An abortifacient is a substance that induces abortion.
The ancient Greek colony of Cyrene at one time had an economy based almost entirely on the production and export of silphium, a powerful abortifacient in the parsley family. Silphium figured so prominently in the wealth of Cyrene that the plant appeared on the obverse and reverse of coins minted there. Silphium, which was native only to that part of Libya, was overharvested by the Greeks and was effectively driven to extinction. The standard theory, however, has been challenged by a whole spectrum of alternatives (from an extinction due to climate factors, to the so-coveted product being in fact a recipe made of a composite of herbs, attribution to a single species meant perhaps as a disinformation attempt).
Many herbs and plants sold "over the counter" today may act as abortifacients, including wild carrot, black cohosh, slippery elm, pennyroyal, nutmeg, mugwort, papaya, vervain, common rue, and tansy. Typically, the labeling will contraindicate use by pregnant women, but will not contain an explanation for this warning. There is no available data on the efficacy of these plants in humans. Some animal studies have found them to be effective. The use of herbs to induce abortion should be avoided due to the risk of serious side effects.
An older 'remedy' popular in the 1970s (previous to Roe vs. Wade) for unwanted pregnancy is using Vitamin C. "A Woman's Book of Choices: Abortion, Menstrual Extraction, RU-486" by Rebecca Chalker and Carol Downer, says to take 6-10 grams of ascorbic acid (pure Vitamin C) a day for 5-10 days.
Mifepristone, a progesterone receptor competitive antagonist, was first approved in 1988 under the trade name Mifegyne for medical termination of early pregnancy in conjunction with a prostaglandin analogue. Mifepristone, also known as RU-486, is marketed under the trade name Mifegyne in France and countries other than the U.S., and under the trade name Mifeprex in the U.S.
Misoprostol, a synthetic prostaglandin E1 (PGE1) analogue, was first approved in 1988 under the trade name Cytotec for reducing the risk of NSAID-induced gastric ulcers. Misoprostol is approved in France under the trade name GyMiso for use with mifepristone for medical abortion. Misoprostol is used off-label with mifepristone for medical abortion in the U.S.
Misoprostol alone is sometimes used for self-induced abortion in Latin American countries where legal abortion is not available, and by some immigrants from these countries in the United States who cannot afford a legal abortion.
Pre-implantation labeling controversy
Some substances might prevent implantation and thus destroy the blastocyst, although their known primary effect is to prevent fertilization. The existence of these post-fertilization mechanisms is debated. There is controversy as to whether pregnancy begins at the moment of fertilization, or at the moment the blastocyst implants in the uterine lining. American federal law and British law mark the beginning of pregnancy at implantation; thus, even if post-fertilization mechanisms were proven, these substances would still be labeled as contraceptives, rather than abortifacients.
The following birth control methods have been proposed to sometimes prevent implantation of a blastocyst, although (except as noted) they primarily work by preventing fertilization:
- Hormonal contraceptives
- Intrauterine device (IUD)
- The lactational amenorrhea method may cause a luteal phase defect (LPD). LPD may interfere with the implantation of embryos.
- Fertility awareness methods — a philosophy professor has speculated that intercourse during the less-fertile times of the cycle might create embryos incapable of implanting (due to aged gametes at the time of fertilization).
- Some herbal contraceptives may work primarily by preventing implantation.
- Kramer, Heinrich, & Sprenger, Jacob. (1487). Malleus Maleficarum. (Montague Summers, Trans.). Retrieved June 3, 2006.
- Riddle, John M. (1992). Contraception and Abortion from the Ancient World to the Renaissance. Cambridge, MA: Harvard University Press.
- Riddle, John M. (1997). Eve's Herbs: A History of Contraception and Abortion in the West. Cambridge, MA: Harvard University Press.
- Article "Emergency Contraception's Mode of Action Clarified" Check
|url=value (help). Population Briefs. Population Council. 11 (2). May 2005. Retrieved 2007-07-08.
Crockett, Susan A.; Harrison, Donna; DeCook, Joe; Hersh, Camilla (1999). "Hormone Contraceptives Controversies and Clarifications". American Association of Pro Life Obstetricians and Gynecologists. Retrieved 2007-07-08.
Alcorn, Randy (2004). "Does the Birth Control Pill Cause Abortions?" (PDF). Eternal Perspective Ministries. Retrieved 2007-07-08.
- Stanford J, Mikolajczyk R (2002). "Mechanisms of action of intrauterine devices: update and estimation of postfertilization effects". Am J Obstet Gynecol. 187 (6): 1699–708. PMID 12501086., which cites:
- Smart Y, Fraser I, Clancy R, Roberts T, Cripps A (1982). "Early pregnancy factor as a monitor for fertilization in women wearing intrauterine devices". Fertil Steril. 37 (2): 201–4. PMID 6174375.
- Díaz S, Cárdenas H, Brandeis A, Miranda P, Salvatierra A, Croxatto H (1992). "Relative contributions of anovulation and luteal phase defect to the reduced pregnancy rate of breastfeeding women". Fertil Steril. 58 (3): 498–503. PMID 1521642.
- Bovens, Luc (2006). "The rhythm method and embryonic death" (PDF). J Med Ethics. 32 (6): 355–6. PMID 16731736.
- Sharma MM, Lal G, Jacob D (1976). "Estrogenic and pregnancy interceptory effects of carrot daucus carota seeds". Indian J. Exp. Biol. 14 (4): 506–8. PMID 992821.