The main purpose of this study is to compare the drug levels of sulfadoxine-pyrimethamine found when given to pregnant women for the prevention of malaria to those found in pregnant women given the same drug with artesunate for the treatment of malaria, and also with those drug levels found in non-pregnant women in other malaria treatment studies.

Pregnancy increases the risk of malaria progression and complications with up to a 10-fold increase in the malaria case fatality rate in areas of low transmission. Sulfadoxine-pyrimethamine (SP) is used widely in Africa for the systematic intermittent presumptive, or preventive, treatment (IPTp) during the second and third trimester of pregnancy and a national program of IPTp with SP has been implemented recently in Mozambique. There is evidence that the kinetics of several other antimalarial drugs are altered in pregnancy to the extent that doses are not adequate in pregnancy, however no published study has included a pharmacokinetic component to confirm that standard doses of SP are optimal in this vulnerable patient group. This study therefore creates the opportunity to study whether the pharmacokinetic properties of SP are altered by physiological changes that occur during pregnancy.

Inclusion Criteria:

• Pregnant female, older than 18 years, > 35kg.
• Gestational age > 16 weeks (fundal height > 16cm) and below 36 weeks gestation.
• Documented informed consent.
• Lives close enough to the study site for reliable follow up and is willing to attend ANC and follow-up visits regularly.

Exclusion Criteria:

• Diagnoses of uncomplicated acute P. falciparum malaria parasitaemia
• Has received anti-malarial treatment in the past 7 days and/or sulfadoxine-pyrimethamine in the past 28 days.
• Known hepatic or renal impairment
• Has received chloramphenicol, cotrimoxazole or tetracyclines (including doxycycline) in the past 7 days or is likely to require these during the study period.
• History of G6PD deficiency.
• Has a history of allergy to any of the study drugs (including other sulphonamides e.g. cotrimoxazole).
• Serious underlying disease that in the opinion of the clinic team and/or Principal Investigator would make the patient unsuitable for the study in terms of their safety or study analysis.
• Imminent delivery expected.
• Prior inclusion in this study.