Chemical zona pellucida thinning with acidified Tyrode's solution: comparison between partial and circumferential...

Area of Science:

• Reproductive Medicine
• Embryology
• Assisted Reproductive Technology

Background:

• Repeated in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) failures can be attributed to various factors, including challenges with embryo implantation.
• Assisted hatching (AH) techniques aim to improve implantation rates by thinning the zona pellucida, the outer shell of the embryo.
• Chemical zona thinning using acidified Tyrode's solution is one method employed in AH.

Purpose of the Study:

• To compare the effectiveness of two chemical zona thinning techniques: partial thinning and circumferential thinning.
• To evaluate the impact of these techniques on implantation and clinical pregnancy rates in patients with a history of IVF/ICSI failure.

Main Methods:

• A study involving 163 patients with at least two previous IVF/ICSI failures.
• Patients were divided into three groups: zona intact (control), partial zona thinning, and circumferential zona thinning.
• Embryos underwent zona thinning using acidified Tyrode's solution prior to transfer.

Main Results:

• The partial thinning group showed significantly higher implantation rates (17.6%) and clinical pregnancy rates (32.2%) compared to the zona intact group (8.9% implantation, 16.7% pregnancy).
• The circumferential thinning group had implantation rates of 11.9% and clinical pregnancy rates of 27.4%, which were not significantly different from the zona intact group.
• Partial zona thinning demonstrated superior outcomes in improving pregnancy success post-embryo transfer.

Conclusions:

• Partial chemical zona thinning is a more effective assisted hatching technique than circumferential thinning for patients experiencing recurrent IVF/ICSI failure.
• This method offers a promising approach to enhance implantation and pregnancy success rates in challenging cases of infertility treatment.