Rethinking Neonatal Body Proportions: Upper Segment to Lower Segment Ratios in a Rural South Indian Cohort.

Area of Science:

• Pediatrics
• Anthropometry
• Genetics

Background:

• The upper segment to lower segment (US:LS) ratio is a critical anthropometric measure for assessing pediatric body proportions and identifying growth disorders.
• Body proportions are influenced by a complex interplay of ethnic, genetic, nutritional, and environmental factors.

Purpose of the Study:

• To establish US:LS ratio reference values for live-born neonates in rural Telangana, India.
• To compare US:LS ratios across sex, gestational age, birth weight, and intrauterine growth status.
• To evaluate the applicability of Western normative US:LS ratio values to the Indian neonatal population.

Main Methods:

• A cross-sectional study involving 998 neonates was conducted in Hyderabad, Telangana, India.
• Crown-heel length and lower segment length (pubic symphysis to heel) were measured; the upper segment was calculated by subtraction.
• Neonates were categorized by sex, gestational age, birth weight, and intrauterine growth status for comparative analysis using independent t-tests and ANOVA.

Main Results:

• The overall mean US:LS ratio was 1.511 ± 0.13, which is lower than typical Western values.
• Male neonates exhibited a significantly higher US:LS ratio (1.519 ± 0.14) compared to females (1.502 ± 0.13; p=0.048).
• Preterm neonates had a significantly higher mean US:LS ratio (1.56 ± 0.15) than term infants (1.510 ± 0.13; p=0.0031).

Conclusions:

• The established US:LS ratio reference values for Indian neonates are lower than those reported in Western literature.
• Significant gender and gestational age-related differences in the US:LS ratio were observed in this population.
• Population-specific reference values are crucial for accurate clinical assessment of neonates for skeletal dysplasia and disproportionate growth.