When the Institute of Medicine made patient centredness one of six goals for the healthcare system, it acknowledged that “the right of patients to be informed decision makers is well accepted, but not always well implemented.”1 There may be no better illustration of the difficulty of putting “responsiveness to the needs, values and expressed preferences of the individual patient” into practice than decisions related to in vitro fertilisation (IVF).

IVF involves clinical, economic, and social issues that are all intertwined. Implanting multiple embryos raises the odds of a successful live birth but increases the risk of multiple births, preterm birth, and undesirable and expensive complications. The risks are lower with single embryo transfer, but so is the success rate.2 Still, patients often perceive the risks of multiple embryo implantation as low, and the prospect of twins as a kind of bonus.3

In the linked randomised controlled trial …