Frozen embryos make better IVF babies
By Wendy Barnaby
New research shows that freezing all embryos for IVF could improve the quality of IVF babies and be cheaper in the long run, according to Dr Abha Maheshwari.
Maheshwari, Consultant in Reproductive Medicine with the NHS Grampian, will announce these findings today at the British Science Festival in Aberdeen.
After studying data on 37,000 pregnancies from fresh and thawed frozen embryos round the world, she and her colleagues found that frozen embryos produced babies 30 per cent less likely to arrive early, 30–40 per cent less likely to have low birthweight and 20 per cent less likely to die. In addition, the mothers had a 30 per cent less likely chance of bleeding during pregnancy.
At the moment, embryos are frozen only if there are any left over after a freshly-made one is implanted.
It is not clear why the quality of the frozen embryos is better than fresh ones. It could be because only good-quality embryos are frozen in the first place. It could be because implanting a fresh embryo soon (up to five days) after the ovaries have been stimulated to produce eggs may affect the lining of the womb so that the embryo does not implant perfectly. Or it may be a combination.
“At the moment, over 60 per cent of all IVF in the UK is funded by patients themselves,” said Dr Maheshwari . “If we could use only frozen embryos, there would be a major change in funding.
“On the current system it would cost more: if a woman has spare embryos, she is charged for freezing them, storing them and coming back to use them.
“But it depends on your end-point. If it’s a positive pregnancy test alone, freezing would be more expensive. But if it’s all the cost of getting someone pregnant, treating the mother’s high blood pressure, careful delivery of the pre-term baby or the low birthweight baby or treating long-term diseases, that’s a different perspective,” she said.
“The initial step must be to provide robust evidence to demonstrate that elective freezing of embryos can increase the chances of having a healthy baby, which would best be performed in the context of a large randomised controlled trial,” she continued.
“In the meantime, my advice to women undergoing IVF is that there should be no concerns about freezing embryos and resulting pregnancies, if your clinic is offering the freezing of spare embryos.”
The international review has just been published in the journal Fertility and Sterility.