Answers to Frequently Asked Questions About...
How Emergency Contraception Works
Does emergency contraception cause an abortion?
No, using emergency contraceptive
pills (also called "morning
after pills" or "day after pills") prevents
pregnancy after sex. It does not cause an abortion. (In fact,
because emergency contraception helps women avoid getting pregnant
when they are not ready or able to have children, it can reduce
the need for abortion.)
Emergency contraceptive
pills or the IUD as emergency
contraception work before pregnancy begins. According to leading
medical authorities – such as the National Institutes of Health and the American College of Obstetricians and Gynecologists –
pregnancy begins when the fertilized egg implants in the lining of
a woman's uterus. Implantation begins five to seven days after sperm
fertilizes the egg, and the process is completed several days later.
Emergency contraception will not work if a woman is already pregnant,
and it also will not harm the woman
or her fetus.
The way emergency contraceptive
pills work depends on where you are in your monthly cycle when
you take them. They may prevent or delay ovulation (release of your
egg), affect the movement of egg or sperm (making them less likely
to meet), interfere with the fertilization process, or prevent implantation
of a fertilized egg. The copper in Copper-T
IUDs can prevent sperm from fertilizing an egg and may also prevent
implantation of a fertilized egg.
For more discussion about how emergency contraception prevents pregnancy,
click here. You
can also read a thorough and up-to-date academic review of the medical
and social science literature, including research into how emergency
contraception works, by clicking
here 
.