How do I use fertility awareness for birth control?

Bottom lineUse fertility awareness for birth control by tracking cervical mucus, basal body temperature, and cycle length together (the symptothermal method) to identify your fertile days, then avoiding unprotected sex or using a barrier during them with a safety margin; it takes daily commitment, is less forgiving of mistakes especially with irregular cycles, offers no STI protection, and is best learned from a trained provider.

Fertility awareness-based methods (also called natural family planning) work by identifying your fertile days each cycle and avoiding unprotected sex then. Done carefully and consistently, they can be effective - but they take commitment and have a higher failure rate with typical use.

What you track

• Cervical mucus - it becomes clear, slippery, and stretchy in your fertile window
• Basal body temperature - a small sustained rise confirms ovulation has happened
• Cycle length - to estimate when ovulation is likely

Combining all three (the "symptothermal" method) is more reliable than any single sign.

How to use it

1. Learn the method properly - ideally with a trained instructor
2. Track your signs every day and record them
3. Avoid unprotected sex (or use a barrier) on fertile days - which means several days before and after ovulation, with a margin for safety
4. Stay consistent - accuracy depends on careful daily tracking

Important limits

• It's less forgiving of mistakes than long-acting methods, and irregular cycles, illness, travel, and poor sleep make it harder
• It offers no protection against STIs
• It may not suit those who can't risk an unplanned pregnancy

Get proper guidance

Learn from a trained provider and talk to a clinician about whether it fits your circumstances.

See how to track your fertile window for the tracking detail.

Femora helps you log cervical mucus, temperature, and cycle length together so your fertile window is clear - while you follow a method you've learned properly.