This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preterm Labour, Subject name: Gynaecology & Obstetrics
For prevention of pre term labour in a patient with a history of a preterm delivery the following is used : 
Select and explain. 
A. Calcium supplements, B. Ecosprin, C. Progesterone, D. Steroids
C: Progesterone
Answer: C: Progesterone 
Explanation: Progesterone can be used for prevention of preterm bih in patients with past history of preterm delivery. It can be given from 16 weeks till 36 weeks to prevent preterm labour. However it is not effective once the contractions have staed.