Contributor: Sean Fox, MD

Educational Pearls:

• Newborns may lose up to 10% of their birth weight in the first week of life

• Weight loss is greatest in exclusively breastfed infants

• Should regain birth weight by age 2 weeks

• Newborns should gain an average of 30g (1 oz) per day in the first 3 months of life

• Some will gain more and some will gain less

• Infants double their birth weight by 6 months of life and triple their weight by 12 months

• A 1-year-old should weigh on average 10 kg (22 lbs)

• A 3-year-old should weigh on average 15 kg (33 lbs)

• 2-year-olds are between 10-15 kg on average

• Weight assessment can help determine causes of forceful vomiting

• Not all “projectile” vomiting is due to pyloric stenosis

• Some infants may experience vigorous vomiting from overfeeding

• Weight estimates can also provide information for quick decisions on medical management for children coming via EMS 

• Helps to prepare medications and dosages based on predicted average weight

References

1. Crossland DS, Richmond S, Hudson M, Smith K, Abu-Harb M. Weight change in the term baby in the first 2 weeks of life. Acta Paediatr. 2008;97(4):425-429. doi:10.1111/j.1651-2227.2008.00685.x

2. Grummer-Strawn LM, Reinold C, Krebs NF; Centers for Disease Control and Prevention (CDC). Use of World Health Organization and CDC growth charts for children aged 0-59 months in the United States [published correction appears in MMWR Recomm Rep. 2010 Sep 17;59(36):1184]. MMWR Recomm Rep. 2010;59(RR-9):1-15.

3. Macdonald PD, Ross SR, Grant L, Young D. Neonatal weight loss in breast and formula fed infants. Arch Dis Child Fetal Neonatal Ed. 2003;88(6):F472-F476. doi:10.1136/fn.88.6.f472

4. Paul IM, Schaefer EW, Miller JR, et al. Weight Change Nomograms for the First Month After Birth. Pediatrics. 2016;138(6):e20162625. doi:10.1542/peds.2016-2625

Summarized & Edited by Jorge Chalit, OMS3

Special thanks to the Carolinas Medical Center for their contribution to this episode

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