(1) Women menstruate for an average of 40 years of their lives.

(2) She had begun to menstruate

(3) Other studies have shown that women undertaking extreme exercise regimens had ceased ovulating and menstruating .

(4) Some women stop menstruating as early as their late 30s.

(5) But considering how much time we spend on that time of the month - from puberty to menopause, the average woman menstruates almost seven whole years - many of us know surprisingly little about it.

(6) Women who start menstruating early in life or who have a late menopause have an increased risk of developing breast cancer.