It is believed that various birth control methods - including the pill - can work by preventing the implantation of a fertilized egg in the uterus. For all contraceptives, this is at most a tertiary function. Implantation is the critical first step in pregnancy, and is recognized by scientific organizations like National Institutes of Health (NIH), American College of Gynecologist (ACOG), American Medical Association (AMA), British Medical Association (BMA) and others as the scientific definition for the beginning of a pregnancy. Therefore, the prevention of implantation comes before the start of a pregnancy and cannot be considered an abortion.
Because these contraceptive methods work prior to implantation, they have been an accepted and widely used means of pregnancy prevention for decades and are widely accepted in the medical and scientific community as a safe and effective means of contraception.
Emergency contraception (EC) works in a very similar way. According to the Association of Reproductive Health Professionals (ARHP), EC works by preventing ovulation (first), fertilization (second), and implantation (third). "They are not abortifacients. They will not interrupt or harm an established pregnancy." This is the case for all contraceptives.
The prevailing medical professional association-the American Medical Association-debated the subject and rejected the idea that these birth control methods are abortifacients after finding no evidence to support the claim. ("Recent Activities: 2001") Additionally, they also endorse EC as a method of contraception.
A World Health Organization report and its guidelines for EC state that a levonorgestrel-only pill has no effect on the endometrium following ovulation, suggesting that it would never work to prevent implantation-the fundamental theory that EC opponents rely on for their argument
American Reproductive Health Professionals: With one-half of U.S. pregnancies resulting from contraception failure, there is a huge space for emergency contraception to be used in preventing unwanted pregnancies and induced abortions. An increase in its availability and use of EC would almost certainly mean fewer abortions, a purported aim of those opposed to its use.
Relevant Links:
Report by American Academy of Family Physicians (AmFam) on Plan B
Report by AmFam suggesting Plan B could reduce abortions
NFPRHA fact sheet on EC
American Academy of Pediatrics Approves EC
Most current fact sheet on EC from Kaiser Family Foundation
