This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abnormal labor, Subject name: Gynaecology & Obstetrics
In classical caesarean section more chances of rupture of uterus is in: 
Select and explain. 
A. Upper uterine segment, B. Lower uterine segment, C. Uterocervical junction, D. posterior uterine segment
A: Upper uterine segment
Answer: A: Upper uterine segment 
Explanation: Upper uterine segment is at more risk of rupture in case of a previous classical cesarean section. Here incision is made on the anterior uterine wall in the upper segment above the reflection of uterovesical fold of peritoneum. It is because such a scar is difficult to appose and healing is not good because of frequent contractions and retraction during puerperium. (Sheila TB of obstetrics 2nd edtn pg 338)