Potential Benefit of r-hLH Addition in Patients Aged 35 to 40 Under Ovarian Stimulation Treatment

This will be an exploratory, prospective, randomized, open-label and controlled trial to evaluate the potential benefit of r-hFSH:r-hLH 2:1 co-treatment starting from COS D1 versus r-hFSH alone in patients aged 35 to 40 under ovarian stimulation treatment.

After signing informed consent form (ICF), all eligible participants will be randomly assigned in a 1:1 ratio to either treatment or control group, and GnRH antagonist protocol will be used in both treatment and control groups.

1. Treatment group: The r-hFSH starting dose will be based on the patient's profile and physician's experience. r-hLH will be added at a ratio of 2:1 starting from day 1 of r-hFSH administration; the dose of r-hFSH during COS will be adjusted by the physician based on clinical experience and the patient's ovarian response, and the r-hFSH: r-hLH dose will be 2:1, continuing to 24\~48 hours prior to trigger drug injection. 2. Control group: r-hFSH alone will be administrated for ovarian stimulation. The r-hFSH starting dose will be based on the patient's profile and physician's experience. The dose of r-hFSH during COS will be adjusted by the physician based on clinical experience and the patient's ovarian response, continuing to 24\~48 hours prior to trigger drug injection.

The estimated treatment duration is 11 days from the first day of COS until 24\~48 h prior to trigger drug injection, and this may vary depending on individual circumstances.

Follicular development, serum E2 and P levels will be monitored during COS according to the investigator site's ART practice until the criteria to administer trigger drug are met to induce final oocyte maturation. Trigger drug administration is to be performed according to the site's routine clinical practice.

Oocyte pick-up (OPU), IVF/ICSI, ET, and luteal phase support (LPS) will be performed according to the site's routine practice. LPS will be started after oocyte retrieval in fresh embryo transfer.

• Number of oocytes [Срок оценки: 24 hours after Oocytes pick up]
• Number of MII oocytes (analyzed in ICSI subgroup only) [Срок оценки: 24 hours after Oocytes pick up]
• Total r-hFSH dose [Срок оценки: 24 hours after ovulation triggering]
• Fertilization rate [Срок оценки: 24 hours after fertilization]
• Blastocyst development rate [Срок оценки: 5 days after fertilization, up to 7 days]
• Utilizable embryo rate [Срок оценки: 5 days after fertilization, up to 7 days]
• Implantation rate [Срок оценки: At 4-6 weeks of amenorrhea after customized timing of embryo transfer]
• Clinical pregnancy rate (per transfer cycle and per oocyte retrieval cycle) [Срок оценки: At 4-6 weeks of amenorrhea after customized timing of embryo transfer]
• Ongoing pregnancy rate [Срок оценки: At 12 weeks of amenorrhea after customized timing of embryo transfer]
• Ovarian sensitivity index (OSI) [Срок оценки: 24 hours after fertilization]
• Follicular output rate (FORT) [Срок оценки: 24 hours after fertilization]
• Follicle oocyte index (FOI) [Срок оценки: 24 hours after fertilization]