The Irrational Attraction of Elective Single-embryo Transfer
The Irrational Attraction of Elective Single-embryo Transfer
In this issue of the journal, Niinimäki et al., colleagues from a pioneering Finnish center in the development of elective single-embryo transfer (eSET), propose the expansion of eSET to suitable women at ages of 40–44 years. This paper offers not only a critique of their proposal but also of eSET in general.
When Templeton and Morris in their groundbreaking 1998 paper in The New England Journal of Medicine demonstrated that in good prognosis patients two-embryo transfers (2ET) resulted in similar pregnancy rates, but greatly reduced high-order multiples, in comparison with transfers of three (or more) embryos, they revolutionized in vitro fertilization (IVF) (Templeton and Morris, 1998). By that time, high-order multiple births had been widely identified as an adverse outcome of IVF (French National Registry, 1995; Society for Assisted Reproductive Technology, American Society for Reproductive Medicine, 1995; Human Fertilisation and Embryology Authority, 1997). The quick subsequent worldwide switch toward 2ET in good prognosis patients occurred because Templeton and Morris had achieved a goal researchers strive for in clinical medicine: they demonstrated improvements in outcomes (i.e. fewer high-order births), without adverse treatment effects (i.e. without reducing the patient's pregnancy chances).
Abstract and Introduction
Abstract
In this issue of the journal, Niinimäki et al., colleagues from a pioneering Finnish center in the development of elective single-embryo transfer (eSET), propose the expansion of eSET to suitable women at ages of 40–44 years. This paper offers not only a critique of their proposal but also of eSET in general.
Introduction
When Templeton and Morris in their groundbreaking 1998 paper in The New England Journal of Medicine demonstrated that in good prognosis patients two-embryo transfers (2ET) resulted in similar pregnancy rates, but greatly reduced high-order multiples, in comparison with transfers of three (or more) embryos, they revolutionized in vitro fertilization (IVF) (Templeton and Morris, 1998). By that time, high-order multiple births had been widely identified as an adverse outcome of IVF (French National Registry, 1995; Society for Assisted Reproductive Technology, American Society for Reproductive Medicine, 1995; Human Fertilisation and Embryology Authority, 1997). The quick subsequent worldwide switch toward 2ET in good prognosis patients occurred because Templeton and Morris had achieved a goal researchers strive for in clinical medicine: they demonstrated improvements in outcomes (i.e. fewer high-order births), without adverse treatment effects (i.e. without reducing the patient's pregnancy chances).