Each Postinor-2 tablet is equivalent to 1 Plan B tablet. The copper in copper-T IUDs can prevent sperm from fertilizing an egg and can also alter the endometrium, thereby inhibiting implantation of a fertilized egg. No, use of emergency contraception does not cause an abortion. In fact, emergency contraception prevents pregnancy and thereby reduces the need for induced abortion. Medical science defines the beginning of pregnancy as the implantation of a fertilized egg in the lining of a woman's uterus.
Implantation occurs five to seven days after fertilization.
Emergency contraceptives work before implantation and not after a woman is already pregnant. This survey also found that only about one percent of American women have ever used emergency contraception. Family planning experts believe that emergency contraception is more widely used in some European countries where emergency contraceptive pills are available specifically packaged in the proper dosages and with instructions. Emergency contraception gives these women a practical option to avoid pregnancy. About half of these unintended pregnancies occur because of some type of contraceptive failure - either a failure of the method or a mistake on the part of the user.