I have a suggestion:

Some women "leak" unexpectedly when they are casein intolerant. I have seen posts on the internet where eliminating casein (dairy) stopped the problem.
This also pertains to kids who bed wet at older ages (beyond diaper times). Stopping casein sometimes works for them too.

But the problem for women in general is multifactorial. The urethra in a female is less than 1 in long. The muscle can get weak or be affected by MS.

Some people find that sympathetic drugs like Sudafed help. (phenylpropanolamine which was a common OTC drug is still used in animals who have incontinence--but it is removed from human use now by FDA because of stroke risk). But other stimulants may work as well. This is the mechanism touted for Cymbalta.... If it were I, I'd choose the Sudafed.

Certainly prolapses, have to be surgically improved.
And there is also cauda equina-- spinal stenosis.
There is nerve failure in MS.

Even simple things like too much Vit C will aggravate due to increased acidic urine which can irritate the urethra. Post menopausal women sometimes get relief from an estrogen cream applied to the vulval area once a week.
So there are MANY issues, with many solutions.

Mrsd - you are right about the estrogen...I was having similar problems and doc recommended it and it has improved significantly. Guess I am in perimenopause and estrogen decline or deficiency (esp since bladder is right in same area) can totally be affected.