Methotrexate For Pregnancy Termination | How It Works.
Methotrexate gives women the opportunity to have a termination performed as early as a week prior to missing their period up to 9 weeks from the last menstrual period.
Methotrexate is not only used to stop the growth of pregnancy tissue, but it is used to treat different cancers (head and neck, breast, female genital tract, psoriasis, rheumatoid arthritis, ulcerative colitis, and other chronic diseases that affect are autoimmune disorders.
It is also used to treat patients with ectopic (tubal) pregnancies which are pregnancies that implant outside of the uterus (fallopian tubes, ovaries, abdomen, liver, diaphragm, etc.).
Methotrexate stops the rapidly growing embryonic and placental cells of early pregnancy from further developing.
Methotrexate used alone can cause miscarriage in close to 85% of patients that use it prior to 6 weeks or less gestation. It generally takes 3 to 4 weeks to begin having spontaneous bleeding and for the miscarriage to occur.
This is why giving Cytotec (Misoprostol) approximately 48 to 72 hours after taking the Methotrexate by mouth or injection has a success rate of 92 to 98%. Cytotec causes the uterus to begin to contract and leads to bleeding similar to a normal period in most women.
Some women experience a little heavier bleeding than their normal period. Patients less than 6 weeks gestation have nearly a 100% success rate with the combination of these medications.
Women who do not want surgery and want their abortion experience to be more private and have the support of spouse, family member, or friend, find this method to be more comfortable from a psychological and physical standpoint.
Methotrexate is extremely safe and effective in terminating pregnancies less than 9 weeks gestation. This medication has been used in our offices for over 16 years and used around the world for over 25 years in performing Medical Abortions.
Methotrexate must be avoided in patients who will be in the sun for a prolonged period of time, or have an allergy to it. Please see General Contraindication to having the medical abortion procedure performed.
Methotrexate For Medical Abortion: The Facts
Methotrexate inhibits hydrofolic acid reductase. Dihydrofolates must be reduced to tetrahydrofolates by this enzyme before they can be utilized as carriers of one-carbon groups in the synthesis of purine nucleotides and thymidylate.
Therefore, Methotrexate interferes with DNA synthesis, repair, and cellular replication. Actively proliferating tissues such as malignant cells, bone marrow, fetal cells, buccal and intestinal mucosa, and cells of the urinary bladder are in general more sensitive to this effect of Methotrexate.
When cellular proliferation in malignant tissues is greater than in most normal tissues, Methotrexate may impair malignant growth without irreversible damage to normal tissues.
Peak serum concentrations of Methotrexate occur 30 to 60 minutes after injection or by the oral route. The terminal half-life reported for Methotrexate is approximately three to ten hours.
Renal excretion is the primary route of elimination and is dependent upon dosage and route of administration. With IV administration, 80% to 90% of the administered dose is excreted unchanged in the urine within 24 hours.
There is limited biliary excretion accounting for up to 10% or less of the administered dose. Circulation of Methotrexate between the liver and intestines is possible.
Renal excretion occurs by glomerular filtration and active tubular secretion. Nonlinear elimination due to saturation of renal tubular reabsorption has been observed in psoriatic patients at doses between 7.5 and 30 mg.
Impaired renal function (creatinine of greater than 1.5 or other evidence of chronic renal disease), as well as concurrent use of drugs such as weak organic acids that also undergo tubular secretion, can markedly increase Methotrexate serum levels.
As the urine creatinine clearance decreases, the Methotrexate levels will increase in the body and may lead to damage of the kidneys and causing acute renal failure and potentially cause maternal death.
How Does Methotrexate Terminate Pregnancy
Antifolates, such as Methotrexate, function by blocking purine metabolism and thus interfering with DNA synthesis, making actively dividing cells susceptible targets.
Methotrexate destroys cytotrophoblasts which are actively dividing only in the S phase of a cell cycle. It has been shown that the cell division rate of cytotrophoblast cells, i.e., the number of cells in the cell cycle at a given time, did not decrease with advanced pregnancy.
However; studies show that the time it takes a cell to complete an entire cell cycle was lengthened from the first trimester to the end of pregnancy.
In essence, the cells do not divide as fast at the end of pregnancy than they do in early pregnancy. Since the time it takes a cell to go through its S phase division does not vary greatly, the longer cell cycle time would imply that the other phases have lengthened.
As the number of weeks in pregnancy increase, the less number of cytotrophoblast cells in the S phase decrease reducing the number cells that Methotrexate can destroy. Thus, the reason that Methotrexate is so highly effective at 6 weeks or less has a logical explanation.
It appears that there is a significant increase in cell cycle length of the cytotrophoblast cells beginning on or around day 50 of gestation and after that, Methotrexate no longer is significantly effective in terminating pregnancies alone.
Studies have shown that Methotrexate alone can cause abortions up to 69% of patients who are 9 weeks pregnant or less.
Combining Misoprostol with Methotrexate leads to a 94 to 99% success of terminating pregnancies between 3 to 9 weeks gestation. Terminating pregnancies before women miss their first menstrual cycle is offered by over 45% of abortion providers.
Contraindications To The Use Of Methotrexate
Women who are allergic or have sensitivity to Methotrexate should not receive the medication. Methotrexate can cause fetal death, teratogenic effects and miscarriage when administered to a pregnant woman.
Pregnancy should be avoided if either partner is receiving Methotrexate; during and for a minimum of three months after therapy for male patients, and during and for at least one menstrual cycle after therapy for female patients.
For women who are breastfeeding, Methotrexate is contraindicated due to the complications it can cause infants which are similar to the ones that occur in adults with the passage of the Methotrexate metabolites in the mother’s breast milk.
For women who have blood dyscrasias (blood disorders), anemia, low platelet counts, low white and red blood cell counts) Methotrexate is contraindicated.
Mild Side Effects
Headaches, blurred vision, chills, nausea, vomiting, rash and swelling on palms and feet, diffuse body pruritic (itchy), cystitis (inflammation of bladder), vaginal discharge, rash, constipation, diarrhea, abdominal and lower back pain, acute kidney and liver disease that normally recovers though there have been incidences where death has occurred, diffuse pulmonary alveolitis vaginal discharge, stomatitis (inflammation around mouth), folliculitis, raised skin, nodules, temporary drop in white and red blood cells.
Where To Get Methotrexate
In most third world countries women can get Methotrexate at pharmacies. It can be purchased over the counter without a prescription.
Additionally; Methotrexate can be bought at abortion clinics or from medical offices where women are treated under the care of a physician.
The Fort Lauderdale Women’s Center is Offering The One Hour Abortion Pill Procedure – 3 to 14 Weeks. Patients who qualify may receive a significant discount in the price of the procedure if they meet certain criteria.
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