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How effective is vasectomy?

Vasectomy is one of the most effective forms of birth control. In the first year after vasectomy, only 15 to 20 of every 10,000 couples will experience a pregnancy.1,2 In comparison, 1,400 of every 10,000 couples have a pregnancy each year using condoms, and 500 of every 10,000 couples experience a pregnancy each year using oral contraceptive pills.1

However, a vasectomy is not effective right away. You still need to use other birth control until the remaining sperm are cleared out of the semen. This takes 15 to 20 ejaculations, or about 3 months. Even then, 1 of every 5 men will still have sperm in his semen and will need to wait longer for the sperm to clear.2

Your health care provider will check your semen for sperm at least once after the surgery. Once the sperm count has dropped to zero, it is safe to assume your vasectomy is now an effective form of birth control.2,3 Until that time, you need to use another form of birth control to make sure your partner does not become pregnant.


  1. American Pregnancy Association. (2003). Overview: Birth control. Retrieved May 23, 2012, from http://www.americanpregnancy.org/preventingpregnancy/birthcontrolfailure.html [top]
  2. American Urological AssociationFoundation. (2011). Vasectomy. Retrieved May 22, 2012, from http://www.urologyhealth.org/urology/index.cfm?article=53 [top]
  3. U.S. Centers for Disease Control and Prevention. (2012). Reproductive health: Contraception. Retrieved May 22, 2012, from http://www.cdc.gov/reproductivehealth/unintendedpregnancy/contraception.htm [top]

Last Updated Date: 11/30/2012
Last Reviewed Date: 11/30/2012
Vision National Institutes of Health Home BOND National Institues of Health Home Home Storz Lab: Section on Environmental Gene Regulation Home Machner Lab: Unit on Microbial Pathogenesis Home Division of Epidemiology Statistics and Prevention Branch Home Bonifacino Lab: Section on Intracellular Protein Trafficking Home Lilly Lab: Section on Gamete Development Home Lippincott-Schwartz Lab: Section on Organelle Biology