T has started saving her BMs for every other day. so when she goes, it's huge. (still breastmilk, too, so very liquidy). she blows out of her diaper each time and we have tried 3 different kinds. dh says to try a bigger diaper (she's in a 3 and 18lbs--i doubt we can go bigger) or put it on looser so it doesn't squeeze out?
any recommendations? or will this pass eventually?

Re: diaper blow out. help!
My friends little girl ALWAYS used to have blowouts. She had them forever. I know she was always scared to leave the house because she would be afraid that she would have a blowout and have to change her diaper, clothes, and wash out the stroller or carseat. It was horrible!
I don't think that they had anything to solve it. She eventually just started having thicker/harder poop. She was formula fed.
Where is it leaking from - sides or back?
The problem with most young babies is that they have no bootie and therefore no waist for the diaper to cinch around. You need something bulky at the back waistline to hold the poop down into the diaper. Try taking a flannel receving blanket (you have plenty of those right!?) and cut it into large squares. Roll it into a cigar shape and place at the back/top of the diaper on poop day. It's a cheap enough solution to be thrown away with the diaper for now (this isn't forever!) or you can wash if you feel guilty.
I've turned 2 of our recieving blankets into many disposable washclothes
Sometimes I wash them.. othertimes, whatever.
This is a GREAT idea!
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Duuude, I totally hear ya. DD was like that for what seemed like forever. I was the mom that was terrified to take her anywhere. I always had TWO emergency outfits, a cover protector for the car seat and about 100 wipes with me ALL.THE.TIME. I'd also have tons of plastic HEB bags and a few towels in my car just in case. And oh, those accidents in public were no fun. I remember one happening in the check-out line at HEB and DH was like"should we go change her here" and I was all "nope, she needs to just chill in her car seat for 15 more minutes until we get home b/c that car seat cover needs to be WASHED now."
Once we started purees and rice cereal/solids, it DID help a lot. But I seemed to be the only one of my friends that had that problem so I just assumed that some babies are a bit more forceful when they poo or something. GL in the meantime!