Comparing the efficacy and pregnancy outcome of intrauterine balloon and intrauterine contraceptive device in the prevention of adhesion reformation after hysteroscopic adhesiolysis in infertile women: a prospective, randomized, controlled trial study

Intrauterine adhesion (IUA), often following endometrial basal layer injury from procedures such as dilation and curettage (especially after miscarriage), infection, or other intrauterine interventions, can lead to partial or complete uterine cavity or cervical canal obstruction. IUA (Asherman syndrome) manifests with hypomenorrhea/amenorrhea, pain, infertility, and adverse pregnancy outcomes. Although hysteroscopic adhesiolysis is the standard treatment, severe cases have high recurrence rates of adhesions. Strategies such as IUDs and intrauterine balloons are used postoperatively to prevent readhesion, but optimal approaches and duration of use remain uncertain. This study aims to compare an intrauterine balloon versus IUDs (placed for 1 or 2 months) in preventing adhesion reformation and to assess subsequent pregnancy outcomes in infertile women with moderate-to-severe IUA.

Prior literature supports postoperative uterine cavity stenting to reduce readhesion after adhesiolysis, including IUDs and balloons. IUDs have historically been used for 2–3 months to physically separate uterine walls and promote endometrial regeneration, though duration consensus is lacking. Balloons can also act as barriers while facilitating drainage and hemostasis. Previous RCTs showed similar efficacy of 7-day IUD versus balloon placement in preventing adhesion recurrence. Complications of prolonged IUD use (e.g., bleeding, infection, incarceration, perforation) are noted in prior reports. Guidelines (e.g., AAGL/ESGE) endorse mechanical barriers and hormonal therapy to aid endometrial repair.

Design: Prospective, randomized, controlled trial at a tertiary university hospital. Ethics: Approved by the IRB of Changzheng Hospital, Shanghai (Approval 2020shenglun-038-01); written informed consent obtained. Participants: 130 infertile women (January–May 2021) with moderate (AFS 5–8) or severe (AFS 9–12) IUA; all had embryo transfer failures. Exclusion: Age >40, other uterine diseases (fibroids, adenomyosis, malformations), significant medical disorders (e.g., thrombophilia, cardiovascular/respiratory disease). Preoperative assessment: Menstrual/reproductive history, prior intrauterine surgeries, and transvaginal ultrasound. Randomization: Computer-generated, 1:1:1 allocation to three groups with allocation concealment via sealed opaque envelopes. Interventions: All underwent hysteroscopic adhesiolysis (Storz hysteroscope, saline distension 120–140 mmHg) under general anesthesia; adhesions divided with hysteroscopic scissors to restore normal anatomy. Postoperative allocation: (A) IUD in situ for 1 month (Yuangong IUD); (B) IUD in situ for 2 months; (C) Foley catheter balloon in situ for 5 days. Perioperative care: Antibiotics—IV sulbenicillin 4 g plus levornidazole for 1 day. Hormonal therapy: Estradiol valerate 4 mg/day for 21 days plus dydrogesterone 10 mg/day for the last 10 days; repeated for a second cycle after withdrawal bleeding. Follow-up: Second-look hysteroscopy in early proliferative phase—at 1 month for balloon group (after 5-day removal) and at 1–2 months for IUD groups (device removed at second look); recurrent adhesions documented. Outcomes: Primary—change in AFS score; endometrial thickness (late proliferative phase); pregnancy outcomes after embryo transfer (two Day-3 high-quality embryos after second-look hysteroscopy). Sample size: Assumed adhesion reformation 40% (IUD groups) vs 15% (balloon), α=0.05, β=0.20; 43 per group required; allowing 10% drop-out, total target 130. Statistics: SPSS v20; one-way ANOVA for continuous outcomes; chi-square for categorical outcomes; significance at P<0.05.

- Participants: 130 randomized; 1 protocol violation (balloon group) excluded; 129 analyzed (n=43 per group). Baseline characteristics were comparable among groups (age, BMI, number of D&Cs, symptoms, baseline AFS score, baseline endometrial thickness). - AFS score: Significantly lower at second-look hysteroscopy versus preoperative in all groups (P<0.05). The magnitude of AFS score reduction was greater in the balloon group than in either IUD-1-month or IUD-2-month groups; no significant difference between the two IUD groups. - Endometrial thickness: Increased significantly from baseline to follow-up in all groups; no significant differences in the degree of increase among groups. - Pregnancy outcomes: After two transfers of D3 high-quality embryos, pregnancies occurred in 23/43 (balloon), 25/43 (IUD 1-month), and 24/43 (IUD 2-month) participants; no significant difference in pregnancy rates among groups. Rates of miscarriage, ectopic pregnancy, and preterm delivery were similar across groups.

Mechanical barriers after adhesiolysis are crucial to reduce postoperative reformation of IUAs and to support endometrial repair. This RCT shows that an intrauterine balloon for 5 days achieved a greater reduction in AFS scores compared with IUD placement for either 1 or 2 months, suggesting better restoration of uterine cavity morphology with the balloon. However, improvements in endometrial thickness and subsequent pregnancy outcomes were similar across all strategies, indicating comparable functional endometrial recovery and reproductive potential among the three methods. Given the potential complications associated with longer IUD indwelling times, the comparable efficacy of 1-month versus 2-month IUD placement suggests that shorter IUD durations may minimize risks without sacrificing benefits. Despite improved cavity morphology, overall reproductive outcomes remain suboptimal, underscoring the need for enhanced postoperative uterine repair strategies to improve fertility outcomes in women with moderate-to-severe IUA.

All three interventions—balloon (5 days), IUD for 1 month, and IUD for 2 months—effectively reduced adhesion recurrence and increased endometrial thickness after hysteroscopic adhesiolysis in women with moderate-to-severe IUA. The balloon yielded a greater reduction in AFS scores than either IUD regimen, though endometrial thickness gains and pregnancy outcomes did not differ significantly among groups. Shortening IUD duration to 1 month may reduce complications while maintaining efficacy. Future research should optimize postoperative repair strategies, evaluate long-term reproductive and offspring outcomes, and include larger, multi-center randomized trials to refine best practices.

- Single-center study with a relatively small sample size, limiting generalizability. - Lack of detailed reporting on complications and adverse events, and no assessment of compliance or standardization with postoperative hormone therapy. - No long-term follow-up on offspring development or patient-reported outcomes/quality-of-life measures. - Absence of a standard-treatment comparator arm beyond the studied interventions. - One protocol violation (timing of second-look hysteroscopy).