Determinants of Birth Weight in Southwestern Nigeria

Background: Birth weight is an important predictor of an infant’s survival and subsequent wellbeing and the likelihood of developing childhood diseases. It is influenced by various maternal and foetal factors affecting the delivery. This study was conducted to determine the factors affecting the delivery of low birth weight (LBW) babies in an urban population in Nigeria. Methodology: The study was carried out at Our Lady of Apostle Catholic Hospital, Oluyoro, Ibadan. The birth register and antenatal case files and records of 3013 booked patients with singleton live births between January 2013 and December 2014 were retrospectively analyzed. Socio-demographic and obstetric data were studied using SPSS version 22. Ethical clearance was obtained from the institution’s Ethical Review Committee. The results were presented in numbers, percentages, frequency tables and charts and the findings were tested for significance using ANOVA. Student t-test was used to treat continuous variables. Level of significance was set at 0.05. Multiple regression analysis was used to explore the potential predictors of birth weight. Results: A total of 3013 singleton deliveries – 1570 (52.1%) males and 1443 (47.9%) females were studied. Presentation was cephalic in the majority – 2821 (93.5%) babies and caesarean section (CS) rate was (41%). There were 234 (7.8%) LBW and 305 (10.1%) macrosomic babies. The maternal ages ranged from sixteen to forty-four years with a mean age of 30.86 ± 4.793 years. The maternal modal age range was 20 to 29 years – 1493 (49.6%) mothers. The mean ± SD maternal age was 30.86 ± 4.793 years. Nulliparity was the mode 32.2% mothers. Most of the mothers 1881 (62.4%) were in the upper social classes. On univariate analysis, maternal age, parity, gestational age at delivery and sex were found to be statistically significant in between groups in determining birth weight. The birth weight was found to increase with parity until the fifth parous experience when it began to decline. The mean birth weight was also found to be higher in male babies than females. On multiple regression, the four factors above retained their association with birth weight. Conclusion: It was concluded that maternal and foetal factors influenced the birth weights of the babies. These factors were the ages and parities of the mothers as well as the sexes and lengths of gestation of the babies. These factors were also good predictors of foetal weight. It is necessary to develop proactive measures to reduce the prevalence of LBW babies.