Maternal exposure to methotrexate and birth defects: a population-based study.

Area of Science:

• Obstetrics and Gynecology
• Teratology
• Pediatric Cardiology

Background:

• Methotrexate is an anti-folate medication.
• Maternal use of methotrexate is a potential teratogenic concern.
• Limited data exists on methotrexate's association with specific birth defects.

Purpose of the Study:

• To investigate the association between maternal methotrexate exposure and major birth defects.
• To identify specific types of birth defects linked to methotrexate exposure.
• To assess the risk of congenital heart defects (CHDs) in infants exposed to methotrexate.

Main Methods:

• Case-control study utilizing data from the National Birth Defects Prevention Study (1997-2009).
• Inclusion of mothers of live-born infants with (cases) and without (controls) major birth defects.
• Telephone interviews to collect data on maternal demographics, pregnancy history, and exposures, including methotrexate.

Main Results:

• A small percentage of case mothers (0.06%) and control mothers (0.04%) reported methotrexate exposure.
• Among exposed cases, 68.8% had congenital heart defects (CHDs), including VSDs and Tetralogy of Fallot.
• Other observed birth defects in exposed cases included microtia, VACTER association, cleft palate, hypospadias, diaphragmatic hernia, and craniosynostosis.

Conclusions:

• Findings suggest a potential association between early pregnancy methotrexate exposure and CHDs.
• The rarity of maternal periconceptional methotrexate exposure necessitates large-scale, population-based studies for confirmation.
• Further research is crucial to definitively evaluate the teratogenic potential of methotrexate.