(HealthDay News) - Women who are trying to get pregnant need to understand their menstrual cycles, especially when they are ovulating.

Ovulation is the release of a mature egg that occurs once during each menstrual cycle, in which the egg is ready to be fertilized.

Here is information to help you understand your monthly ovulation cycle, courtesy of the American Pregnancy Association:

• A menstrual cycle is measured from the first day of one menstrual period to the first day of the next menstrual period.
• A menstrual cycle typically lasts between 28-32 days, but it can be shorter or longer.
• Determine the date of ovulation by calculating the middle of your menstrual cycle -- ovulation typically occurs between day 11 and day 21 of a cycle.
• Ovulation can also be calculated by counting 12 to 16 days before the first day of your next period.