Why is the first day of menstruation black? Is it a physiological or pathological reason?

If the menstrual blood is only black on the first day after menstruation and turns red at other times, it is usually caused by physiological reasons and there is no need to worry too much; if it is black all the time, it may be caused by diseases such as endometritis, uterine fibroids, uterine cold, qi and blood deficiency, etc., and needs timely treatment.

Normally, the color of menstruation is dark red, because menstrual blood is often mixed with shed endometrial fragments, mucus and vaginal epithelial cells. Many women find that their menstrual blood is dark on the first day of their period and feel scared. So, why is the color of menstruation dark on the first day of menstruation?
1. Physiological reasons <br/>It is a normal physiological phenomenon that most women have less menstrual flow and dark menstrual blood on the first day of menstruation. This is mainly because the endometrium sheds less on the first day of menstruation, and the menstrual blood is less, which often accumulates in the uterine cavity and is oxidized. The oxidized menstrual blood is often black.
2. Pathological causes
1. Gynecological diseases <br/>If you have diseases such as endometritis and uterine fibroids, it may cause blood stasis. Not only will the color of menstrual blood be very dark or even black on the first day of menstruation, but the color of menstrual blood at other times will also be obviously darker.
2. Cold uterus <br/>Eating cold food or catching a cold in the abdomen before menstruation may lead to cold uterus, poor blood circulation in the uterine cavity, blood stasis, the appearance of black blood on the first day of menstruation, and symptoms of dysmenorrhea.
3. Qi and blood deficiency <br/>When women are weak, they may experience less menstrual volume, darker menstrual color, general weakness, and fear of cold. This symptom will not only appear on the first day of menstruation, but also accompany the entire menstrual period.