After six months, they use xray instead of ultrasound. From what I've seen/read, that's about the only difference in the way it's treated. How it's treated will depend on the severity of it. Things like double nappies don't help after a young age. I know someone who's child wasn't diagnosed until about 8-9 months (from memory) but her treatment was exactly the same as DD1's who was diagnosed at 7 weeks.