Hi there - My older daughter will be 6 in December and she does not have CF but she does have a urination problem. She still wears a pull up at night too. The doc has checked her urine and blood test to to check glucose too. We ended up having to go to a pediatric urologist because she has an overactive bladder and she has to take Detrol LA for this problem. She does much better on the medication during the daytime but before getting on the medication the amount of times she was having to go to the bathroom was like a handicap to our day it was so much. Sometimes she still goes alot but much less than before. We've tried taking her off of the medication 2 times and within about 3 wks. we have to put her right back on it. He said it could be something she grows out of soon or it could be a long time, we'll just have to keep trying. She never wets herself during the day, she just has the sensation she has to go all the time and then relaxes enough at night to really soak her pull up. I buy the thicker night time pull-ups for her.
HTH! Let me know if you have any more questions about this.