Health Topics
Efficacy Chart
Online Birth Control Education
Efficacy
A birth control method's effectiveness is estimated based on the percentage of women who experience an unintended pregnancy in one year using a particular method. This may also be stated as a method's failure rate: the percentage of women experiencing pregnancy during a one year period of method use.
Two rates are reported for each method of birth control: the theoretical rate (or perfect) and the actual user (or typical) rate. The theoretical rate estimates how well a method performs when used as intended and consistently by "perfect" users. The actual (typical) user rate estimates how well a method performs when all of the errors and problems that people typically encounter with a method are taken into account.
Failure Rates of Birth Control Methods
Method |
% of Women Experiencing an Unintended Pregnancy within the First Year of Use |
|
|---|---|---|
Typical Use |
Perfect Use |
|
| No Method | 85 |
85 |
| Spermicides | 29 |
18 |
| Withdrawal | 27 |
4 |
| Periodic Abstinence | ||
| • Calendar | N/A |
9 |
| • Ovulation Method | N/A |
3 |
| • Sympto-thermal | N/A |
2 |
| • Post-ovulation | N/A |
1 |
| Diaphragm | 16 |
6 |
| Contraceptive Sponge | ||
| • never given birth before | 16 |
9 |
| • previously given birth | 32 |
20 |
| Condom | ||
| • Female (Reality) | 21 |
5 |
| • Male | 15 |
2 |
| Combined Pill and Minipill | 8 |
0.3 |
| Evra Patch | 8 |
0.3 |
| NuvaRing | 8 |
0.3 |
| Depo-Provera | 3 |
0.3 |
| IUD | ||
| • ParaGard (copper T) | 0.8 |
0.6 |
| • Mirena (LNG-IUS) | 0.1 |
0.1 |
| Female Sterilization | 0.5 |
0.5 |
| Male Sterilization | 0.15 |
0.10 |
Emergency Contraceptive Pills: Treatment initiated within 120 hours after unprotected inercourse reduces the risk of pregnancy by 75%-89%.
Online Birth Control Education |
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last reviewed: Spring 2005