These treatment regimens vary depending on the brand of contraceptive. A Simple Proposal to Reduce Unintended Pregnancies. Individual pharmacists have refused to fill emergency contraception prescriptions. Their refusals are often on the grounds of not wanting to facilitate abortions. The use of emergency contraception will not abort an established pregnancy.
Emergency contraception prevents pregnancy by delaying ovulation or preventing implantation.
Medical science defines the beginning of pregnancy as the implantation of a fertilized egg in the lining of a woman's uterus. Implantation occurs 5 to 7 days after fertilization. Despite the recent difficulties of obtaining ECP specific products, the greatest barrier to using ECP is the paucity of prospective information provided to reproductive age women. The need for ECP often arises during evening or weekend hours. As a result, the 72 hour time constraint is exceeded by the time one is able to arrange a visit to a health care professional.