In Canada in 2004, approximately 3% of reported abortions were done using pharmaceutical drugs.1 Medical abortion is considered successful if complete expulsion of the embryo and placenta occurs without the need for surgery to complete the abortion.

Medical abortion is not commonly recommended in pregnancies past the first 49-63 days because of the increase in incomplete abortion, heavy and prolonged uterine bleeding and ongoing pregnancy past this stage.2 When severe bleeding or pain is present, surgical techniques are used to complete the abortion.3,4

Medical abortion takes longer than surgical abortion, is less effective, and requires more clinic visits. Medical abortion results in heavier, more prolonged bleeding, and more pain, nausea and vomiting than surgical abortion.5 Medical abortion has a 10 fold greater risk of serious infection and death than surgical (suction curettage) abortion.6,7,8

Medical abortion is preferred over surgical abortion by some women because of its effectiveness in early pregnancy, or because it does not require anesthetics or use of surgical instruments. Other women prefer it because it is more private and possibly more accessible, and because it may more closely resemble natural miscarriage.9,10

Most medical abortions involve the use of a combination of drugs that work together to bring about the abortion over a period of a number of days or weeks.

Medical Abortion Methods

  • Methotrexate and Vaginal or Oral Misoprostol
  • Misoprostol
  • Mifepristone and Misoprostol
  • Labor Induction Methods (instillation methods)
  • Saline Abortion
  • Urea
  • Prostaglandins

In Canada, methotrexate and misoprostol are used together for medical abortion up to 49 days of pregnancy.

Methotrexate breaks down the cell layer that attaches the embryo to the wall of the uterus, depriving the embryo of essential nutrients and resulting in its death.11,12
Misoprostol is a synthetic prostaglandin that causes the cervix to soften and dilate,.13,14and the uterus to contract and expel the embryo or fetus.15,16,17

Abortion with methotrexate and misoprostol requires several clinic visits. During the first visit, methotrexate is injected, followed at 2-7 days with misoprostol pills at home or at a clinic, either inserted into the vagina or taken by mouth.18,19,20,21 A follow-up visit is required after 1 to 3 weeks to determine if the abortion has occurred.

The methotrexate and misoprostol abortion regimen causes complete abortion in 70-97% of cases.22 While most of the abortions occur within the first hours or days after taking the misoprostol, 20 to 35% will take up to several weeks.23,24 A surgical abortion is scheduled to complete the abortion if it has not occurred by that point because the drugs used can cause birth defects.25,26,27

Side effects of medical abortion using methotrexate and misoprostol include: significant cramping pain and heavy bleeding during the abortion, along with nausea, vomiting, diarrhea, headache, fever, and chills; prolonged bleeding for one to seven weeks afterwards, and infection; birth defects if the pregnancy is ongoing and the fetus survives.28,29,30,31

Misoprostol

Misoprostol is a synthetic prostaglandin that causes the cervix to soften and dilate, and the uterus to contract and expel the embryo or fetus.

Misoprostol is used vaginally in abortions up to 56 days since the first day of the last menstrual period. When used alone, Misoprostol causes complete abortion in 22-94% of cases.32,33

Early side effects are worse with this method than with other methods of medical abortion, and include pain, dizziness, nausea, vomiting, diarrhea, chills and rashes.34 Heavy and prolonged bleeding and infection are associated with medical abortion in general. Misoprostol is generally used with another drug because of the higher incidence of side effects and lower rate of effectiveness when it is used alone.35

Misoprostol is commonly used in surgical abortions as well, to soften and dilate the cervix, and to reduce bleeding.36

Mifepristone and Misoprostol

Mifepristone, also known as RU-486 or the ‘abortion pill’, used together with misoprostol is the most commonly used medical abortion combination worldwide.37,38,39,40,41

Mifepristone is not approved for abortion in Canada. In 2001, the only Canadian trial of Mifepristone was stopped after the death of a woman from toxic shock brought on by a bacterial infection related to her abortion;42 similar deaths were recorded elsewhere.43,44,45

Mifepristone causes abortion by blocking the action of progesterone. Progesterone prepares the uterine lining for implantation and is essential for maintenance of the pregnancy. Progesterone also suppresses uterine contractions.

Mifepristone causes the uterine lining to break down, resulting in detachment of the embryo from its source of nutrition. It causes the cervix to soften and dilate. It also makes the body release prostaglandins and increases the effects of these prostaglandins in causing the uterus to contract.46

Mifepristone/misoprostol abortions are quicker than methotrexate/misoprostol abortions. Both regimens have similar rates of complete abortion, side effects and complications. Serious infection and heavy, prolonged bleeding are the most notable side effects, along with nausea, vomiting, diarrhea and headache.47

Labor induction methods (instillation methods)

In Canada in 2004, less than 1% of reported abortions used labor induction methods, such as instillation of saline, urea or prostaglandin solutions into the amniotic sac.48

Saline abortion

Saline abortion refers to the injection of a concentrated salt solution into the amniotic sac through the mother’s abdomen. The solution burns and kills the fetus, stops placental functioning, and stimulates labor.49

Saline abortions are rare in Canada,50 due to maternal deaths and a high level of side effects.51,52

Urea

No urea abortions were reported in Canada for 2004.53 Although urea instillation abortions are safer than saline abortions, the abortion takes a long time to occur.54 Urea is sometimes used in D&E abortions to kill the fetus and soften its bones to make it easier to remove.55

Prostaglandins

Less than 1% of reported abortions in Canada in 2004 were listed as prostaglandin abortions.56 Prostaglandins can be injected into the amniotic sac or taken by the mother to induce abortion. However, due to a high rate of side effects, as well as cases of temporary fetal survival, this is not a common abortion method. Sometimes saline or urea are injected into the amniotic sac to ensure the fetus will be dead when it is delivered, or the fetus is killed by an injection of potassium chloride or digoxin into the fetal heart or amniotic sac.57

Other reported methods

In addition to the methods listed above, there are other methods of abortion infrequently used in Canada. Combinations of the above methods may also be listed under “Other” in statistical reports.

References:
  1. Health Care Statistics. “Therapeutic Abortion Survey,” 2007.
  2. Cristin-Maitre S, Bouchard P, and Spitz IM. “Medical termination of pregnancy.” New England Journal of Medicine March 30 2000; 342(13): 947.
  3. Cristin-Maitre. et al. p. 949.
  4. Wiebe E, Dunn S, Guilbert E, Jacot F, Lugtig L. “Comparison of Abortions induced by Methotrexate or Mifepristone followed by Misoprostol.” Obstetrics and Gynecology May 2002; 99(5) Part 1:813-816.
  5. Cristin-Maitre. et al. p. 954.
  6. Creinen M, Blumenthal P, Shulman L. “Mifepristone-Misoprostol Medical Abortion Mortality.” Medscape General Medicince 2006; 8(2): 3.
  7. Harvey SM, Beckman LJ, Satre SJ. “Choice of and Satisfaction with Methods of Medical and Surgical Abortion Among U.S. Clinic Patients.” Family Planning Perspectives Sept/Oct 2001; 33(5): 212-216.
  8. Grimes. et al. p. 623-624.
  9. Harvey. et al. p. 214.
  10. Creinen. et al. p. 1-4.
  11. Cristin-Maitre. et al. p. 948.
  12. Wiebe. et al. p. 813.
  13. Stubblefield. et al. p. 175-177.
  14. Wiebe. et al. p. 813.
  15. Cristin-Maitre. et al. p. 946-947.
  16. Wiebe. et al. p. 813.
  17. Stubblefield. et al. p. 175-177.
  18. Cristin-Maitre. et al. p. 948.
  19. Stubblefield. et al. p. 176-177.
  20. Wiebe. et al. p. 814.
  21. Creinen. et al. p. 1-4.
  22. Moreno-Ruiz NL, Borgatta L, Yanow S, Kapp N, Wiebe ER, Winikoff B. “Alternatives to mifeprostone for early medical abortion.” International Journal of Gynecology & Obstetrics March 2007; 96(3): abstract.
  23. Cristin-Maitre. et al. p. 949.
  24. Wiebe. et al. p. 815.
  25. Cristin-Maitre. et al. p. 949, 952.
  26. Stubblefield. et al. p. 177.
  27. Abortion Rights Coalition of Canada. “Position Paper # 18: Abortion methods: an Overview.” January, 2006
  28. Cristin-Maitre. et al. p. 949, 952.
  29. Stubblefield. et al. p. 177.
  30. Wiebe. et al. p. 815-817.
  31. Grimes. et al. p. 623.
  32. Cristin-Maitre. et al. p. 949.
  33. Stubblefield. et al. p. 177.
  34. Cristin-Maitre. et al. p. 949.
  35. Stubblefield. et al. p. 177.
  36. Stubblefield. et al. p. 175-176.
  37. Grimes. et al. p. 622.
  38. Harvey. et al. p. 212.
  39. Wiebe. et al. p. 814.
  40. Stubblefield. et al. p. 176.
  41. Creinen. et al. p. 1.
  42. Laliberte J. “Still no mifepristone for Canada: is it safe?” National Review of Medicine Sept 30, 2005; 2(16):1.
  43. Creinen. et al. p. 1-4.
  44. Stubblefield. et al. p. 177.
  45. Fischer MD, Bhatnagar J, Guarner J, Reagan S, Hacker JK, Van Meter SH, Poukims V, Whiteman DB, Iton A, Cheung M, Dassey MD, Shieh WJ, Zaki SR. “Fatal toxic shock syndrome associated with clostridium sordiellii after medical abortion.” New England Journal of Medicine Dec 1, 2005; 353(22): 2352-2360.
  46. Grimes. et al. p. 622.
  47. Wiebe. et al. p. 813-818.
  48. Health Care Statistics. “Therapeutic Abortion Survey,” 2007.
  49. Neubardt S, Schulman H. “Techniques of Abortion, 2nd Ed.” Little, Brown and Company Inc., 1977: 67-94.
  50. Health Care Statistics. “Therapeutic Abortion Survey,” 2007.
  51. Neubardt. et al. p. 94.
  52. Stubblefield. et al. p. 179.
  53. Health Care Statistics. “Therapeutic Abortion Survey,” 2007.
  54. Stubblefield. et al. p. 179.
  55. Hern. p. 144-146, 153.
  56. Health Care Statistics. “Therapeutic Abortion Survey,” 2007.
  57. Stubblefield. et al. p. 179.