Women who become pregnant with previously frozen in vitro fertilization (IVF) embryos tend to have healthier babies and fewer complications than those who have fresh embryos implanted, research suggests.
Fertility doctors found that mothers had a lower risk of bleeding in pregnancy with embryos that had been frozen and thawed, and went on to have fewer pre-term and low-birthweight babies.
Fertility clinics in Britain usually transfer fresh embryos into women several days after they have been given hormone injections that stimulate their ovaries to release eggs. These are extracted and fertilized before being implanted.
Any embryos that are not used can be frozen for use months or years later.
The new results raise questions about the way fertility treatment is offered in the UK. If mothers and babies fare better with previously frozen IVF embryos, it may make sense to freeze more or most embryos.
Abha Maheshwari, a senior lecturer at Aberdeen University and consultant in reproductive medicine with NHS Grampian, described the results at the British Science Festival in Aberdeen.
“We have to explore further what is the cause of frozen embryos giving us better pregnancies or lesser complications in the pregnancy,” Maheshwari said.