Neonatal weight loss at a US Baby-Friendly Hospital.

Few if any studies have examined weight loss among term newborns by weighing infants daily for the first week of life. Perhaps because so few data exist, there is no standard in the United States for normal newborn weight loss. Our objective was to investigate normal newborn weight loss among infants born in a US Baby-Friendly hospital, by weighing infants daily for the first week of life. Using a prospective cohort design, infants born at an urban Boston, MA, hospital were enrolled within 72 hours of delivery and weighed daily for the first week of life. In hospital, infant weight was obtained from the medical record; post discharge, a research assistant visited the home daily and weighed the baby. All feeds in week 1 of life were recorded. Birth-related factors potentially affecting weight loss were abstracted from the medical record. Complete data were collected on 121 infants. Mean weight loss was 4.9% (range=0.0% to 9.9%); 19.8% (24 of 121) of infants lost >7% of their birth weight; no infant lost >10%. Maximum percent weight loss was significantly associated with feeding type: exclusively and mainly breastfed infants lost 5.5%, mainly formula-fed infants lost 2.7% and exclusively formula-fed infants lost 1.2% (P<0.001). Type of delivery and fluids received during labor were not associated with weight loss. Clinical practices at a Baby-Friendly hospital, which support and optimize breastfeeding, appear to be associated with only moderate weight loss in exclusively and mainly breastfed infants.