Local experience with zona drilling, zona cutting and sperm microinjection

Area of Science:

• Reproductive Medicine
• Assisted Reproductive Technology
• Infertility Treatment

Background:

• Severe male infertility presents significant challenges in achieving conception.
• Previous assisted reproductive technologies like zona drilling (ZD) and zona cutting (ZC) showed limited success.
• The need for more effective sperm microinjection techniques was evident.

Purpose of the Study:

• To evaluate the efficacy of subzonal sperm microinjection (SZI) for treating severe male infertility.
• To compare the success rates of SZI against zona drilling (ZD) and zona cutting (ZC).
• To assess fertilization rates, embryo morphology, and pregnancy outcomes.

Main Methods:

• Clinical trials conducted between 1987 and 1992.
• Inclusion of zona drilling (ZD), zona cutting (ZC) with protocol modifications (oocyte shrinkage, Day 3 embryo transfer), and subzonal sperm microinjection (SZI).
• Evaluation of fertilization rates, embryo quality, clinical pregnancy rates, and implantation rates.

Main Results:

• Zona drilling (ZD) improved fertilization but resulted in poor embryo morphology and no pregnancies.
• Zona cutting (ZC) showed improvements with protocol modifications, but pregnancy rates remained low (16.6% per transfer).
• Subzonal sperm microinjection (SZI) achieved a 34.4% fertilization rate, a 30.8% clinical pregnancy rate per transfer, and an 18.4% implantation rate per embryo.

Conclusions:

• Subzonal sperm microinjection (SZI) is a successful and effective treatment for severe male infertility.
• SZI demonstrated superior clinical pregnancy and implantation rates compared to zona drilling (ZD) and zona cutting (ZC) under trial conditions.
• SZI represents a significant advancement in assisted reproductive technology for male factor infertility.