Half a month without menstruation did not detect pregnancy, may be related to endocrine diseases, ovarian function abnormalities or other factors, need to do relevant examinations for further diagnosis and treatment. Normal menstrual cycle is 21~35 days, menstruation delayed half a month did not come, if the blood chorionic gonadotropin test results are normal, can rule out pregnancy, cause menstruation delay is mainly due to the following factors: 1. Endocrine diseases: such as abnormal thyroid function, hyperprolactinemia, etc., all of which affect ovarian function and lead to menstrual disorders. 2. Abnormal ovarian function: work, mental, environmental factors, if the work pressure is too large, the mental state is not good, or external environmental factors, will lead to abnormal ovarian function, affecting menstruation. 3. Other factors: such as taking certain drugs can also lead to delayed menstruation. Therefore, if you are not pregnant but have delayed menstruation, it is recommended that you go to the hospital in time for examination to clarify the cause of the disease and then follow the doctor’s instructions to deal with the treatment.