Submicroscopic malaria infections and inadequate IPTp-SP coverage among pregnant women in rural Burkina Faso: an observational study

Background Malaria in pregnancy is a major cause of maternal and neonatal morbidity in sub-Saharan Africa. Intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP), reduces malaria-associated adverse outcomes but routine diagnostics miss low-density infections, and coverage remains suboptimal in many endemic settings. Methods We conducted an observational study (June 2023-June 2024) at a health centre in Koubri, central Burkina Faso, combining a cross-sectional assessment at the first antenatal care (ANC) visit with retrospective abstraction of routine ANC and delivery records. At enrolment, pregnant women were tested by real-time PCR; microscopy and rapid diagnostic test (RDT) were performed when available. IPTp-SP doses, follow-up testing, and birth outcomes were extracted from facility registers. Modified Poisson regression with robust variance was used to identify predictors of PCR-confirmed infection, factors associated with low birthweight ( LBW, <2500 g) and the association between cumulative IPTp-SP doses and PCR positivity. Results At first ANC, PCR detected Plasmodium infection in 30.1% (155/515) of women. Among 183 women tested by all three methods, PCR prevalence was 23.5% versus 8.2% by microscopy and 8.7% by RDT, with approximately two-thirds of infections missed by routine diagnostics. Primigravidae had twice the infection risk of multigravidae (aPR 2.14, 95% CI 1.21–3.79),). Each additional IPTp-SP dose was associated with lower infection prevalence (aPR 0.89, 95% CI 0.80–0.99). Most women (78.6%) received ≥3 doses, but only 18.9% reached ≥5 doses, Among 225 deliveries, LBW prevalence was 14.7% ( PCR-confirmed infection at first ANC was associated with increased LBW risk (aPR 1.52, 95% CI 1.01–2.28). Conclusion Routine ANC diagnostics substantially underestimated malaria prevalence among pregnant women Higher IPTp-SP dosing was associated with reduced infection during pregnancy. but few women achieved five or more doses. Primigravidae and women living far from facilities had both lower coverage and higher infection risk. Earlier and more frequent ANC attendance, is essential to maximize the protective potential of IPTp-SP.