This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Which is the most common complication during vaginal delivery in a diabetic women : \nSelect and explain. \nA. Uterine ineia, B. Shoulder dystocia, C. Postpaum hemorrhage, D. Excessive moulding of head', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Shoulder dystocia', 'role': 'assistant'}]