In plain words
A weight nadir is the lowest point of a newborn's weight after birth. Almost all babies lose some weight in the first days, while milk is coming in. The nadir usually falls around day three to five. After that, most babies start to gain. Your pediatrician will compare your baby's weight with the usual pattern on a chart. Losing more than expected, or not starting to regain by about two weeks, is a reason for a check, and your provider will guide what happens next. Weight is one sign among several, including feeds and diapers.
The deeper version
Early weight loss in exclusively breastfed term newborns is typically about 7 percent of birth weight at its maximum, with nadir near day three to four, and the Flaherman nomogram (Pediatrics 2015) gives percentile-based expectations derived from a large US cohort. Dewey et al. (2003) documented that and excess weight loss were associated with suboptimal feeding behavior. Regain to birth weight by about two weeks is the usual standard in newborn follow-up. Interpretation of the nadir depends on gestational age, feeding method, intrapartum fluids, and maternal factors. Some clinicians now question the rigidity of nomograms and favor a combined assessment with feeding observation and output.
Where it comes up
- Newborn weight: the early drop and regainingBaby Basics
- Is my baby getting enough?Feeding Your Baby
- Pediatrician visits in the first weeksBaby Basics
- Growth spurts and feeding changesFeeding Your Baby
What mothers here say about weight nadir
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Sources
- Flaherman VJ et al. — Early weight loss nomograms for exclusively breastfed newborns. Pediatrics 2015
- Dewey KG et al. — Risk factors for suboptimal infant breastfeeding behavior, delayed onset of lactation, and excess neonatal weight loss. Pediatrics 2003
- American Academy of Pediatrics — Breastfeeding Handbook for Physicians, 2nd edition, 2014