## **Core Concept**
Cervical cancer originates from the cervix, often due to persistent infection with high-risk types of human papillomavirus (HPV). Early detection significantly improves prognosis. Symptoms may not appear until the disease is advanced, but there are specific signs and screening methods for early detection.

## **Why the Correct Answer is Right**
The correct answer, **postcoital bleeding**, is a classic early symptom of cervical cancer. This symptom occurs due to the tumor's disruption of the normal cervical architecture, leading to bleeding after sexual intercourse. This symptom is significant because it can prompt early investigation and diagnosis.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While **abnormal vaginal discharge** can be a symptom of cervical cancer, it is not as specific or as early a symptom as postcoital bleeding. Discharge can be due to many conditions, making it less specific for cervical cancer.
- **Option B:** **Pelvic pain** can occur in cervical cancer but is typically a later symptom. It results from the tumor's invasion into surrounding tissues and structures, leading to pain.
- **Option C:** **Leg swelling** is not an early symptom of cervical cancer. It might occur in advanced stages if the cancer causes lymphatic obstruction or significant pelvic vein compression.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **postcoital bleeding** is a red flag symptom that warrants immediate investigation for cervical cancer. Screening methods like the Pap smear and HPV testing are crucial for early detection, but awareness of symptoms like postcoital bleeding can lead to earlier diagnosis and treatment.

## **Correct Answer:** . **postcoital bleeding**