Your period may not be the only painful part of your menstrual cycle – isn't being a woman fun? Here's everything to know about ovulation.

"This is the fertility window, and it usually occurs about two weeks before your period, in the middle of the menstrual cycle," Frederick says. By the time your period comes up, that egg is long gone.

Researchers at the National Institute of Environmental Health Sciences in Durham, North Carolina, said Friday that a woman's fertile window -- the six days each month when she is most likely to ...