Anthropometric measurements in sudanese newborns: Value in measuring weight at birth and its relationship with maternal characteristics

Abstract

In developing countries, low birth weight (LBW) (<2,500 g) is the strongest determinant of infant morbidity and mortality. In this chapter we describe a method to measure birth weight (BW) using anthropometric measurements and investigate the effect of maternal age, anthropometry, education and socio-economic status on determining the risk for LBW and preterm birth. Anthropometric measurements were performed in 1,000 singleton Sudanese newborns and their mothers. Maternal measurements (including weight, height and mid-upper-arm circumference) and 11 newborn anthropometric measurements were taken within 24 h of delivery. In addition, maternal age, education and socio-economic status were recorded. Correlation analysis and multivariate regression analysis with backward selection were used to investigate the value of newborn anthropometric measurements in measuring birth weight and the effect of maternal variables on gestational age and birth weight. A simple formula utilizing chest (CC), mid thigh (MT) and head (HC) circumferences measured in cm was obtained to predict BW as follows: BW(g) = 97*CC + 74*MT + 85*HC - 4,000, with a standard error of 285 g. For birth weights <2,000 g the specificity of the formula was near 100% and the sensitivity was >80%. Applying a cut-off point of 2,500 g, all infants (100%) with birth weight <2,000 g were correctly identified. Among maternal characteristics birth order was the strongest determinant of birth weight. Firstborn babies were nearly twice likely to be LBW than infants of multiparous mothers. All maternal anthropometric measurements and age were positively correlated (p < 0.001) with birth weight to a variable extent; however, maternal anthropometry explained less than 6% of the variability of the newborn anthropometry. The postpartum maternal lean body mass (LBM) was found to be the major associate of newborn size (birth weight, body lengths and body circumferences), while skin fold thicknesses were mainly associated with maternal age and maternal BMI. Maternal education was significantly associated with birth weight and body circumferences (except the abdominal) and the ponderal index increased significantly with increasing number of years of education. No association between social class and newborn anthropometry was obtained. Our formula combining chest, mid thigh and head circumferences was found to predict birth weight. Birth order and the postpartum maternal LBM were found to be the most important maternal parameters which influence birth weight and the risk for LBW. The duration of maternal education, and not social class, was found to significantly affect the risk for LBW.