Factors associated with risk of preterm delivery in Tanzania: A case-control study at Muhimbili National Hospital

Objective To determine factors associated with risk of preterm delivery among pregnant women delivering at Muhimbili National Hospital in Tanzania.Methods A 1:1 case-control study was conducted to assess maternal sociodemographic, lifestyle, and current and previous obstetric factors associated with risk of preterm delivery. Mothers of preterm infants were regarded as cases and those of term infants were controls. Chi-square test and logistic regression were used to assess association between the factors and risk of preterm delivery.Results A total of 222 case-control pairs were studied. Maternal type of employment (P = 0.039), previous preterm delivery (P = 0.002), previous spontaneous abortion (P = 0.004), uterine scar (P < 0.001), parity (P = 0.034), number of prenatal care visits (P = 0.032), premature rupture of membranes (PROM) (P < 0.001), placenta previa (P = 0.002), bleeding during second trimester (P = 0.004), pre-eclampsia (P < 0.001), and maternal anemia (P = 0.033) were associated with risk of preterm delivery. The main risk factors associated with preterm delivery included previous preterm delivery (odds ratio [OR] 13.23, 95% confidence interval [CI] 1.72-101.95), placenta previa (OR 12.63, 95% CI 1.63-97.98), and PROM (OR 8.77, 95% CI 1.33-4.60).Conclusion Close monitoring of pregnant women who present any of the risk factors is important to prevent or reduce the risk of preterm delivery in Tanzania.