An enlarged prostate is not the only cause of incontinence. Certainly, many elderly men as they age, experience urinary urgency, nocturia or difficulty starting flow and cessation of their urine flow, as their prostate enlarges each decade. But many women also experience urinary incontinence, and some children and some adolescents (for a variety of behavioral or physiological reasons)
Many women can experience “stress” urinary incontinence due to changes that occur during pregnancy or post childbirth. Women have a shorter urethra and there is a lot of pressure on this structure during childbirth. Pelvic floor muscles can be weakened or damaged during childbirth and this can affect sphincter control also, and hence some incontinence. (Weakened pelvic floor muscles can also affect elderly men and contribute to stress incontinence)
“Overflow” urinary incontinence can occur when the bladder cannot empty completely and the gradually gets filled with residual urine. This happens mostly with an enlarged prostate that causes bladder outlet obstruction.
A “weak and overextended” bladder muscle that is unable to contract is another common cause of incontinence. This can in turn be caused by factors such as diabetic sensory neuropathy, herniated discs or spinal stenosis.
During menopause, the urethras supporting structures, muscles and connective tissue, can weaken due to hormonal changes. Constipation, obesity or a chronic cough can also contribute to stress incontinence in both sexes.
Incontinence can be a side effect of certain medications also. Some medications have a diuretic effect (eg frusemide) causing increased urination or can cause diarrhoea (eg metformin). If this becomes significant, it could lead to incontinence.