This method is done by tracking one’s menstrual cycle and recognizing the body’s fertile signs. It is important to know on which days to avoid sex or to use condoms. When counting, the first day of bleeding is day 1 in the menstrual cycle. You can get pregnant on days 8-19 if cycles are a month apart. This method works well when used correctly and requires the partner’s support. It is most effective when the woman has a regular pattern of periods.