L.,
I'd strongly suggest having your daughter seen by a specialist. My oldest daughter, now 22 years old, had the same problem and when she was 5 years old, we took her in to see the pediatrician and he did an ultrasound to check things out. What we found out, we were, of course, not expecting. She was actually missing a kidney and the one she did have was enlarged (which is normal under the circumstances to make up for the one that isn't there). Her bladder was also deformed, having a diverticulum (pocket or weakened area in the bladder wall) where the missing kidney and ureter would have normally been attached. She wasn't purposely wetting the bed, urine collected in this pocket and leaked out uncontrollably.
When we arrived back in Texas a few years later (this all occurred in Germany - non-military), the problem had not resolved so we took her to a pediatric urologist (Thomas Bartholomew, MD) and the diverticulum had ballooned considerably, resembling a "Mickey Mouse ear" on the side of her bladder. Surgery seemed to be the best bet, so at age 10, the diverticulum was removed. For the next few years, until my daugher was in high school, she took prophylactic antibiotics to prevent recurring UTIs, which helped.
Since she was about 14 or 15, she's been fine with no problems. She's been taught all these years the importance of staying well hydrated and having good hygiene to keep the one kidney she had as healthy as possible.
What caused this deformity to begin with? It's never been 100% proven, but as a practicing midwife, I've done a lot of research on this. My daugher was small for gestational age - only 5 1/2 lbs at term. Although I don't have it in any medical records, I suspect she had a 2-vessel umbilical cord (only 1 umbilical artery, not 2 as is normal with the one vein present), instead of the normal 3-vessel cord. Such defects in the unrinary system are common with these babies. All my other children are normal.
All this info and my daughter's story is not to say that your daughter has a similar problem, but if I were you, I'd have it checked out. There might be a physiological reason for her bed-wetting problems. It's not always psychological!
Blessings,
R.
R. Rabenschlag, LM, CPM, CD(DONA), CLD, ICCE-CD
Midwife, Doula, Childbirth and Lactation Educator
Multiple Blessings Childbirth Services
Serving the San Antonio area
Tel: ###-###-####