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.

Specific participant selection criteria include:

• Presenting for care after quickening and before onset of labor (i.e. in the second or third trimester of pregnancy)
• Age between 16 years and 44 years, inclusive
• Willingness and ability to follow up with study visits and activities through the duration of pregnancy and at delivery
• Absence of history of serious adverse reaction to sulfa drugs
• Absence of history of serious adverse reaction to artemisinin-based drugs (depending on national policy on treatment of malaria in pregnancy)
• Absence of HIV infection (both because guidelines for malaria prevention in pregnancy for HIV-infected women differ from those for HIV-negative women, and in order to avoid confounding of pregnancy outcomes by HIV-related complications or treatments in this early evaluation)
• Absence of history of or current obstetrical complications (e.g. pre-eclampsia, eclampsia, hypertension during pregnancy, post-partum hemorrhage, evidence of multiple gestation)
• Absence of chronic disease (e.g. diabetes mellitus, sickle cell disease)
• Absence of evidence of severe acute disease requiring inpatient management or referral
• Provision of written informed consent
• Enrollment Hb ≥7 g/dL