There is only a little blood for the first three days of menstruation, which may be due to luteal insufficiency or other reasons.
1. Luteal insufficiency: the corpus luteum is a vascularized gland-like structure transformed by the follicle after ovulation. If there is insufficient oestrogen secretion before ovulation, it will lead to luteal underdevelopment and premature atrophy, and then the secretion function of the body will decline, resulting in a shortened menstrual cycle and an abnormal amount of menstruation, which in some cases may be manifested as a small amount of bleeding a few days before the onset of menstruation.
2. Other reasons: only a little blood for three days before menstruation may also be abnormal uterine bleeding, in addition to insufficient corpus luteum function, it may also be localized endometrial abnormalities, such as uterine fibroids, endometrial polyps and so on. In addition, the use of intrauterine devices and other factors can also lead to irregular bleeding.
If there is only a little bleeding for the first three days of menstruation, you should go to the hospital for a detailed examination and symptomatic treatment for the cause.