A Cochrane review included 17 trials (14 481 women), of which only 6 were adequately concealed. Chloroquine (given weekly), pyrimethamine (weekly or monthly), proguanil (daily), pyrimethamine-dapsone (weekly or fortnightly), and mefloquine (weekly), or intermittent preventive therapy with sulfadoxine-pyrimethamine (given twice, three times or monthly) were evaluated against placebo or no intervention.
Antimalarials reduced placental parasitaemia (RR 0.54, 95% CI 0.43 to 0.69; 7 trials, n=2 830), increased mean birthweight by around 93 g (MD 92.72 g, 95% CI 62.05 to 123.39; 9 trials, n=3936), reduced low birthweight (RR 0.73, 95% CI 0.61 to 0.87; 8 trials, n=3619). Trials were underpowered to detect differences in perinatal deaths. In women in their first or second pregnancy, antimalarial drugs reduced severe antenatal anaemia by around 40% (RR 0.60, 95% CI 0.47 to 0.75; n=2503; 3 trials, high quality evidence) and the risk of any anaemia by around 17% (RR 0.83, 95% CI 0.74 to 0.93; 5 trials, n=3662), antenatal parasitaemia by around 61% (RR 0.39, 95% CI 0.26 to 0.58; 7 trials, n=3663, high quality evidence).
Comment: The quality of evidence is downgraded by limitations in study quality (e.g., inadequate or unclear allocation concealment and lack of blinding).