Predictive accuracy of perceived baby birth size for birth weight: a cross-sectional study from the 2016 Ethiopian Demographic and Health Survey

OBJECTIVES: The study was designed to evaluate the accuracy of maternally perceived baby birth size assessments as a measure of birth weight and examine factors influencing the accuracy of maternal size assessments.

STUDY DESIGN: Cross-sectional study.

SETTING: The study is based on national data from the 2016 Ethiopian Demographic and Health Survey.

PARTICIPANTS: We included 1455 children who had both birth size and birth weight data.

MAIN OUTCOME MEASURES: Predictive accuracy of baby birth size for low birth weight.

Level of discordance between maternally perceived birth size and birth weight including factors influencing discordance.

RESULTS: Mother-reported baby birth size had low sensitivity (57%) and positive predictive value (41%) to indicate low birth weight but had high specificity (89%) and negative predictive values (94%).

The per cent of agreement between birth weight (<2500 g vs ≥2500 g) and maternally perceived birth size (small size vs average or above) was 86% and kappa statistics indicated a moderate level of agreement (kappa=0.41, p<0.001).

Maternal age, wealth index quintile, marital status and maternal education were significant predictors of the discordance between birth size and birth weight.

CONCLUSIONS: Maternal assessment of baby size at birth is an inaccurate proxy indicator of low birth weight in Ethiopia.

Therefore, a mother’s recall of birth size should be used as a proxy indicator for low birth weight with caution and should take maternal characteristics into consideration.