The follicle monitoring report can indicate the size of the follicle, its growth rate, the number of follicles and which side of the ovary it is located on, as well as the thickness of the lining. Under normal circumstances, the growth rate of follicles is 1.5-2mm per day. If the monitoring starts on the 12th day of menstruation, then by the time it reaches the 14th day, it is almost around 18mm, the size of this follicle, which is clinically referred to as the dominant follicle. If it further increases in size, after reaching 20mm, ovulation may occur, and at this time you can choose to have intercourse to increase the chances of pregnancy. The endometrium is usually 10~12mm thick during ovulation, and too thin or too thick endometrium will affect the chances of pregnancy. If through the ultrasound examination, found that the follicle 20mm or more, reached 25mm, or no ovulation, then it may be caused by follicular luteinization, this generally will be followed by further atrophy, there will be no ovulation. During ovulation, it is recommended to clinically monitor the follicle by ultrasound, and if necessary, intramuscular injection of chorionic gonadotropin can be given when the follicle diameter reaches 18mm, which will prompt the follicle to rupture and discharge the egg.