Is there a difference between medication abortion and emergency contraception
(also known as the morning after pill)?

Yes, medication abortion and emergency contraception are different. The use of emergency contraception does not cause an abortion. In fact, emergency contraception prevents pregnancy and thereby reduces a woman's need for an abortion.

Medical science defines the beginning of pregnancy as the implantation of a fertilized egg in the lining of a woman's uterus. Implantation begins five to seven days after fertilization (and is completed several days later). Emergency contraceptives work before implantation and not after a woman is already pregnant. If a woman takes emergency contraception when she is already pregnant, emergency contraception will not interfere with the established pregnancy and it is not teratogenic. More information on emergency contraception can be obtained at This site is available in English, French, Spanish, and Arabic.

Medication abortion works by terminating an existing pregnancy. Thus, medication abortion only works after fertilization and implantation have occurred.

Reference: [1] Finer L, Henshaw S. Abortion Incidence and Services in the United States in 2000. Perspectives on Sexual and Reproductive Health. 2003; 35(1): 6-15.

If you have questions about medication abortion, please visit our page on frequently asked questions.

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Last updated: September 2009