Malaria Rapid Diagnostic Tests (RDTs) in Pregnancy: Detection of Placental Malaria

Malaria prevention measures for pregnant women are critical and available, but the effectiveness of intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine, a cornerstone in this prevention effort, is declining with increasing parasite resistance. New drugs for IPTp are being considered, but there are disadvantages to presumptive use of the few remaining efficacious antimalarials. An alternative approach may involve screening with diagnostic tests to better target efficacious antimalarial treatment to asymptomatic women with laboratory evidence of malaria infection. Light microscopy of peripheral maternal blood misses a large proportion of cases, and PCR is unavailable in routine health care settings. Preliminary evidence suggests that detection of parasite antigen in peripheral blood may provide an accurate indicator of clinically significant infections and predict pregnancy outcomes. Therefore, screening with RDTs may offer an accurate and practical way to identify pregnant women who will benefit from targeted therapy for placental malaria infection. Antigen detection thresholds vary widely among RDTs, and the distribution of target antigens in peripheral blood circulation is expected to differ; therefore, the potential value of RDTs in this population can best be established by evaluating the detection of placental parasitemia for highly-characterized RDTs, enabling results to be extrapolated to other products and programs. The study described here is proposed to address this question.