The delayed menstruation after HPV vaccination requires consideration of several issues, which are generally not considered to be related to HPV vaccine: 1. exclude whether there is pregnancy; 2. need to consider whether you are worried, stay up late, sleep poorly, or have dietary problems that cause abnormal follicle development and ovulation, resulting in delayed menstruation. If neither of these problems is present, further ultrasound examination is needed to see if there are endometrial problems or endocrine reproductive hormone problems, and the specific situation needs to be analyzed after the examination results. If the period does not come once in a while, more than two months, and the ultrasound examination has a certain thickness of the endometrium, you can use progesterone to have a period and then observe the next period. If the next period is still late or prolonged for a long time, you need to consider whether there is an ovulation disorder or reproductive endocrine problem. If the next period returns to normal, it is not relevant.