月经周期是每个育龄女性都有的一种生理现象,是子宫内膜在雌激素的作用下的一种周期性的增生脱落。一般来说女性月经周期的长短主要取决于女性的卵巢内卵泡的发育成熟期的长短过程,而大多数女性黄体期的长短都是相同的,大约都有天左右。可见如果女性卵泡发育期长则月经周期相对会长一些,反之则月经周期也就短一些。月经周期在天之间并保持自己的规律的女性是属于正常的,不过在没有性行为的几个月或几年内如果推迟和提前一周都是正常的现象。另外很多因素都会影响到月经,比如年龄——在岁 Menstrual cycle is a physiological phenomenon of each woman of childbearing age, is the endometrium under the action of estrogen in a periodic hyperplasia off. In general, the length of the female menstrual cycle depends mainly on the duration of development and maturation of ovarian follicles in women, while the length of the majority of female luteal phase are the same, about a day or so. Shows that if the female follicle growth period of the menstrual cycle is relatively longer, and vice versa the menstrual cycle will be shorter. It is normal for a woman to have regular menstrual cycles between days and to maintain her own laws, but it is normal to postpone and advance one week in a few months or years without sexual intercourse. Many other factors can affect menstruation, such as age - at the age of