Pampers Swaddlers Size 1 = IQ Test?

peanut701

LO just outgrew her newborn swaddlers diapers so we moved to size 1. The past 2 days, she's woken up from her nap with urine up the back of her clothes. I feel like a complete idiot asking this, but what am I doing wrong? These diapers were not heavily soaked and she wasn't asleep long, because the wet clothes startled her awake. Do I need to pull them up higher in the back? Or fasten them tighter? Or maybe she didn't outgrow the newborns after all (she's 9lb 2oz)?