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': 'Delayed labour occurs in:a) Early use of epidural anesthesia with analgesiab) Early use of analgesiac) Unripened cervixd) Preeclampsiae) Use of sedative early in course of labour \nSelect and explain. \nA. bcde, B. abce, C. acde, D. abde', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Delayed/prolonged labour:\n“Labour is said to be prolonged when the combined duration of the first and second stage is more than the arbitrary time limit of 18 hours or when the cervical dilatation rate is less than 1 cm/hr and descent of the presenting part is < 1 cm/hr for a period of 4 hours (WHO-1994).”\nCauses of Prolonged labour:', 'role': 'assistant'}]