Inclusion Criteria:

• Confirm diagnosis with adenomyosis by using transvaginal ultrasonography (MUSA consensus) and/or pelvic magnetic resonance imaging.
• Age between 18 - 42
• Undergo less or equal to three previous IVF cycles
• Indicate for frozen embryo transfer
• Agree to have not more than two day-3 embryo or one blastocyst (day-5 and day-6) transferred
• Not participating in any other study

Exclusion Criteria:

• Embryos from IVM cycle
• Having uterine or adnexal abnormalities (e.g., intrauterine adhesions, unicornuate/ bicornuate/ arcuate uterus; unremoved hydrosalpinx, endometrial polyp, submucosal leiomyoma, or leiomyoma with endometrial cavity distortion)
• Having contraindications for exogenous hormones administration: breast cancer, risks of venous thromboembolism
• Embryos from the oocyte donation cycle.
• Patients with a history of GnRH injection within three months, measured from the last GnRHa injection to the study screening date.