Intermittent preventive treatment with sulfadoxine-pyrimethamine versus weekly chloroquine prophylaxis for malaria in pregnancy in Honiara, Solomon Islands: a randomised trial.

Background: Solomon Islands is a malarious nation in the Pacific with all four human Plasmodium species present. Although chloroquine prophylaxis is recommended for pregnant women, its effectiveness is uncertain because of chloroquine resistance.

Methods: We conducted a parallel-group, open label, individually randomised superiority trial comparing weekly chloroquine prophylaxis (CQ) with intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) between August 2009- June 2010 among pregnant women aged 15 to 49 years. Participants were randomised at the first antenatal visit using a computer-generated sequence and followed until delivery. Data on mosquito avoidance measures, and pregnancy outcomes were collected.

Results: Because of the low prevalence of malaria, enrolment was prematurely terminated. Among 660 participants (336 in CQ arm, and 324 in IPTp), 68% used a bednet, 53% used window-screens, and 26% lived in a house sprayed in the last 6 months; 91% used at least one of these methods. Peripheral parasitemia at enrolment was 1.5%. At delivery there were no differences between weekly CQ and IPTp in placental parasitemia (0/259 vs. 1/254) or peripheral parasitemia (2/281 vs. 1/267). There were no differences in maternal anaemia, birth outcomes or serious adverse events. A self-reported sulfa-allergy required non-inclusion for 199 of 771 ineligible women (26%).

Conclusions: The use of SP for IPTp is not suitable for prevention of malaria in pregnancy in Solomon Islands, given the low malaria prevalence and the possible high prevalence of sulfa-allergy. Scaling up of transmission-reducing interventions has probably contributed to the malaria reduction in Honiara.

Trial registration: NCT00964691 ClinicalTrials.gov.