Incidence and recurrence risk of low birth weight in Northern Tanzania: A registry based study

Low birth weight (LBW) is an important indicator of newborn survival. It is associated with higher risk of morbidity, mortality and long-term health consequences. Little has been done on incidence and recurrence risk of LBW in developing countries including Tanzania. This study aimed to determine the incidence and recurrence risk of LBW among women who delivered at Kilimanjaro Christian Medical Center (KCMC), Tanzania.

A hospital-based prospective cohort study was conducted using maternally-linked data from KCMC birth registry between 2000 and 2010. A total of 26,191 women delivered singleton live babies during the study period. Of these, 4,603 (17.6%) had subsequent pregnancies. The recurrence risk of LBW was estimated using a multivariable log-binomial regression model. A robust variance estimator was used to account for correlation between births of the same mother.

The incidence of LBW was 7.1%. The absolute recurrence risk of LBW was 28.1%. This corresponds to a relative risk (RR) of 5.08-fold, 95% CI 4.01-6.45). Antenatal care visits (<4) (RR: 5.00; 95% CI 3.58-6.98), preterm birth (RR: 4.55; 95% CI 3.21-6.43), positive HIV status (RR: 7.49: 95% CI 3.91-14.36) and preeclampsia (RR: 4.37; 2.60-7.35) in the first pregnancy were important predictors of LBW recurrence.

The incidence of LBW and its recurrence was high in the study population. Women with previous history of LBW had higher risk of recurrent LBW in subsequent pregnancies. Identification of factors associated with LBW recurrence, proper post-partum care management to ensure Healthy Timing and Spacing of Pregnancy, Pre-conception care and close clinical follow-up during subsequent pregnancy may help reduce LBW recurrence.