Fresh versus frozen-thawed blastocyst transfer in high responders

Abstract

Objective: This study aimed to investigate and compare the pregnancy and live birth rates in IVF cycles of frozen-thawed embryo transfers and fresh embryo transfers in a group of women with a high risk of Ovarian hyperstimulation syndrome (OHSS).

Material and methods: The study group consisted of 254 women with a high level of response to controlled ovarian hyperstimulation. The patients who received fresh cycle embryo transfers with calcium infusions are referred to as the Fresh Ca+ group, and those without the calcium therapy are called the Fresh Ca- group; and we used correspondingly similar terminology for the Frozen group.

Results: We observed no statistically significant differences between the cycles of fresh and frozen-thawed embryo transfers in patients with a high risk of OHSS in terms of implantation, clinical pregnancy, and live birth rates. Furthermore, these implantation, clinical pregnancy and live birth rates were not different in the cycles with or without calcium treatment. There was no statistical difference in the OHSS rates between the fresh and frozen-thawed cycles; although, the OHSS rates were less in the two calcium infusion groups (Fresh Ca+ and Frozen-thawed Ca+) than in the without-calcium group. There was no OHSS development in the subjects of the Frozen-thawed Ca+ group.

Conclusion: Our study results suggest that fresh and frozen-thawed embryo transfers have similar IVF results in patients with a high risk of OHSS. Calcium infusion is beneficial in preventing OHSS without altering pregnancy rates. Both IVF protocols with calcium infusion can safely be applied in high-responder patients without lowering success rates.

Keywords: OHSS; blastocyst transfer; fresh cycle; high responder; thaw.