Embryo transfer: timing and techniques.

Since the first successful human in vitro fertilization (IVF) pregnancy nearly 40 years ago, remarkable progress has been made in assisted reproductive technology (ART). Improvements in oocyte retrieval, embryo culture, genetic screening, and embryo selection have contributed to dramatic improvements in IVF outcomes. A more robust understanding of embryologic development has driven innovation in not only the timing of embryo transfer but also the number of embryos to transfer. Additionally, overcoming the technical hurdle of embryo vitrification has given both physicians and patients several benefits including the flexibility to mitigate effects of superovulation on the endometrium, limit the number of embryos transferred, afforded an opportunity to screen the quality of embryos both by evaluating in vitro development as well as preimplantation genetic testing. Within this review, we highlight in a stepwise fashion the considerations for embryo transfer timing and technique that physicians and patients alike must consider when undergoing an IVF cycle.