As scientific evidence from the UK and the USA in the 1980s was questioning the usefulness of episiotomy, the rate in France increased from 38% in 1981 to 58.4% in 1996. In 1996, the World Health Organization recommended limiting the episiotomy rate to 10%. This article aims to examine this paradox through an analysis of the French medical debate on episiotomy during the 1980s and 1990s. Drawing on an analytical corpus composed of 192 articles published in French professional journals of obstetrician-gynaecologists and midwives, it shows that the majority of these health professionals considered episiotomy to be a preventive intervention. The most influential professional organizations and experts manage to refute most of the international alerts on the limitations and side effects of episiotomy through the constant production of new justifications and competing knowledge for the procedure. In the 1980s, episiotomy was seen as a means to prevent tearing and thus avoid perineal dysfunction. Episiotomy and perineal re-education (which developed into a new health sector) were put forward as ‘the’ solution to the problem. From the mid-1990s onwards, the focus shifted from the mother to the baby as episiotomy was promoted as a way to reduce the risk of newborn mortality and morbidity. This article shows that the alerts and controversies on the assumed iatrogenic effects of biomedical technologies and practices were silenced through efficient and dynamic production of competing knowledge about their assumed benefits. © 2021 The Author