what is the fertile period each cycle
1 28 day periods: If your period typically lasts 28 days, ovulation will occur on day 14 of your cycle. So your most fertile days will be days 12, 13, and 14.  35 day periods: If you have a longer menstrual cycle, ovulation will occur on day 21 and your most fertile days will be days 19, 20, and 21.