Fetal Myelomeningocele After Maternal Methotrexate Administration: A Case Report

Folate supplementation in women of reproductive age has a well-established role in the prevention of neural tube defects. Methotrexate is a commonly used drug which functions by inhibiting normal folate metabolism in active cells. An association between fetal methotrexate exposure and myelomeningocele might be expected, considering this relationship. However, to our knowledge, no cases of myelomeningocele secondary to in utero methotrexate exposure have been reported.

We present the case of a gravid patient who, having received methotrexate for management of an ectopic pregnancy, was lost to follow-up and returned several weeks later carrying an intrauterine pregnancy. The fetus was found prenatally to be suffering from multiple congenital anomalies. At birth the infant demonstrated many of the abnormalities commonly associated with fetal methotrexate syndrome, including craniosynostosis and talipes equinovarus. Most interestingly, the newborn was also diagnosed with a lumbar myelomeningocele and concomitant type II Chiari malformation, as is often associated with such a neural tube defect.

Methotrexate exposure may impact the fetal risk of myelomeningocele. Patients should be counseled thoroughly on the importance of follow-up care.