Experts have been divided over whether the culture media in which eggs are fertilized during in vitro fertilization (IVF) have lasting impacts on embryonic development. In a paper published in Human Reproduction this week (August 23), researchers from the Maastricht University Medical Center in the Netherlands and their colleagues detail the first randomized controlled trial to compare two IVF culture media, finding that one of the preparations created more viable embryos and higher fertility rates than the other. Babies born using this culture also weighed about a third of a pound less, the team found. “It’s reasonable to believe that different media compositions can affect embryo development,” David Ball, an embryology lab director in Seattle who was not involved in the trial, told STAT News.
The clinics involved in the study stopped using the culture shown to produce fewer viable embryos, STAT reported, but the study only compared two of the roughly 20 IVF culture media commercially available.
The difficulty clinics face in choosing IVF media is bolstered by the fact that companies that produce cultures are not required to list the exact compositions of their products. The labels on culture media give ingredients without exact proportions, the researchers noted in their paper. Now that it’s known that this substrate can affect fertility and offspring health, “not knowing the exact composition of their IVF culture media is no longer an option for clinical embryologists,” Hans Evers, editor in chief of Human Reproduction, wrote in an accompanying editorial.