why does period blood turn black
There is also a chance that your black period blood is caused by an infection or STD. Uterus infections can cause blackening as well as many STDs. Women that have sex during their cycle also experience black bleeding because the blood was pushed back into the vagina and can become trapped as a result.
Causes of Black Period Blood. Brown or dark discharge can be due to remnants of old endometrial tissues. This happens when the uterus is cleaning out old tissues and changing into newer ones. While in other cases the blood is exposed to oxygen thus the color change.