Ovarian stimulation, laboratory techniques, and embryo transfer

Ovarian stimulation protocols were chosen by the treating physician based on age, ovarian reserve, and semen parameters. All patients received injectable gonadotropins: FSH and/or human menopausal gonadotropin (HMG). One of three ovarian stimulation protocol types were employed: gonadotropin-releasing hormone (GnRH) antagonist, GnRH antagonist with clomiphene citrate, or microdose leuprolide acetate. Oocyte retrieval was performed via ultrasound-guided transvaginal aspiration 35 hours after trigger administration.

In IVF and embryo banking cycles, conventional insemination was used for all cycles, which is standard in our lab, except where intracytoplasmic sperm injection (ICSI) was indicated based on semen parameters or male history. Embryos were then cultured until fresh transfer, trophectoderm biopsy for PGT-A, or cryopreservation based on patient preference and physician orders.

In oocyte cryopreservation cycles, oocytes were vitrified, thawed, and fertilized with ICSI using techniques previously described by our group [20, 21]. Embryos were then cultured until transfer, trophectoderm biopsy for PGT-A, or cryopreservation based on patient preference and physician orders.

Embryo transfer protocols were chosen by the treating physician. A programmed or hormone-replaced embryo transfer protocol was used for patients who underwent fresh embryo transfer. A programmed, natural cycle, or modified natural cycle (with letrozole, clomiphene citrate, or gonadotropins) embryo transfer protocol was used for patients who underwent frozen embryo transfer.