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In the study, women of size who were active during pregnancy had shorter labors (13.4 hours vs. 19.2 hours) than those who were more sedentary.
The effect seemed particularly strong for women who had given birth before (multips). "Obese" multips who were active in pregnancy had labors of about 6.2 hours, vs. 16.7 hours for obese multips who were not active in pregnancy.
The difference in cesarean rates between those who were active in pregnancy and those who were not did not rise to statistical significance in this study, but as we wrote about recently, other research has suggested that exercise in pregnancy might reduce the risk for cesareans as well.
One caution is that this study was small, so that limits the conclusions from it. Perhaps there were simply not enough participants to show a significant difference in cesareans. On the other hand, its relatively small size might also have magnified the effect on labor length. So there is that caveat.
And of course, this finding is only a correlation. There are plenty of people who exercise religiously and end up with long labors and/or cesareans, and some people who don't exercise at all and have easy short labors and births. Exercising is no guarantee of anything, but it does seem likely to reduce the odds of problems. For example, some research suggests that regular exercise during pregnancy might reduce the risk for gestational diabetes in obese women.
Potentially reducing labor length is just one more reason for women of size to exercise during pregnancy. It's a low-tech intervention that is very unlikely to harm (barring the rare contraindications to exercise in pregnancy) and seems likely to be helpful.
If exercising is something you already do, good work! Keep it up. Regularity of exercise is more important in pregnancy than its intensity. You don't have to run marathons to benefit. Just get out and move most days of the week.
If exercise is something you can improve on, get started. Choose a form of exercise that you enjoy. Walking, swimming, dancing, prenatal yoga, riding an exercise bike, and water aerobics are all forms of exercise that are very friendly to pregnant women of size. And remember, any amount you do is better than none.
You'll feel better for having exercised, trust me (I definitely felt better in my pregnancies when I exercised). And maybe it will pay off with a shorter labor, fewer complications, or less chance of a cesarean too.
J Sports Med Phys Fitness. 2015 Nov 12. [Epub ahead of print] Impact of physical activity during pregnancy on obstetric outcomes in obese women. Tinius R1, Cahill AG, Cade WT. PMID: 26564274
AIM: Maternal obesity is associated with complications and adverse outcomes during the labor and delivery process. In pregnant women with a healthy body weight, maternal physical activity during pregnancy is associated with better obstetric outcomes; however, the effect of maternal physical activity during pregnancy on obstetric outcomes in obese women is not known. The purpose of the study was to determine the influence of self-reported physical activity levels on obstetric outcomes in pregnant obese women. METHODS: A retrospective chart review was performed on 48 active obese women and 48 inactive obese women (N=96) who received prenatal care and delivered at the medical center during the past five years. Obstetric and neonatal outcomes were compared between the active and inactive groups. RESULTS: Obese women who were active during pregnancy spent less total time in labor (13.4 hours vs. 19.2 hours, p=0.048) and were less likely to request an epidural (92% vs. 100%, p=0.04). When stratified by parity, active multiparous women spent significantly less total time in labor compared to inactive multiparous (6.2 hours vs. 16.7 hours, p=0.018). There were no statistical differences between groups in rates of cesarean deliveries or neonatal outcomes. CONCLUSION: Maternal physical activity during pregnancy appears to improve obstetric outcomes in obese women, and this improvement may be more pronounced among multiparous women. Our finding is of particular importance as pregnant obese women are at higher risk for adverse and delivery outcomes.