We have been having a problem with DS not pooping. He's wetting plently of diapers but it's been 6 days since he's pooped.
Anyway, DS has gone from 9 lbs 1 oz at birth, was 8 lbs 5 oz when he left the hospital, and was back at 8 lbs 14 oz 3 days later when we went to the pedi. At his one month appointment he was 11 lbs 7 oz and today, a week later, was 12 lbs 2 oz. We were there today due to the not pooping.
They told me to make sure i'm only feeding every 2 hours or more and that he must be eating so much so fast that he can't proccess it and is getting stopped up.
I feel terrible.  I'm not force feeding him, just feeding him on demand, which could be anywhere from every hour to every 2-5 hours depending on his sleep.  I don't keep track I just go by his cues.  I feel like I'm failing my baby.  I've been working on oversupply issues and forceful letdowns so this is just icing on my poop cake. 
Re: Repost from breastfeeding-EBF and gaining too much?
You've done nothing wrong. Having a new baby is a learning experience for all of us. None of us went into this knowing exactly what our babies needed 100% of the time. We're not mind-readers.
You've done everything right. You've fed your baby when you saw he was hungry. This is just a fluke thing.
My only advice would be to just wait for LO to act more hungry than just the little cues. I'd wait for him to become more insistent, if that makes any sense.
GL!
It's normal for breastfed babies to not poop every day. Our pedi said once a week isn't uncommon.
ETA: Don't worry, you're doing fine. It's hard to overfeed a breastfed baby and I don't think he's gaining too much at all. Also, if he hasn't pooped in 6 that could definitely make his weight look higher than it really is. I don't know about everyone else but I prefer weighing myself after going to the bathroom.
med-free birth x2, breastfeeding, baby wearing SAHM
My BFP Chart
Yeah, I've heard this too. In fact, everything I've read says that you shouldn't worry until it's been much longer or they're not peeing. I'm surprised your pedi acted concerned.
I read the same thing in my AAP book.
We go for our 2 mo appt in Sept and I figure I'll be in a similar boat as you as far as weight goes. DD was 7-9 at birth and 7-10 at her appt 3 days after we got out of the hospital. She was 8-12 one week later (though I'm still trying to attribute at least a few oz to her wet diaper...)
I've nursed 3 kids so far and am starting on my 4th. (just saying I'm a btdt mom)
My first baby was born 5 weeks early and gained a pound a week for his first 6 weeks- he really did catch up fast and was a chubby and very healthy baby. No doctor ever said anything negative about his weight- and he is now a lean mean lanky 12 year old.
Eva went from birth = 7lb 15oz to one week = 8lb 4 oz to three weeks 10 lb 25 oz .... I think she's doing GREAT!!!
As for the pooping- although it is totally normal for breastfed babies to skip many days- up to a week even- typically that pattern does not start for a few more months. In a baby this young I wouldn't know what to make of it- and might worry myself that he wasn't eating ENOUGH- if it wasn't for the OBVIOUS fact that he must be eating plenty...I don't know what to make of that- the trouble signs I'd be worried about are all cancelled out by his great weight gain. >stumped<
My EBF baby came home from the hospital at 8 lbs 15 oz, (born at 9 lbs 11 pz) and was 12 lbs 1 oz at her one-month appointment. Doctor thinks her weight gain is great.
I'd be a little stumped about the no pooping, but he's obviously gaining well.... Mine often doesn't pee or poop overnight, which is bizarre to me. She went 9 or 10 hours with no poop, then has had some pretty spectacular ones since....