When a girl reaches puberty, the structures of her pelvic floor mature. Estrogen hormone receptors of the urethra and pelvic floor in women help maintain pelvic floor tone and increase urethral resistance. After the age of 40 to 45 and into the seventh, eighth, or even ninth decade, the growth of the prostate gland accelerates. A change in the balance of hormones in aging men alters the prostate gland. With prostate enlargement, the base of the bladder can become distorted, and obstructing tissue can cause increasing urethral resistance.
Voiding patterns vary, depending on the severity of the obstruction.
Prostatism can occur, a condition marked by symptoms of frequency, urgency, and nocturia. If the obstruction continues, the bladder may not be able to empty and urinary retention can occur. Childbirth, especially repeated deliveries, can either temporarily or permanently distort or traumatize the pelvic floor and urethral anatomy in women. However, the pelvic ligaments, muscles, and urethra are stretched during pregnancy and become lax with time especially after menopause. After menopause, levels of estrogen in the body decrease, causing the structure of the pelvic floor to atrophy and the urethral mucosa to become thin and friable.