At the age of 42, menstruation 9 days ahead of the amount of particularly low may be related to perimenopausal syndrome, ovarian luteal abnormality, uterine cavity abnormalities and other reasons, and should be promptly paid attention to. Women in the normal menstrual cycle, the general cycle of 21 ~ 35 days, due to life factors as well as the state of the impact, there may be a certain deviation, the general advance or delayed within 7 days are normal phenomenon. 1. Perimenopausal syndrome: menopause is a normal physiological phenomenon after the female organism reaches a certain age, the beginning of the time is usually at the age of 45~55 years old, at the age of 42 years old, when this kind of situation occurs, it is very likely to be the manifestation of perimenopausal syndrome. 2. Ovarian corpus luteum abnormality: 42 years old menstruation 9 days in advance of the amount of particularly small is not normal, may indicate the existence of ovarian corpus luteum abnormality, which leads to hormone secretion disorders, the body appears to come on the condition of early. 3. Abnormalities of the uterine cavity: the symptoms may also be due to the presence of uterine cavity problems, such as cervical polyps, submucous fibroids, such problems will, to a certain extent, lead to abnormal uterine bleeding, which is mistaken for an abnormal menstrual cycle of the body. There may also be other reasons why a 42 year old’s menstrual period is 9 days early and unusually low in volume. It is recommended that you visit a hospital in a timely manner and undergo a complete examination to determine the cause of the problem, and then give targeted treatment or therapy.