According to the American Pregnancy Association, a woman ovulates between day 11 and day 21 of her menstrual cycle. The days of a woman's period are included in this count. The day that a woman ovulates depends on the le... More »

A woman's egg lives in the uterus for 12 to 24 hours after ovulation. This short time period makes it critical to understand ovulation to increase chances of pregnancy. More »

Make an ovulation chart by using a calendar and writing down the first day of the menstrual period for several months, recommends What to Expect. Count the number of days between the beginning of two consecutive periods,... More »

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The most common reason for having two periods in one month is when a woman has a short cycle and one period occurs at the beginning of the month, and then about 24 days later, another occurs at the end of the month, acco... More »

A woman can use a calendar to track her menstrual cycle by marking or circling each date of her period on the calendar, starting from the first day of the period, explains GirlsHealth.gov. She can count her full cycle fr... More »

A menstrual period that only lasts a single day is not normal or common, but every woman's cycle is different, explains Mayo Clinic. Women should closely monitor their start date, end date, flow and pain levels each mont... More »

Black period blood is usually just a sign that old blood is leaving the uterus toward the end of a woman's menstrual cycle, according to WebMD. It is likely not a cause for concern but can indicate in some cases that a w... More »