Hormone-free Antral Retrieval for Viable Embryo Storage & Transfer

This is a single-arm, prospective, open-label, adaptive pilot study designed to evaluate the feasibility of serial unstimulated transvaginal oocyte retrieval followed by CAPA-IVM for euploid embryo accumulation in infertility patients with robust ovarian reserve.

Approximately 30 participants will be enrolled. Participants will undergo serial unstimulated transvaginal oocyte retrieval procedures targeting visible 4-9 mm antral follicles. Retrieved cumulus-oocyte complexes will undergo CAPA-IVM, followed by intracytoplasmic sperm injection, blastocyst culture, preimplantation genetic testing for aneuploidy, and embryo vitrification/accumulation. Euploid embryos generated across retrievals will be accumulated for subsequent single euploid embryo transfer according to the protocol and site clinical practice.

The study will be conducted in two stages. Stage 1 will enroll approximately 10 participants using initially defined serial retrieval timing to evaluate feasibility, safety, follicle availability, and retrieval interval optimization. Following review of Stage 1 safety, feasibility, follicle emergence, and endocrine data, Stage 2 will enroll approximately 20 additional participants. Retrieval intervals in Stage 2 may be adjusted if supported by interim findings.

The study will summarize retrieval-specific and participant-level outcomes, including follicle counts, oocyte yield, oocyte maturation, fertilization, blastocyst development, PGT-A results, euploid embryo yield, embryo accumulation, and progression to single euploid embryo transfer. Safety and tolerability will be assessed throughout the study, including procedure-related complications, anesthesia/sedation-related events, antibiotic-related reactions, retrieval deferrals or discontinuations, and other adverse events.

Inclusion criteria

• Signed informed consent.
• Female participant aged 18-35 years.
• Diagnosis of infertility requiring IVF/ICSI, including unexplained infertility or mild male factor infertility.
• BMI 18-30 kg/m².
• AMH ≥2.5 ng/mL.
• AFC ≥12.
• Basal FSH <8 IU/L.
• Ovaries accessible for transvaginal retrieval.
• Willing to undergo serial unstimulated TVORs with adaptive retrieval timing.
• Willing to undergo CAPA-IVM, ICSI, blastocyst culture, PGT-A, embryo vitrification/accumulation, and single euploid embryo transfer.
• Willing to undergo serial ultrasound and endocrine monitoring.
• Willing and able to comply with study procedures and follow-up.

Exclusion criteria

• Prior ovarian surgery.
• Ovarian endometrioma.
• Inaccessible ovaries.
• Significant uterine factor expected to compromise implantation, pregnancy, or live birth.
• Significant medical comorbidity that would increase risk of TVOR, pregnancy, or study participation.
• AMH <2.5 ng/mL.
• AFC <12.
• Basal FSH ≥8 IU/L.
• BMI <18 or >30 kg/m².
• Current smoking or nicotine use within 3 months of screening.
• Active pelvic infection, untreated STI, or acute urinary tract infection.
• Contraindication to transvaginal oocyte retrieval, anesthesia/sedation, pregnancy, or antibiotic prophylaxis.
• Known chromosomal abnormality in the participant or sperm source that would confound study outcome assessment.
• Severe male factor infertility requiring surgical sperm retrieval, unless specifically permitted by the final protocol.
• Recent exposure to teratogenic radiation, drugs, or toxins.
• Current participation in another interventional clinical trial that may confound outcomes.
• Previous participation in the CARE study.