Methotrexate (MTX), a folate antagonist, is used in various fields, including malignancies and rheumatoid or inflammatory autoimmune diseases. MTX is used for the non-surgical treatment of ectopic pregnancies and the elective termination of pregnancy. The teratogenic effects of MTX have been recognized since the 1960s. Fetal methotrexate syndrome (FMS) was established based on the study of congenital anomalies. Generally, there is a risk of FMS when MTX is used between four and six weeks after conception. Here, we reviewed the literature regarding MTX usage and described a case of FMS that was born with a rare anomaly, such as tibial hemimelia, in a mother who had received MTX 4 months before conception for the management of an ectopic pregnancy.
Keywords: congenital malformation; fetal methotrexate syndrome; methotrexate.