Does meiotic spindle normality predict improved blastocyst development, implantation and live birth rates?

Area of Science:

• Reproductive biology
• Embryology
• In vitro fertilization

Background:

• Oocyte spindle assessment is crucial for successful fertilization and embryo development.
• Intracytoplasmic sperm injection (ICSI) is a common assisted reproductive technology.
• Predicting oocyte quality is essential for optimizing IVF outcomes.

Purpose of the Study:

• To evaluate the correlation between meiotic spindle normality and blastocyst formation.
• To determine the relationship between spindle normality and implantation rates.
• To assess the impact of spindle normality on live birth rates following ICSI.

Main Methods:

• Prospective observational study involving 100 patients undergoing ICSI.
• Oocyte meiotic spindles were imaged using Oosight microscopy before ICSI.
• Spindle normality was assessed by two independent researchers; blastocyst quality was evaluated by blinded researchers.

Main Results:

• Of 711 oocytes with visible spindles, 29% had normal spindles (NS) and 71% had abnormal spindles (AS).
• Fertilization rates were significantly higher in NS oocytes.
• Implantation and live birth rates were higher for NS oocytes, and all ongoing pregnancies originated from NS oocytes.

Conclusions:

• Oocyte spindle assessment using polarized light microscopy is a valuable predictor of pregnancy potential.
• Abnormal spindle oocytes may form good-quality blastocysts but have a low likelihood of live birth.
• Spindle assessment can enhance embryo selection for single embryo transfer, improving IVF success rates.