This test indicates the window of implantation, with the aim of optimising the timing of embryo transfer. This approach is also called ‘personalised embryo transfer’ (pET). The test is more likely to benefit women who show a displaced window of implantation. However, implantation is complex and depends on a number of factors. Hence, there is no guarantee of a successful outcome after ERA and personalised embryo transfer. Importantly, there are no good research studies proving that the test improves the chance of having a baby from treatment.