Risk factors associated with pre-term birth in Dar es Salaam, Tanzania: a case-control study

Background: Preterm birth remains one of the most serious problems in obstetrics care. Its aetiology is complex and multifactorial. This study was carried out to determine risk factors for preterm birth in Dar es Salaam City inTanzania.
Methods: This case-control study was conducted in three municipal hospitals namely, Amani, Mwananyamala and Temeke in Dar es Salaam. It involved 377 pairs of women with preterm birth (cases) and term birth (controls). Eligible women who agreed to participate and who signed the consent form completed a short interview regarding demographic and lifestyle factors, had their baby examined for maturity, and had their medical records abstracted. All cases and controls were interviewed face-to-face using a specially designed questionnaire. Multivariate logistic regression after controlling for potential confounders was used to measure the strength of associations between preterm birth and related factors.
Results: Several significant risk factors associations with pre-term birth were multiple pregnancies (AOR = 8.6; 95%CI 4.5-16.5; p-value <0.001), untreated vaginal discharge (AOR = 5.2; 95%CI 1.1-24.4; p-value 0.034), public prenatal care (AOR = 2.1; 95%CI 1.1-4.1; p-value 0.017), untreated urinary tract infection (AOR = 2.7; 95%CI 1.2-6.1; p-value 0.016), complication during pregnancy (AOR = 2.7; 95%CI 1.3-5.3; p-value 0.004), cervical incompetence (AOR = 11.6; 95%CI 1.1-121.5; p-value 0.04), polyhydramnios (AOR = 8.3; 95%CI 1.7-40.2; p-value 0.008), and lack of antenatal visits (AOR = 5.1; 95%CI 1.4-17.8; p-value 0.042).
Conclusion: This study has identified several risk factors for preterm birth in the city of Dar es Salaam. It is important that planners design community-based interventions to address complications from preterm birth.