Physical activity in pregnancy: a Norwegian-Swedish mother-child birth cohort study

BACKGROUND Physical activity during pregnancy is important for maternal and offspring health. Optimal conditions during pregnancy may help reduce the burden of noncommunicable diseases. National and international guidelines recommend at least 150 minutes of physical activity of at least moderate intensity per week. To optimize physical activity in pregnant women, it is important to identify factors associated with higher levels of physical activity. OBJECTIVE This study aimed to explore types and levels of physical activity in midpregnancy in Norway and Sweden and to identify factors associated with higher levels of physical activity. MATERIALS AND METHODS From the population-based mother-child cohort Preventing Atopic Dermatitis and Allergies in Children study recruiting 2697 women in Norway and Sweden from 2014 to 2016, we included 2349 women who answered an electronic questionnaire at enrollment in midpregnancy. Women were asked about regular physical activity in the last 2 weeks of pregnancy and afterward for types and levels of physical activity in pregnancy and before pregnancy and socioeconomic status, lifestyle, and maternal health. Logistic regression analyses were used to identify factors associated with higher levels of physical activity in pregnancy, defined as >30 minutes per session of ≥2 times per week of moderate- or high-intensity brisk walking, strength training, jogging, and bicycling. RESULTS No regular physical activity during the last 2 weeks before answering the questionnaire at midpregnancy was reported by 689 women (29%). In this study, 1787 women (76%) reported weekly strolling during pregnancy. Regular physical activity at least twice weekly in the first half of pregnancy was reported as brisk walking by 839 women (36%), bicycling by 361 women (15%), strength training by 322 women (14%), and other activities by