Menopause is the transition period in a woman's life when her ovaries stop producing eggs, her body produces less estrogen and progesterone, and menstruation becomes less frequent, eventually stopping altogether. Some women, menstrual flow comes to a sudden halt. More commonly, it slowly stops over time. During this time, the menstrual periods generally become either more closely or more widely spaced. This irregularity may last for 1 - 3 years before menstruation finally ends completely. Before this the cycle length may shorten to as little as every 3 weeks.