An enlarged prostate can narrow the urethra, making urination difficult.

“So, as the prostate enlarges, it's right around the urethra. It's a walnut-shaped gland sits underneath the bladder around the urethra, and it can narrow the urethra or the P-tube. And so over time, you can imagine, like, if you're, I always give this example, if you're sucking from a straw, right? You're drinking from a straw. If you have a wide diameter straw, it's really easy to drink. If your straw gets really narrow, like, say you take a coffee straw and you drink out of that, it's very difficult to drink. Very similarly, it can become very difficult to urinate if you're enlarged prostate.”