The goal of this randomized clinical trial is to determine whether intramyometrial ergometrine injection or intramyometrial carbetocin injection is more effective in reducing blood loss during and after abdominal myomectomy in women undergoing surgery for symptomatic uterine fibroids.

The main questions it aims to answer are:

Does intramyometrial ergometrine reduce intraoperative and postoperative blood loss during abdominal myomectomy?

Does intramyometrial carbetocin reduce intraoperative and postoperative blood loss during abdominal myomectomy?

Is there a difference between the two drugs in the need for blood transfusion and postoperative hemoglobin drop?

Researchers will compare intramyometrial ergometrine injection with intramyometrial carbetocin injection to see which intervention is more effective in controlling surgical bleeding and improving surgical outcomes.

Participants will:

Undergo abdominal myomectomy for uterine fibroids

Receive either intramyometrial ergometrine or intramyometrial carbetocin during surgery

Be monitored for intraoperative blood loss, postoperative blood loss, hemoglobin changes, and need for blood transfusion

Uterine leiomyomas are the most common benign tumors of the female reproductive tract and frequently require surgical management when symptomatic. Abdominal myomectomy remains the standard fertility-preserving surgical option for women with large or multiple intramyometrial fibroids. However, excessive intraoperative and postoperative blood loss continues to be a major challenge during myomectomy and is associated with increased morbidity, blood transfusion requirements, prolonged hospitalization, and delayed recovery.

Several pharmacological and surgical strategies have been investigated to minimize blood loss during myomectomy, including mechanical tourniquets, vasoconstrictors, uterine artery occlusion, and uterotonic agents. Among uterotonics, methylergometrine maleate and carbetocin are well-established agents that induce sustained uterine contractions and may reduce bleeding by compressing uterine vasculature. Methylergometrine, an ergot alkaloid, has long been used in obstetric hemorrhage, while carbetocin, a long-acting oxytocin analogue, offers prolonged uterotonic activity with a favorable pharmacokinetic profile. Despite their individual use, comparative data on their intramyometrial administration during abdominal myomectomy remain limited.

This prospective, double-blind, randomized comparative clinical trial is designed to evaluate and compare the effectiveness of intramyometrial methylergometrine versus intramyometrial carbetocin in reducing blood loss during and after abdominal myomectomy. The study will be conducted at Fayoum University maternity hospitals over an anticipated period of 20 months. To minimize bias, all procedures will be performed by the same surgical team following a standardized operative technique.

Participants will be randomly allocated to one of two intervention arms. In the first arm, methylergometrine maleate diluted in saline will be injected intramyometrially around the myoma before uterine incision. In the second arm, carbetocin diluted in saline will be administered in the same intramyometrial manner. The injections will be given circumferentially around the myoma, approximately 1-2 cm from its margins, and repeated as needed according to the number of myomas. Allocation concealment will be ensured using sequentially numbered opaque sealed envelopes, and double blinding will be maintained by coding the study drugs, with the allocation key retained by a designated supervisor until study completion.

A standardized abdominal myomectomy technique will be used in all cases, including Pfannenstiel incision, careful enucleation of myomas, meticulous hemostasis, layered uterine closure, and routine use of intraperitoneal drainage. Intraoperative blood loss will be quantified using a gravimetric method combined with suction measurements, while postoperative blood loss will be assessed via drain output. Perioperative monitoring will include vital signs, laboratory investigations, and clinical assessment for adverse events.

Safety monitoring will focus on drug-related side effects, hemodynamic changes, thromboembolic manifestations, and postoperative complications. The need for intraoperative or postoperative blood transfusion will be determined according to predefined clinical and laboratory criteria. Participants will be followed postoperatively until discharge and reassessed during early follow-up to ensure recovery and detect delayed complications.

The findings of this study are expected to provide evidence-based guidance on the optimal intramyometrial uterotonic agent for reducing blood loss during abdominal myomectomy, thereby improving surgical safety and patient outcomes in gynecologic practice.

Inclusion Criteria:

• Female participants aged 25 to 48 years
• Body mass index (BMI) < 35 kg/m²
• Symptomatic uterine fibroids requiring surgical management (e.g., abnormal uterine bleeding, pelvic pain, or pressure symptoms)
• Intramyometrial uterine myomas classified as FIGO types 3 to 6, diagnosed by transvaginal ultrasonography or magnetic resonance imaging
• Maximum diameter of the largest myoma ≤ 20 cm
• Eligible for and scheduled to undergo abdominal myomectomy
• Able and willing to provide written informed consent

Exclusion Criteria:

• FIGO type 0, 1, 2, 7, or 8 myomas (intracavitary, submucosal, pedunculated subserosal, cervical, or adnexal)
• History of pelvic inflammatory disease, peritonitis, or significant abdominal or pelvic infection
• History of prior uterine surgery
• Use of hormonal treatment within 3 months prior to enrollment
• Contraindication to methylergometrine or carbetocin, including:
• Known drug allergy
• Hypertension
• Cardiac or pulmonary disease
• Chronic endocrine or metabolic disease (e.g., diabetes mellitus)
• Renal or hepatic impairment
• High risk of bleeding, including:
• Known bleeding disorders
• Current use of antiplatelet or anticoagulant therapy
• Preoperative anemia (hemoglobin < 10 g/dL)
• BMI ≥ 35 kg/m²
• Intraoperative conversion from myomectomy to hysterectomy

This study is open to participants who self-identify as female, as the intervention is performed in individuals with a uterus undergoing abdominal myomectomy for uterine fibroids.

It is not yet determined whether de-identified individual participant data (IPD) will be shared. If sharing is approved, only de-identified IPD necessary to reproduce the primary analyses may be made available to qualified researchers, and results will also be reported in aggregate form in publications.