This is
called fertility awareness — some people use it to prevent pregnancy, and others use it to try to get pregnant.
There are a few ways to monitor your fertility for birth control — they're
called Fertility Awareness Methods (FAMs for short).
Also
called fertility awareness, natural family planning (NFP) is an umbrella term for various ways to forecast the time in your cycle when you are most likely to get pregnant — such as monitoring your daily temperature, checking for changes in cervical mucus and counting the days since your last period.
Not exact matches
If you're super organized and ultra-committed to your period tracking app, you might consider a
fertility awareness method, also sometimes
called natural family planning or the rhythm method.
They
called their organization the
Fertility Awareness Network (FAN).
Fertility awareness methods help you track your menstrual cycle so you'll know when your ovaries release an egg every month (this is
called ovulation).
Learn about Conscious Preconception, including
fertility awareness and
calling in the child you are meant to have.