Focus on intracytoplasmic morphologically selected sperm injection (IMSI): a mini-review.

Area of Science:

• Reproductive Medicine
• Andrology
• Embryology

Background:

• Male-factor infertility often necessitates assisted reproductive technologies like intracytoplasmic sperm injection (ICSI).
• Standard ICSI relies on light microscopy for sperm selection, potentially overlooking ultrastructural defects impacting fertilization and development.
• Severe sperm head abnormalities are linked to reduced fertilization, implantation, and pregnancy rates.

Purpose of the Study:

• To review the theoretical basis and clinical outcomes of intracytoplasmic morphologically selected sperm injection (IMSI).
• To evaluate the impact of IMSI on sperm selection and assisted reproductive technology success rates.
• To highlight the need for standardized indications and further research into IMSI's efficacy.

Main Methods:

• Literature review of studies investigating the theoretical basis and clinical outcomes of IMSI.
• Analysis of sperm selection processes at high magnification (×6000) during IMSI.
• Comparison of IMSI outcomes with conventional ICSI based on available reports.

Main Results:

• IMSI allows for superior assessment of sperm nuclear morphology compared to standard ICSI.
• Several reports indicate that IMSI is associated with improved implantation and clinical pregnancy rates.
• Lower abortion rates have been observed in studies utilizing IMSI compared to ICSI.
• Conflicting results exist regarding the correlation between abnormal sperm nucleus shape, DNA fragmentation, and clinical outcomes.

Conclusions:

• IMSI represents an advancement in sperm selection for assisted reproduction, potentially improving outcomes in male infertility.
• Standardized clinical indications for IMSI are currently lacking, necessitating further prospective randomized studies.
• While promising, the definitive advantages of IMSI in specific patient groups require confirmation through rigorous research.