Prostate ultrasound is usually only mildly uncomfortable. A transrectal scan feels like pressure, fullness or brief cramping when a small probe is inserted into the rectum; lubricant and local anesthetic gel reduce discomfort. A transabdominal scan (over the lower belly) is typically painless. If a biopsy is taken, expect more soreness, minor bleeding and tenderness for a few days; serious pain is uncommon.

An ultrasound of the prostate is a diagnostic scan using high-frequency sound waves to create images of the prostate and surrounding tissues. Performed transrectally (common) or transabdominally, it assesses size, nodules, inflammation or abscess, guides prostate biopsies and evaluates causes of urinary symptoms. It involves no radiation, is usually outpatient, and may cause mild discomfort during a transrectal exam.

Five warning signs of an enlarged prostate are: 1) increased urinary frequency, especially at night (nocturia); 2) sudden urgency to urinate; 3) weak, slow, or interrupted urine stream; 4) difficulty starting urination or straining; and 5) sensation of incomplete bladder emptying with post-void dribbling. Early assessment can help manage symptoms and rule out infection or cancer.

Transrectal ultrasound can show suspicious prostate abnormalities and is commonly used to guide biopsy needles, but ultrasound alone cannot reliably detect or rule out prostate cancer. Many tumors are isoechoic and invisible on ultrasound; multiparametric MRI is more accurate for locating lesions. Definitive diagnosis requires prostate biopsy with pathological examination, often prompted by raised PSA or abnormal imaging.

The main cause of prostate enlargement (benign prostatic hyperplasia) is age-related hormonal changes, especially increased dihydrotestosterone (DHT) activity within prostate tissue that stimulates cell growth. A changing balance between androgens and estrogens and local growth factors also contributes. Risk rises with advancing age, and genetics and metabolic conditions (obesity, diabetes) can further increase likelihood.

No—fasting is generally not required for a prostate ultrasound. For a transabdominal scan you’ll usually be asked to have a full bladder (drink water and avoid urinating beforehand). For a transrectal ultrasound you typically don’t need to fast; specific prep (enema, antibiotics, or temporary anticoagulant adjustments) may apply if a biopsy is planned. Follow the imaging centre’s instructions.