TITLE:
Embryo Survival after Vitrification in Different Ovulation Induction Protocols: A Randomized Prospective Study
AUTHORS:
Francesca Sciarra, Sofia Nardi, Michela Alessandri, Arianna Pacchiarotti
KEYWORDS:
Ovulation Induction Protocols, Vitrification, Embryo Survival
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.13 No.11,
November
5,
2025
ABSTRACT: Objective: To compare embryo quality and survival after vitrification using two different ovulation induction protocols—one based on highly purified human chorionic gonadotropin (HP-hCG) and the other on a gonadotropin-releasing hormone (GnRH) agonist (triptorelin)—regardless of the risk of ovarian hyperstimulation syndrome (OHSS). Materials and Methods: A prospective randomized study was conducted at the MAP Unit of San Filippo Neri Hospital, Rome, Italy, including 57 women undergoing frozen embryo transfer between January 2018 and March 2021. Participants were randomly assigned to receive ovulation induction with either 10,000 IU of HP-hCG or 0.2 mg/mL of triptorelin acetate. Oocytes were retrieved, fertilized via ICSI, cultured to the blastocyst stage, vitrified, and later thawed. Outcome measures included post-thaw embryo survival rate, number and maturity of retrieved oocytes, fertilization rate, blastulation rate, implantation rate, pregnancy rate, and miscarriage rate. Results: No significant difference was observed in post-thaw embryo survival between the two groups (HP-hCG: 90%; triptorelin: 91%). The HP-hCG group showed a significantly higher number of mature oocytes retrieved (p = 0.004). All other embryological and clinical parameters, including fertilization, blastulation, implantation, pregnancy, and miscarriage rates, were comparable between groups. Conclusion: Both ovulation induction protocols yielded similar embryo survival and clinical outcomes following vitrification and thawing. However, the use of HP-hCG resulted in a higher number of mature oocytes retrieved, suggesting it may be more advantageous for patients with a poor ovarian response. Conversely, triptorelin may be preferable for patients at risk of OHSS.