An ectopic pregnancy occurs when a fertilized egg implants and grows outside the uterus, most frequently within a fallopian tube. This condition cannot progress to a viable pregnancy. Without timely intervention, ectopic pregnancies can lead to significant complications, including internal bleeding. Methotrexate offers a non-surgical treatment option for certain cases.
Understanding Methotrexate for Ectopic Pregnancy
Methotrexate (MTX) is a medication typically used for ectopic pregnancies that halts cell growth. It functions as a folic acid antagonist, interfering with DNA synthesis, a process vital for cell division. By disrupting this process, methotrexate effectively stops the development of rapidly dividing embryonic and placental tissue. This action allows the body to gradually reabsorb the ectopic tissue, often preserving the affected fallopian tube.
Methotrexate is considered for small, unruptured ectopic pregnancies in medically stable patients. Treatment is recommended when the pregnancy hormone, human chorionic gonadotropin (hCG), is below 5000 mIU/mL and no fetal cardiac activity is seen on ultrasound. These criteria help identify cases likely to respond to medical management.
Initial Steps Before Administration
Before administering methotrexate, healthcare providers conduct diagnostic and blood tests to ensure the patient is a suitable candidate. Quantitative human chorionic gonadotropin (hCG) levels are measured, with serial measurements determining if the pregnancy is progressing abnormally. An ultrasound confirms the ectopic pregnancy’s location, size, and checks for fetal cardiac activity or internal bleeding.
Additional blood tests, including a complete blood count and liver/kidney function tests, evaluate overall health and organ function, as methotrexate is processed by these organs. The patient’s Rh status is also determined; Rh-negative individuals may receive an Rh immunoglobulin injection if necessary. Healthcare providers counsel patients on the treatment plan and potential side effects, ensuring informed consent before administration.
The Administration Procedure
Methotrexate for ectopic pregnancy is administered as an intramuscular injection, typically into the buttock or thigh. Dosage is calculated based on the patient’s body surface area, usually 50 mg per square meter. This individualized dosing helps ensure an appropriate and effective amount of medication is given.
Typically, a single dose is sufficient. A second dose may be required if hCG levels do not sufficiently decline after the initial treatment. The injection is quick and may cause a brief stinging sensation. This procedure is typically outpatient, allowing the patient to return home.
Post-Administration Monitoring and Care
Following methotrexate injection, careful monitoring confirms treatment success and manages side effects. Serial quantitative hCG blood tests are performed on day 4 and day 7 post-injection, then weekly until undetectable. A 15% hCG decline between day 4 and day 7 indicates effective treatment.
Patients may experience various expected side effects. Common symptoms include mild to moderate abdominal pain or cramping, nausea, fatigue, vaginal bleeding or spotting, stomach upset, headache, and mouth sores. Contact a healthcare provider immediately if severe pain, heavy bleeding (soaking a maxi pad per hour for two consecutive hours), or dizziness and fainting occur, as these indicate serious complications.
During treatment and recovery, patients must follow specific lifestyle precautions. Avoid folic acid supplements and prenatal vitamins, as they counteract methotrexate. Also avoid alcohol and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or aspirin, as they increase side effect risk. Sexual intercourse, heavy lifting, and strenuous exercise are restricted until hCG levels normalize. To prevent harm to a future pregnancy, wait at least three months after the last methotrexate dose before attempting to conceive.