What oral GnRH antagonist regimen (dose, add‑back therapy, timing, and duration) should be used to shrink uterine fibroids before laparoscopic myomectomy?

Oral GnRH Antagonist Regimen for Preoperative Fibroid Reduction Before Laparoscopic Myomectomy

Administer relugolix 40 mg, elagolix, or linzagolix orally once daily for 12 weeks (3 months) before laparoscopic myomectomy, combined with low-dose estradiol/norethindrone acetate add-back therapy throughout the entire treatment course to mitigate hypoestrogenic side effects while achieving significant fibroid volume reduction and correcting anemia. 1

Specific Dosing and Duration

• Relugolix 40 mg orally once daily is the most studied oral GnRH antagonist for preoperative use, taken for 12 weeks up to the day before surgery. 2, 3
• Alternative oral GnRH antagonists include elagolix and linzagolix, which have demonstrated equivalent efficacy in reducing fibroid volume by 18–30% and controlling bleeding symptoms. 1, 4, 5
• The 3-month (12-week) preoperative course is the standard duration that balances maximal fibroid shrinkage with acceptable bone density effects when add-back therapy is used. 1, 2

Mandatory Add-Back Hormone Therapy

• Concurrent low-dose estradiol/norethindrone acetate (E2/NETA) add-back therapy must be initiated simultaneously with the GnRH antagonist to prevent severe hypoestrogenic symptoms (hot flashes, headaches, hypertension) and clinically significant bone mineral density loss. 1, 4
• GnRH antagonist monotherapy without add-back should never exceed 3–6 months due to unacceptable bone loss and intolerable vasomotor symptoms. 6
• The fixed-dose combination products (e.g., relugolix + estradiol + norethindrone as Myfembree) are FDA-approved and eliminate the risk of omitting add-back therapy. 7

Timing Relative to Surgery

• Begin oral GnRH antagonist therapy exactly 12 weeks before the planned laparoscopic myomectomy date. 2
• Continue daily dosing up to the day before surgery to maintain maximal fibroid volume reduction and minimize intraoperative blood loss. 2, 3
• Do not extend treatment beyond 12 weeks preoperatively unless there is a surgical delay, in which case continue add-back therapy to protect bone density. 6

Adjunctive Measures During Preoperative Treatment

• Start oral iron supplementation immediately when initiating GnRH antagonist therapy to correct anemia from chronic heavy menstrual bleeding before surgery. 7
• Add tranexamic acid (1300 mg orally three times daily during bleeding episodes) if breakthrough bleeding persists despite adequate GnRH antagonist therapy during the preoperative period. 1, 7, 6
• NSAIDs for 5–7 days during any breakthrough bleeding episodes provide analgesia and modestly reduce menstrual blood loss. 7, 6

Expected Outcomes and Monitoring

• Anticipate menstrual bleeding cessation within approximately 7 days of starting therapy, with rapid symptom control. 7
• Expect fibroid volume reduction of 18–30% after the 12-week preoperative course, which translates to reduced intraoperative blood loss, shorter operative time, and lower risk of postoperative anemia. 2, 4, 5
• Monitor hemoglobin levels at baseline and at 4–6 weeks to confirm anemia correction before proceeding with surgery. 7

Critical Pitfalls to Avoid

• Never use GnRH antagonist monotherapy without add-back for more than a few months, as this causes severe hypoestrogenic symptoms and significant bone mineral density loss that compromises patient safety. 1, 6
• Do not confuse oral GnRH antagonists with parenteral GnRH agonists (leuprolide); antagonists avoid the initial flare-up effect and have more rapid onset of action, making them preferable for preoperative use. 4, 3
• Counsel patients that fertility is suppressed during treatment, so contraception is not required, but normal reproductive function resumes after discontinuation. 1, 7
• Recognize that fibroid regrowth and symptom recurrence occur rapidly after stopping therapy, so surgery should be scheduled promptly after the 12-week course. 1, 6

Comparison to GnRH Agonists

• Oral relugolix 40 mg daily for 12 weeks produces equivalent uterine volume reduction and perioperative outcomes compared to leuprolide acetate 1.88–3.75 mg subcutaneous injection every 4 weeks for three doses. 2, 3
• Patient preference varies: some prefer daily oral medication to avoid injection pain, while others prefer monthly injections to avoid the burden of daily adherence. 3
• Both regimens require add-back therapy for courses longer than a few months. 1, 6