Early weight loss nomograms for formula fed newborns.

OBJECTIVES: To develop nomograms depicting percentiles of weight loss by hour of age for both vaginal and cesarean-delivered newborns who are exclusively formula fed.

METHODS: Data regarding delivery mode, race/ethnicity, feeding type, and weights were extracted from electronic medical records of the birth hospitalization at 14 Kaiser Permanente Northern California hospitals between 2009 and 2013. Newborns whose first feeding was formula from a cohort of 161 471 healthy, term, singleton neonates born at ≥36 weeks' gestation between 2009 and 2013 were identified. Quantile regression was used to create nomograms stratified according to delivery mode; percentiles of weight loss were estimated as a function of time among formula-fed neonates. Weights measured subsequent to any breast milk feeding were excluded. Percentiles were determined through 48 and 72 hours of age for those born vaginally and via cesarean delivery, respectively.

RESULTS: A total of 7075 formula-fed newborns had weights recorded; 4525 were delivered vaginally, and 2550 were born via cesarean delivery. The median weight loss was 2.9% at 48 hours after vaginal delivery; weight loss>7% was rare. For cesarean-delivered neonates, median weight losses at 48 and 72 hours were 3.7% and 3.5%, respectively; weight loss>8% was rare.

CONCLUSIONS: For newborns who are formula fed, these results provide nomograms depicting percentiles of weight loss according to mode of delivery. These plots can be used to classify early weight loss according to percentile and may enable early identification of feeding difficulties or other neonatal morbidities.