(HealthDay News) – The rheumatoid arthritis drug leflunomide is not a major cause of birth defects in women who inadvertently become pregnant while taking the drug, although pregnancy should be avoided, according to a study in the July issue of Arthritis & Rheumatism.

Building on a previous study showing that leflunomide was not linked to adverse pregnancy outcomes, Matteo Cassina, MD, from the University of Padua in Italy, and colleagues examined birth outcomes in 45 pregnant women exposed to leflunomide: 16 who were exposed during the first trimester and 29 who were exposed prior to conception.

The researchers found that livebirths were experienced by all 16 women exposed to leflunomide during the first trimester and by 27 women (93%) exposed before conception. There were two infants with major malformations, both from mothers exposed during pregnancy. At least some of the defects observed could be attributed to other causes.

“These data provide additional reassurance that leflunomide is not a major human teratogen in women who inadvertently become pregnant while taking leflunomide and who undergo the washout procedure,” Cassina and colleagues conclude. “However, until more conclusive data become available, women receiving such therapy should still be advised to use contraceptive methods and avoid pregnancy.”

The study was supported by Sanofi-Aventis; one author disclosed financial ties to pharmaceutical companies, including Sanofi-Aventis.

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