Method Effectiveness vs. User Effectiveness

photo courtesy of Birdsandbees.org

photo courtesy of Birdsandbees.org

When discussing the effectiveness rates of various methods of birth control, you should be aware that there is a difference between the effectiveness of the method and the effectiveness of use.  Method effectiveness is defined as the effectiveness with perfect use.  In other words, the number of unexpected pregnancies which occurred when the method was correctly and consistently used over a period of time.  On the other hand, user effectiveness is defined by the actual practices of the couples using the method, both correctly and incorrectly, over that same period of time, which is usually one year.

The chart below describes some common birth control methods, along with their method and user effectiveness rates, based on 2,000 users and one year of use.  For comparison, having unprotected sex with absolutely no method of birth control used results in pregnancy 85% of the time.

Birth Control Method User Effectiveness Failure Rate Method Effectiveness Failure Rate
Male latex condom 15% 2%
Combined oral contraceptive pill 9% 0.3%
Diaphragm with spermicide 16% 6%
Intrauterine device with copper 0.8% 0.6%
Birth Control Patch 8% 0.3%
NuvaRing birth control ring 9% 0.3%
Depo Provera birth control shot 3% 0.3%
Today contraceptive sponge 32% 20%

 

The number one reason for the difference between the user and method effectiveness rates is simply failure to follow the given instructions for the item.  For example:

  • Birth control pills should be taken at the exact same time every day.
  • Condoms should be stored in a cool, dry place at all times prior to use, and should never be used if they are past the expiration date.
  • Diaphragms and cervical caps must completely cover the cervix.
  • IUD users should conduct a monthly check to make sure the device is properly in place.

The takeaway is that whatever birth control method you choose for yourself, it is important to be as educated as possible about it for the best results.

Please keep in mind that our effective rating is 99.3% effective and best explained on our website.

 

Sources:

http://en.wikipedia.org/wiki/Comparison_of_birth_control_methods

http://ccli.org/nfp/effectiveness/methodvsuser.php

http://womenshealth.about.com/od/birthcontrol/a/contraceptive_failure.htm