Cycle basics
Your fertility cycle starts on day one of your period (proper bleeding, not spotting) 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.
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.
How does your fertility change during your cycle?
Your fertile days are not a fixed event but you can usually work out when your green days begin - the infertile days at the end of your cycle.
The infertile days at the beginning of your cycle - your amber days - are more difficult to identify so they are only relatively infertile.
The infertile days at the beginning of your cycle - your amber days - are more difficult to identify so they are only relatively infertile.
When you start using FAM, you only have unprotected sex on your green days.
Some FAM users continue to do this, especially if they have any cycles that are less than 26 days long.
Find out how to identify your green days.
Some FAM users continue to do this, especially if they have any cycles that are less than 26 days long.
Find out how to identify your green days.