ABSTRACT
There has been a running controversy as to whether there is a continuing increase in successful pregnancy with an increase of embryo number beyond two or three. For example, Templeton and Morris
reported on more than 44 000 cycles analyzed by the Human Fertilisation and Embryology Authority in the UK.1 As expected, the risk of multiple births was lower with two-compared with three-embryo transfer. However, they also concluded that when more than four eggs were fertilized, there was no higher pregnancy rate with three versus two embryos. We must assume that those programs with lower results would tend to transfer three embryos, and that three rather than two embryos would be transferred when embryo quality was reduced. Without a prospective randomized trial, such data are fatally flawed.
