When less really is more: reducing embryo manipulation to lower metabolic stress and improving long term outcomes.

The use of assisted reproductive technologies (ARTs) to treat human infertility has increased exponentially in recent years. In addition to improved access to care for infertile patients, there is a significant increase in ART utilization in individuals without infertility, who electively chose to freeze their gametes and embryos for future use. Importantly, the number of procedures performed on eggs (egg freezing and thawing, increase in intracytoplasmic sperm injection (ICSI) utilization) and embryo (embryo biopsy for preimplantation genetic testing (PGT), freezing and thawing) has also increased over time. Here we review the laboratory animal evidence indicating how an increase in the number of procedures performed may be associated with increase in embryonic stress, altered in utero growth and possible neonatal and long-term consequences. These data suggest that minimizing the number of gamete and embryo procedures to the minimum required is a wise approach, while waiting for human data to provide further guidance.