Antenatal receipt of sulfadoxine-pyrimethamine does not exacerbate pregnancy-associated malaria despite the expansion of drug-resistant Plasmodium falciparum: clinical outcomes from the QuEERPAM study.

BACKGROUND: Antenatal intermittent preventive therapy with 2 doses of sulfadoxine-pyrimethamine (IPTp-SP) is the mainstay of efforts in sub-Saharan Africa to prevent pregnancy-associated malaria (PAM). Recent studies report that drug resistance may cause IPTp-SP to exacerbate PAM morbidity, raising fears that current policies will cause harm as resistance spreads.
METHODS: We conducted a serial, cross-sectional analysis of the relationships between IPTp-SP receipt, SP-resistant Plasmodium falciparum, and PAM morbidity in delivering women during a period of 9 years at a single site in Malawi. PAM morbidity was assessed by parasite densities, placental histology, and birth outcomes.
RESULTS: The prevalence of parasites with highly SP-resistant haplotypes increased from 17% to 100% (P < .001), and the proportion of women receiving full IPTp (≥2 doses) increased from 25% to 82% (P < .001). Women who received full IPTp with SP had lower peripheral (P = .018) and placental (P < .001) parasite densities than women who received suboptimal IPTp (<2 doses). This effect was not significantly modified by the presence of highly SP-resistant haplotypes. After adjustment for covariates, the receipt of SP in the presence of SP-resistant P. falciparum did not exacerbate any parasitologic, histologic, or clinical measures of PAM morbidity.
CONCLUSIONS: In this longitudinal study of malaria at delivery, the receipt of SP as IPTp did not potentiate PAM morbidity despite the increasing prevalence and fixation of SP-resistant P. falciparum haplotypes. Even when there is substantial resistance, SP may be used in modified IPTp regimens as a component of comprehensive antenatal care.