IVF culture medium affects post-natal weight in humans during the first 2 years of life.

Study Question: Is post-natal growth during the first 2 years of life in IVF singletons affected by type of medium used for culturing human embryos during an IVF treatment?

Summary Answer: The in vitro culture of human embryos in medium from Cook resulted in singletons with a lower weight during the first 2 years of life compared with singletons born after embryo culture in medium from Vitrolife.

What Is Known Already: In a previous study, we reported that type of medium used for culturing human IVF embryos during the first few days after fertilization until fresh embryo transfer significantly affects fetal growth and consequently birthweight of the resulting singletons.

Study Design, Size, Duration: From July 2003 to December 2006, a total of 1432 IVF treatment cycles with fresh embryo transfer were randomly allocated to have all embryos cultured in medium from Vitrolife AB (n = 715) or from Cook (n = 717).