This paper examines argumentation in doctor-patient interactions, with a special focus on antenatal consultations between doctors and pregnant women, using the extended pragmadialectical theory of argumentation. The data comprise two case studies, extracted from forty doctor-pregnant women interactions which were purposively selected from a private hospital in Ibadan, Nigeria. The findings show that depending on the stage of the interaction, the doctor and the pregnant women have interchangeable roles as protagonists and antagonists. The interactants tend to use causal argumentation scheme while employing subordinative and complementary coordinative argumentation structures. The interactants also employ different strategic manoeuvres at different argumentative stages of the critical discussion. Thus, the study shows the influence of the medical communicative activity type on the argumentative activities that can occur in a critical discussion. The study also recommends that argumentation should be included in the medical training of health personnel in order to enhance patient-centred communication
