“Women who inadvertently become pregnant while taking mefloquine should be reassured that the risk of malformations is low (within background levels) and that use of mefloquine does not indicate therapeutic abortion,” Dr. Patricia Schlagenhauf from University of Zurich Center for Travel Medicine, Zurich, Switzerland told Reuters Health in an email.
Dr. Schlagenhauf and colleagues used the F. Hoffmann-La Roche global drug safety database to investigate the safety of the fetus following exposure to mefloquine in the periconception period and during pregnancy.
Among 2246 maternal prospective cases, there were 43 birth defects in 978 deliveries (a birth prevalence of 4.39%). There was no specific pattern of malformations. There were 43 other pregnancy-related or perinatal disorders and 889 normal infants.
Their duration of mefloquine use was between 6 and 91 days, with most exposures (2139/2246, 95.2%) occurring before conception and/or during the first trimester of pregnancy. All congenital malformations occurred in infants of women exposed during this period.
Twelve women who delivered infants with birth defects had relevant medical history, including a history of drug abuse, alcohol use, hypothyroidism, hepatitis B, smoking, preeclampsia, spontaneous abortions, previous miscarriages, family history of epilepsy, or other unspecified mental handicap.
There were 2 birth defects and 12 normal infants among the 14 deliveries of 22 prospective both-parent exposure cases. Both birth defects occurred in cases where the exposure was in the periconception period and during the first trimester.
The March of Dimes estimates that about 4% of infants annually are born with a major birth defect or congenital malformation. Other organizations have reported prevalences of congenital malformations ranging from 0.8% to 6.5%.
“To the best of my knowledge, there are no reliable data on the number of pregnant women to travel to malaria endemic areas but the latest statistics from the US show a 14% increase in imported malaria cases in 2010 and that 41 cases occurred in pregnant women (only 5% of these women used appropriate chemoprophylaxis),” Dr. Schlagenhauf said. “The authors of the US Malaria Surveillance report state ‘Pregnant women traveling to areas in which malaria is endemic are at higher risk for severe malaria and must use appropriate malaria prevention strategies including chemoprophylaxis.’ Malaria prevention recommendations are available online (http://www.cdc.gov/malaria/travelers/drugs.html).”
The study was funded by F. Hoffmann-La Roche, which employed all the authors except Dr. Schlagenhauf, who also received research funding, honoraria for speaking at conferences, and consultancy fees from F. Hoffmann-La Roche.