Safety of Mefloquine and Other Antimalarial Agents in the First Trimester of Pregnancy

6ackground:Safe and effective antimalarials are required to protect pregnant women from the harmful effects of malaria. Methods: Data were collected from two separate prospective cohorts to ascertain the safety of chloroquine-proguanil, sulfadoxine-pyrimethamine (SP), and mefloquine taken in the first trimester of pregnancy. Results: In a traveler cohort of 236 pregnant women, spontaneous abortions were reported in 7.6% of 99 women taklng chloroquine-proquanil, 0% of 19 taking sulfadoxine-pyrimethamine, and 9.1% of 118 women taking mefloquine. Anomalies were identified in 1.7%, 0% and 0% of the same cohort, respectively. Differences in rates of adverse outcomes between the three groups were not statistically significant. In a pharmaceutical database of 331 and 153 women exposed to mefloquine and SP, respectively, the overall rate of abnormal outcomes (spontaneous abortions plus fetal anomalies) was not significantly different (p=.29). Spontaneous abortions were significantly higher with mefloquine than SP (9.1% and 2.6%, respectively; p=.Ol), but the higher rate was comparable to background rates (7%-11%). Fetal anomalies in the mefloquine group (4.8%) were lower than the SP group (7.8%), but this was statistically not significant (p=.19), and was comparable with the background rate of 4.6% (p=.84). However, mefloquine exposure resulted in a significantly higher rate of therapeutically induced abortions, undertaken for perceived risk to the fetus, compared with SP (pe.0001). Conclusion: From the clinical data available, there is no indication that the risk of taking mefloquine in the first trimester of pregnancy is greater than that from any of the other antimalarials studied and the risk is considerably lower than that associated with falciparum malaria. Malaria infection in nonimniune pregnant women carries a poor prognosis, including spontaneous abortion in up to 60% of cases, fetal loss, and a maternal mortality rate of up to lo%." Women are advised to abstain from travel to highly malarious areas while pregnant or to avoid getting pregnant during travel to those areas.2 If travel is unavoidable, malaria chemoprophylaxis is required, and has been limited to chloroquine alone or in combination with proguanil. Surveys have shown that this coinbination is less effective than other antimalarial^.',^ Studies have now shown that fortnightly dapsonepyrimethamine prophylaxis,' niefloquine pro phyla xi^,',^ and two separate treatment doses of sulfadoxinepyrimethamine (SP) are effective against the deleterious etrects of malaria in the second/third trimester of pregnancy.' Significant adverse outcomes were not reported