Supplementary Material for: Physiological postnatal weight loss nomograms in exclusively breastfed healthy infants (≥36 weeks) during initial birth hospitalization from an arid region: A prospective cohort study

Introduction: Postnatal weight loss in infants is physiological, but excessive loss predisposes for dehydration and other morbidities. Existing nomograms, primarily developed in temperate climates, may not apply to arid regions as environmental conditions influence weight loss patterns. This study aimed to develop hour-specific percentile nomograms for postnatal weight loss in exclusively breastfed, healthy infants (≥36 weeks) from an arid region, facilitating early identification of those at risk of excessive loss.
Methods: A prospective cohort study was conducted between November 2021 and February 2023 at a tertiary center in Western India. Exclusively breastfed infants ≥36 weeks without major morbidities were enrolled and weighed twice daily until 100 hours after birth or discharge. Infants with abnormal clinical/biochemical findings or requiring any milk supplementation were censored. Quantile regression was used to generate percentile curves for weight loss.
Results: Out of 2458 enrolled infants, 29.6% got censored, so 1730 (1134 vaginal, 596 caesarean) were included in the final analysis, contributing to 10,346 weight measurements. Median weight loss was 7.4% for vaginal and 8.7% for caesarean births; ≥10% loss occurred in 9.4% and 22.4% of infants, respectively. Distinct patterns and nadirs were observed based on mode of delivery. Compared to existing nomograms, our data showed greater early weight loss but quicker recovery after 48 hours.
Conclusions: These nomograms provide region-specific reference standards for monitoring postnatal weight loss among exclusively breastfed infants in a semi-arid to arid region, offering a basis for further validation in other arid settings globally.