My 3 month old DD (BF'ing) has THE most runny nappies. I don't remember my DS' being quite as bad. Whether it's to do with the 2 rotavirus vaccines which he didn't have I'm not sure. Anyway her nappies are horrific and I'm struggling to keep them contained IYSWIM. As soon as I lay her down, poo explodes up her back. I have always used Pampers in the past but they are hopeless for her. I've tried Lidl and had the same problem. I'm now trying Sainsbury's own as they are the only ones I've found which are elasticated at the back. I tried going up a size but that didn't solve the problem. She's just on the 15lbs which is the very bottom of size 4. I've gone back down to size 3 Sainsbury's own to see if that works. Anyone else have this problem with exploding poo up the back? Am I doing something wrong?