Effects of Carrier's sex on the outcome of embryos and pregnancies in 412 couples undergoing preimplantation genetic testing for structural rearrangements.

Study Design: To ascertain whether the carrier's sex affects the outcome of embryos and pregnancies in couples undergoing preimplantation genetic testing for structural rearrangements (PGT-SR).

Methods: This retrospective study comprised 412 couples with reciprocal translocations (RecT), Robertsonian translocations (RobT), or inversions (INV) between January 2017 and October 2022. We applied next-generation sequencing (NGS) on 2588 embryos after trophectoderm (TE) biopsy.

Results: Genetically transferable blastocyst rate was higher in the male carrier group (34.0 % vs 31.7 %, P = 0.013) relative to the female carrier group whereas other embryo and pregnancy outcomes remained similar. Further analysis revealed that this result was primarily due to the alteration of segregation patterns in the RobT subgroup, in which the proportion of alternate segregation was higher (84.3 % vs 66.4 %, P < 0.001) in male carriers compared with female carriers. In the RecT subgroup, the genetically transferable blastocyst rate between male and female carriers was similar although the segregation models also changed, such that the frequency of the adjacent-1 segregation pattern was higher in male carriers than in female carriers (42.5 % vs 34.7 %, P = 0.002). In addition, interchromosomal effect (ICE) did not differ between male and female carriers although ICE was lower in male carriers of the RobT subgroup (pure ICE: 35.50 % vs 44.30 %, P = 0.14; total ICE: 35.50 % vs 40.30 %, P = 0.32) and higher in male carriers of the INV subgroup (pure ICE: 42.3 % vs 37.20 %, P = 0.33; total ICE: 40.90 % vs 36.00 %, P = 0.36).

Conclusions: The carrier's sex was closely associated with the genetically transferable embryo rate in couples undergoing PGT-SR, principally resulted from the change in segregation pattern in the RobT subgroup but not in the RecT and INV subgroups.