IVF Culture Media Affects Embryo Outcomes

The composition of laboratory cultures used during in vitro fertilization (IVF) affects the resulting embryos and babies, according to a new study.

Researchers at Maastricht University Medical Center (MUMC; The Netherlands), Radboud University Nijmegen Medical Centre (Nijmegen, the Netherlands), and other institutions conducted a multicenter, double-blind randomized controlled trial in 836 couples scheduled for an IVF or an intracytoplasmic sperm injection (ICSI) treatment at one of the six participating centers in the Netherlands between July 2010 and May 2012. The researchers compared the use of human tubal fluid (HTF; 419 couples) or G5 (417 couples) as embryo culture media in IVF. The primary outcome was live birth rate.


In all, 383 babies were born alive, of which 300 were singletons and 80 were twins. Birth weight was lower in the G5 group than the HTF group, with an average difference of 158 grams. In addition, more singleton babies were born prematurely in the G5 group, and even after adjustment for gestational age at birth and gender, average birth weight was still lower in the G5 group. On the other hand, a greater number of embryos cultured in the G5 medium were good enough to be implanted, and implantation rates when using fresh embryos were significantly higher, as were pregnancy rates. The study was published on August 23, 2016, in Human Reproduction.

“We have shown that human embryos that are cultured in vivo are sensitive to their environment, and that something is programmed into these embryos during those few days before transfer to the womb that still has an effect nine months later,” said senior author John Dumoulin, MD, director of the IVF laboratory at MUMC. “This means that we should be careful and we should no longer blindly accept new culture media, or other alterations in laboratory or clinical procedures, without first rigorously studying effectiveness and safety.”

“It has already been shown that birth weight of children born to sub-fertile couples who were conceived naturally is lower than of children in the general population. There must be some patient-related factors in play resulting in a lower birth weight in these particular couples,” concluded Dr. Dumoulin. “Perhaps in our study, the G5 babies are the 'normal' ones, with a birth weight that is correct for their particular origin from sub-fertile couples, while the HTF babies are too heavy. We just know too little at the moment.”

There is no uniform regulation of embryo culture media. In Europe, the majority of media approved for use carry the CE mark, but other can still be used. In the United States, media must obtain approval from the Food and Drug Administration (FDA). Overall, fertility centers choose the media they want to use according to their own preferences.

Related Links:
Maastricht University Medical Center
Radboud University Nijmegen Medical Centre