Intrauterine adhesions (IUA) caused by endometrial basal layer injury can lead to reduced menstrual flow, infertility, recurrent pregnancy loss, and poor reproductive outcomes. Hysteroscopic adhesiolysis with uterine cavity reconstruction is the standard treatment, but women with moderate to severe IUA still have high rates of re-adhesion and unsatisfactory endometrial repair after surgery.

Injectable platelet-rich fibrin (i-PRF) is an autologous blood-derived biologic material that can be prepared at the bedside. Compared with conventional platelet-rich plasma, i-PRF may provide a more sustained release of growth factors and form a fibrin scaffold after intrauterine administration, which may help protect the wound surface, support endometrial regeneration, improve blood perfusion, and reduce postoperative re-adhesion.

This prospective randomized controlled study will evaluate the efficacy and safety of intrauterine i-PRF perfusion in women with moderate to severe IUA after hysteroscopic adhesiolysis. Participants will be assigned to receive either i-PRF intrauterine perfusion or sodium hyaluronate intrauterine treatment after surgery. The study will compare postoperative uterine cavity recovery, endometrial thickness and blood flow, clinical pregnancy outcomes, and safety events. The goal is to determine whether i-PRF can improve endometrial regeneration and reproductive outcomes and provide evidence for an optimized postoperative treatment strategy for moderate to severe IUA.

Intrauterine adhesions (IUA) are caused by injury to the endometrial basal layer, usually after intrauterine procedures or infection, and may result in hypomenorrhea, amenorrhea, infertility, recurrent miscarriage, and impaired reproductive function. Hysteroscopic adhesiolysis with uterine cavity reconstruction is the standard treatment. However, for women with moderate to severe IUA, postoperative endometrial regeneration remains inadequate, re-adhesion is common, and pregnancy outcomes remain suboptimal.

Autologous platelet concentrates have shown potential in tissue repair. Previous work by the study team suggested that intrauterine platelet-rich plasma (PRP) after transcervical resection of adhesions may reduce re-adhesion and increase endometrial thickness, but the effect may be limited by rapid biologic activity loss. Injectable platelet-rich fibrin (i-PRF), a second-generation autologous platelet concentrate, remains in liquid form before administration and then rapidly forms a fibrin gel in the uterine cavity. This material may act as both a physical barrier and a biologically active scaffold, while allowing sustained release of growth factors that support tissue repair, angiogenesis, and modulation of local inflammation.

This study is a prospective randomized controlled clinical trial conducted at Beijing Obstetrics and Gynecology Hospital, Capital Medical University. The objective is to evaluate the efficacy and safety of intrauterine i-PRF perfusion after hysteroscopic adhesiolysis in women with moderate to severe IUA and to compare it with sodium hyaluronate intrauterine treatment.

Women of reproductive age with moderate to severe IUA, defined according to the Chinese diagnostic and grading standard (CSGE score >=9), who have a strong fertility desire and plan to undergo hysteroscopic adhesiolysis will be screened for enrollment. Participants who meet all eligibility criteria and provide informed consent will be randomly assigned in a 1:1 ratio to one of 2 groups.

All participants will undergo standard hysteroscopic adhesiolysis with uterine cavity reconstruction and placement of a uterine cavity balloon. In the experimental group, 3 mL of freshly prepared autologous i-PRF will be perfused into the uterine cavity through the balloon drug channel immediately after surgery and again on postoperative day 5. In the control group, 3 mL of sodium hyaluronate will be administered through the same route immediately after surgery. Both groups will also receive postoperative artificial cycle treatment and prophylactic antibiotics according to the study protocol.

The study will assess both efficacy and safety. Efficacy endpoints include postoperative uterine cavity morphology and re-adhesion rate based on second-look hysteroscopy after 2 menstrual cycles, endometrial thickness, endometrial volume, and endometrial blood flow assessed by transvaginal ultrasound during the implantation window, and clinical pregnancy outcomes during follow-up. Safety assessments include body temperature, abdominal pain, vaginal discharge, blood routine testing, coagulation-related events, and monitoring for infection or thrombotic complications.

Participants will be followed during hospitalization, within 1 month after discharge, after 2 menstrual cycles for hysteroscopic and ultrasound reassessment, and again at 6, 12, and 24 months for reproductive outcomes. The planned sample size is 200 participants, with 100 in each group.

This study aims to determine whether intrauterine i-PRF perfusion can improve endometrial regeneration and repair, reduce postoperative re-adhesion, improve endometrial receptivity and pregnancy outcomes, and provide clinical evidence for a practical and safe regenerative treatment strategy for moderate to severe IUA.

Inclusion Criteria:

• Female participants aged 20 to 40 years
• Moderate to severe intrauterine adhesions caused by endometrial injury, defined according to the Chinese diagnostic and grading standard (CSGE score >=9)
• Strong desire for fertility
• Normal ovarian function
• Planned to undergo hysteroscopic adhesiolysis with uterine cavity reconstruction
• Willing to comply with follow-up requirements
• Able and willing to provide written informed consent

Exclusion Criteria:

• Contraindications to hysteroscopic uterine cavity reconstruction surgery
• Use of aspirin or other antiplatelet nonsteroidal anti-inflammatory drugs within 10 days before or after surgery
• Hematologic disorders, including platelet dysfunction, severe anemia, or blood-borne infection
• Contraindications to postoperative estrogen or progestin treatment
• Other uterine diseases, such as congenital uterine malformation, adenomyosis, or submucosal fibroids
• Other causes of infertility, including endocrine abnormalities, polycystic ovary syndrome, diminished ovarian reserve, premature ovarian insufficiency, or premature ovarian failure
• History of pelvic malignancy or pelvic radiotherapy
• Severe hepatic or renal dysfunction
• Contraindications to pregnancy
• Male partner-related infertility factors, such as abnormal semen findings

This is an open-label study. No masking procedures are described in the protocol. Randomization will be implemented using a computer-generated random number table, and allocation concealment will be maintained with sealed opaque envelopes until group assignment.