Successful trial of labour can be expected in: March 2008
**Core Concept**
The question pertains to the management of labor in a patient with a previous uterine scar, typically from a cesarean section. The underlying principle being tested is the selection of candidates for a trial of labor after cesarean (TOLAC).
**Why the Correct Answer is Right**
A successful trial of labor can be expected in a patient with a previous low-transverse uterine incision, also known as a class B uterine incision. This type of incision is associated with a lower risk of uterine rupture during a subsequent trial of labor. The risk of uterine rupture is significantly higher in patients with a previous upper segment uterine incision (class A) or a vertical incision (class C).
**Why Each Wrong Option is Incorrect**
**Option A:** Patients with a previous upper segment uterine incision (class A) or a vertical incision (class C) are not suitable candidates for a trial of labor due to an increased risk of uterine rupture. These patients are generally recommended to undergo a repeat cesarean section.
**Option B:** Patients with a previous multiple gestation or a history of uterine surgery other than a cesarean section may not be ideal candidates for a trial of labor. However, the presence of a low-transverse uterine incision is the primary determining factor for a successful trial of labor.
**Option D:** Patients with a previous classical cesarean section or a history of uterine rupture are not suitable candidates for a trial of labor.
**Clinical Pearl / High-Yield Fact**
A mnemonic to remember the classification of uterine incisions is: "LUCAS" (Low-Transverse, Upper Segment, Classical, Active). This can help differentiate between the types of uterine incisions and their associated risks.
**Correct Answer:** C.