Risk factors for low birth weight in Bale zone hospitals, South-East Ethiopia : a case-control study

Background: Low birth weight (LBW) is closely associated with foetal and neonatal mortality and morbidity, inhibite growth and cognitive development and resulted chronic diseases later in life. Many factors affect foetal growth and thus, the birth weight. These factors operate to various extents in different environments and cultures. The prevalence of low birth weight in the study area is the highest in the country. To the investigator's knowledge in Bale Zone, no study has yet been done to elucidate the risk factors for low birth weight using case control study design. This study was aimed to identify the risk factors of low birth weight in Bale zone hospitals. Methods: A case-control study design was applied from April 1st to August 30th, 2013. A total of 387 mothers (136 cases and 272 controls) were interviewed using structured and pretested questionnaire by trained data collectors working in delivery ward. For each case, two consecutive controls were included in the study. All cases and controls were mothers with singleton birth, full term babies, no diabetes mellitus and no hypertensive. The data were entered and analyzed using SPSS version 16.0 statistical package. The association between the independent variables and dependent variable (birth weight) was evaluated through bivariate and multiple logistic regression analyses. Result: Maternal age at delivery <20 years (adjusted odds ratio (AOR) = 3; 95 % confidence interval (CI) = 1.65-5.73), monthly income <26 United States Dollarr (USD) (AOR = 3.8; 95 % CI = 1.54-9.41), lack of formal education (AOR = 6; 95 % CI = 1.34-26.90), being merchant (AOR = 0.1; 95 % CI = 0.02-0.52) and residing in rural area (AOR = 2.1; 95 % CI = 1.04-4.33) were socio-economic variables associated with low birth weight. Maternal risk factors like occurrence of health problems during pregnancy (AOR = 6.3; 95 % CI = 2.75-14.48), maternal body mass index <18 kg/m(2) (AOR = 6.7; 95 % CI = 1.21-37.14), maternal height <1.5m (AOR = 3.7; 95 % CI = 1.22-11.28), inter-pregnancy interval <2 years (AOR = 3; 95 % CI = 1.58-6.31], absence of antenatal care (OR = 2.9; 95 % CI = 1.23-6.94) and history of khat chewing (AOR = 6.4; 95 % CI = 2.42-17.10) and environmental factors such as using firewood for cooking (AOR = 2.7; 95 % CI = 1.01-7.17), using kerosene for cooking (AOR = 8.9; 95 % CI = 2.54-31.11), wash hands with water only (AOR = 2.2; 95 % CI = 1.30-3.90) and not having separate kitchen room (AOR = 2.6; 95 % CI = 1.36-4.85) were associated with low birth weight. Conclusion: Women who residing in rural area, faced health problems during current pregnancy, had no antenatal care follow-up and use firewood as energy source were found to be more likely to give low birth weight babies. Improving a mother's awareness and practice for a healthy pregnancy needs to be emphasized to reverse LBW related problems.