There may not be a "medical" issue in terms of infection or anatomy, but there is a condition called nocturnal enuresis (meaning simply nighttime bedwetting) that is not possible to "train" a child out of! My son had it and took medication until he was about 12. He tried to stop it at around 9 or 10 but the problem came back. We spoke to the pedi as well as a noted pediatric urologist, and learned that many kids (more often boys, but not exclusively) have this problem and take the medications well into teenage years, even up to 18. I'm not a big fan of medication when you can avoid it, believe me, but this absolutely changed our lives for the better! There were no side effects and it was just taken once at night.
Waking him up caused nothing but sleep disruption for everyone - a really really bad thing. Changing sheets is a nightmare - and yes, we used waterproof pads in between 2 fitted sheets so we could quickly strip the bed. But he was still wet and it was disruptive in the middle of the night. We used those terrible alarms which were awful and didn't work anyway.
By 7, he wanted to go on sleepovers, and at 9 he wanted to go to camp - none of this would have been possible without the medication. When he went to a friend's house, we simply sent a single pill in a plain bottle and told the other parent either the truth or that it was an allergy pill. All the kids thought it was an allergy pill. No embarrassment, no TMI. At camp, all the kids were (unfortunately) taking meds for one thing or another, so it was a non-issue. The nurses just gave him his pill since kids couldn't keep meds in their bunks for obvious reasons.
Your daughter could grow out of this in 6 months, or she could have it for years. You should talk to your doctor and at least discuss all the possibilities.
I agree with others as well as you that she should not think she is being punished with pull-ups or thought less of because she can't control it. And she needs her sleep. So do you.
Good luck!