This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Gynae), Subject name: Gynaecology & Obstetrics
Average Duration of first stage of labour in primigravida is - 
Select and explain. 
A. 6 hours, B. 12 hours, C. 16 hours, D. 18 hours
B: 12 hours
Answer: B: 12 hours 
Explanation: Ans. is 'b' i.e., 12 hours StageDefinitionFirstFrom the onset of true labor to full dilation of cervix. Avg duration: 12 hours in primigravida & 6 hours in multigravidaSecondFrom full dilation of cervix to birth of the baby.Avg duration : 2 hours in primi & 30 mins in multi gravidaThirdFrom birth of the baby to delivery of the placenta. 15 minutesFourth1 h observation period following delivery of the placenta