The reasons for the sudden decrease in menstrual flow after IUD removal are mainly related to factors such as uterine adhesions, endocrine disorders, and the type of birth control ring. 1. Uterine cavity adhesion: mainly because the removal of the IUD caused damage to the uterine lining, and later can not recover in time, then it is easy to cause adhesions in the uterine cavity, affecting the endothelial exfoliation, resulting in a small amount of menstruation. 2. Endocrine disorders: mainly after the removal of the IUD, the uterine cavity endometrium environment suddenly changed, then it will affect the body’s hormone levels, so it will form a short period of time to reduce the amount of menstruation. 3. The reason for the type of birth control ring: for example, if you choose a copper-containing active birth control ring, then copper ions will be released during the implantation of the ring, which will produce aseptic inflammatory stimulation and make the endometrium show abnormal atrophic changes, which will result in low menstrual flow within a short period of time after the removal of the ring. If you continue to have low menstrual flow after removing the IUD, it is recommended that you go to the hospital in time to find the cause of the problem and then follow the doctor’s instructions for treatment to avoid delaying the condition.