system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which of the following drug is category B (adequate studies in pregnant woman have failed to demonstrate a fetal risk)?
assistant
The correct answer is  Category B drugus are the one that have shown no risks in animal studies, but human studies do not exist or also if adverse effect have been seen in animal studies with no such effect im well controlled human trials. eg.ranitidine,paracetamol. TEXT BOOK OF OBSTETRICS,Sheila Balakrishnan,2nd edition,page no.564