The present study, titled “Comparison of Dienogest and Elagolix in Improving Endometriosis-Associated Pain and Quality of Life in Women with Endometriosis: An Open-Label, Double-Arm, Randomized Controlled Trial”, is designed as an open-label, double-arm, randomized controlled trial employing block randomization with variable block size and allocation concealment using sequentially numbered, opaque, sealed envelopes (SNOSE). The study will be conducted in the Department of Obstetrics & Gynaecology, AIIMS Patna, India.

Eligible participants will be Indian women aged 15–49 years diagnosed with endometriosis based on symptoms, clinical findings, and ultrasound, presenting with associated pain, planned for medical management, and having an endometrioma measuring less than 5 cm. Women with asymptomatic endometrioma larger than 5 cm, those planned for infertility treatment, cases of scar endometriosis, and women with contraindications to either study drug will be excluded.

A total of 80 participants will be recruited, with 40 in each arm. The sample size has been calculated assuming an effect size (Cohen’s d) of 0.6, with a 95% confidence interval, 80% power, and an additional 10% allowance for attrition. Participants in the control group will receive Dienogest 2 mg orally once daily for 90 days, while those in the intervention group will receive Elagolix 150 mg orally once daily for 90 days.

The primary outcome will be the change in endometriosis-associated pain at 3 months, measured using the Numerical Rating Scale (NRS). Secondary outcomes will include changes in quality of life at 3 months, assessed using the Endometriosis Health Profile-30 (EHP-30), and the side-effect profile of both drugs at 3 months. Data will be collected at baseline, 4 weeks, 8 weeks, and 12 weeks (±5 days).

Statistical analysis will include descriptive statistics, t-test, chi-square test, difference-in-difference analysis, and logistic regression to assess confounders and predictors, with statistical significance set at p less than 0.05. The study has received approval from the institutional ethics committee. Approval from the Drug Controller General of India (DCGI) is not required as both study drugs are already approved for this indication in India. Registration in the Clinical Trials Registry-India (CTRI) is planned.

The investigators hypothesize that Elagolix will provide greater pain relief and improved quality of life compared to Dienogest, with a more favorable side-effect profile.