The small opening of the cervix is clinically referred to as the tight inner opening of the cervix. If it is particularly tight, it will affect the sperm to enter the uterine cavity through the inner opening to reach the fallopian tubes, and it will not be able to unite with the egg to form a fertilized egg which will affect the pregnancy. It is recommended to perform a cervical dilation procedure. After 3-7 days of menstruation, when there is no inflammation and no contraindications, the cervical dilation rod is slowly dilated from the 4th by aseptic operation. If the number 4 has already passed the internal opening, it is recommended not to dilate a larger dilation rod enough to improve the tightness of the internal opening, and intercourse at the time of ovulation will improve the chances of pregnancy.