The culture media used in in vitro fertilisation may have a significant effect on the success of the procedure and the health outcomes of the foetuses, researchers say today.
In its early days, salt solutions were used for in vitro fertilisation culture media, but this soon progressed into more complex solutions.
Today, commercially available culture media are usually chosen. Some are fairly simple, containing eight to ten different salts and sugars, while others have up to 80 ingredients including amino acids, lipids, vitamins, trace ions and bioactive molecules such as hormones and expression modulators.
These currently available commercial culture media "show high degrees of variability", says Dr Hans Evers, editor of Human Reproduction.
In the journal today (24 August), Dr Evers states that it is difficult to link specific culture medium ingredients to outcomes, as their composition is often unclear. He believes that the complete formulation of culture media should be disclosed.
Also in the journal is a report of the first ever randomised controlled trial comparing two different culture media known as HTF and G5.
Dr Sander Kleijkers of Maastricht University Medical Centre, The Netherlands, and colleagues analysed information on 836 couples.
Live birth rates were not significantly different, but number of utilizable embryos per cycle, implantation rate and clinical pregnancy rate were significantly higher for the G5 group. However, birthweight was significantly lower in the G5 group, and more singletons were born preterm in this group.
"The effect of other culture media on perinatal outcome remains to be determined," write the team.
They conclude: "This suggests that the millions of human embryos that are cultured in vitro each year are sensitive to their environment. These findings should lead to increased awareness, mechanistic studies and legislative adaptations to protect offspring during the first few days of their existence."
Kleijkers, S. H. M. et al. Influence of embryo culture medium (G5 and HTF) on pregnancy and perinatal outcome after IVF: a multicenter RCT. Human Reproduction 24 August 2016 doi:10.1093/humrep/dew156
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