Chloroquine prophylaxis against vivax malaria in pregnancy: a randomized, double-blind, placebo-controlled trial.

Objective: To assess the safety of chloroquine (CQ) as prophylaxis against Plasmodium vivax infection during pregnancy.

Method: One thousand pregnant Karen women were enrolled in a randomized, double-blind, placebo-controlled trial of chemoprophylaxis with chloroquine (500 mg phosphate (or 300 mg base) weekly). Women received a median (range) chloroquine phosphate total dose of 9500 (1500-17 500) mg.