Neonatal weight matters: An examination of weight changes in full-term breastfeeding newborns during the first 2 weeks of life

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Background: Weight changes in the early weeks of life are important indicators of newborn wellness. Yet, little is known about weight loss patterns for breastfeeding newborns. Research aim: This study aimed to compare weight changes and exclusive breastfeeding rates in newborns who lost ≤ 7% and > 7% of their body weight after birth. Methods: A prospective, observational cohort study was completed. Newborns who lost ≤ 7% made up Group 1 and newborns who lost > 7% of birth weight made up Group 2. Mothers used a digital scale to weigh their newborns daily until 14 days of life. Newborn intake and outputs were also recorded. Results: Mean (with standard deviation in parentheses) weight loss for all newborns (N = 151) was 7.68% (2.35%). Newborns in Group 1 (n = 67) lost 5.7% (0.99%) and newborns in Group 2 lost 9.3% (1.87%). More than half of healthy, full-term newborns (56%) lost > 7%. On Day 14, the exclusive breastfeeding rate for newborns in Group 2 was significantly less than for those in Group 1 (60% vs. 82%; p = .033). Newborns gained a mean of 1.1% body weight daily; those in Group 1 gained 1.2% daily, and those in Group 2 gained 1.0% daily. Conclusion: Weight loss > 7% may be a normal phenomenon among breastfeeding newborns. Newborns who lost > 7% had a lower exclusive breastfeeding rate at 2 weeks of age. After the weight nadir was reached, most newborns gained weight at a similar pace, despite differences in early weight loss.

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Journal of Human Lactation