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Exposure analysis methods impact associations between maternal physical activity and cesarean delivery
Marit L Bovbjerg1, Anna Maria Siega-Riz, Kelly R Evenson
1College of Public Health and Human Sciences, Oregon State University, Corvallis, OR.
Journal of Physical Activity & Health
|February 11, 2014
Summary
Maternal physical activity (PA) levels during pregnancy did not show a clear link to cesarean birth risk. Associations may be nonlinear and depend on gestational age, suggesting category-based analyses may be inaccurate.
Area of Science:
- Obstetrics and Gynecology
- Maternal Health
- Epidemiology
Background:
- Conflicting evidence exists regarding the association between maternal physical activity (PA) and cesarean delivery rates.
- Understanding this relationship is crucial for optimizing maternal and infant outcomes.
Purpose of the Study:
- To investigate the association between maternal physical activity (PA) and the risk of cesarean delivery.
- To explore potential nonlinear relationships and gestational age-dependent effects.
Main Methods:
- A cohort of 1205 pregnant women without prior cesarean delivery provided 7-day PA recalls via telephone at two gestational windows (17-22 and 27-30 weeks).
- PA was analyzed as a continuous, nonlinear variable using binomial regression, controlling for key covariates.
- Cesarean delivery outcomes were obtained from medical records.
Main Results:
- Dose-response curves for PA and cesarean risk exhibited an inverse J-shape at 17-22 weeks and a reversed J-shape at 27-30 weeks.
- Total PA at 27-30 weeks showed a strong association with cesarean risk, which diminished upon excluding high PA levels (>97.5th percentile).
Conclusions:
- No clear evidence of an association between overall physical activity and cesarean birth was found.
- The study suggests that the relationship between PA and cesarean risk is nonlinear and gestational age-dependent.
- Categorizing maternal PA may limit analytical accuracy.
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