Determinants of premature births in two central hospital Harare, Zimbabwe, 2011.

Introduction: Prematurity is a major determinant of neonatal morbidity and mortality in Zimbabwe. Although 8-10% of deliveries are premature , prematurity contributes 33% of neonatal deaths. Identifying local risk factors for prematurity could help incoming up with local intervention and prevention strategies.

Design: 1:1 unmatched case control study.

Setting: Harare and Parirenyatwa central hospitals maternity units.

Subjects: All mothers who delivered in the units June to July 2011. Acase was a mother who had delivered a premature baby and control was a mother who delivered a term baby.

Results: We interviewed 188 cases and 188 controls. Independent risk factors for premature delivery were -A previous premature delivery [AOR 3.15 95% CI 1.17 8.49, 4.61] being admitted with a medical complication in pregnancy[AOR 2.15 95% CI 1.18-3.92]. Birth interval > 24 months [AOR 0.26 95% CI 0.12 0.59] being well nourished evidenced by BMI ≥20kg/m [ AOR 0.926 95% CI 0.88 0.97] and MUAC ≥23cm [AOR 0.95 95% CI 0.91 0.95] reduced the risk of premature delivery. HIV test was done on 87% of participants, 12% were positive (66% controls, 33% cases) (p≤0.001).

Conclusion: Birth interval < 24 months, previous premature delivery, only one ANC attendance, maternal under nutrition and being hospitalized with complications in pregnancy were associated with premature delivery. There was no association with HIV infection. Efforts should be made to give food supplements to pregnant undernourished women.