Menstruation 11 days in advance is considered to be ovulation bleeding, puberty or menopause menstrual irregularities, endocrine disorders, luteal insufficiency and so on. 1. Ovulation bleeding: when menstruation is 11 days early, it is usually in the ovulation period, and a small number of women will have a small amount of uterine lining shedding due to a transient drop in hormone levels, which some people will mistake for menstruation. 2. Irregular menstruation during puberty or menopause: During puberty, due to the immaturity of the hypothalamus-pituitary-ovarian axis, there will be irregular menstruation. During menopause, due to the decline of ovarian function, the hormone level in the body decreases, which will also lead to irregular menstruation. 3. Endocrine disorders: women in their childbearing years sometimes suffer from endocrine disorders due to stress, obesity and other factors, which can lead to irregular menstruation. 4. Luteal insufficiency: women will enter the luteal phase after ovulation. If the luteal phase declines prematurely due to insufficient secretion of progesterone and other factors, it will cause shortening of the luteal phase, and pre-menstrual period will occur. It is recommended to go to the hospital for a detailed examination after 11 days of early menstruation to clarify the cause of the disease and then deal with the symptoms.