Regular vacation refers to menstruation. The absence of menstruation may be caused by endocrine disorders, pregnancy, bad habits and other reasons, which need to be analyzed specifically. 1. Endocrine disorders: Women’s menstruation is affected by the hormones secreted by the endocrine organs, and endocrine disorders will affect menstruation and lead to absence of menstruation. 2. Pregnancy: If a woman who has sex doesn’t have her period, the first thing to consider is whether she is pregnant or not, which can be determined by blood HCG and ultrasound examination. 3. Individual’s bad habits: for example, irregular life and diet, staying up late, labor, mental stress, emotional depression, etc., will cause endocrine imbalance, resulting in menstruation. There may be other reasons for not having menstruation, so it is recommended to go to the hospital for examination to identify the cause of the disease and then treat the symptoms.