Research news: March 2012
Lancet 2012; doi:10.1016/S0140-6736(11)61267-1
For the best chance of a live baby, women having in vitro fertilisation (IVF) need no more than two implanted embryos, say researchers. Increasing the number to three does not result in more live births for women of any age, it just increases the chance of complications, such as preterm birth and low birth weight. This new study challenges current recommendations by the UK Human Embryo and Fertilisation Authority, which allow transfer of three embryos for women over 40 years.
In an analysis of data collected by the authority between 2003 and 2007, transfer of two embryos was associated with significantly better odds of a live baby than transfer of one in women of all ages. Although the risk of twins, prematurity, and low birth weight also went up with transfer of an extra embryo, the absolute increase was less for older women than for younger ones.