Higher chromosomal abnormality rate in blastocysts from young patients with idiopathic recurrent pregnancy loss

Objective: To determine whether the incidence of chromosomal abnormalities in blastocysts is higher in patients with idiopathic recurrent pregnancy loss (iRPL) who underwent preimplantation genetic testing for aneuploidy (PGT-A) than in those who underwent preimplantation genetic testing for monogenic defects (PGT-M). Design: Retrospective cohort study. Setting: University-affiliated reproductive center. Patient(s): A total of 62 patients with iRPL underwent 101 PGT-A cycles (iRPL group), and 212 patients underwent 311 PGT-M cycles (control group). Interventions(s): Blastocyst biopsy and comprehensive chromosome screening technologies, including single-nucleotide polymorphism microarrays and next-generation sequencing. Main Outcome Measure(s): Incidence of chromosomal abnormalities in blastocysts and clinical miscarriage (CM) rate. Result(s): Stratification analysis by maternal age showed an increased incidence of chromosomal abnormalities in the iRPL group aged <= 35 years (48.9% vs. 36.9%), whereas no significant increase was found in the iRPL group aged >35 years (66.9% vs. 61.4%). After transfer of euploid embryos, women aged <= 35 years with iRPL exhibited an increased CM rate compared with the control group (26.1% vs. 3.1%). Conclusion(s): Young patients with iRPL have a significantly higher rate of chromosomal abnormalities in blastocysts compared with patients with no or sporadic CM. Although euploid embryos were transferred after PGT-A, young patients with iRPL had a higher CM rate, which may indicate that chromosomal abnormalities might not be the only causal factor for iRPL. Therefore, the role of PGT-A in iRPL still needs to be clarified. (C) 2019 by American Society for Reproductive Medicine.