A Meta-Analysis of Outcomes in Rescue ICSI and IVM for Assisted Reproductive Technology (ART)
Presented as an oral session at ESHRE 2025 by Avenues Clinic
Rethinking How We Respond to Fertilisation Failure in IVF
Despite advances in embryology and ovarian stimulation, 5–15% of IVF cycles experience low oocyte maturation or complete fertilisation failure. For these patients, standard protocols may offer little hope.
Two strategies, rescue ICSI (intracytoplasmic sperm injection) and rescue IVM (in vitro maturation), have been proposed as salvage techniques. But until recently, routine use was limited by concerns around embryo quality, aneuploidy risk, and long-term outcomes.
This newly presented systematic review and meta-analysis provides timely evidence for their clinical impact, especially following the UK HFEA’s 2023 approval of rescue ICSI for routine use.
Study Summary: A 30-Year Review of Rescue IVM and Rescue ICSI
Objective
To evaluate whether rescue ICSI and IVM improve fertilisation, pregnancy, and live birth rates in ART — and whether they should be routinely offered in low-fertilisation cycles.
Design
- Systematic review and meta-analysis
- PRISMA-guided methodology
- 38 studies included (1992–2023)
- 24 rescue IVM (7,183 cycles)
- 14 rescue ICSI (2,475 cycles, 1,377 transfers)
Key Findings: Rescue Strategies Improve Clinical Outcomes
Rescue IVM (In Vitro Maturation)
- Maturation rates:
- 68% for GV-to-MII
- 57% for MI-to-MII
- Blastulation rates:
- 21% (MI-to-MII)
- 16% (GV-to-MII)
- Clinical pregnancy rate: 19% (MI-matured oocytes)
- Miscarriage rate: 67% in GV-MII cycles
- Frozen vs. fresh survival:
- Higher survival pre-vitrification (95%) vs. post (82%)
- Significant benefit for cycles with <9 mature eggs
- Clinical pregnancy: 56% vs. 47% (p<0.001)
- Live birth: 65% vs. 48% (p<0.001)
Rescue ICSI
- Fertilisation rate: 68%
- Clinical pregnancy rate: 45%
- Implantation rate: 30%
- Live births: 709 recorded
- Malformation rate: 0.3%
- Polyploidy rate: 6%
- No increase in adverse neonatal outcomes
Estimated national impact: Routine adoption could lead to 1,700+ additional live births annually in the UK alone.
Why This Matters: A Shift in ART Strategy
Low fertilisation or immature oocytes often lead to cycle cancellation — which is financially and emotionally costly for patients.
This analysis suggests that rescue IVM and ICSI offer a safe, effective alternative:
- Preventing total cycle failure
- Increasing the number of embryos available for transfer
- Improving live birth outcomes without increasing malformation risks
These interventions may especially benefit patients with low oocyte yield or poor fertilisation history.
Limitations and Caution
- Heterogeneity across study protocols and populations
- Suboptimal outcomes for GV-stage rescue IVM
- Long-term neonatal outcomes still under-studied
Further prospective trials are essential to guide embryo selection, refine culture conditions, and validate safety outcomes across diverse ART populations.
Conclusion: Time to Reconsider “Rescue” as Routine?
The findings presented at ESHRE 2025 support a shift toward proactive use of rescue IVM and ICSI in carefully selected IVF cycles.
Rather than a last resort, these approaches may soon become a standard part of ART strategy — improving embryo availability, boosting live birth rates, and reducing cancelled cycles for patients facing the steepest odds.