Electronic Medical Records (EMR)s are intrinsic to modern-day clinics. Understanding the roles, i.e., the unintended functions of EMR systems in their context of use can guide the design of EMR systems and clinics to better integrate them. To understand the roles of EMR systems in antenatal care check-ups, we conducted a field-based observational study at an antenatal care clinic in a Japanese university hospital. We observed 37 antenatal care check-ups where we looked at how the EMR system affects the communication between the involved parties and supports or hinders the clinical process. Our data analysis resulted in 10 EMR roles, namely: the wingman, the third wheel, the accomplice, the bouncer, the messenger, the summarizer, the bureaucrat, the assistant, the gossip, and the alien. Through the roles, this study reveals multiple EMR design considerations and opportunities for improving both the human-EMR and human interactions in antenatal care settings.