Low dose weekly methotrexate in early pregnancy. A case series and review of the literature

Objective. To assess the teratogenic risk of low dose weekly pulses of meth otrexate (MTX) inadvertently taken during the first trimester of pregnancy. Methods. We assessed pregnancy and neonatal outcome of 4 patients with rheu matic disease treated with weekly pulses of 5 to 15 mg of MTX for a mean du ration of 4 years. Results. The 4 patients had continued MTX treatment from one to 6 weeks of gestation. One patient miscarried at Week 6, the other pregnancies ended wi th the delivery of healthy children. Chromosome analysis of one child was n ormal. Conclusion. In spite of the absence of congenital anomalies in our cases, s afe contraception in fertile patients who start low dose weekly MTX is mand atory.