Both P.falciparum and P.vivax malaria are important determinants of pregnancy outcome in south East Asia. We conducted the first trial of intermittent preventive therapy in pregnancy (IPT), and intermittent screening and treatment (IST) against the strategy of single screening and treatment (SST) for the control of malaria in pregnancy in Indonesia.
The trial was conducted in two sites with low (Sumba) and moderate transmission (Papua). Pregnant women between 16-30 weeks gestation were recruited from 78 randomly assigned (1:1:1) clusters. Women in IST and SST clusters were screened with rapid diagnostic tests (RDT). Dihydroartemisinin-piperaquine (DP) was used for malaria treatment and prevention (IPT). The primary outcome was malaria infection at delivery, defined as a composite of maternal or placental malaria detected by placental histology, microscopy, RDT or PCR-confirmed Loop mediated isothermal amplification (LAMP).
Between May 2013 and April 2016, 2,279 women were randomized to IPT (n=681), IST (n=854) and SST (n=744). At enrolment, the prevalence of malaria (any measure) was lower in the IST arm (6%) than the SST (13%) or IPT arms (11%). At delivery, malaria infection was lower in the IPT than SST arm: 61/528 (12%) vs 128/633 (20%), RR =0.57 (95% CI 0.41-0.80) and IST arm: 84/713 (12%) RR=0.56 (0.41-0.77). IPT prevented 92% of patent (microscopic) infections (RR=0.08, 0.01-0.61), p=0.0147, and 41% of the sub-microscopic infections (RR=0.59, 0.39-0.91, p=0.0173). Overall, only 5 infections were detected by RDT in the IST arm, and 18 in the SST arm. There were no differences in adverse pregnancy outcomes relative to SST (IPT: RR=1.16, 0.87-1.55, IST: RR=1.00, 0.72-1.303).
Monthly IPT with DP halved the incidence of malaria during pregnancy and at delivery, but monthly screening with current RDTs did not detect more malaria than the SST strategy. More studies with highly sensitive RDTs are needed in Asia.