Complex chromosomal rearrangements induce embryonic chromosomal imbalance and significantly compromise reproductive outcomes

This study evaluated Preimplantation Genetic Testing for Structural Rearrangements (PGT‑SR) outcomes in carriers of complex chromosomal rearrangements (CCRs). Four CCR couples underwent PGT‑SR, and 20 karyotypically normal couples underwent Preimplantation Genetic Testing for Aneuploidy (PGT‑A) as controls. Embryo biopsies were analyzed by next‑generation sequencing (NGS), and Mapping Allele with Resolved Carrier Status (MaReCs) was used for breakpoint mapping. Literature data from 31 additional CCR carriers (222 embryos) were also summarized. Among the four CCR couples in this study, 14 blastocysts were biopsied. The high‑quality blastocyst rate (57.1%, 8/14) and euploidy rate (14.29%, 2/14) were significantly lower than in controls (71.5% and 42.37%, respectively; P < 0.05). In the literature cohort of 222 embryos, for CCR types A (three‑way), B (double two‑way), and C (exceptional), the high‑quality blastocyst rates (37.50%, 44.44%, and 32.91%) and chromosomal abnormality rates (86.25%, 92.06%, and 88.61%) showed no significant differences; the overall euploidy rate (11.26%) was significantly lower than that in the PGT‑A control group (42.37%, P < 0.001). In conclusion, CCR carriers show impaired embryonic potential and markedly lower euploidy rates. While Type B CCR embryos have good morphology, their genetic normality is extremely poor, ruling out morphology-only selection. Instead, PGT-SR combined with high-resolution breakpoint mapping is required to reliably identify viable embryos for healthy pregnancy.