Intrusions specifically related to a mother's infant and an increase in prevalence of Obsessive Compulsive Disorder (OCD) has both been observed in the perinatal period. Such intrusions have been observed to be a source of distress in some mothers. However, as compared to postnatal depression, the literature has demonstrated a lack of research and training of health professionals in perinatal OCD (pOCD). Health visitors provide a clear role in checking mothers' wellbeing postnatally and present an opportunity for research and training. The present study aimed to provide health visitors with an understanding of intrusions and the cognitive-behavioural model of OCD, equipping them with skills in identification and normalising. The key aim was then to examine the effects of the training on mothers. Health visitors attended a ninety-minute training session in pOCD and intrusions. Mothers who saw these health visitors were compared to mothers who saw health visitors who had not received this training, forming an experimental group and a control group respectively. Postal questionnaires found significantly lower results in the experimental group for how bothered mothers were by the intrusions they experienced. The questionnaire did not detect the mechanism for this lower result in the experimental group (i.e. whether health visitors were normalising intrusions for the experimental group). There was no significant difference between groups in time spent completing compulsions or in symptoms of depression, anxiety and stress. Pre and post-training health visitor data found increased consideration of pOCD as a diagnosis. A critical review of the study is discussed. Further research is suggested to explore impact of training on mothers with clinical level pOCD and to examine the effects of the provision of normalising in itself.