IVF embryo choices and pregnancy outcomes.

Abstract

Investigate the chromosome status and transfer outcomes of embryos selected using routine "best morphology" IVF practices. A prospective multi-center, non-selection cohort study involving patients undertaking IVF treatment. Study entry conditions were blastocyst biopsy, >1 embryo with chromosome analysis and frozen transfer of the best morphology embryo. Primary analyses were βhCG positive, implantation, ongoing pregnancy and birth rates and pregnancy-stage progression failures. After transfer, embryo chromosome status was assigned and outcomes divided into two primary groups - euploids (n=135) and aneuploids (n=53). Compared to euploid embryo transfers, aneuploid embryos had significantly lower primary outcomes (+βhCG: 67% vs. 30%, p<0.0001; IR: 56% vs. 19%, p<0.0001; ongoing week 12: 51% vs. 9%, p<0.0001; and livebirths: 50% vs. 8%, p<0.0001, respectively). Transfers were further subdivided into smaller groups according to their main chromosomal feature. Stage analysis showed higher failure rates for aneuploids to initiate a pregnancy (p<0.0001), higher subclinical miscarriage rate (p=0.0402) and higher clinical miscarriage rate (p=0.0038). Routine morphology-based embryo selection resulted in a high euploid selection rate but a significant number of aneuploid embryos were still inadvertently selected for transfer (28%) with the subsequent high failure rates for pregnancy initiation and progression having implications for appropriate patient management.