Cycle basics
Your fertility cycle starts on day one of your period (proper bleeding, not spotting - or a pill withdrawal bleed) and lasts till the day before your next period starts.
Day one of your period is cycle day one.
Count from this day to the day before your next period to get your cycle day and your cycle length.
For example if your period starts on cycle day 29, your cycle length is 28 days.
It's easiest to use FAM as contraception if your cycles are between 21 and 35 days long, and don't vary by more than seven days.
You can still use it if your cycles are not this regular but you will have more days when you need to use condoms or other precautions.
Count from this day to the day before your next period to get your cycle day and your cycle length.
For example if your period starts on cycle day 29, your cycle length is 28 days.
It's easiest to use FAM as contraception if your cycles are between 21 and 35 days long, and don't vary by more than seven days.
You can still use it if your cycles are not this regular but you will have more days when you need to use condoms or other precautions.
How fertility changes during your cycle
The early days of your cycle are amber or relatively infertile because this is where things are most likely to go wrong, mainly because you can't predict ovulation.
You use calculations like shortest cycle in the last year minus 20 to identify your first fertile day. You can't predict ovulation but you can use your history to work out the earliest time you are likely to be fertile.
Once you have enough data about your waking temperature, you can use earliest first higher temperature in the last year minus 8 to identify your first fertile day.
The infertile days at the end of your cycle are green because they are based on live data. This helps you confirm that ovulation has been and gone and your fertile days are over for this cycle.
The most helpful and obvious data is probably a sustained rise in your your waking temperature. You double-check this with cervical fluid, ovulation tests or cervix checks (a vintage fertility indicator).
You use calculations like shortest cycle in the last year minus 20 to identify your first fertile day. You can't predict ovulation but you can use your history to work out the earliest time you are likely to be fertile.
Once you have enough data about your waking temperature, you can use earliest first higher temperature in the last year minus 8 to identify your first fertile day.
The infertile days at the end of your cycle are green because they are based on live data. This helps you confirm that ovulation has been and gone and your fertile days are over for this cycle.
The most helpful and obvious data is probably a sustained rise in your your waking temperature. You double-check this with cervical fluid, ovulation tests or cervix checks (a vintage fertility indicator).
