The objective of this study was to improve by a two day training on interpersonal communication (IPC), the professional communication skills of nurses during antenatal care (ANC), and to obtain higher levels of knowledge among the pregnant women after the visit. The head-nurses of 22 health facilities in 3 rural health districts in Cameroon were randomly assigned to either the intervention group A or the control group B. Participants in group A received at the start of the study a two-day interactive training on ANC emphasizing on IPC skills, whereas participants of group B were trained after 10 months. Group A and B were compared at the start and 10 months later. The effect of training on IPC was measured applying the Roter interaction analysis system (RIAS) to analyze the audio-recorded consultations and by structured patient questionnaires. Only the 128 visits from the twelve providers participating in both assessments were analyzed. The IPC-training increased the frequency of understandable explanations of health topics relevant to pregnant women, particularly HIV/AIDS. Women were significantly better informed about the treatment when consulted by trained providers. In contrast, training appeared to have little influence on women's opportunities to give their points of view (concepts), to ask questions or to address their financial problems regarding the prescribed treatments or procedures. Training of providers in IPC showed some promising, but overall limited effects. Evaluations of communication training with validated tools such as RIAS will help to establish on the long-run IPC-guidelines for primary health care contexts in rural Africa.