Physical activity and sedentary time during pregnancy and associations with maternal and fetal health outcomes: an epidemiological study.

Background: Physical activity is generally considered safe for the pregnant woman as well as for her fetus. In Sweden, pregnant women without contraindications are recommended to engage in physical activity for at least 30 min per day most days of the week. Physical activity during pregnancy has been associated with decreased risks of adverse health outcomes for the pregnant woman and her offspring. However, there are at present no recommendations regarding sedentary behavior during pregnancy. The aim was to examine the level of physical activity and sedentary time in a representative sample of the pregnant population in Sweden, and to explore potential effects on gestational age, gestational weight gain, birth weight of the child, mode of delivery, blood loss during delivery/postpartum, self-rated health during pregnancy and risk of pregnancy-induced hypertension and preeclampsia.

Methods: This was an epidemiological study using data from the prospective, population-based NorthPop study in Northern Sweden and information on pregnancy outcomes from the national Swedish Pregnancy Register (SPR). A questionnaire regarding physical activity and sedentary time during pregnancy was answered by 2203 pregnant women. Possible differences between categories were analyzed using one-way Analysis of variance and Pearson's Chi-square test. Associations between the level of physical activity/sedentary time and outcome variables were analyzed with univariable and multivariable logistic regression and linear regression.

Results: Only 27.3% of the included participants reported that they reached the recommended level of physical activity. A higher level of physical activity was associated with a reduced risk of emergency caesarean section, lower gestational weight gain, more favorable self-rated health during pregnancy, and a decreased risk of exceeding the Institute of Medicine's recommendations regarding gestational weight gain. Higher sedentary time was associated with a non-favorable self-rated health during pregnancy.

Conclusions: Our study showed that only a minority of pregnant women achieved the recommended level of physical activity, and that higher physical activity and lower sedentary time were associated with improved health outcomes. Encouraging pregnant women to increase their physical activity and decrease their sedentary time, may be important factors to improve maternal and fetal/child health outcomes.