The American Society for Reproductive Medicine (ASRM) announced the release of new guidelines on the number of embryos to transfer in vitro fertilisation (IVF) treatment. Because embryo quality and maternal age greatly affect pregnancy rates, it is recommended that different numbers of embryos be transferred to patients depending on individual circumstances.
The ASRM Practice Committee report recommends that in patients with the most favourable prognosis, no more than two high-quality embryos should be transferred during IVF. This number should increase for patients with a worse prognosis - so that for patients with the least chance of success (for example, where the female partner's age is between 35 and 40), no more than five good quality embryos should be transferred. 'We want to maximize the chances of a successful pregnancy and decrease the risk of multiple gestation,' said Phil McNamee, M.D., President of the Society for Assisted Reproductive Technology (SART). 'This change is the result of our careful monitoring of the outcomes of assisted reproductive procedures', he added.
Research published in the Journal of the American Medical Association suggests that the number of embryos transferred can be limited without reducing the live birth rate. Dr Laura A Schieve and colleagues studied 35,554 IVF transfer procedures that took place at 300 US clinics. Women between the ages of 20 to 29 and 30 to 34 years achieved maximum live birth rates of 43 per cent and 36 per cent respectively when two embryos were transferred. When three embryos were transferred, the multiple birth rate was as high as 45.7 per cent for women aged 20 to 29 and 39.8 per cent for women aged 30 to 34. The rate was less than 25 per cent for women aged 40 to 44 even if five embryos were transferred.