What is methotrexate? Methotrexate is a medication that can be used to treat a variety of conditions, including certain cancers, rheumatoid arthritis, and inflammatory conditions. It can also be used to treat an ectopic pregnancy or a pregnancy in an undetermined location.
Why is methotrexate used to treat ectopic pregnancy? Methotrexate treatment has a success rate of about 65-95% in treating ectopic pregnancy and pregnancy of undetermined location. The success rate depends on your pregnancy hormone levels (hCG) at the time of treatment. In small doses, methotrexate is safe to use although it has a few side effects. Advantages of using methotrexate include not having to use general anaesthetic, or surgery and it helps to preserve the fallopian tube.
How does methotrexate work? Methotrexate stops the growth of rapidly dividing cells, including embryonic, fetal, and early placental cells. This stops the tissues from growing bigger and prevents them from rupturing. Eventually, the pregnancy tissues get reabsorbed by the body.
How is the methotrexate treatment given? Methotrexate is given as a single injection into the muscles of your leg or buttock. However, 1 in 7 women (15%) may require a second dose of methotrexate injection.
Following your methotrexate injection, your hCG will be tested several times. Your doctor will look for a drop in the hCG levels, which indicates that the condition is resolving. However, it is not uncommon for the hCG levels to sometimes rise during the first few days of treatment, followed by a drop.
If your hCG levels have dropped satisfactorily after one week, it will then be tested on a weekly basis until they are low enough to suggest that the treatment has been successful. This usually takes about a month but may take up to three months or more in certain cases.
If your hCG levels have not dropped as expected by one week, you may need another ultrasound scan, after which a second dose of methotrexate injection or surgery is administered, depending on your clinical condition.
What are the side effects of methotrexate treatment? With methotrexate, sometimes you may experience some mild abdominal pain after the treatment, though this should not be severe and usually settles with paracetamol or similar pain relief medications. Other occasional side effects (affecting up to 15% of women) include nausea, vomiting, indigestion or fatigue.
In very rare instances, it can affect the liver or blood cell counts. This is uncommon and is usually mild and transient. You will have follow-up blood tests to ensure that this has resolved.
Treatment of ectopic pregnancy or pregnancy of undetermined location with methotrexate is not known to have any long-term effects on the ovary or affect its capacity to produce eggs in the future.
Will this drug affect my chances of becoming pregnant again? It is recommended that you do not conceive within three months following methotrexate treatment.
Your chances of having a successful pregnancy in the future following methotrexate treatment is as good as after any surgical management for the same condition.
Pregnancies following completion of methotrexate therapy are not associated with increased risk of abnormalities, miscarriages, or other pregnancy complications.
Are there any precautions that I need to take after receiving methotrexate treatment? Avoid alcohol and vitamin containing folic acid until your pregnancy hormone levels are back to normal.
Avoid aspirin or anti-inflammatory drugs (such as ibuprofen, diclofenac, naproxen, etc.) for one week after treatment.
It is likely that the pain may worsen slightly in the first week after the injection as the pregnancy tissue dissolves and the hormone levels fall. You may experience some vaginal bleeding like a period. If you have severe pain or heavy vaginal bleeding, please return to the hospital emergency department immediately.
It is important that you use adequate contraception for three months after taking methotrexate therapy or for six months if you had additional doses of methotrexate.
It is very important that you attend your follow-up appointments until your pregnancy hormone levels are back to normal.
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