Methotrexate for Ectopic Pregnancy

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For ectopic pregnancies, many times you have a choice between taking a medication or having surgery. Right now, there is only one medication used to treat ectopic pregnancies, called methotrexate. This medication stops the growth of cells that are rapidly dividing, such as pregnancy cells. It was originally developed to be a cancer drug, because cancer is also a condition where cells are rapidly dividing. And because it is a cancer drug, it is only given in hospitals and under very careful monitoring circumstances.

choosing methotrexate

Methotrexate for ectopic pregnancy works as well as surgery in certain situations:

  • You have low pregnancy hormone levels (<5000)
  • An embryo isn’t seen in the pregnancy sac or if the embryo doesn’t have a heartbeat yet
  • If the ectopic pregnancy is small or isn’t even visible on ultrasound.

But if these conditions aren’t present, the methotrexate has a higher chance of not working. It’s important to have a long conversation with your doctor about what the chances are of it working or not working for you.

Methotrexate is given as an intramuscular injection, most often into your buttocks. There are a few different dosing regimens—a single injection, two doses three days apart, or multiple doses every other day for at least a week. Which schedule of treatment your doctor chooses is in part based on how far along your pregnancy is, how high your pregnancy hormone levels are, and how large the ectopic pregnancy is on ultrasound. The further along in the pregnancy you are, the more doses of methotrexate you usually receive.

coming back for blood tests

After you get your first dose of methotrexate, your doctor is going to give you a very detailed schedule of when to come back for blood tests. These tests monitor the levels of your pregnancy hormone. Even though your hormones may go up initially after you get the methotrexate, they should shortly thereafter start to come down. Your doctor is watching most carefully for the pregnancy levels between day four of treatment—in reality the third day after the injection, as the injection day is considered “day one”—and the level on day seven.

Your doctor is expecting to see a 15% drop in the level of pregnancy hormone between these two tests. If your hormone levels have dropped that much in this first week, then you’ll usually get blood tests on a weekly basis until the hormone level reaches essentially zero. This can take as short as four weeks, but it can take up to three months depending on how long it takes for the pregnancy to resolve.

importance of the testing schedule

Your doctor may seem very obsessive, telling you about which days you must come back for testing. This focus on specific days reflects the knowledge that we have about how the hormone levels drop after methotrexate if the medication is working to treat an ectopic pregnancy. The day four and day seven values are very important because it’s specifically here that the 15% drop needs to be seen for us to be reassured that the medication is working. If you miss one of these blood draws, your doctor needs to guess what the levels might have been. Even if she’s super-smart, she’s not a wizard, and it’s very hard to then know if the ectopic is being adequately treated.

One of the reasons that a person might not choose methotrexate for ectopic pregnancy and may choose surgery is because it may be hard for her to come back on the schedule of days for the follow-up. Think about this carefully as you’re making this decision as to which kind of treatment you want.

If the pregnancy hormone levels stagnate (level off) or go back up, it’s a sign the medication is not working. You may get an additional dose of methotrexate at this point, but there’s a higher likelihood that you’ll need surgery.

how methotrexate feels

The most common side effect of methotrexate is some cramping belly pain. This pain usually occurs in the first one to two days of treatment. You may also start or continue to see vaginal bleeding or spotting, or have other GI side effects, like nausea, vomiting, or indigestion.

There are rare side effects that you need to know about, but they are much less common

  • Skin sensitivity to sunlight
  • Inflammation of the membrane covering the eye
  • Sore mouth and throat
  • Temporary hair loss (really rare)
  • Severe low blood counts (bone marrow suppression)
  • Inflammation of the lung (pneumonitis)

The most important symptoms to look out for are an increase in pelvic pain or any lightheadedness or dizziness. These signs could indicate that the pregnancy is starting to rupture, and that you’re starting to bleed internally. Also call your doctor if you see blood in your vomit, get sores on your mouth or lips, or have signs of unusual bleeding or bruising, like blood in your urine or stools that are black and tarry.

During the methotrexate treatment period for an ectopic pregnancy, stop taking your prenatal vitamins. You also need to avoid alcohol, penicillin, and anti-inflammatory medications like ibuprofen or naproxen. If you need pain medication for cramping during this time period, Tylenol is your safest choice.

how do you know if methotrexate worked?

Ectopic pregnancies are deemed “treated” when your weekly hormone levels return to zero. It may be strange to rely on blood tests, rather than your symptoms, to tell you that the pregnancy is over. When you take medication for a “typical” miscarriage, your body will start to have cramping and bleeding. These symptoms mark the passage of the pregnancy tissue and gives you reassurance that the pregnancy is ending. With an ectopic, though, the pregnancy doesn’t “pass through” your uterus, cervix, and vagina the way a typical miscarriage does. Instead, it starts to necrose, or shrink up, and eventually either passes out or may even be absorbed by your body. Therefore, you won’t see as much bleeding or have as much pain as you do with a typical miscarriage.

why you bleed like a “regular” miscarriage

The lining of your uterus in an ectopic pregnancy is still somewhat built up, however. After all, your uterus senses pregnancy hormone, and knows that you’re pregnant. So it’s making changes to support a pregnancy even though one isn’t there. So, this fluffy lining of your uterus will need to shed, just like a period, as the pregnancy is ending. But the bleeding looks just like that—more like a period than a miscarriage. The bleeding may start soon after you get your first dose of methotrexate, or it may take a little while to start. So, bleeding and cramping aren’t sufficient signs to know that the medication is working or not. Instead, the only thing that tells your doctor that things are going in the right direction are the blood tests.

It can be really annoying to come back for so many blood tests, especially if you’re working or in school or have kids to take care of. But those follow up blood tests are vitally important so you and your doctor both know that the pregnancy is resolving.