Low menstrual flow in dark brown color is considered to be related to endocrine disorders, and at the same time, for women of childbearing age who are sexually active, it is necessary to be alert to the possibility of ectopic pregnancy, preeclampsia, and other undesirable pregnancies. 1. Endocrine disorders: for patients with high stress or gynecological endocrine diseases such as polycystic ovary syndrome, endocrine disorders affect the normal growth and discharge of female follicles, and the lack of progesterone in the body leads to irregular stripping of the endothelium, resulting in low menstrual flow, dark color and other manifestations. 2. Adverse pregnancy: If the patient has a combination of ectopic pregnancy, preeclampsia and other adverse pregnancies, due to the poor quality of the embryo, low levels of progesterone in the body, or the fertilized egg is planted in the fallopian tube and other weak muscle places, some women will have a small amount of dark-colored vaginal blood at the time when their menstruation should come and it will be mistaken as the onset of menstruation. For women who have a small amount of dark brown menstrual bleeding, it is recommended that they go to the gynecology department of a regular hospital for a complete blood HCG, ultrasound and other relevant examinations to determine the cause of the problem and then actively treat it under the guidance of the doctor.