Conventional in vitro fertilisation rather than intracytoplasmic sperm injection when only one oocyte is retrieved: Time to overcome irrational fears.

BACKGROUND: The use of intracytoplasmic sperm injection (ICSI) currently extends beyond male factor infertility, notably replacing conventional in vitro fertilisation (IVF) in scenarios like limited oocyte availability, where it is used as a precaution against complete fertilisation failure. While existing studies on the use of conventional IVF in such situations provide some reassurance, the available evidence is somewhat insufficient and ICSI is commonly used.

AIMS: To evaluate whether conventional IVF can be a feasible option when only one oocyte is retrieved.

MATERIALS AND METHODS: A retrospective study was performed to evaluate the fertilisation rate with conventional IVF in women retrieving only one oocyte and whose partner had normal semen. The study aimed at evaluating whether the fertilisation rate was aligned with the threshold indicated by recognized IVF laboratory performance indicators (Vienna Consensus). Clinical pregnancy and live birth rates were secondary outcomes.

RESULTS: Out of 304 cycles with a single oocyte inseminated with conventional IVF, 209 achieved normal fertilisation and 82 did not. Thirteen had no mature oocytes. The fertilisation rate was 69% (95% CI: 63-74%) and increased to 72% (95% CI: 66-77%) when immature oocytes were excluded. The fertilisation rate surpassed the minimum competency threshold of the Vienna Consensus (60%), even if below the benchmark value (75%). Clinical pregnancy and live birth rates per oocyte retrieval were 10% and 8%, respectively. Univariate and multivariate analyses failed to identify any predictive factor of fertilisation.

CONCLUSION: Conventional IVF with one oocyte met Vienna Consensus standards even if it fell short of higher benchmarks.