Methotrexate
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Methotrexate is occasionally used to treat cancer during pregnancy, usually after the first trimester. Use in early pregnancy can cause birth defects in the baby.
What is it?
Methotrexate (Jylamvo®, Methofill®, Metoject®, Nordimet®, Zlatal®) is used to treat a range of health conditions. The dose depends on the condition being treated:
• Low doses (usually up to 25 mg per week) are used for autoimmune diseases, such as rheumatoid arthritis, Crohn’s disease, and psoriasis
• Higher doses are used for some cancers
• Single high doses (~50 mg/m²) are used to treat an ectopic pregnancy (when a pregnancy develops outside the womb, usually in a fallopian tube)
Benefits
What are the benefits of using methotrexate in pregnancy?
Methotrexate treatment can prevent serious illness and death in women with an ectopic pregnancy. It also reduces the chance of fallopian tube damage that might affect future fertility.
Methotrexate is only used to treat cancer during pregnancy if other treatments are unlikely to be as effective.
Methotrexate should not be used in pregnancy to treat autoimmune diseases.
Risks
What are the risks of using methotrexate in pregnancy?
Methotrexate use in early pregnancy can increase the risk of:
• Miscarriage
• Birth defects
• Reduced growth of the unborn baby
The risk is higher with high doses, which are known to cause a pattern of birth defects affecting the face, skull, limbs, and bones.
Lower doses (used for autoimmune disease) may increase the risk of miscarriage. Birth defects have very occasionally been reported with lower doses.
Methotrexate can remain in your body after stopping treatment. You will usually be advised by your specialist to wait at least three months before trying to conceive.
Alternatives
Are there any alternatives to taking methotrexate in pregnancy?
Yes, there are usually safer treatment options during pregnancy. Many autoimmune conditions can be managed with other medicines, and some conditions may improve during pregnancy, meaning treatment can sometimes be reduced or changed.
If you are planning a pregnancy, please speak to your doctor before trying to conceive so your treatment can be reviewed and adjusted if needed.
No treatment
What if I prefer not to take medicines in pregnancy?
It is important that illnesses in pregnancy are well managed. Untreated illness can be harmful to both mother and baby.
• Poorly controlled autoimmune disease can increase the risk of miscarriage, preterm birth, and low birth weight
• Some cancers may need ongoing treatment to protect the mother’s health
A doctor will help you weigh up the risks and benefits and decide on the safest option.
Will I or my baby need extra monitoring?
As part of routine antenatal care, most women are offered a detailed scan at around 20 weeks of pregnancy to check the baby’s development.
If you have taken methotrexate during the first trimester, or in the month before pregnancy, you may be offered a more detailed scan. This will focus on the areas that can be affected by methotrexate, mainly the baby’s skull and face, fingers and toes, and spine and ribs. You may also be offered additional scans to monitor your baby’s growth.
Women with conditions treated with methotrexate are usually monitored more closely during pregnancy to ensure they remain well.
Are there any risks to my baby if the father has taken methotrexate?
There is no good evidence of an increased risk to your baby if your partner took methotrexate around the time of conception.
For more information, please see the bump leaflet on paternal methotrexate exposure.
Who can I talk to if I have questions?
If you have any questions about the information in this leaflet, please speak with your health care provider. They can access more detailed medical and scientific information from www.uktis.org if needed.