Relationship between physical activity and physical and mental health status in pregnant women: a prospective cohort study of the Japan Environment and Children's Study

概要

Although conventional studies and guidelines have recommended establishing exercise habits for pregnant women, a consensus regarding the recommended upper and lower limits of the physical activity (PA) levels during pregnancy have not been reached yet. This prospective cohort study examined the relationships between PA levels before and during pregnancy, as well as physical and mental health status, to report appropriate PA levels during pregnancy. This study screened the fixed data of 104,102 women enrolled for the Japan Environment and Children’s Study (JECS), a nationwide birth cohort study launched in 2011. Records of 82,919 women were used for the analysis after excluding the data of pregnant women with multiple births (n = 1994), pregnancy complications (n = 14,758), or missing data (n = 4431). PA levels before and during pregnancy were measured using the International Physical Activity Questionnaire-Short Form. Physical and mental health status at two-time points of the first and second to third trimesters were assessed by the 8-Item Short Form Health Survey. Binomial logistic regression analysis with multiple imputations revealed that moderate PA for over 720 min/week and vigorous PA before pregnancy were associated with poorer mental health in the first trimester (adjusted odds ratio (AOR): 1.087–1.376). Walking in the second and third trimesters was associated with better physical and mental health during the same period (AOR: 0.855–0.932). Moderate PA over 1080 min/ week and vigorous PA in the second and third trimesters were associated with poorer mental health during the same period (AOR: 1.223–1.873). An increase of over 4135.4 MET–min/week and decreased PA levels during pregnancy were associated with poorer mental and physical health (AOR: 1.070–1.333). In conclusion, engagement in walking, moderate PA, or vigorous PA for under 360 min/week before pregnancy was acceptable, however, performing vigorous PA for over 360 min/week before pregnancy was not recommended to produce health benefits during the first trimester. In the second and third trimesters, it was probably be better to spend more time walking. Meanwhile, moderate PA for over 1080 min/week or vigorous PA might not be better to achieve health benefits. Furthermore, we recommended maintaining or increasing PA levels up to 1702.9 MET– min/week during pregnancy since a decrease and excessive increase in PAs from the first to the second and third trimesters were associated with poor physical and mental health status.

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