A new study has found that children born via IVF are typically taller than those born naturally. Newborn IVF babies created from a fresh embryo transferred back into the mother, also tended to be about 190g lighter than naturally conceived children.
The study was led by Dr. Mark Green from the University of Auckland's Liggins Institute and is one of its kind. “There's been four million children born from IVF ... we wanted to see what the long-term implications were,” he said.
His study showed that babies conceived with fresh, as opposed to thawed, embryos, were on average up to 2.6cm taller than children born without assisted conception. The team looked at healthy, pre-pubescent children aged between four and 11, of which 72 were born from IVF using fresh embryos, 43 IVF children from frozen embryos and 94 naturally conceived children. Height difference was more prominent in girls they found. Dr Green said, “We've got no real hypothesis on why that might be, we do know that a lot of different things affect males and females in utero.”
Dr. Green explained, “We don't know the reasons for the height difference…But can I suggest that it may have something to do with the hormones that are given to the mother to stimulate the ovary in fresh embryo transfer…Fresh embryos are usually of a better quality than frozen embryos which may be a contributing factor to differences in height in the resulting children.”
He suggested that more research into IVF born babies was needed to understand the effects. “We need more long-term studies because we know some of the later diseases, such as diabetes and cardiac disease, can be affected by events that happen during gestation, and they don't really occur till the 40s or 50s,” Dr Green said.
The research was presented at The Fertility Society of Australia's annual scientific meeting in Adelaide, on Wednesday.
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