The last three decades have seen considerable progress in the development of culture media for ART and infertility treatment. Basic research on the metabolism of mammalian preimplantation embryos demonstrated the specific needs in the evolving stage of the embryo growing in vitro. Two different philosophies led to two different culture strategies for human preimplantation embryos: the ‘back-to-nature’ or sequential culture principle, and ‘let-the-embryo-choose’ or one-step culture principle. Both systems are commercially available and the discussion between the different groups of scientists is ongoing. As a matter of fact, all ART culture media currently used are not optimal for the growing human preimplantation embryo. However, further research is needed to reduce stress to the human preimplantation embryo and determine how many embryos from a treatment cycle are capable of producing a live birth.

Keywords: Culture media, back-to-nature, ‘let-the-embryo-choose’, media components