Evidence check: CYP2C19 in the context of fertility

The role of CYP2C19 in fertility is not well supported by strong evidence. CYP2C19 is a drug-metabolizing enzyme primarily involved in the breakdown of medications such as certain antidepressants (e.g., citalopram) and proton pump inhibitors. Some mechanistic studies suggest a possible influence on estrogen metabolism, but clinical data linking CYP2C19 variants directly to fertility outcomes are limited and inconsistent. Therefore, genetic testing for CYP2C19 is not recommended as a fertility assessment tool. Its main relevance lies in pharmacogenetics: variants can affect drug efficacy and side effects, which may indirectly impact fertility if medications are used. For fertility evaluation, established markers like AMH, FSH, and lifestyle factors are more evidence-based. The evidence level for CYP2C19 in fertility is best described as mechanistic/unclear.