RT Journal Article SR Electronic T1 First-day weight loss predicts eventual weight nadir for breastfeeding newborns JF Archives of Disease in Childhood - Fetal and Neonatal Edition JO Arch Dis Child Fetal Neonatal Ed FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP F488 OP F492 DO 10.1136/archdischild-2012-303076 VO 98 IS 6 A1 Valerie J Flaherman A1 Michael W Kuzniewicz A1 Sherian Li A1 Eileen Walsh A1 Charles E McCulloch A1 Thomas B Newman YR 2013 UL http://fn.bmj.com/content/98/6/F488.abstract AB Objective To examine the relationship between high (≥5%) weight loss during the first 24 h after birth and eventual excess weight loss (EWL) of ≥10% of birth weight. Design Retrospective cohort study. Setting Kaiser Permanente Northern California hospitals. Patients 63 096 infants born at ≥36 weeks in 2009–2010, of whom 59 761 (94.5%) had a weight subsequent to birth weight measured at <24 h. Main predictor measure Per cent of birth weight lost by 24 h of age. Main outcome measure Weight nadir, defined as the lowest recorded inpatient or outpatient weight in the first 30 days after birth, expressed as a percentage of birth weight. Results Among infants who breastfed at least once, mean (±SD) weight nadir was 6.3±3.5% below birth weight, and 9.6% of the newborns lost ≥10% of birth weight. Among 2670 infants who lost ≥5% of their birth weight in the first 24 h, 782 (29%) eventually developed EWL, compared with 4840 (8%) of 57 109 infants who lost <5% (p<0.0005). In multivariate analysis, ≥5% first-day weight loss predicted eventual EWL (≥10%) with an OR of 4.06 (95% CI 3.69 to 4.46) after adjusting for gestational age, method of delivery, maternal race/ethnicity and hospital of birth. Conclusions High first-day weight loss predicts eventual weight nadir and can be used to identify infants who might benefit from targeted interventions to support breastfeeding and prevent EWL.