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Larger infant size at birth reduces the negative association between prepregnancy body mass index and the duration of breastfeeding
Author(s) -
Rasmussen Kathleen M.,
Leonard Stephanie A.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.589.12
Subject(s) - breastfeeding , medicine , body mass index , overweight , birth weight , obstetrics , pregnancy , demography , gestational age , mass index , pediatrics , endocrinology , biology , sociology , genetics
Women who are overweight or obese prepregnancy have shorter durations of producing milk (PM) and feeding breast milk exclusively (FBM‐ex) than normal‐weight women. We proposed that infant size at birth may reduce the negative associations between prepregnancy body mass index (BMI) and the durations of PM and FBM‐ex. We used data from 2798 subjects in the Infant Feeding Practices Study II and characterized infant size at birth as weight‐for‐gestational age (WGA). To assess possible mediation of the associations between maternal BMI and the durations of PM and FBM‐ex by infant size at birth, Baron and Kenny's methods, the Sobel test, and bootstrapping were used. As expected, prepregnancy BMI was negatively associated ( P <0.0001) with the durations of PM and FBM‐ex; it also was positively associated ( P <0.0001) with infant size at birth. However, infant WGA was positively associated ( P <0.0003) with the durations of PM and FBM‐ex after adjustment for BMI. Thus, the negative associations between BMI and the durations of PM and FBM‐ex were reduced by infant WGA; that is, the statistical removal of infant size at birth increased the magnitude of the negative associations between BMI and the durations of PM and FBM‐ex. Thus, the tendency of heavier mothers to deliver heavier infants reduces the true magnitude of the association between maternal prepregnancy BMI and shortened breastfeeding duration. Funded by FDA, USDA/Hatch.