Determinants of preterm birth among mothers who gave birth at public hospitals in the Amhara region, Ethiopia: A case-control study

Background Preterm birth (PTB) is a public health issue worldwide. In developing nations, like Ethiopia, PTB is under reported and underestimated. However, it is the leading cause of neonatal and under-five mortality in Ethiopia. Besides, limited and non-comparative research studies to date has been conducted in the country to address the prevalence of PTB. Therefore, this study aims to determine predictors of PTB. Methods Hospital-based unmatched case control study was employed on a sample of 139 cases and 278 controls from October 2017 to December 2017 in the Amhara region, Ethiopia. The cases and controls were proportionally allocated in each hospital based on the last one-year case flows. As soon as a case was identified, the respective two controls were enrolled until the required sample size was satisfied. The outcome variable was measured by using either last menstrual period (LMP), early ultrasound result, or Ballard maturity examination. Face-to-face interviews were conducted using a standardized, structured, and pre-tested questionnaire to collect data. The collected data was entered into Epi-data and exported into SPSS for analysis. Independent variables with p-values < 0.25 in the bivariate analysis were entered into multivariable logistic regression models with forward logistic regressions method to control the influence of covariates. Ethical clearance was ensured. Results A total of 134 cases and 268 controls participated with a response rate of 96.4%. After adjusting for covariates, the following variables were associated with PTB: residing in rural areas [AOR = 2.99: 95% CI 1.19, 7.48], low maternal age [AOR = 3.47: 95% CI 1.11, 10.83],