Assisted hatching improves implantation rates on cryopreserved-thawed embryos. A randomized prospective study.

Area of Science:

• Reproductive Medicine
• Embryology
• In Vitro Fertilization

Background:

• Cryopreserved-thawed embryos exhibit lower pregnancy rates than fresh embryos.
• Zona pellucida hardening in cryopreserved embryos may impede implantation.
• Limited research exists on assisted hatching for cryopreserved embryos.

Purpose of the Study:

• To evaluate the efficacy of assisted hatching on the implantation rate of cryopreserved-thawed day 2 embryos.
• To determine if acidic Tyrode's solution improves outcomes in assisted hatching procedures.
• To compare implantation and pregnancy rates between assisted hatching and control groups.

Main Methods:

• A prospective randomized study involving 253 cryopreserved-thawed embryo cycles.
• Embryos were assigned to assisted hatching or a control group using pseudorandomization.
• Assisted hatching was performed using acidic Tyrode's solution one hour before embryo transfer.

Main Results:

• The implantation rate was significantly higher in the assisted hatching group (11.4%) compared to the control group (5.8%) (P<0.05).
• No significant difference was observed in clinical pregnancy or positive serum HCG rates between the groups.
• Age did not show a significant impact on outcomes, though few women over 38 were included.

Conclusions:

• Assisted hatching with acidic Tyrode's solution effectively increases the implantation rate of cryopreserved-thawed embryos.
• This method presents a viable strategy to improve IVF success with cryopreserved embryos.
• Further research may explore optimal application across different patient demographics.