Effectiveness of Natural Birth Control Methods :
When comparing contraceptive effectiveness,
- Typical use refers to failure rates for people who do not consistently or always correctly use their birth control. These rates usually apply to the average person as it is sometimes difficult to always and reliably use birth control the correct way
- Perfect use refers to failure rates for those whose use is consistent and always correct
- 100% effective
- Data indicates that women who use no birth control and who are sexually active for one year have an 85% chance of becoming pregnant in that year
- It is important to note, however, that this number is highly variable and is dependent on age and frequency of intercourse
- 50% if she is 19 to 26 years old
- 40% if she is 27 to 34 years of age
- 30% if she is 35 to 39 years old
- Typical use: all of the various fertility awareness based methods are between 78% to 88% effective
- Perfect use: all of the various fertility awareness based methods are between 95% to 97% effective
- Of every 100 women who use a type of fertility awareness based method, 12 to 22 will become pregnant in first year with typical use and 3 to 5 will become pregnant with perfect use
- Typical use: 82% effective
- Perfect use: 96% effective
- Of every 100 women whose partners use withdrawal, 18 will become pregnant (with typical use) and 4 will become pregnant with perfect use
- Typical use: 95% effective
- Perfect use: 98% effective
- Of every 100 women who use LAM, 5 will become pregnant within the first 6 months (with typical use) and less than 2 will become pregnant with perfect use
- Effectiveness rates only apply to women who are exclusively breastfeeding for the first 6 months post partum
Sources:
Rachel K. Jones, Julie Fennell, Jenny A. Higgins, and Kelly Blanchard "Better than nothing or savvy risk-reduction practice? The importance of withdrawal." Contraception June 2009 79:407410.
UpToDate. "Pregnancy rate (percent) during first year of use." Accessed: July 7, 2009 via private subscription.


