My son never did that.. but he poops squatting now and always preferred to poop in an upright position (ie on my hip or me holding him with his legs scrunched up) . lol. He holds onto things and squats and poops now at almost a year old.
I bet it is the position!
If you want to, try setting her up in your lap similar to how she sits in her carseat, she may pooh like that .. or if she'll tolerate it just put her in her carseat (say, before you're gonna go somewhere) and rock her in it for a little bit and then see if she poohed so you can take her out and change her diaper before you leave. Always strap em in tho, even if you're just gonna sit there and rock her - my son could wriggle out of stuff like that REALLY young. If it's a convertible seat I guess you'll just have to wait til you get to where you're going.. knowing you'll need to stop to change her! :)
at 9:53 AM on Feb. 19, 2010