Wetting in Pants

I have a 4 year old stepdaughter that just recently starting wetting in her pants...her mother just had a baby in March, and I believe that could be the case because she is now not the youngest anymore...from 3 to 4 she never wet the bed or in her pants...now when she leaves her moms she wets her pants or when she is playing...any ideas on what i can do about this problem...its getting quite frustrating!

[frustratedmom007]

My daughter started doing this at age 4 after training herself at age 3.  When we moved she started having accidents.  IT got worse and worse.  She is almost 8 and its a bad habit now.  SHe never out grew it.  SHe's been to every imaginable doctor and no cure.  Don't think it will just go away.  I'm still looking for answers.  What I used to thik was asmall problem is now a BIG problem.  School is the biggest problem because she won't change after an accident.