If the menstrual period is delayed for 10 days and the test paper is not pregnant, it may be caused by abnormal detection, endocrine disorders, polycystic ovary syndrome and other factors. 1. Abnormal detection: the use of early pregnancy test paper test, the detection method is not correct or the test paper is abnormal, will lead to abnormal results, if necessary, should seek medical treatment for blood and urine HCG test, can be clearly diagnosed. 2. Endocrine disorders: may be related to pituitary tumors, hypothyroidism and other factors, can make the body’s hormone levels abnormal, will affect the menstruation, will lead to menstruation delayed for too long. 3. Polycystic Ovary Syndrome (PCOS): It may be related to heredity, excessive obesity, poor lifestyle and dietary habits, etc. It can affect women’s menstrual cycle and make the menstrual cycle disturbed, which can lead to delayed menstruation and, in serious cases, can also affect women’s pregnancy. If your period is delayed for 10 days and the test paper is not pregnant, and there are other abnormalities, it is recommended that you go to the gynecology department of the hospital for an examination to clarify the causes of the disease and then carry out reasonable treatment under the guidance of the doctor.