Systematic Review of Expected Weight Changes After Birth for Full-Term, Breastfed Newborns.

OBJECTIVE: To summarize the findings of recent studies on neonatal weight changes that occur in the early weeks of life among full-term, breastfed newborns.

DATA SOURCES: Using the keywords breastfeeding, newborn, infant, weight, weight loss, and growth, we searched PubMed, Cumulative Index of Nursing and Allied Health Literature, Cochrane Library, and MEDLINE for primary studies and secondary analyses. We also reviewed the reference lists of retrieved articles.

STUDY SELECTION: Quantitative studies published in the English language from 2015 through 2019 that focused on newborn weight changes. From a total of 827 records initially screened, we included 11 studies in this analysis.

DATA EXTRACTION: Two authors independently reviewed the selected articles with the use of the Johns Hopkins Nursing Evidence-Based Practice Synthesis and Recommendations Tool. To determine evidence levels and quality ratings, we evaluated the consistency and generalizability of study results, sample sizes, study designs, adequacy of controls, and definitive nature of the conclusions.

DATA SYNTHESIS: By 2 days after birth, mean weight loss among neonates was 6% to 7% of birth weight, and by Day 3, mean weight loss was usually 7% to 8%. The nadir of lost birth weight occurred on Days 2, 3, or 4 after birth. At times, breastfed newborns lost 10% or more of their birth weight. By 10 to 14 days, most newborns regained their birth weight. Rates of exclusive breastfeeding decreased when newborns lost greater amounts of weight. Compared with past studies, more sample groups in this review included exclusively breastfed newborns and weight assessments beyond birth hospitalization.

CONCLUSION: Weight loss is commonly 7% to 8% of birth weight or greater by the third day after birth among healthy, full-term, breastfed newborns.