What is Perfect Use?

The effectiveness of contraception is normally determined by the so called Pearl Index. This can be measured for perfect (method failure rate) or typical use. Method failure rate is when one uses the method of contraception correctly and according to guidelines. The Pearl Index for method failure rate has, in general, a higher safety-level than for typical use. In order to achieve the highest possible safety level, one should strive to achieve perfect use.

What is perfect use of Natural Cycles? In a nutshell:
- Measure your basal body temperature with correct type of thermometer (basal thermometer)
- Measure basal body temperature according to instructions
- Always check your data for the same day, never "assume" based on future predictions
- Use protection on red days (we recommend using condoms)