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
All are risk factors for preterm delivery except : 
Select and explain. 
A. Absence of fetal fibronectin at < 37 weeks, B. Previous history of preterm baby, C. Asymptomatic cervical dilatation, D. Chylamydial infection of genital tract
A: Absence of fetal fibronectin at < 37 weeks
Answer: A: Absence of fetal fibronectin at < 37 weeks 
Explanation: Absence of fetal fibronectin at < 37 weeks