A Cochrane review included 5 RCTs involving a total of 6 759 participants. Two trials randomized individual women and three trials randomized communities. In sub-Saharan Africa, ITNs, compared with no nets, reduced placental malaria in all pregnancies (RR 0.79, 95% CI 0.63 to 0.98, 4 trials). They also reduced low birthweight (RR 0.77, 95% CI 0.61 to 0.98) and fetal loss in the first to fourth pregnancy (RR 0.67, 95% CI 0.47 to 0.97), but not in women with more than four previous pregnancies. For anaemia and clinical malaria, results tended to favour ITNs, but the effects were not significant.
In Thailand where malaria is not endemic, one trial randomizing individuals to ITNs or untreated nets showed a reduction in anaemia and fetal loss in all pregnancies but not for clinical malaria or low birthweight.