Why can’t I have surgery during my menstrual period? There are four main reasons. (1) More bleeding during menstrual surgery Under normal circumstances, the dynamic balance between coagulation and anticoagulation is the key for the body to maintain the state of blood flow in the body and prevent blood loss. In the process of maintaining the normal circulation of blood in the body, the coagulation system, anticoagulation and fibrinolytic system, blood vessels and blood cells constitute the four basic links of coagulation and anticoagulation balance. We know that menstrual blood is usually not coagulated due to the fibrinolytic effect of fibrinolytic enzymes, which leads to high fibrinolytic activity of menstrual blood and facilitates the liquefaction and discharge of menstrual blood and tissue fibers. However, when surgery is performed during menstruation, this effect becomes detrimental, leading to a bleeding tendency in the body. It has been reported in the literature that vWF, FVIII and platelet function in the blood are at their lowest levels during menstruation. In addition, the inevitable tissue trauma during surgery activates and depletes a large number of coagulation factors and the fibrinolytic system is relatively hyperactive. If surgery is performed during this period, more blood will leak from the trauma surface during surgery, which will affect the surgical operation; more blood will leak after surgery, which may cause secondary problems such as airway compression (e.g. thyroid surgery). (2) Decreased immune function during menstruation affects the improvement of the disease and the healing of the incision Decreased body resistance can easily cause infection of the incision, respiratory system and urinary system, which is detrimental to the patient’s recovery. (3) Increased pain sensitivity during menstruation Studies have shown that women are more sensitive to pain during menstruation. The pattern of activation of pain-related brain regions is altered when one is menstruating; however, the relationship between sex hormones and nociception is not well understood. In addition, dysmenorrhea associated with menstruation may interfere with the diagnosis of postoperative complications and delay treatment. (4) It is not conducive to postoperative care. Menstrual surgery inevitably creates difficulties for life care, does not facilitate the retention of catheters, and increases the chance of urinary tract infection. Some patients are too nervous before surgery, resulting in endocrine dysfunction and early menstruation, and it is better to suspend surgery if it can be detected in time. However, menstruation is not an absolute contraindication to surgery. For emergency surgery that cannot be postponed, adequate preparation should be made before surgery; care should be taken during surgery to strive for complete hemostasis; and close observation and prevention of infection should be made after surgery. For patients with irregular menstrual cycles, it is best to ask for a gynecological consultation to manually adjust the menstrual cycle in order to reduce medical risks. Therefore, after the patient is admitted, the surgeon must ask for a detailed menstrual history and also know the time of the patient’s last menstrual period. The most appropriate time for surgery is 3 to 5 days after the menstruation clears.