Embryonic development in human oocytes fertilized by split insemination

Area of Science:

• Reproductive medicine
• Embryology
• In vitro fertilization

Background:

• Poor prognosis in vitro fertilization (IVF) cycles present challenges for achieving successful outcomes.
• Conventional insemination and intracytoplasmic sperm injection (ICSI) are standard fertilization methods.
• Optimizing fertilization techniques is crucial for improving IVF success rates.

Purpose of the Study:

• To compare the laboratory outcomes of intracytoplasmic sperm injection (ICSI) versus conventional insemination.
• To evaluate fertilization rate and embryonic development in poor prognosis IVF cycles.
• To determine the efficacy of ICSI in specific IVF scenarios where it's not typically indicated.

Main Methods:

• Sibling oocytes were randomly assigned to either conventional insemination or ICSI.
• Patients undergoing IVF with specific poor prognosis criteria were included, excluding severe male factors.
• Key outcomes assessed included fertilization rate (FR), total fertilization failure, and embryonic development at days 3 and 5.

Main Results:

• Intracytoplasmic sperm injection (ICSI) demonstrated a significantly higher fertilization rate (90.5%) compared to conventional insemination (72.7%).
• The percentage of blastocysts developed by day 5 was significantly higher in the ICSI group (55.9%) than the conventional group (25.9%).
• While cleavage stage embryo development showed a marginal difference, blastocyst formation was notably improved with ICSI.

Conclusions:

• Intracytoplasmic sperm injection (ICSI) can significantly enhance fertilization rates and blastocyst development in specific poor prognosis IVF cycles.
• Tailoring the fertilization method to individual patient circumstances can lead to improved in vitro fertilization outcomes.
• These findings suggest a potential role for ICSI beyond severe male factor indications.