[In vitro fertilization failures related to a sperm hyperactivation defect: indication for microinjection?]

Area of Science:

• Reproductive biology
• Human embryology
• Infertility research

Background:

• Sperm hyperactivation (HA) is a critical physiological process enabling sperm to penetrate the egg's outer layer, the zona pellucida.
• Understanding the correlation between sperm hyperactivation and fertilization rates is essential for diagnosing and treating male infertility.
• Previous research suggests a necessary role for hyperactivation in successful fertilization.

Purpose of the Study:

• To investigate the relationship between sperm hyperactivation rates and fertilization rates in in vitro fertilization (IVF) attempts.
• To identify potential thresholds of hyperactivation indicative of fertilization failure.
• To evaluate the efficacy of intracytoplasmic sperm injection (ICSI) for couples experiencing fertilization issues related to low hyperactivation.

Main Methods:

• Analysis of sperm samples from 114 in vitro fertilization (IVF) attempts.
• Assessment of sperm hyperactivation (HA) rates.
• Correlation analysis between HA rates and fertilization rates.
• Evaluation of fertilization outcomes following ICSI in cases with low HA.

Main Results:

• No significant correlation was found between overall sperm hyperactivation (HA) rates and fertilization rates in the studied IVF population.
• A high proportion of fertilization failures (16 out of 21) occurred in cases with low HA (<10%).
• For couples with low HA undergoing ICSI, fertilization rates (48%) were comparable to the general ICSI success rates in the group.

Conclusions:

• Sperm hyperactivation rate alone may not be a reliable predictor of IVF fertilization success.
• Low sperm hyperactivation (<10%) is strongly associated with fertilization failure.
• ICSI is an effective alternative for achieving fertilization in couples with low sperm hyperactivation.