In British medical research, the transition from abortion to miscarriage, to describe early pregnancy loss, occurred in the late twentieth century. A 1985 letter to The Lancet by a group of eminent obstetricians was long considered unilaterally to have prompted this shift. More recently, however, this conclusion was challenged, and it was suggested instead that the transition constituted natural language change, as medical professionals responded to their changing social and professional milieu. This paper, however, uses a pioneering statistical modelling technique to demonstrate decisively that the 1985 Lancet letter was indeed pivotal in promoting miscarriage as an acceptable variant for use in medical journals. The abrupt nature of the vocabulary shift in question is made clear through the pioneering application of the statistical modelling technique change point analysis. This methodological innovation demonstrates clearly the decisive impact of the 1985 letter, while also showcasing the remarkable suitability of change point analysis to the study of such sudden linguistic changes. With an increasing emphasis on patient-centred models of care, it is likely that further prescriptive interventions relating to medical language will be made in coming years. Indeed, beyond the medical profession, there are already increasing calls for further reform to the language of pregnancy loss. To understand how such language reforms might successfully be enacted, and to ensure that linguistic prescriptivism is employed only where change is appropriate, proportionate, and evidence-based, it is necessary to understand fully this historical precedent. Against the backdrop of recent 'lay' demands for reforms, this paper affirms the decisive impact of the 1985 intervention, and considers the ramifications of this finding for the study of linguistic prescriptivism and future medical language reform.