Time to take human embryo culture seriously.

STUDY QUESTION: Is it important that end-users know the composition of human embryo culture media? SUMMARY ANSWER: We argue that there is as strong case for full transparency concerning the composition of embryo culture media intended for human use. WHAT IS KNOWN ALREADY: Published data suggest that the composition of embryo culture media may influence the phenotype of the offspring. STUDY DESIGN, SIZE, DURATION: A review of the literature was carried out. PARTICIPANTS/MATERIALS, SETTING,
METHODS: Data concerning the potential effects on embryo development of culture media were assessed and recommendations for users made. MAIN RESULTS AND THE ROLE OF CHANCE: The safety of ART procedures, especially with respect to the health of the offspring, is of major importance. There are reports from the literature indicating a possible effect of culture conditions, including culture media, on embryo and fetal development. Since the introduction of commercially available culture media, there has been a rapid development of different formulations, often not fully documented, disclosed or justified. There is now evidence that the environment the early embryo is exposed to can cause reprogramming of embryonic growth leading to alterations in fetal growth trajectory, birthweight, childhood growth and long-term disease including Type II diabetes and cardiovascular problems. The mechanism for this is likely to be epigenetic changes during the preimplantation period of development. In the present paper the ESHRE working group on culture media summarizes the present knowledge of potential effects on embryo development related to culture media, and makes recommendations. LIMITATIONS, REASONS FOR CAUTION: There is still a need for large prospective randomized trials to further elucidate the link between the composition of embryo culture media used and the phenotype of the offspring. We do not presently know if the phenotypic changes induced by in vitro embryo culture represent a problem for long-term health of the offspring. WIDER IMPLICATIONS OF THE
FINDINGS: Published data indicate that there is a strong case for demanding full transparency concerning the compositions of and the scientific rationale behind the composition of embryo culture media. STUDY FUNDING/COMPETING INTERESTS: This work was funded by The European Society for Human Reproduction and Embryology. No competing interests to declare.