Data on the burden of MIP in low transmission areas, such as Latin America, are very limited; there is even less information on the efficacy of case management of MiP. The treatment recommendations for MiP in Latin American countries have been changing rapidly in recent months; currently, either artemether-lumefantrine (AL) or mefloquine-artesunate (MA) is the first line treatment for P. falciparum (depending on country); however, no data exists on the efficacy of these drugs for the treatment of malaria in pregnancy in Latin America to support their use. We propose a multi-center 2-arm open-label randomized Phase 4 clinical trial to assess safety and efficacy of the present therapies, AL and MA. We hypothesize that the drugs will both be efficacious for use in pregnant women in Brazil.