FACTORS ASSOCIATED WITH ABNORMAL BIRTH WEIGTH IN NIGERIA

Abstract

Weight at birth plays a major role in the survival, physical growth and mental development of an infant. Birth weight can be classified into three categories, low birth weight (defined by birth weight < 2.5 kg), normal birth weight (defined by birth weight ≥2.5 kg< 4.0 kg), and high birth weight (defined by birth weight > 4.0 kg). More than 15.5% (20 million) of all infants births worldwide were born with abnormal birth weight and 95.6% of these were in developing countries. About 14% of all births in Nigeria were born with abnormal birth weight. Most research on birth weight outcomes in Nigeria have focused mainly on identifying risk factors of clinical/medical importance and have largely ignored socio-demographic and economic factors which encompasses maternal characteristics such as genetic endowment, socio-cultural, demographic, and medical conditions. The objective of this study was to examine the factors associated with abnormal birth weight (low birth weight and macrosomia) in Nigeria. This study used a secondary data set. The data set was obtained from the 2013 Nigeria Demographic and Health Survey (NDHS). This is a descriptive cross-sectional study conducted among 28,596 women of reproductive age in Nigeria. Bivariate Analysis was used to determine the association between various variables. A p-value of less than 0.001 and 0.05 were considered as statistically significant. Predictors of low bi11h weight and High birth weight were investigated using multinomial logistic regression model. The mean age of the respondents was 29.45±6.92years. The mean birth weight of the baby was 3.24±0.76, with 3143 (11.1%) reporting having a low birth weight baby, 22134 (77.4%) having normal birth weight baby and 3319 (11.6%) having high birth weight baby respectively. Fourteen Thousand Three Hundred and Eighty Seven (50.3%) gave birth to male children while 14209 (49.7%) have female children. Majority (97. 1%) gave birth to singleton babies while 2.9% have twin babies. Variables which remained statistically significant and associated with abnormal birth weight include maternal age, maternal educational level, marital status, wealth index, place of residence, Antenatal visits, and region for socio-demographic and economic factor. Maternal BMI, were also statistically significant while maternal smoking and parity were not significantly associated with abnormal birth weight for maternal socio-demographic and economic factors. Maternal BMI, Child's sex and Twin children were also statistical significant while preceding birth interval and parity were not significantly associated with abnormal birth weight for biophysical characteristics and foetal-related factors. Based on final multivariate multinomial model, twin children were 4 times more likely to be low birth weight babies [AOR=4.07, 95%Cl=3.46-4.80] while they were 0.5 times less likely to be high birth weight babies [AOR=0.50, 95%CI=0.36-0.68). Married women were 0.6 less likely to have low birth weight babies [AOR=0.60, 95%CJ=0.47-0.77] while Divorce women were 1.63 times more likely to have high birth weight babies (AOR=1.63, 95% CI=1.09-2.43). The study identified a number of maternal socio-demographic and economic factors that significantly associated with abnormal birth weight. It also demonstrates that certain maternal biophysical characteristics and foetal-factors could play a role in the infant birth weight and are preventable through simple public health approaches. Therefore, in order to reduce this menace in Nigeria, holistic approaches such as health education maternal nutrition improvement in socio-economic indices, and increasing the quality and quantity of the antenatal care services are of paramount importance.