A follicle is a blister-like substance secreted by the ovarian cortex. In women of childbearing age, follicles grow and develop in the ovary after menstruation has cleared, and when the follicle grows and develops to about 2cm during ovulation, it is called a mature follicle. The egg will survive for 48 hours, and it is only after sex during ovulation that the egg and sperm will combine and develop into a fertilized egg, and the woman will be able to get pregnant. If the follicles are immature, small, or unable to ovulate, the woman will become infertile and will need to undergo a gynecological ultrasound and sex hormone test in a timely manner, and be treated with medication or surgery depending on the cause. The growth and development of follicles is affected by the follicle growth hormone secreted by the pituitary gland, and is also related to the nutritional and other functions of the woman’s body.