Whether follicle 0.8 is normal or not depends on which stage of menstruation it is. Follicles can vary in size at different stages of menstruation and are related to estrogen levels. At the beginning of menstruation the follicles are relatively small, between 0.05-0.2 mm in diameter. As time goes on and hormone levels increase the follicles will gradually grow, and before ovulation the follicles can reach a maximum diameter of 18-23 mm. A follicle of 0.8 mm is a pre-ovulatory follicle and is normal if it is before the 10th day of menstruation. If it is after the 10th day of menstruation, it should grow into a mature follicle and follicle 0.8 mm is abnormally small. If the menstrual cycle is inaccurate, the ovulation period will also be inaccurate. You can determine the real ovulation period according to the pelvic ultrasound examination, the follicle 0.8 mm is not yet the ovulation period, you can continue to monitor the growth of the follicle by checking the pelvic ultrasound every day, generally the growth to 18 mm or more will have the possibility of ovulation.