Embryo selection versus natural selection: how do outcomes of comprehensive chromosome screening of blastocysts compare with the analysis of products of conception from early pregnancy loss (dilation and curettage) among an assisted reproductive technology population?

OBJECTIVE To compare the incidence of numerical chromosomal abnormalities (NCAs) reported after preimplantation genetic screening (PGS) analysis compared with that reported after cytogenetic analysis of products of conception after spontaneous abortion. DESIGN Retrospective study. SETTING Private academic in vitro fertilization center. PATIENT(S) Cytogenetic reports of patients who underwent an IVF cycle with PGS of at least one biopsied embryo were compared with cytogenetic analysis reported from patients who had dilation and curettage (D&C) for the treatment of a spontaneous abortion after assisted reproductive technology (ART) treatment. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Frequencies for each numerical chromosomal abnormality from both groups were compared. RESULT(S) A total of 1,069 NCAs were reported after PGS (trisomy 54.3%, monosomy 45.7%, no polyploidies), resulting in a trisomy/monosomy ratio of 0.82. A total of 447 NCAs was reported after D&C (trisomy 83%, polyploidy 10.7%, monosomy 6.3%). The aneuploidies most frequently identified were similar in both groups and included 15, 16, 18, 21, and 22. Monosomies (n = 28, 6.3%) were rarely observed in the group that underwent D&C after ART. CONCLUSION(S) This review provides an analysis of the most commonly identified NCAs after PGS and in first-trimester D&C samples in an infertile population utilizing ART. Although monosomies comprised >50% of all cytogenetic anomalies identified after PGS, there were very few identified in the post-D&C samples. This suggests that although monosomies occur frequently in the IVF population, they commonly do not implant. Despite this difference, this study demonstrated that the specific NCAs observed after PGS analysis and D&C were comparable.