In the second cycle, a prolonged 5-month suppression led to a significant reduction of the uterine size, lower serum estradiol levels, and optimal endometrial preparation, achieving an ongoing pregnancy and delivery of a healthy baby at 36 weeks of gestation.<h4>Conclusion</h4>This case supports the potential benefit of extended GnRH-a and letrozole suppression with intensive luteal phase support for patients with severe adenomyosis, suggesting that individualized protocols may be beneficial and warrant further investigation in similar complex cases. Here, GNRH1 is linked to adenomyosis.