Higher Birth Weight Improves Rates of Exclusive Breastfeeding Through 3 Months

Background. Exclusive breastfeeding through 3 months is a Healthy People 2020 goal, yet most US infants who initiate breastfeeding receive formula before 3 months. The effect of birth weight on exclusive breastfeeding has not been previously studied. Methods. We analyzed data from a randomized trial of probiotics for healthy infants to determine the effect of birth weight and other predictors available at birth on any breastfeeding and exclusive breastfeeding through 3 months. We used backward stepwise logistic regression to examine the effect of maternal age, education, feeding plan, delivery method, and parity and infant birth weight and gestational age on the outcomes of any and exclusive breastfeeding through 3 months. Results. Birth weight was strongly associated with exclusive breastfeeding through 3 months (odds ratio = 6.23 [95% confidence interval = 2.27-17.1] per kilogram birth weight), adjusting for maternal college education and maternal plan to breastfeed exclusively. However, birth weight was not associated with any breastfeeding at 3 months when adjusting for the same predictors. Discussion. Smaller newborns were more likely to receive formula before 3 months in this study population. Educating mothers of smaller babies and their physicians about normal newborn growth patterns might reduce unnecessary formula use for smaller newborns.