The use of single embryo transfer to reduce the incidence of twins: Implications and questions for practice from the ‘towardSET?’ project

Abstract

In vitro fertilisation treatments where multiple embryos are transferred are associated with high multiple birth rates leading to a corresponding high infant morbidity. Here we review the results from a multidisciplinary project which aimed to combine state of the art statistical modelling of routine clinical data with consideration of patient perspectives to explore options for reducing multiple birth incidence by increased use of single embryo transfer (SET). Modelling was based on a large multicentre cohort, supplemented by analysis of HFEA register data. Patient perspectives were explored in qualitative interviews and focus groups. The data confirm the reduction of around one-third in the chance of a live birth for any couple in moving from double embryo transfer (DET) to SET in a fresh cycle. This can be somewhat offset by appropriate patient and cycle selection for SET, with many suggested schemes performing similarly, although many patients perceive such selection as unfair. If we take a complete cycle perspective, and consider the transfer of all good-quality embryos with cryopreservation then it is possible for SET to match or even outperform DET. However, the additional treatment cycles are seen by patients as physically and emotionally burdensome. Such treatments will require optimisation of embryo freezing policies and a number of options are explored.

Keywords:

• In vitro fertilisation
• single embryo transfer
• multiple births
• twin births
• predictive models
• cohort study
• patient perspectives

Acknowledgements

Authors thank the other members of the towardSET team, Mark Hirst and Brian Lieberman, the contributing centres along with the Advisory Group for their advice and support. The project was funded by the NIHR Health Technology Assessment programme (project number 05/43/01) and is be published in full in the Health Technology Assessment journal (Roberts et al., 2010b). The views and opinions expressed are those of the authors and do not necessarily reflect those of the Department of Health or our advisors. SAR is supported by the by the NIHR Manchester Biomedical Research Centre.

Declaration of interest:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.