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Association Between Change in Physical Activity During Pregnancy and Infant Birth Weight
Kennedy M Peter-Marske1, Kathryn R Hesketh2,3, Amy H Herring4
1Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. kennedy_peter@unc.edu.
Insights
Physical activity (PA) during pregnancy, whether total, recreational, or non-recreational, and changes in PA, did not significantly impact infant birth weight or size for gestational age (SGA). Findings suggest PA levels and their fluctuations are not key determinants for these birth outcomes.
Area of Science:
- Obstetrics and Gynecology
- Maternal-Fetal Medicine
- Public Health and Epidemiology
Background:
- Physical activity (PA) during pregnancy is encouraged for maternal and fetal well-being.
- Understanding the impact of PA intensity and changes throughout gestation on infant outcomes is crucial.
Purpose of the Study:
- To examine associations between total, recreational, and non-recreational physical activity (PA) during pregnancy and infant birth weight and small for gestational age (SGA).
- To investigate the relationship between changes in PA levels during pregnancy and these infant outcomes.
Main Methods:
- 1467 participants from the Pregnancy, Infection, and Nutrition 3 Study reported PA at two time points (17-22 and 27-30 weeks' gestation).
- Absolute and perceived PA intensities were assessed, along with changes in weekly PA hours.
- Multivariable linear and logistic regressions were used to analyze associations with birth weight z-scores and SGA, adjusting for covariates.
Main Results:
- Total and recreational PA, assessed by absolute intensity, showed no significant associations with birth weight or SGA.
- Non-recreational PA at T2 and its change were linked to increased birth weight, but perceived PA intensities were largely unassociated.
- Neither absolute nor perceived PA intensities were associated with SGA.
Conclusions:
- In this observational study, changes in physical activity (PA) levels during pregnancy were not associated with significant differences in infant birth weight.
- Fluctuations in both recreational and non-recreational PA did not demonstrate a clear link to altered birth weight or SGA.
- The findings suggest that PA quantity and changes therein may not be primary drivers of birth weight or SGA in this cohort.
Objective:
We assessed whether total, recreational, and non-recreational physical activity (PA) assessed twice during pregnancy, and its change, were associated with infant birth weight and small for gestational age (SGA).
Methods:
We included 1467 Pregnancy, Infection, and Nutrition 3 Study participants who self-reported PA at time 1 (T1: 17-22 weeks' gestation) and time 2 (T2: 27-30 weeks' gestation). We assessed last week absolute intensities of PA (moderate: 4.7-7.1 METs; and vigorous: > 7.1 METs) and perceived intensities. Change in hours/week of PA was assessed continuously or categorically (increase or decrease ≥ 1 hour, and no change). Associations of continuous PA hours/week at T1, T2, and its change, with sex-specific z-scores of birth weight, were assessed using multivariable linear robust regressions. We used logistic regressions to assess categorical PA measures with SGA. Models were adjusted for adequacy of maternal weight gain, general health, maternal age, parity, race/ethnicity, and smoking.
Results:
Hours/week of total and recreational absolute intensities of PA at T1, T2, and its change were generally not associated with birth weight, although two measures of non-recreational PA at T2 and its change were associated with increased birth weight. Perceived intensities of PA (at T1, T2, and its change) were largely not associated with sex-specific z-scores of infant birth weight. Absolute and perceived intensity PA were not associated with SGA.
Conclusions For Practice:
In this observational cohort, increases and decreases in PA during pregnancy were not associated with differential changes in birthweight or SGA.
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