The causes of delayed menstruation after hysteroscopy may be pregnancy, endocrine disorders, thinning of the uterine lining, polycystic ovary syndrome and so on. 1. Pregnancy: after hysteroscopic surgery, women have sex, pregnancy can cause menstrual pause, which is a physiological phenomenon. 2. Endocrine disorders: If the patient is affected by mental stress, excessive weight loss and dieting after hysteroscopic surgery, it may lead to endocrine disorders in the body, and the disruption of hormone levels in the body will cause delayed menstruation. 3. Thinning of the uterine lining: Hysteroscopic surgery will cause damage to the uterine lining, and the thinning of the uterine lining may cause delayed menstruation. 4. Polycystic Ovary Syndrome (PCOS): In patients with polycystic ovary syndrome (PCOS), the estrogen and progesterone levels in the body are out of balance, and the endometrium is unable to proliferate normally, which may lead to delayed menstruation. There are many reasons for delayed menstruation after hysteroscopy, so patients are advised to consult a doctor in time to find out the cause.