Chilean reference of length at birth

Area of Science:

• Neonatal anthropometry
• Public health
• Biostatistics

Background:

• Establishing population-specific references for neonatal anthropometry is crucial for accurate growth assessment.
• Previous references may not accurately reflect the anthropometric characteristics of the Chilean newborn population.

Purpose of the Study:

• To generate a sex- and gestational age-specific reference for length at birth (LB) in the Chilean population.
• To provide a tool for identifying potential growth deviations in Chilean newborns.

Main Methods:

• A cross-sectional observational study utilizing pooled Chilean newborn data from 2000 to 2016.
• Exclusion of multiple births and data with missing or extreme values for LB, GA, and sex.
• Calculation of LB centiles using the GAMLSS method for 5,010,963 newborns (24-42 weeks gestation).

Main Results:

• A reference for length at birth by sex and gestational age was established for the Chilean population.
• Girls exhibited a lower length at birth compared to boys across most gestational ages.
• The generated percentiles demonstrated acceptable consistency with the INTERGROWTH-21st standard, with differences generally below 1 cm and 1%.

Conclusions:

• The developed Chilean reference for length at birth is methodologically sound and aligns with international standards.
• This reference can be utilized in clinical and epidemiological settings to assess Chilean newborns.
• It aids in identifying individuals or populations at increased risk for adverse perinatal and infant outcomes related to birth length.