Longer pregnancy with physical activity
Moderate physical activity during pregnancy is associated with longer pregnancies, according to a 2012 study from the Norwegian Mother and Child Cohort Study (MoBa). Pregnant women who were physically active 3-5 times a week had a 26 per cent reduced risk of premature birth. Previously, activity and exercise in the latter part of pregnancy were believed to initiate birth.
- 13 per cent of the women reported that they did not participate in any physical activity at either week 17 or week 30 of pregnancy
- 12.6 per cent reported at least three activities per week at both times.
The difference in length of pregnancy between these two groups was 1.6 days, which is a relatively small difference.
Physically active pregnant women were more likely to have a lower body mass index, a longer education, a higher age and smoked less than other pregnant women. Yet even when the analyses were adjusted for the favourable effect of this, differences in pregnancy duration were sustained.
However, the most physically active (pregnant women who were active six times or more per week) had no difference in length of pregnancy than those who did not exercise at all. There was also no significant difference in the percentage of prematurity compared to the inactive women.
About the study
Over 61,000 pregnant women who gave birth in 2000 to 2006 were included in this sub-study, where data about physical activity from week 17 and week 30 of pregnancy were analysed. Different types of physical activity, such as dancing, swimming, brisk walking and regular exercise were included. Twin pregnancies and pregnancies with complications that required rest were not included in the study.
A lower risk of gestational diabetes, pre-eclampsia and postnatal depression has previously been seen in pregnant women who are physically active. Together with this study, there is good evidence that regular physical activity throughout pregnancy is beneficial.
Med. Sci. Sports Exerc. 2012; 44: 1067–1074. Exercise during pregnancy and the gestational age distribution: A cohort study. Owe KM, Nystad W, Skjærven R, Stigum H, Bø K.