**Core Concept**
Myomectomy for fibroid uterus is a surgical procedure that involves the removal of uterine fibroids, which can be associated with significant blood loss due to the rich vascular supply of the uterus. Effective management of blood loss is crucial to ensure a safe and successful outcome.

**Why the Correct Answer is Right**
To reduce blood loss during myomectomy, the use of uterine artery ligation is a recommended technique. This involves ligating the uterine arteries, which are the primary blood vessels supplying the uterus, thereby reducing blood flow to the surgical site. This technique can be performed laparoscopically or during open surgery. Uterine artery ligation reduces the risk of blood loss and transfusion requirements, making it a valuable tool in the management of fibroid uterus.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because using a tourniquet to control blood flow to the uterus may not be effective due to the rich collateral blood supply of the uterus.

**Option B:**
This option is incorrect because preoperative embolization of the uterine arteries may not be necessary in all cases, and its effectiveness in reducing blood loss during surgery is still a topic of debate.

**Option C:**
This option is incorrect because the use of a harmonic scalpel may not significantly reduce blood loss during myomectomy, as it only controls bleeding at the surgical site.

**Clinical Pearl / High-Yield Fact**
The use of uterine artery ligation during myomectomy can reduce blood loss by up to 50% and transfusion requirements by up to 30%.

**Correct Answer:** C. Uterine artery ligation.