Different fertility awareness-based methods (FABMs) suit different menstrual cycle characteristics due to their different guidelines around identifying fertile days. 

If you currently have regular cycles (length: 24-38 days) then any method may be suitable for you. If you’re considering a sympto-thermal method then these are well suited for those with regular cycles.

If you currently have irregular cycles (length: >38 days) then a mucus-only method like Billings may be suitable for you. This is because it focuses on identifying patterns of fertility rather than a single fertile window each cycle.

If you’re currently postpartum then a sympto-hormonal method like Marquette or a mucus-only method like Billings may be suitable for you.

All fertility awareness-based methods (FABMs) listed below have been developed based on a scientific understanding of hormones, biomarkers, ovulation and the menstrual cycle. However not all have been subject to effectiveness studies using their specific charting protocols. 

Peer-reviewed studies are available for methods including Sensiplan (sympto-thermal), Marquette (sympto-hormonal) and Billings (mucus-only). Read this review to learn more about the evidence base for these and other FABMs.

Most FABMs recommend abstinence on potentially fertile days if trying to avoid pregnancy. Some FABMs (particularly sympto-thermal methods) may be accepting of barriers, withdrawal and alternative sex if these align with your values. 

The number of potentially fertile days identified each cycle – when you need to modify your sexual practices if charting to avoid pregnancy – will vary depending on your chosen FABM and personal menstrual cycle characteristics. 

Double-check sympto-thermal methods such as Sensiplan tend to identify more potentially fertile days while allowing unprotected sex at any time before the fertile window opens if charting to avoid pregnancy. 

Mucus-only methods such as Billings tend to identify fewer potentially fertile days but sex is only possible on non-consecutive evenings of infertile days before peak day is confirmed if charting to avoid pregnancy.

All FABMs allow sex at any time after ovulation is confirmed if charting to avoid pregnancy.

Different fertility awareness-based methods (FABMs) have different ways of identifying potentially fertile days using scientifically validated biomarkers. 

Many methods require you to cross-check at least two biomarkers. For example sympto-thermal methods cross-check cervical fluid with temperature while sympto-hormonal methods cross-check cervical fluid with hormone tests. 

Methods with a cross-check may identify more potentially fertile days than those without. Some people see this as an advantage in terms of being more cautious and potentially enabling higher effectiveness for avoiding pregnancy. Other people see this as a disadvantage in terms of requiring more days with abstinence, barriers, withdrawal or alternative sex.

Learning with an educator is recommended if you’d like to achieve maximum effectiveness for avoiding pregnancy. Educators can help to fast-track the learning process and build your confidence by confirming your chart interpretations and answering any questions you may have along the way! 

Some methods including Billings and Marquette can only be learned from educators. These two methods tend to be quite affordable to learn with payment plans and scholarships often also available if needed. 

Other methods can be learned from educators or self-taught using a handbook. For example Sensiplan offers a concise handbook for its double-check sympto-thermal method. Chart reviews with educators are still recommended for maximum confidence and effectiveness if you choose to self-teach in this way.