Many miscarriages occur due to chromosomal problems, and may not be preventable. But there are many miscarriages that result from the loss of euploid embryos. Why are these pregnancies lost? Where is the problem, and what can be done? There is a pervasive and harmful idea that miscarriages are nature’s way of dealing with an abnormal pregnancy, and therefore they cannot really be prevented, and we do not need to try to prevent them. This idea ignores the fact that there are several steps that can be taken to reduce the risk of miscarriage. This lecture asks the questions: what can a woman or couple do to reduce their risk of miscarriage? What can a healthcare provider do to reduce the risk of miscarriage? What is evidence? What are the limitations in the evidence? The recently updated evidence-based NICE, RCOG and ESHRE guidelines form the foundation of this lecture.