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

Authors

  • Penelope A. Phillips-Howard,

    Corresponding author
    1. P. A. Phillips-Howard, PhD: Malaria Unit, Division of Control of Tropical Diseases, World Health Organization, Geneva, Switzerland
      Reprint requests: Dr. P. A. Phillips-Howard, CDC/KEMRI, PO Box 1578, Kisumu, Kenya.
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  • Robert Steffen,

    1. R. Steffen, MD, PhD, J. Schildknecht, MD, and E. Fuchs, MD: Division of Communicable Diseases, Institute of Social and Preventive Medicine, University of Zurich, Switzerland
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  • Lydia Kerr,

    1. L. Kerr and B. Vanhauwere, MD, Drug Safety, F. Hoffman-La Roche, Basel, Switzerland
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  • Bart Vanhauwere,

    1. L. Kerr and B. Vanhauwere, MD, Drug Safety, F. Hoffman-La Roche, Basel, Switzerland
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  • Janine Schildknecht,

    1. R. Steffen, MD, PhD, J. Schildknecht, MD, and E. Fuchs, MD: Division of Communicable Diseases, Institute of Social and Preventive Medicine, University of Zurich, Switzerland
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  • Elisabeth Fuchs,

    1. R. Steffen, MD, PhD, J. Schildknecht, MD, and E. Fuchs, MD: Division of Communicable Diseases, Institute of Social and Preventive Medicine, University of Zurich, Switzerland
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  • Ralph Edwards

    1. R. Edwards, MD, PhD: WHO Collaborating Centre for International Drug Monitoring, Uppsala, Sweden.
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Reprint requests: Dr. P. A. Phillips-Howard, CDC/KEMRI, PO Box 1578, Kisumu, Kenya.

Abstract

Background: 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 taking 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=.01), 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 (p < .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.

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