**Core Concept**
Leiomyomas (fibroids) can impair fertility by distorting the uterine cavity, altering cervical mucus, or causing hormonal imbalances. Addressing infertility in this context requires intervention that reduces estrogen levels, which drive fibroid growth and disrupt reproductive function.

**Why the Correct Answer is Right**
GnRH agonists suppress gonadotropin secretion, leading to a sharp drop in estrogen levels. This results in atrophy of leiomyomas and improved uterine morphology, thereby enhancing fertility potential. Unlike hormonal contraceptives or progestins, GnRH agonists directly target the root hormonal driver of fibroid growth. Clinical studies show improved pregnancy outcomes after treatment in women with fibroids and infertility.

**Why Each Wrong Option is Incorrect**
Option A: Combined oral contraceptive pills contain estrogen and progestin, which may promote fibroid growth and worsen uterine distortion, thus worsening infertility.
Option B: DMPA (dienogest) is a progestin that can cause endometrial thinning and may reduce fertility, making it unsuitable for infertility management.
Option D: Ulipristal is a progesterone receptor modulator used for fibroid shrinkage, but it is primarily indicated for symptomatic relief and not specifically for improving fertility outcomes.

**Clinical Pearl / High-Yield Fact**
GnRH agonists are the only agents proven to reduce fibroid size and improve fertility in women with uterine leiomyomas — a key point in managing infertility due to fibroids. Always consider fertility goals when choosing treatment.

✓ Correct Answer: C. GnRH agonist