**Core Concept**
Oral contraceptives (OCs) contain estrogen and progesterone, which affect various physiological processes to prevent pregnancy. The question is about a specific side effect or risk associated with OC use.

**Why the Correct Answer is Right**
The primary mechanism of OCs is to inhibit ovulation through negative feedback on the hypothalamic-pituitary-gonadal axis. However, OCs also affect blood clotting by increasing the production of clotting factors and decreasing the production of anticoagulant proteins. This leads to an increased risk of venous thromboembolism (VTE). **Option C** is the correct answer because it is directly related to the procoagulant effects of OCs.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not directly related to the common side effects of OCs. While OCs may affect lipid profiles, they are not primarily known for causing hypertriglyceridemia.
* **Option B:** This option is not accurate. OCs are not primarily associated with an increased risk of hypertension. In fact, some studies suggest that OCs may have a protective effect on cardiovascular risk factors in certain populations.
* **Option D:** This option is not a well-established side effect of OCs. While OCs may affect mood and libido, they are not primarily associated with an increased risk of depression.

**Clinical Pearl / High-Yield Fact**
Remember that OCs increase the risk of VTE, especially in the first year of use and in women with additional risk factors such as smoking, obesity, or a family history of VTE. Always consider these factors when prescribing OCs.

**Correct Answer:** C.