Fluids have two roles: the first role is mainly to come to check whether the fallopian tubes are open or not, in this case it only needs to be done once, and it is recommended that the patient do it within 3-7 days of clean menstruation. The second role is mainly used to treat chronic tubal and pelvic inflammatory diseases, this treatment is also called hysterosalpingography. The uterine injections are required to be started after the patient’s period has been cleared for 3 days, with an interval of about 3 days in between. Overall, it is important for the patient to have no vaginal bleeding after the pass before having a second pass, so the exact number of days between passes also depends on the patient’s specific situation. If there is bleeding, the interval should be slightly longer, and if there is no bleeding, the interval can be slightly shorter. Overall, the interval between passages is about 3-5 days.