Dangerous period is not a technical term, but a generic term used to refer to the period of ovulation in women who have regular menstrual periods, usually about 14 days before the next menstrual period. This period is called the “danger period” because it is easy to get pregnant. However, for those with irregular periods, it is not possible to deduce the approximate date of ovulation, which can be monitored by ultrasound or ovulation test strips. Dangerous period is not absolute, the opposite of dangerous period is called “safe period”, ovulation will be affected by psychological, mental, environmental and other aspects, there may be early ovulation or delayed ovulation, so even if it is not ovulation, there is still a possibility of pregnancy. If you do not want to have children in the near future, you should take protective measures during sexual intercourse to avoid unwanted pregnancy.