At the conclusion of hysteroscopic adhesiolysis, recruited patients will be randomized to one of the two treatment groups by computer-generated numbers: [1] Immediate Intrauterine Balloon therapy (I-IUB) group: Immediately place a Foley-catheter intrauterine balloon which will be removed after 7 days after surgery; [2] Delayed Intrauterine Balloon therapy (D-IUB) group： insertion of a Foley-catheter to distend the uterine cavity 2 weeks and 4 weeks after hysteroscopic adhesiolysis; A second-look hysteroscopy will be carried out in the early proliferative phase 6 weeks after the surgery.