Risk Factors Associated with Preterm Birth at a Tertiary Teaching Hospital in Dar es Salaam, Tanzania: An Unmatched Case-Control Study.

Background: Preterm birth contributes to significant neonatal and under-five mortality and morbidities. This study assessed the risk factors associated with preterm births at a tertiary teaching hospital in Dar es Salaam, Tanzania. Methods: Case-control study to compare risk factors of preterm birth amongst 140 women with preterm deliveries as cases and 280 women with term deliveries as controls. A structured interviewer-administered questionnaire was used. Univariate and multivariable logistic regression analyses were done using STATA version 17 software. Results: The proportion of preterm deliveries was 17.9%. Women with less than four antenatal visits were three times more likely to have a preterm birth than those with four or more attendances (aOR 3.6, 95% CI 1.95-6.57, P < 0.001). The odds of preterm birth increased among women who experienced antepartum haemorrhage (aOR 25.7, 95% CI 12.72-52.03, P < 0.001), pre-eclampsia/eclampsia (aOR 29.9, 95% CI 7.78-115.41, P < 0.001) and preterm membrane rupture (aOR 62.8; 95% CI 23.51-168.21, P < 0.001). Among multiparous women, short interpregnancy intervals, prior preterm birth, or stillbirth increased the odds of preterm birth. Conclusion: Poor antenatal attendance, obstetric complications, and premature rupture of membranes were among the identified risk factors. All could be addressed by quality antenatal care.