Purpose: Although literature suggests that physical activity may reduce preeclampsia risk, most prior studies have relied on retrospective exposure assessment. We aimed to assess prospectively the relation between recreational physical activity before and during pregnancy and risk of preeclampsia.
Methods: We used data from a 1996-2003 cohort study of 2241 pregnant western Washington State residents. During structured interviews conducted at 15 wk of gestation, on average, women reported recreational activities during the year before pregnancy and during the previous 7 d. Preeclampsia diagnosis was established for 111 women using medical record data and standard guidelines.
Results: Recreational activity in the year before pregnancy was nonstatistically significantly associated with reduced preeclampsia risk (adjusted odds ratio [OR] for any vs none 0.55, 95% confidence interval [CI] 0.30-1.02). Any activity during early pregnancy was not strongly associated with preeclampsia risk (adjusted OR = 1.07, 95% CI = 0.67-1.69). Compared with women who reported no recreational activity before or during early pregnancy, risk was nonsignificantly lower among those who were active only before pregnancy (OR = 0.73, 95% CI = 0.30-1.77) and during both periods (OR = 0.76, 95% CI = 0.34-1.73). Those who were active only in early pregnancy had nonsignificantly increased preeclampsia risk (OR = 2.03, 95% CI = 0.71-5.81).
Conclusion: These results corroborate previous case-control studies suggesting that prepregnancy recreational activity reduces preeclampsia risk. The absence of an association with early-pregnancy recreational activity in this cohort may be due to misclassification of usual early-pregnancy activity.