Menstruation and the menstrual cycle fact sheet | womenshealth.gov What happens during the menstrual cycle? What is a typical menstrual period like ? What kinds of problems do women have with their periods? When does a girl ...
月經週期- 维基百科，自由的百科全书 月經週期，又称作經期、生理期，是人類女性在生理上的循环周期，发生在其他的 哺乳類動物則是經歷動情週期。有性繁殖可能與否和月經週期有著密切的關係。
