Relationship between postnatal foot length and selected anthropometric parameters in the estimation of gestational age among Nigerian neonates

Abstract

Background: Anthropometric parameters such as body weight, body length, occipitofrontal circumference and foot length are known to increase with gestational age. The estimated gestational age (EGA) is the approximate duration of pregnancy to the nearest two weeks at the point of birth.

Objective: To determine if there is a relationship between postnatal foot length and anthropometric parameters such as body weight, body length and occipito-frontal circumference in the estimation of gestational age among Nigerian neonates.

Methods: At the Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria, a cross-sectional study was carried out among 260 neonates with EGA 30- 42 weeks within the first 48 hours of life between December 2017 and December 2019. Postnatal foot lengths were measured with Vernier digital caliper while body weight, body length and occipitofrontal circumference (OFC) were also measured using standard procedures. 

Results: The postnatal foot length, body weight, body length and occipitofrontal circumference showed steady rise with increasing estimated gestational age. The boy weight ranged from 1.19± 0.14kg at 30 weeks to 3.41±0.44 at 42 weeks. The range of body length was 37.78±2.58cm at 30weeks to 50.60±1.67cm at 42 weeks. The occipitofrontal circumference also ranged from 26.65±1.47cmat 30 weeks to 35.40±1.63cm at 42 weeks. The foot length had strong correlation with the body weight (r = 0.892), body length (r = 0.754) and OFC (r = 0.801) in the preterm neonates. In the term neonates, the foot length had moderate correlations with each of the three parameters (r = 0.632, r = 0.473and r = 0.496).

Conclusion: Postnatal foot length had the highest correlation with body weight among preterm and term neonates hence, it will be a useful proxy for birth weight in the estimation of gestational age among Nigerian neonates.