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Round Spermatid Injection (ROSI) as a Last Resort in High-Risk Azoospermia: Chain of Outcome Metrics and Real-World
Ümran Karabulut Doğan1, Erhan Hüseyin Cömert2, Tuğçe Baykara3
1Department of Obstetrics and Gynecology, Acıbadem Kayseri Hospital, Melikgazi 38140, Kayseri, Turkey.
Journal of Clinical Medicine
|April 14, 2026
Summary
Round spermatid injection (ROSI) has very low feasibility and effectiveness in routine practice for male infertility. Most cycles do not reach procedural feasibility, limiting overall success rates and reliable safety assessments.
Area of Science:
- Reproductive Medicine
- Infertility Treatment
- Assisted Reproductive Technology
Background:
- Round spermatid injection (ROSI) is an experimental option for severe male factor infertility when mature sperm are unavailable.
- Identifying critical constraints in the ROSI procedure is crucial for improving success rates.
- Assessing the safety profile of ROSI in clinical practice is essential.
Purpose of the Study:
- To determine the stage that most limits overall success in routine Round Spermatid Injection (ROSI) cycles.
- To evaluate the safety signal associated with ROSI procedures.
- To analyze outcomes using a chain-of-outcome framework.
Main Methods:
- Retrospective single-center cohort study of 221 ROSI-evaluated cycles (2021-2024).
- Analysis of outcomes including cycle feasibility, fertilization (2PN), blastocyst development, embryo transfer, and clinical pregnancy.
- Use of a chain-of-outcome framework with explicit denominators and exact confidence intervals.
Main Results:
- ROSI feasibility was low, observed in only 2.3% of initiated cycles.
- Clinical pregnancy occurred in 80% of the few (n=5) cycles reaching transfer, but overall pregnancy rate was 1.8% per initiated cycle.
- High early attrition and small denominators limited the precision of downstream outcome and safety assessments.
Conclusions:
- Overall effectiveness of ROSI is limited by very low procedural feasibility and substantial early attrition.
- Downstream outcomes appear favorable only in a small subset of cycles that reach fertilization and transfer.
- Safety inference remains imprecise due to small sample sizes, highlighting the instability of conditional estimates.
