Research
Obstetrics
Strenuous exercise during pregnancy: is there a limit?

Presented as a poster at the 32nd annual meeting of the Society for Maternal-Fetal Medicine, Dallas, TX, Feb. 6-11, 2012.
https://doi.org/10.1016/j.ajog.2012.07.021Get rights and content

Objective

The purpose of this study was to evaluate fetal responses to strenuous exercise in physically active and inactive women.

Study Design

Forty-five healthy women (15 who were nonexercisers, 15 who were regularly active, 15 who were highly active) underwent a peak treadmill test at 28 weeks' gestation to 32 weeks 6 days' gestation. Fetal well-being (umbilical artery Doppler indices, fetal heart tracing/rate, biophysical profile [BPP]) was evaluated before and after exercise. Uterine artery Doppler scans were also obtained.

Results

Umbilical and uterine artery Doppler indices were similar among activity groups and did not change with exercise (P > .05). BPP and fetal heart tracings were reassuring in all groups. However, subgroup analyses showed transient fetal heart rate decelerations after exercise and elevated umbilical and uterine artery Doppler indices in 5 highly active women. After this, BPP and fetal heart tracings were reassuring.

Conclusion

Overall fetal well-being is reassuring after short-duration, strenuous exercise in both active and inactive pregnant women. A subset of highly active women experienced transient fetal heart rate decelerations and Doppler changes immediately after exercise. Athletes may push beyond a threshold intensity at which fetal well-being may be compromised. However, potential impact on neonatal outcomes is unknown.

Section snippets

Materials and Methods

The current study is part of a larger investigation of exercise during pregnancy; results regarding fetal responses to current exercise recommendations for moderate and vigorous intensity exercise have been published.5 The present study includes unpublished data on fetal well-being and uterine artery Doppler data in response to strenuous exercise.

Participants included healthy women with low-risk, accurately dated (last menstrual period confirmed by first or second trimester ultrasound scans)

Results

Forty-five healthy pregnant women were divided into 3 groups by physical activity level. Subject characteristics have been reported previously.5 Briefly, groups were similar in age, body mass index, and gestational age (P > .05). Mean ages for the women who were nonexercisers, regularly active, and highly active were 32.9, 34.3, and 32.9 years, respectively. All women were normal weight before pregnancy. Gestational age at the time of testing was 30.7 ± 1.1, 30.2 ± 0.9, and 30.3 ± 1.0 weeks for

Comment

There are 2 primary findings from this study. First, overall fetal well-being was reassuring after strenuous exercise in women who were both exercisers and nonexercisers. Second, a small subset of highly active women demonstrated transient FHR decelerations and alterations in umbilical and uterine artery Doppler indices immediately after exercise.

With strenuous exercise, all participants, regardless of activity status, reported perceived exertion ratings that were consistent with strenuous

References (21)

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Supported in part by grant number L30 HD062349-01 from the Clinical Loan Repayment Program, National Institute of Child Health and Human Development (L.M.S.).

The authors report no conflict of interest.

Reprints not available from the authors.

Cite this article as: Szymanski LM, Satin AJ. Strenuous exercise during pregnancy: is there a limit?. Am J Obstet Gynecol 2012;207:179.e1-6.

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