The following are some of the cases: 1, in the reproductive stage of the female menstrual cycle is regular in about 28-35 days, early or delayed 1 week are normal, there is a normal sexual life of women, menstruation for a long time and pregnancy-related, pregnancy testing, if there is no pregnancy means amenorrhea, can take progesterone or injection of progesterone under the guidance of a doctor, after stopping the drug will be 2. If a young girl in puberty does not have a period, it means that the ovarian function is not yet complete, and there are no follicles and ovulation, so there is no need to treat this situation, and the period will come after the ovarian function is complete. 3. It is a normal physiological phenomenon.