Why Is My Menstrual Flow Light and Dark in Color?

Less menstrual flow with dark color can be a normal phenomenon, or it can be caused by diseases such as ectopic pregnancy and endometrial damage. If a woman's menstrual blood appears darker and the duration from the start of menstruation to the end is less than a week, it is generally considered normal and does not require excessive concern. However, if black blood is discharged during menstruation and there has been sexual activity or abortion before, it is advisable to consider the possibility of underlying diseases.

1. Menstruation is formed by the shedding of the endometrium and its outflow through the vagina. The speed of endometrial shedding varies, and if the shedding is slow, dark blood may appear initially, resulting in a small amount of menstrual flow. Generally, after 2 to 3 days, the menstrual blood returns to its normal dark red color. Therefore, if the duration from the appearance of dark blood to the complete end of menstruation does not exceed one week, it is considered normal.

2. Less menstrual flow with dark color is a manifestation of poor drainage of menstrual blood within the uterine cavity, which is related to qi stagnation and blood stasis, as well as coldness in the uterus.

3. If a woman has previously undergone abortion or uterine cleaning, and subsequently experiences dark menstrual blood during each menstruation, it indicates a reduced menstrual flow and suggests endometrial damage that is difficult to recover, resulting in scanty menstrual flow. It is advisable to undergo a vaginal ultrasound examination one week before menstruation to assess the thickness of the endometrium and take targeted measures accordingly.