Asymptomatic bacteriuria and its associated fetomaternal outcomes among pregnant women delivering at Bugando Medical Centre in Mwanza, Tanzania

Abstract

Background Asymptomatic bacteriuria (ASB) affects 23.9% of pregnant women globally and, if left untreated, can lead to adverse fetomaternal outcomes. In Tanzania, ASB prevalence has ranged from 13% to 17% over the past decade. Yet, its impact on fetomaternal outcomes remains unexplored, hindering the development of screening strategies, antimicrobial therapies, and preventive measures for this vulnerable population. Methods A cross-sectional analytical study was conducted on 1,093 pregnant women admitted for delivery at Bugando Medical Center (BMC) in Mwanza, Tanzania, from July to December 2022. Socio-demographic, obstetric, and clinical data were collected from the women, along with mid-stream urine samples for analysis. Fetomaternal outcomes were assessed within 72 hours after delivery. Results The median age of participants was 29 years (range: 15-45 years). ASB prevalence among pregnant women was 16.9% (185/1093), with a 95% CI of 14.6-19.3%. Risk factors for ASB included anemia (OR: 5.3; 95% CI = 3.7-8.2, p-value <0.001) and a history of antenatal care admission (OR 4.2; 95% CI = 2.9-6.1, p-value <0.001). Among all participants, 82 (7.5%), 65 (5.9%), 49 (4.5%), and 79 (7.2%) experienced pre-term labor (PTL), premature rupture of membrane (PROM), preeclampsia, and delivered newborns with low birthweight (LBW), respectively. Among the 185 patients with ASB, the respective proportions of PTL, PROM, preeclampsia, and LBW were 25.4%, 17.3%, 9.2%, and 12.4%. Multivariable logistic regression analysis revealed significant associations between ASB and PTL [OR (95% CI): 8.8 (5.5-14.5); p-value <0.001], PROM [OR (95% CI): 4.5 (2.5-8.0); p-value <0.001], and LBW [OR (95% CI): 2.0 (1.2-3.5); p-value = 0.011]. Escherichia coli (50.8%) and Klebsiella pneumoniae (14.05%) were the most common pathogens, with low resistance rates to nitrofurantoin, amoxicillin-clavulanate, and cephalosporins-antibiotics considered safe during pregnancy-ranging from 8.2% to 31.0%. Conclusion The prevalence of ASB among pregnant women in Tanzania remains high and is associated with adverse fetomaternal outcomes. Integrating routine urine culture screening for all pregnant women, irrespective of symptoms, and providing specific antimicrobial therapies during antenatal care can help prevent adverse pregnancy outcomes.