Purpose: Preimplantation genetic testing for aneuploidy (PGT-A) has become increasingly controversial since normal euploid births have been reported following transfer of embryos diagnosed as "abnormal." There is an increasing trend in transferring "abnormal" embryos; but it is still unknown how many IVF centers transfer "abnormal" embryos and with what efficiency.
Methods: We performed a worldwide web-survey of IVF centers to elucidate PGT-A related practice patterns including transfer of human embryos found "abnormal" by PGT-A. Participating centers reflected in vitro fertilization (IVF) cycles in the USA, Canada, Europe, Asia, South America, and Africa.
Results: One hundred fifty-one IVF centers completed the survey; 125 (83%) reported utilization of PGT-A. Europe had the highest utilization (32.3%), followed by the USA and Canada combined at 29.1%. The leading indications for PGT-A were advanced maternal age (77%), followed by recurrent implantation failure (70%), unexplained pregnancy loss (65%), and sex determination (25%); 14% of respondents used PGT-A for all of their IVF cycles; 20% of IVF units reported transfers of chromosomally "abnormal" embryos, and 56% of these took place in the USA, followed by Asia in 20%. Remarkably, 106 (49.3%) cycles resulted in ongoing pregnancies (n = 50) or live births (n = 56). Miscarriages were rare (n = 20; 9.3%).
Conclusions: The transfers of "abnormal" embryos by PGT-A offered robust pregnancy and live birth chances with low miscarriage rates. These data further strengthen the argument that PGT-A cannot reliably determine which embryos should or should not be transferred and leads to disposal of many normal embryos with excellent pregnancy potential.
Keywords: Aneuploidy; Embryo mosaicism; IVF; Pre-implantation genetic testing.