Should methotrexate be avoided in early pregnancy?

What are the risks associated with methotrexate during pregnancy?

Methotrexate, a medication used to treat various conditions such as rheumatoid arthritis, psoriasis, and certain types of cancer, has been linked to potential harm when used during early pregnancy.

Studies suggest that exposure to methotrexate during the first trimester of pregnancy is associated with a higher risk of fetal abnormalities and miscarriage [1]. In fact, the drug's manufacturer warns against its use during the first three months of pregnancy.

How long should methotrexate be avoided after conception?

Experts recommend that women stop using methotrexate at least three months prior to attempting pregnancy to minimize the risk of harm to the developing fetus [2]. However, it is essential to discuss individual circumstances with a healthcare provider to determine the best course of action.

What are the mechanisms by which methotrexate affects the fetus?

Methotrexate works by inhibiting dihydrofolate reductase (DHFR), an enzyme necessary for cell division, including that of rapidly growing cancer cells and the fetus [3]. However, the drug's effect on the developing fetus can lead to potential harm.

Can methotrexate be safely restarted after pregnancy?

When women stop using methotrexate during pregnancy due to its potential risks, it is essential to reintroduce the medication under close supervision of a healthcare provider after pregnancy. A slow reinitiation of the drug is crucial to minimize the risk of adverse effects [4].

Who are the patients most at risk of methotrexate's adverse effects during pregnancy?

Women with rheumatoid arthritis or psoriasis may be more vulnerable to the potential harm of methotrexate during pregnancy due to the severity of their condition [5]. It is essential to weigh the risks and benefits of treatment against the potential harm to the fetus.

Sources:

1. [1] https://www.drugpatentwatch.com/medication-identifier/medwatch/0010101
2. [2] https://emedicine.medscape.com/article/2063510-overview
3. [3] https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-and-Conditions/Psoriatic-Arthritis/Understanding-Your-Baby-After-Cancer-Treatment
4. [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443417/
5. [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4439647/