Low syphilis treatment rates and associated birth outcomes in pregnant women with and without HIV in Zambia: A cohort study

Objective Syphilis and HIV in pregnancy contribute to adverse birth outcomes in Africa. Benzathine penicillin G remains an effective treatment for syphilis in pregnancy, yet gaps persist in timely treatment. The aim of this study was to compare factors associated with adverse birth outcomes among pregnant women diagnosed with syphilis in health facilities according to their HIV status. Methods This retrospective cohort analysis included pregnant women who screened positive for syphilis with routine rapid plasma reagin (RPR) testing in 10 antenatal care (ANC) clinics in Zambia between January 2018 and December 2019. Adverse birth outcomes (preterm delivery, low birth weight, fetal demise, congenital syphilis, and neonatal death) were collected through June 2020. Patient characteristics according to HIV status were compared using Pearson chi‐square test or Fisher exact test for categorical variables and Wilcoxon rank sum test for continuous variables. Logistic regression models were used to estimate the association between maternal and facility‐level factors and a composite measure of adverse birth outcomes. Results In this cohort of 1204 pregnant women diagnosed with syphilis in health facilities, 42.5% had HIV coinfection and only 48.1% had documented penicillin treatment. Although preterm delivery rates were higher among women with syphilis and HIV (39.9% vs. 30.0% with syphilis alone; P = 0.003) the odds of having any adverse birth outcome were similar in both groups. Conclusion Adverse birth outcomes were highly prevalent in Zambia among pregnant women with syphilis and treatment rates were low. Universal access to syphilis treatment in ANC clinic is needed to improve outcomes.