Maternal exercise and growth in breastfed infants: a meta-analysis of randomized controlled trials.

BACKGROUND AND OBJECTIVES Studies have revealed that women who breastfeed their infants may be reluctant to exercise due to concerns that to do so would adversely affect their breast milk and consequently the growth of their infants. In this review, we seek to systematically review and statistically synthesize evidence from randomized controlled trials (RCTs) that have assessed the effects of maternal exercise on breastfed infant growth (weight gain and gain in length). METHODS Searches of the following electronic bibliographic databases were performed to identify RCTs: Cochrane Library (CENTRAL), Medline/PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and SPORT Discus. RCTs that compared any type of exercise intervention with other treatments or no treatment in women exclusively or predominately breastfeeding were eligible for inclusion, as were trials involving exercise as a cointervention. Two authors extracted data from studies independently. RESULTS Four RCTs (5 comparisons) were included in the meta-analysis of infant weight gain that incorporated 170 participants. In breastfed infants, maternal exercise did not significantly affect infant weight gain (difference in mean weight gain = 18.6 g [95% confidence interval: -113.52 to 150.80, P = .73]). Only 1 trial assessed infant gain in length; no difference between the exercise and control groups was reported. Trials were classified as moderate or good methodological quality (moderate risk of bias). CONCLUSIONS It appears that mothers can exercise and breastfeed without detriment to the growth of their infants, but this is based on limited evidence, and more research is required before this finding is confirmed.