Ovulation of a 17*14mm follicle can occur in about 2~4 days if developmental elimination has not occurred, because the diameter of a mature follicle is about 18~22mm. The follicle grows 1~2mm per day, and a 17*14mm follicle takes about 2~4 days to develop into a mature follicle of 18~22mm. Follicle development begins during the menstrual period and matures about 14 days before the next menstrual period, when it is stimulated by the relevant hormones to be discharged. Intercourse at this time will increase the chances of conception. For those who are preparing for pregnancy, follicle maturity can be monitored by ultrasound in a timely manner, while persistent immature follicles may indicate pathological factors in the human body, which require timely medical attention. If the follicles do not continue to develop during continuous monitoring, it is necessary to consult a doctor in time to identify the cause of the disease and carry out active treatment under the guidance of the doctor.