The proportion of low birthweight babies weighing less than 2. Frozen embryo babies typically had a longer gestation period an average of 0. Lead researcher Suzanne Cawood, deputy head of embryology at the Centre for Reproductive and Genetic Health in London, said the study was important because prematurity and low birthweight were both risk factors for poorer health in later life.
But she said further research was needed to test the hypothesis. Infertility Network UK chief executive Clare Lewis-Jones said the new study supported the move to transferring only one embryo at a time. This cuts down the multiple pregnancy rate - which is higher in IVF than natural conception - with health benefits for mother and baby.
Dr Williams said no associations were found, but her study used only a small cohort. Professor Pinborg said that there were almost no blastocyst transfers included in her studies, as it is a newer procedure and outside the date range of the data included. Was there any difference specifically when using donor eggs and sperm? None of the experts on the speaker panel were aware of any adverse health outcomes. Are the pattern of low birthweight, catch-up rates and health outcomes the same for IVF and spontaneously conceived babies?
Professor Brison said this was a good question, but all data on long term effects of birthweight and catch-up growth is based on normally conceived babies. But we don't know the mechanism, or whether it applies to IVF children.
And we won't know for many years. Norcross said, in conclusion, that research priorites need to be established for the long-term follow up of children born following IVF, and such multi-disciplinary research needs to be properly funded. Tuesday 16 March By posting a comment you agree to abide by the BioNews terms and conditions. Syndicate this story - click here to enquire about using this story. Home Articles News Comment Reviews. Archive Current edition Subscribe.
Donating time Financial support. Objectives Background Reader testimonials People. Writing articles Writing scheme. Log in Register. By Annabel Slater. Appeared in BioNews No growth or development differences for children conceived via IVF. Cancer risk higher in IVF babies with birth defects. Association between embryo freezing and cancer risk in children. IVF temporarily changes babies' epigenetics. Receive an email when new articles are posted on. Please provide your email address to receive an email when new articles are posted on.
You've successfully added to your alerts. You will receive an email when new content is published. Click Here to Manage Email Alerts. We were unable to process your request. Please try again later. Fortunately, modern practice does not require the transfer of multiple embryos and therefore the risk of multiple pregnancy has dropped considerably. We do need to remember that on average women who conceive with IVF are older, and we know that increased age brings with it slightly increased risks in pregnancy.
However, in healthy women, these risks remain low even up to age IVF babies have been very closely followed up, and with now more than 6 million babies born from IVF, we are getting a very reassuring picture of their health. There is some evidence that IVF babies conceived after fresh embryo transfer are born a little smaller than spontaneously conceived babies, and while this may in part reflect parental factors related to infertility , we think that the IVF process itself may be involved.
This is supported by the observation that babies born after frozen thaw transfer are if anything slightly larger than spontaneously conceived babies.
At this time however, these differences do not appear to have significant long-term consequences and many IVF babies are now healthy parents of naturally conceived children! However, we do need to keep researching the health of IVF babies, and recently it has been suggested that growing embryos in the laboratory environment might have subtle effects on future development. Again, these appear minor but need to be followed up.
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