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Aerobic exercise for women during pregnancy

  • Review
  • Intervention


  • MS Kramer

Prof Michael Kramer, McGill University, Faculty of Medicine, 1020 Pine Avenue West, Montreal, Quebec, H3A 1A2, CANADA.



Physiological responses of the fetus (especially increase in heart rate) to single, brief bouts of maternal exercise have been documented frequently, suggesting that maternal exercise might have beneficial or adverse effects on pregnancy outcome.


The objective of this review was to assess the effects of advising healthy pregnant women to engage in regular (at least two to three times per week) aerobic exercise on physical fitness, labour and delivery, and the outcome of pregnancy.

Search strategy

The Cochrane Pregnancy and Childbirth Group trials register was searched and researchers in the field were contacted. Date of last search: January 2002.

Selection criteria

Acceptably controlled comparisons of prescribed aerobic exercise programmes.

Data collection and analysis

One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information.

Main results

Ten trials involving 688 women were included. The trials were not of high methodologic quality. Five trials reported significant improvement in physical fitness in the exercise group, although differences in measures used to assess fitness prevent a quantitative pooling of results. Six trials reported on pregnancy outcomes. A statistically significant increased risk of preterm birth (relative risk (RR) = 2.29 [95% confidence interval 1.02 to 5.13]) in the exercise group is inconsistent with the absence of effect on mean gestational age [+0.0 (-0.4 to +0.4) weeks] and may have been biased by post-randomization exclusion of women with preterm labor. Results bearing on fetal growth (birth weight, length, and head circumference) were highly variable. One trial found improvements among exercising women in several aspects of self-reported body image, including muscle strength, energy level, and body build.

Authors' conclusions

Regular aerobic exercise during pregnancy appears to improve (or maintain) physical fitness and body image. Available data are insufficient to infer important risks or benefits for the mother or infant.

Plain language summary

Plain language summary

Women engaging in regular aerobic exercise during pregnancy improve their physical fitness and body image, but other effects on the woman and her baby are unknown

Aerobic exercise is vigorous physical activity that stimulates breathing and blood circulation. The trials reviewed included noncontact exercise such as swimming, static cycling, and general floor exercise programs. The review found evidence that pregnant women who engage in aerobic exercise for up to one hour, three to four times a week, improve their physical fitness and body image. There is too little evidence from trials to show whether there are other effects on the woman and her baby.

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