Body mass index and weight-for-length ratio references for infants born at 33-42 weeks gestation: a new tool for anthropometric assessment

Clin Nutr. 2011 Oct;30(5):634-9. doi: 10.1016/j.clnu.2011.03.010. Epub 2011 Apr 27.


Background & aims: The risk of childhood obesity, an increasingly prevalent problem worldwide, might be predictable by early body mass index measurements. This study sought to develop body mass index and weight-for-length ratio references for infants born at 33-42 weeks gestation and to validate these data against the growth curves of the World Health Organization Multicenter Growth Reference Study.

Methods: Data were collected from the Neonatal Registry of Rabin Medical Center for all healthy singleton babies born live at 33-42 weeks gestation. Crude and smoothed reference tables and graphs for body mass index and weight-for-length ratio by gestational age were created for males and females, separately.

Results: Birth weight, length, and body mass index percentiles for full-term neonates were similar to the World Health Organization study, reinforcing the generalizability of our reference charts for infants born at 33-42 weeks. Cutoff values for small for date (<5th, <10th percentile) and large for date (>85th, >95th percentile) infants differed across gestational ages in both pre-term and full-term infants.

Conclusions: As body proportionality indexes provide an assessment of body mass and fatness relative to length, we suggest that BMI and Wt/L ratio percentiles be added to weight and length growth curves as a routine intrauterine growth assessment at birth.

Publication types

  • Validation Study

MeSH terms

  • Algorithms
  • Anthropometry / methods*
  • Birth Weight*
  • Body Mass Index*
  • Body Size*
  • Cross-Sectional Studies
  • Female
  • Fetal Growth Retardation / diagnosis
  • Fetal Macrosomia / diagnosis
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Small for Gestational Age
  • Israel
  • Male
  • Premature Birth / pathology*
  • Reference Values
  • Registries
  • Sex Characteristics