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
Fibronectin in fetus indicates: 
Select and explain. 
A. Post dated pregnancy, B. Preterm labor, C. Pre-eclampsia, D. None
B: Preterm labor
Answer: B: Preterm labor 
Explanation: Preterm labor