancy may reduce preeclampsia risk while increasing levels of sedentary activity may increase disease risk.