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
Ventouse in 2nd  stage of labour is contraindicated in: 
Select and explain. 
A. Persistent occipito-posterior position, B. Heart disease, C. Uterine inertia, D. Preterm labour
D: Preterm labour
Answer: D: Preterm labour 
Explanation: None