Active Selection and Single Embryo Transfer: Insights from Virtual Trials

Abstract

Transferring embryos that are most likely to successfully implant and develop is important in optimising the efficiency of assisted conception. Slow-freezing of spare embryos has a high attrition rate; thus, actively selecting a viable embryo for a fresh transfer can theoretically result in a superior cumulative live birth rate compared to a conventional assessment of morphology. However, with vitrification and its much lower attrition rate, active selection may not deliver an improved cumulative live birth rate, as more viable embryos may be excluded due to the limitations of the technique than are lost due to warming attrition. For some women, the principal benefits of active selection techniques are likely to be associated with a reduction in the number of miscarriages and a reduced time to achieve a successful pregnancy or start another stimulated cycle. Active selection procedures need to be safe, accurate, and effective, without jeopardising the chance of a live birth. The analysis presented in this paper shows that, from the perspective of a self-funding woman, adding a costly active selection option is entering into a lottery for a better result that is most likely to offer no advantage and even the possibility of an inferior outcome for some. Gauging willingness-to-pay to avoid miscarriage and to reduce treatment time is likely to be complex, and depends on who is making the decision and how they are counselled. Evaluating cost-effectiveness, for which the unit of health is one live birth, is unlikely to be helpful in supporting a case for public funding or private insurance for a better selection technique. The author of this paper explores the theoretical potential of active embryo selection to optimise a full cycle of assisted conception, with particular reference to single embryo transfer.