Impact of intermittent preventive treatment of malaria in pregnancy with sulfadoxine–pyrimethamine on sexually transmitted and reproductive tract infections: results from a randomized trial in Uganda

BACKGROUND: In sub-Saharan Africa, sexually transmitted and reproductive tract infections (STIs/RTIs) are important but underdiagnosed risk factors for adverse pregnancy outcomes. Sulfadoxine-pyrimethamine (SP), used for the intermittent preventive treatment of malaria in pregnancy (IPTp), may reduce the STI/RTI burden due to its antimicrobial activity. We assessed the impact of IPTp regimens on STI/RTI prevalence and evaluated associations between STIs/RTIs and adverse birth outcomes. METHODS: We conducted a secondary analysis of a randomized-controlled trial comparing monthly IPTp with SP, dihydroartemisinin-piperaquine (DP), or DP+SP among pregnant women in Uganda. Vaginal swabs collected at or near delivery were tested for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Group B Streptococcus (GBS) by using GeneXpert; bacterial vaginosis was assessed by using Nugent scoring. Log-binomial regression was used to compare STI/RTI prevalence between IPTp arms; IPTp-DP served as the reference arm. Multivariable Poisson regression with robust standard errors was used to evaluate associations between infections and preterm delivery, term low birthweight (LBW), overall LBW, and small-for-gestational age. RESULTS: Among the 2265 participants assessed, the IPTp-SP arm had an 80% [95% confidence interval (CI): 67%-88%] lower prevalence of C. trachomatis (2.5% vs 12.4%) and a 35% (95% CI: 1%-57%) lower prevalence of GBS (7.7% vs 11.7%) at delivery compared with the IPTp-DP arm. Chlamydia trachomatis was associated with increased preterm delivery [prevalence ratio (PR) = 1.86, 95% CI: 1.07-3.25] and GBS was associated with increased term LBW (PR = 2.08, 95% CI: 1.06-4.08). CONCLUSION: Monthly IPTp-SP may reduce the risk of adverse birth outcomes through its activity against C. trachomatis and GBS, highlighting its potential non-malarial benefits.