Live Birth After Letrozole-stimulated Cycles Versus Hormone Replacement Treatment Cycles for the First Frozen Embryo Transfer in Women With PCOS

Live Birth After Letrozole-stimulated Cycles Versus Hormone Replacement Treatment Cycles for the First Frozen Embryo Transfer in Women With PCOS: a Randomized Controlled Trial

This is a multicenter randomized controlled trial comparing the efficacy and safety of two endometrial preparation protocols for the first frozen embryo transfer cycle in PCOS with whole embryo freezing. Subjects will be randomized to letrozole-stimulated group or hormone replacement treatment group in their first frozen embryo transfer cycle, and their pregnancy and perinatal outcomes during this cycle will be followed up and analysis.

Inclusion Criteria:

• 1. women diagnosed with PCOS according to modified Rotterdam criteria;
• 2. Women who are participating in their first cycle of IVF or ICSI.
• 3. Women whose IVF/ICSI ovarian stimulation protocol was either GnRH antagonist protocol or long agonist protocol.
• 4. Women with whole embryos freezing.
• 5. Women aged 20 to 38 years old;
• 6. Women BMI 18 kg/m2 to 30 kg/m2
• 7. Women with at least one good-quality embryo suitable for transfer, including day 3 cleavage stage embryo with grade 7CI /8CI and day 5 or day 6 blastocyst with grade 4BB or higher.

Exclusion Criteria:

• 1. Women who has a history of recurrent spontaneous abortion.
• 2. Women with unilateral/bilateral oophorectomy.
• 3. Women with untreated Hydrosalpinx.
• 4. Women with a uterine cavity abnormality, such as a uterine congenital malformation, untreated uterine septum (except shallow uterine septum), adenomyosis, submucous myoma, or moderate to severe intrauterine adhesions.
• 5. Women with uncontrolled diabetes mellitus, thyroid disease and hypertension.
• 6. Women who are indicated and planned to undergo preimplantation genetic test (PGT).