Mosaic embryo transfer versus euploid embryo transfer after PGT-A: a systematic review and meta-analysis.
Ignacio Cristóbal Quevedo, Ignacio Cristóbal Garcia
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In 30 seconds
This systematic review and meta-analysis compared reproductive outcomes after mosaic versus euploid embryo transfer following PGT-A, pooling eight studies with 1904 mosaic and 9332 euploid transfers. Overall, mosaic transfers had a lower pooled live birth and ongoing pregnancy rate (RR 0.74, 95% CI 0.64 to 0.85), although results were heterogeneous and the prediction interval included no difference. A prospective double-blind trial found equivalent outcomes when embryo classification was concealed. Outcomes varied by aneuploidy type and complexity: segmentary mosaicism approached euploid outcomes, while whole-chromosome and more complex mosaicism had poorer results.
Key findings
- Pooled live birth and ongoing pregnancy rate was lower after mosaic transfer (RR 0.74, 95% CI 0.64 to 0.85; I² = 78%; 95% prediction interval: 0.41 to 1.34).
- Miscarriage was more frequent in the pooled analysis after mosaic transfer (RR 1.57, 95% CI 1.05 to 2.35; I² = 72%).
- Segmentary mosaicism approached euploid outcomes (RR 0.90, 95% CI 0.81 to 1.00), whereas whole-chromosome mosaicism had poorer outcomes (RR 0.60, 95% CI 0.53 to 0.68; interaction P < 0.001).
- A prospective double-blind trial found equivalent outcomes across mosaic grades when embryo classification was concealed (RR 0.98; non-inferiority confirmed).
Why it matters
The pooled results suggest that reproductive potential after mosaic embryo transfer is not uniform: aneuploidy type and chromosomal complexity are associated with differing outcomes. However, the concealed-classification trial raises the possibility that selection practices or other confounding contribute to observed differences. These findings help frame counselling and embryo prioritization while underscoring uncertainty in comparisons with euploid transfers.
What to keep in mind
The pooled evidence was heterogeneous, and the prediction interval for the primary outcome included no difference. Obstetric and perinatal outcomes were supported by low or very low certainty evidence.