Prevalence, trends, and maternal risk factors of adverse birth outcomes from a hospital-based birth defects surveillance system in Kampala, Uganda, 2015-2022

Abstract

Background: Adverse birth outcomes (ABOs) cause significant infant morbidity and mortality in resource-limited settings. Many of the maternal risk factors associated with ABOs can be prevented. We present the prevalence, trends, and risk factors of selected ABOs from a hospital-based birth defects surveillance program in Kampala, Uganda.

Methods: We analyzed data for all mothers with singleton deliveries collected from four urban hospitals between 2015 and 2022. Prevalence of preterm birth [PTB], low birth weight [LBW], small for gestational age [SGA], and stillbirth [SB] and maternal HIV seroprevalence were calculated among 222,427 births. SB was defined as infant born without life ≥ 28 weeks of gestation, LBW as term live birth weighing < 2500 g and PTB as live birth born < 37 weeks of gestation. Time trends of ABOs by maternal HIV status and age were computed using quasi-Poisson regression model and presented graphically. Risk factor associations were estimated using robust Poisson models adjusting for infant sex, hospital of delivery, and birth year.

Results: Prevalence of PTB, LBW, SGA, and SB were 14.8%, 4.3%, 17.8%, and 3.1%, respectively. Maternal HIV seroprevalence was 7.7%. Compared to mothers aged 25-34 years, young adolescents 10-18 years was associated with PTB (adjusted risk ratio [aRR]: 1.44, 95% confidence interval (CI): 1.38-1.50); LBW (1.65,1.51-1.81); and SGA (1.18; 1.12-1.24). HIV seropositivity was associated with PTB (1.18; 1.14-1.22), LBW (1.54; 1.43-1.65), and SGA (1.28; 1.23-1.33). Compared to starting ANC in the first trimester, no antenatal care (ANC) was associated with PTB (2.44; 2.33-2.56), LBW (1.80; 1.55-2.09), SGA (1.37; 1.27-1.49), and SB (3.73; 3.32-4.15) and late attendance with LBW (1.09; 1.02-1.16), SGA (1.26; 1.22-1.30), and SB (1.09; 1.02-1.17). Our findings also indicate a rising trend in PTB among adolescent and young women aged 10-24 years, and a declining trend in LBW and SGA over time (ptrend < 0.05 for all).

Conclusions: Young maternal age, maternal HIV, and late or no ANC attendance were associated with ABO. Childbearing in the ages 25-34, preventing HIV in women, and supporting early and frequent ANC attendance are important in improving birth outcomes.

Keywords: Adverse birth outcomes; Low birth weight; Preterm birth; Small for gestational age; Stillbirth.