Follicles do not grow very fast, usually at a rate of 1.5-2.0mm per day. A mature follicle is about 18-25mm. 14 days before the next menstrual period is the day of ovulation, when the follicle is mature, you can check the development of the follicle by ultrasound, the follicle development is too big or too small will affect ovulation. If the follicle development is abnormal, the ovarian function may be impaired, which may be caused by abnormal hormone secretion in the body. It is best to have a blood test for hormone six and use estrogen medication under the guidance of a doctor, such as using estradiol valerate tablets to improve ovarian function. If the follicle development is small, you can also use ovulation drugs such as clomiphene under the guidance of a doctor. It is also advisable to pay attention to rest, strengthen diet and nutrition, and arrange intercourse during ovulation in time for pregnancy.