Parental balanced translocation carriers do not have decreased usable blastulation rates or live birth rates compared with infertile controls

Objective: To determine whether translocation carriers have a reduced number of usable blastocysts compared with infertile controls.

Design: Retrospective cohort study.

Setting: Single infertility practice.

Patient(s): All cycles of balanced translocation carriers undergoing in vitro fertilization with preimplantation genetic testing for structural rearrangements at a single infertility center compared with an age-matched control cycles of infertile patients undergoing preimplantation genetic testing for aneuploidy from January 2012 to August 2022.

Intervention(s): Balanced translocation carriers.

Main outcome measure(s): The primary outcome measures were blastulation rate, usable blastulation rates, and live birth rate (LBR). The secondary outcome measures were sustained implantation rate, fertilization rate, number of oocytes retrieved, number of metaphase II oocytes, total blastulation failure, number of 2-pronuclear embryos, and number of euploid embryos. Outcome measures were compared between male translocation carriers and controls, female translocation carriers and controls, and Robertsonian and reciprocal translocation carriers.

Result(s): A total of 1,291 retrieval cycles from 993 patients were included, of whom 255 patients were translocation carriers, whereas 738 were controls. Of those with translocations, 30 (11.5%) were Robertsonian carriers, and 231 (88.5%) were reciprocal carriers. There was a statistically significant difference in the blastulation rate between carriers and controls (59.5% vs. 62.1%). However, usable blastulation rates (47.2% vs. 50.0%) were equivalent between groups. There were no differences in the number of oocytes retrieved (18.5 vs. 18.3), number of 2-pronuclear embryos (13.4 vs. 12.5), sustained implantation rate (71.9% vs. 75.1%), or LBR (63.3% vs. 66.1%) between translocation carriers and controls. In both male and female translocation carriers vs. controls, there were no differences in usable blastulation rates or LBRs. When comparing Robertsonian with reciprocal translocation carriers, the rates of blastulation, usable blastulation, sustained implantation, and live birth were equivalent.

Conclusion(s): Despite fewer euploid embryos, there were no differences in the rates of usable blastulation or live birth in balanced translocation carriers, regardless of sex of affected partner or type of rearrangement, compared with controls. Routine karyotyping for blastulation failure may not be necessary on the basis of these findings.