Causes of small follicles Follicle small refers to the size of mature follicles in the ovary being less than 10mm. The main reasons for small follicles are as follows: 1. Decreased ovarian function: As women age, their ovarian function will gradually decline, resulting in a reduction in the number and quality of follicles. 2. Improper diet: Overeating, lack of nutrition, excessive weight loss, etc. will all affect the size of follicles. 3. Hormone imbalance: Insufficient or fluctuating pre-ovarian hormone secretion may lead to