First posted on Introibo ad altare Dei 10 December 2006
Plan B, so called "emergency contraception," is the registered trademark of the Woman's Capital Corporation, a subsidiary of Duramed Pharmaceuticals, Inc., which in turn is a subsidiary of Barr Pharmaceuticals, Inc. So, Plan B is marketed by a subsidiary of a subsidiary of a corporation. I suppose that's how these things go in the corporate world. Anyway, Plan B consists of two pills of a synthetic progestin, levonorgestrel. The first pill is to be taken within 72 hours of "unprotected intercourse" or "known or suspected contraceptive failure". The second pill should be taken within 12 hours of the first. Now, the idea behind Plan B is really nothing new, as there have been any number of "off label" regimens around for "morning after pills" since at least the time I was in medical school (1980's) and, I'm not proud to say, I have had rare occasions in my former life to prescribe them. All the regimens involved giving mega-doses of birth control pills to the lady over a short period of time, a procedure which had the effect of making her really miserable: nauseous, vomiting, and generally wretched. The few of times I prescribed it, none of the women got pregnant, but since over 92% of the women in this situation don't become pregnant anyway, who knows if it was because of The Pills or simply because the odds were against it. Please note: Plan B is not the same things as The Abortion Pill, RU-486 (mifepristone, trade name Mifeprex). It's not even similar. Plan B is a different kind of drug, which works by a different mechanism. Plan B is just a glorified birth control pill. We'll take up The Abortion Pill some other day.
So, Plan B isn't The Abortion Pill. But, does it cause abortions? In a word, yes, just like regular birth control pills do. Before getting into it, though, let's talk some physiology. Fertilization takes place up in the fallopian tube, and the new embryo is gently milked down the tube by peristaltic action, to be squirted into the womb, where she then implants in the lush uterine lining, all set up to help her grow. This trip down the tube generally takes about five days. In other words, there's about five days, on average, between conception and implantation. Here is a question: when does pregnancy begin? With conception, of course, when an embryo appears. A standard embryology textbook definition reads like this:
"Development of the embryo begins at Stage 1 when a sperm fertilizes an oocyte and together they form a zygote." 
The National Bioethics Advisory Commission agrees. In 1997, they defined an embryo as the developing organism from the time of fertilization until differentiation has occurred, when the organism becomes known as a fetus. Finally, to round out our definitions, we'll crack a recent dictionary. "Pregnancy (1a): the condition of being pregnant. And, finally, pregnant (1a): containing unborn young within the body. When is a woman pregnant? When she contains unborn young within her body. What is an unborn young? An embryo. What is an embryo? A human being which results from, and is present at the completion of, fertilization. A lady is pregnant when she has an embryo inside of her body, which occurs at the moment of conception. Simple, right?
Wrong. In the 1960's, the American College of Obstetricians and Gynecologists changed the definition of pregnant, canceling the old definition, and substituting the following: pregnancy begins at implantation. ACOG even invented a new word for the pre-implantation embryo: preembryo. It's interesting to note that the term, preembryo, was actually not invented by ACOG. It was invented in 1979 by a frog embryologist who coined it deliberately to "reduce the status of the early human embryo." The purpose of inventing the term is the same as redefining the beginning of pregnancy: to legitimize contraceptives. A contraceptive prevents conception. An abortifacient causes an abortion. If pregnancy begins at conception, anything which prevents implantation is, by definition, causing an early abortion. However, if we redefine pregnancy as beginning at implantation, then something which prevents implantation is a contraceptive, not an abortifacient. Get it?
Birth control pills work by three major mechanisms: suppression of ovulation, thickened cervical mucous which impedes sperm travel, and prevention of implantation of the embryo by altering the uterine lining. The first two are contraceptive actions. However, the third is "contraceptive" only if pregnancy is defined as beginning at implantation. If pregnancy begins at conception, then this third mechanism by which birth control pills act is abortifacient.
This brings us to the claim that Plan B "is not an abortifacient". Woman's Capital Corporation notes in their own brochure that the mechanism of Plan B can be either inhibition of ovulation or prevention of implantation, just like any other birth control pill. Therefore, Plan B can function as an abortifacient, and the statement in the handout is an objective lie: Plan B is an abortifacient, or can be, just like any other hormonal method of contraception. Only by incorporating ACOG's lie that pregnancy doesn't begin until implantation can the Woman's Capital Corporation make their claim that Plan B isn't abortifacient.
In August, 2006, the FDA approved Plan B for over the counter sale, even though Plan B contains fifteen times the amount of hormone found in the usual birth control pill. There is simply no data out there on the effects of single or repeated mega-doses of oral hormones in Plan B, yet frequent use of the inexpensive, over the counter drug is what we can expect from the teenage and college age populations to whom it is targeted.
A final word on the name, "Plan B". Nothing summarizes the relationship between contraception and abortion more succinctly than the pithy name that Woman's Capital Corporation chose for their billion dollar baby. In the contraceptive world, abortion is what you do when the contraceptive fails. It's Plan B.
 "About Plan B" available at www.go2planb.com
 England, M.A. Life Before Birth 2nd. Ed. England: Mosby-Wolfe, 1996, p.31 Cited in National Council of U.S. Catholic Bishops - Pro-Life Activities, "What is an embryo?" at www.nccbuscc.org/prolife/issues/bioethic/fact298.htm
 Cloning Human Beings. Report and Recommendations of the National Bioethics Advisory Commission. Rockville, MD. Gov't Printing Office, 1997, Appendix 2. My emphasis.
 Webster's Third New International Dictionary of the English Language Unabridged Springfield: Merriam-Webster Inc 1993.
 Gold, R.B. "The Implications of Defining When a Woman is Pregnant" The Guttmacher Report on Public Policy. 8:2, May 2005. Available at www.guttmacher.org/pubs
 Grobstein, C. "External Human Fertilization" Scientific American, 240; 1979, p.57-67.
 cited in "Doublespeak: False Term 'Pre-embryo' Re-emerges Warns Bioethicist Claudia Navarini" Orthodoxy Today, www.orthodoxytoday.org 20 Sep 2005.
 "Plan B Manufacturer Admits Morning After Pill Can Cause Death of an Embryo." Richard Stith, Ph. D. Life Site News, 7 September 2006, LifeSiteNews.com at www.lifesite.net It was this article that first directed me to the Plan B brochure website listed above.
 Worthington, M. "How Plan B Does Harm to Women." Ethics and Medics 31(12) Dec, 2006