Intermittent treatment to prevent pregnancy malaria does not confer benefit in an area of widespread drug resistance

Abstract

Background: Millions of African women receive sulfadoxine-pyrimethamine (SP) as intermittent preventive treatment during pregnancy (IPTp) to avoid poor outcomes that result from malaria. However, parasites resistant to SP are widespread in parts of Africa, and IPTp may perversely exacerbate placental infections that contain SP-resistant parasites.

Methods: The study used a cross-sectional design. We determined IPTp use in a delivery cohort of 880 pregnant women in Muheza, Tanzania, by report and by plasma sulfa measurements, and we examined its effects on maternal and fetal delivery outcomes.

Results: In the overall cohort, IPTp was not associated with decreased odds of placental malaria or with increased mean maternal hemoglobin or mean birth weight. Unexpectedly, IPTp was associated with decreased cord hemoglobin level and increased risk of fetal anemia, which may be related to in utero SP exposure.

Conclusions: IPTp does not improve overall pregnancy outcomes in Muheza, Tanzania, where SP-resistant parasites predominate and may increase the odds of fetal anemia. As parasite resistance increases in a community, the overall effect of IPTp may transition from net benefit to neutral or net harm.

Figures

Figure 1.

Maternal peripheral plasma sulfa concentration is strongly associated with cord plasma sulfa concentration (r = 0.84; P < .001).

Figure 2.

Increasing cord plasma sulfa concentration predicts decreasing cord hemoglobin level (−0.4 g/dL per 10 μg/mL increase in sulfa; P = .05) and decreasing cord red blood cell count (−1.1 × 105 RBC/μL per 10 μg/mL increase in sulfa; P = .05).