Pregnancy and fetal outcomes after exposure to mefloquine in the pre- and periconception period and during pregnancy.

Background: Pregnant women who travel to malarious areas and their clinicians need data on the safety of malaria chemoprophylaxis.

Methods: The effect of exposure to mefloquine on pregnancy and offspring outcomes was evaluated using the F. Hoffmann-La Roche global drug safety database for the time frame 31 January 1986 through 26 October 2010. We investigated pregnancy and fetal outcomes in maternal, paternal, and both-parent exposure cases with a focus on congenital malformations and fetal loss. The main outcome measures were birth defect prevalence and types of malformations.

Results: A total of 2506 cases of mefloquine exposure during pregnancy or in the pre- and periconception period were evaluated. Most cases were maternal prospective (outcome of the pregnancy unknown at the time of reporting; n = 2246 [89.6%]) followed by maternal retrospective cases (outcome of the pregnancy known at the time of reporting; n = 227 [9.0%]), with small numbers of paternal and both-parent exposure cases. Of the total 2246 mefloquine maternal prospective exposures (95.2%), 2139 occurred before conception and/or during the first trimester. Of 1383 maternal prospective cases with known outcome, 978 (70.7%) resulted in delivery, 405 (29.3%) resulted in abortion (112 spontaneous, 293 therapeutic), and 43 resulted in birth defects, corresponding to a birth defect prevalence of 4.39% (43 of 978). Prospective cases overall showed no specific pattern of birth malformations.

Conclusions: The drug safety database analysis of mefloquine exposure in pregnancy showed that the birth defect prevalence and fetal loss in maternal, prospectively monitored cases were comparable to background rates.