Causes of Dark Menstrual Blood

Menstrual blood is a mixture of blood, shed endometrial tissue, cervical mucus, and vaginal secretions. The volume and color of menstrual flow are closely related to a woman’s overall health. In daily life, some women may notice blood clots or dark-colored menstrual blood. So, what causes menstrual blood to appear black? Below, we address this question.

Causes of Black Menstrual Blood

1. Qi Stagnation and Blood Stasis

This pattern commonly manifests as variable menstrual flow volume, purplish-red blood, presence of clots, and irregular or sluggish menstruation—often due to qi stagnation and blood stasis. It may also be accompanied by abdominal pain and breast tenderness during menstruation. Regular circulation-promoting therapies, qi-regulating treatments, and interventions to alleviate dysmenorrhea are recommended.

2. Cold in the Blood

Delayed menstrual cycles, reduced flow volume, dark-black menstrual blood with clots, lower abdominal pain, and cold intolerance suggest “cold in the blood.” This condition arises when external cold pathogens invade the body, causing cold-induced stagnation of qi and impaired blood circulation. Therefore, women must prioritize warmth and avoid cold exposure during menstruation.

3. Kidney Deficiency

Women with kidney deficiency often experience menstrual cycle irregularities and relatively scanty flow, with blood appearing reddish or dark-red. Additional symptoms may include soreness and weakness in the lower back and knees, dizziness, tinnitus, lower abdominal pain, and frequent nocturnal urination—indicating the need for kidney-tonifying therapy. Moreover, certain gynecological conditions—including vaginitis, cervical erosion, and pelvic inflammatory disease—can also contribute to dark menstrual blood.

4. Deficiency of Both Qi and Blood

Early or delayed menstruation, increased or decreased flow volume, deep-colored menstrual blood, abdominal pain, dizziness, blurred vision, fatigue, and pallor may all indicate deficiency of both qi and blood—requiring targeted tonification of qi and blood.

The above outlines potential causes of black menstrual blood. However, it is crucial to recognize that persistently black menstrual blood warrants medical attention. Women should maintain a positive emotional state, minimize psychological stress and mood fluctuations, practice good menstrual hygiene to prevent infection, and avoid excessive physical exertion and sexual activity during menstruation. We hope this information proves helpful.