Menstruation delayed 15 days without pregnancy may be physiological, but also drug factors, pathological factors such as inflammation of the reproductive system, ovarian dysfunction, polycystic ovary syndrome, thyroid disease, tumors and other causes. 1. Physiological factors: for women with a history of sexual intercourse, a 15-day delay in menstruation to check for non-pregnancy may be a result of the formation of a fertilized egg, and the HCG concentration has not reached the standard for detecting early pregnancy, which is a normal phenomenon. 2. Drug factors: if you take progestin drugs such as dydrogesterone, progesterone, etc., can have an impact on the function of the hypothalamic-pituitary-ovarian axis, thus causing the above symptoms. 3. Pathological factors (1) Inflammation of the reproductive system: such as chronic endometritis, chronic cervicitis and other inflammatory stimuli can destroy the uterine lining, thus causing scanty menstruation, delayed menstruation and other symptoms. (2) Ovarian dysfunction: stress, late night, excessive weight loss, etc. can make the hypothalamus-pituitary-ovary axis function abnormally, and hormone level disorders, resulting in delayed menstruation. (3) Polycystic ovary syndrome: in addition to delayed menstruation or amenorrhea, it can also be accompanied by hyperandrogenic symptoms such as acne, hirsuteness and weight gain. (4) Thyroid disease: such as hyperthyroidism, hypothyroidism, etc., thyroid hormones can affect ovarian function, thus affecting hormone secretion and causing delayed menstruation. (5) Tumors: such as pituitary tumors, ovarian tumors, etc. can cause endocrine abnormalities, resulting in delayed menstruation or even menopause. If you have symptoms of delayed menstruation, it is recommended to consult gynecological ultrasound, hormone six, blood HCG and other tests in time to find out the cause and then treat it positively so as not to delay the condition.