Chloroquine for Malaria in Pregnancy

In areas of high malaria endemicity, typical of much of sub-Saharan Africa, despite having achieved semi-immunity to malaria in adulthood, women become vulnerable to malaria infection during pregnancy, especially during their first or second pregnancy. They have increased rates of infection in the peripheral blood and high concentrations of parasites can be found in the placenta. On histological examination, mature asexual parasites, forms that are not usually detected in the peripheral blood, accumulate in the placenta. Pregnancy-specific variant surface antigens are responsible for the increased vulnerability of pregnant women to malaria because they are unrecognized by the immune systems of women who encounter them for the first time in their first pregnancy. In subsequent pregnancies, women develop immunity to these parasite surface antigens and the parasites are cleared by the host response. Plasmodium (P) falciparum infection during pregnancy has important health consequences for both pregnant women and their newborns. Adverse outcomes of pregnancy-associated malaria that have been documented in Malawi include maternal anemia, low birth weight (LBW), and increased infant mortality. The primary objective of the study is to compare weekly chloroquine prophylaxis and chloroquine intermittent preventative therapy (IPT) for malaria in pregnancy (IPTp) to the standard practice [IPTp with sulfadoxine-pyrimethamine (SP)] with respect to prevention of placental malaria. The secondary objectives are: to compare weekly chloroquine prophylaxis and chloroquine IPTp to the standard practice (IPTp with SP) with respect to prevention of malaria during pregnancy; to compare weekly chloroquine prophylaxis and chloroquine IPTp to the standard practice (IPTp with SP) with respect to prevention of the adverse maternal and newborn effects of pregnancy-associated malaria. The exploratory objective identify the vulnerable periods during pregnancy when malaria infection is more likely to cause placental infection, maternal anemia, and low infant birth weight. This is a randomized controlled trial to compare chloroquine as IPT or chloroquine as chemoprophylaxis to IPTp with SP. Women will be randomized after Screening and enrollment, and they begin the assigned treatment between Week 20 and Week 28 gestation. Specimens will be collected at every prenatal visit and any time the participant is ill to determine if malaria is present. Pregnant women will be monitored during pregnancy, and newborns will be assessed at birth and followed until they are approximately 14 weeks of age. Participants will be randomized to one of the following regimens: Chloroquine approximately 1,500 mg base over 3 days, twice during pregnancy (2 tablets on Day 0, 2 tablets on Day 1, 1 tablet on Day 2); Chloroquine base 600 mg (2 tablets) loading dose followed by 300 mg (1 tablet) orally once per week until delivery; SP 1500 mg/75 mg twice during pregnancy.

Inclusion criteria

Women who present to the Ndirande Antenatal Clinic (ANC) and meet the following inclusion criteria will be enrolled in the study: -Before the end of 27th week of gestation -First or second pregnancy -Anticipate remaining in Blantyre until 14 weeks after delivery -Agree to deliver at the Ndirande Health Centre or Queen Elizabeth Central Hospital (QECH) -Provision of informed consent

Exclusion criteria

-Chronic use (>14 days) of any medication with antimalarial or antifolate activity -Human immunodeficiency virus (HIV) infection -Known high-risk pregnancy requiring regular supervision of an obstetrician -Allergy to any of the study drugs