If the patient had a very good period before the hysteroscopy or examination and has a low menstrual volume and dark color after the procedure, there are two main possibilities: first, conception after the hysteroscopy treatment, conception followed by preterm miscarriage or ectopic pregnancy, resulting in abnormal vaginal bleeding, which can be determined by checking blood and urine HCG, ultrasound, progesterone and other related tests. Secondly, the endometrium is damaged or inflammation of the endometrium after hysteroscopy or treatment, resulting in adhesions in the endometrium and adhesions in the cervical canal leading to low menstrual flow and dark color. In this case, ultrasound can be done. If the endometrium is really thin, the possibility of this condition is highly suspected, but if you want to confirm the diagnosis, hysteroscopy should be done again.