The goal of this investigator-initiated single-site clinical trial is to compare the overall quality of life of participants taking Relugolix combination therapy (Rel-CT) following excisional surgery for endometriosis to participants that do not take Rel-CT following the same surgery. Rel-CT is an FDA approved form of medical treatment for endometriosis. It is known to work in treating endometriosis pain. However, investigators do not know whether or not there is a benefit to beginning Rel-CT immediately following surgery. This study will test if patients who take Rel-CT after surgery have better quality of life and less chance the endometriosis comes back, requiring additional surgery.

The main question it aims to answer is:

- Does taking Rel-CT following excisional surgery for endometriosis result in higher Endometriosis Health Profile 30 (EHP-30) scores, indicating a positive impact on overall health-related quality of life and well-being?

Participants will:

• Be randomly assigned to one of two treatment groups. One treatment group will take study drug Rel-CT after having excisional surgery, and the other treatment group will just have the surgery alone.
• Be asked to complete questionnaires, called the Endometriosis Health Profile 30 (EHP-30) at 4 timepoints. The first time is before surgery, then at follow-up visits at 1 month, 3 months, and 6 months. The survey has 30 questions that ask about pain, control, powerlessness, emotional well-being, social support, and self-image.

Researchers will compare the two treatment groups (Rel-CT and non Rel-CT) to see if there is a change in EHP-30 scores.

The design of this study will be an unblinded randomized controlled trial of medical suppression with once daily Relugolix combination therapy (Rel-CT) following excisional surgery for endometriosis performed by high volume minimally invasive gynecologic surgeons. Women over the age of 18 scheduled to undergo a laparoscopic surgery for endometriosis will be screened and if agree and consented to participate will be randomized to either Rel-CT following surgery or no post-operative hormonal suppression using a block randomization with blocks 2 and 4. The surgeon will not have access to the randomization schedule to reduce selection bias. Inclusion criteria will include: 1) Patients over the age of 18 planning to undergo an elective laparoscopic/robotic procedure for known or suspected endometriosis. Exclusion criteria will include: 1) Patients with known contraindications to REL-CT; 2) Any form of hormonal suppression of endometriosis within the protocol guidelines; 3) Primary language other than English/Spanish; 4) Patients without histologic evidence of endometriosis following their surgical procedure; 5) Patients interested in pregnancy within the 12 months following their surgical procedure.

The primary outcome will be change in Endometriosis Health Profile 30 (EHP-30) score. A preoperative EHP-30 will be completed by all patients enrolled in the study within 4 weeks of their scheduled surgical procedure and then again postoperatively at 1 month, 3 months, and 6 months. Investigators expect that postoperative use of REL-CT will lead to a clinically meaningful improvement in EHP-30 scores compared to surgery alone. In addition, investigators will gather data on our secondary outcomes: These data could be very helpful in informing providers and patients of the utility of medical suppression of endometriosis using REL-CT following surgery.

Inclusion criteria

• Age ≥ 18 years
• Planning to undergo an elective laparoscopic or robotic procedure for known or suspected endometriosis

Exclusion criteria

-A known contraindication to REL-CT. Contraindications include:

• High risk of arterial, venous thrombotic, or thromboembolic disorder
• Pregnancy Known osteoporosis
• Current or history of breast cancer or other hormone-sensitive malignancies
• Known hepatic impairment or disease
• Undiagnosed abnormal uterine bleeding
• Known hypersensitivity to components of Rel-CT
• The patient did not discontinue hormonal suppression within the required timeline:

Trans-Dermal, Oral Medication, Patch, or Vaginal Ring: day before surgery

Intrauterine Device or Sub-Dermal Implant: removed at surgery

Injectable Medication: at least 12 weeks before surgery

• Primary language other than English/Spanish
• Interested in pregnancy within the 6 months following the surgical procedure.
• If pregnancy test performed during pre-surgical work up is positive, the patient will no longer be a candidate for endometriosis surgery and will therefore not be eligible for the study.
• Patients without histologic evidence of endometriosis following their surgical procedure will be removed from the study prior to receiving the study intervention.
• Patients who undergo a surgical intervention more invasive than the planned laparoscopic or robotic excisional surgery, such as open abdominal surgical repair, will be removed from the study prior to receiving the study intervention.

biological female at birth and meeting criteria for endometriosis

Participants and providers will know if participants are assigned to the treatment arm to take Rel-CT or not.