I have a 5 months old who started rice and oat cereals about 3 weeks ago. Since then, her bowels has slowed down significantly. Previously she was going daily, then every other day. Last week, she went 3 days without going. As of today, she's on her 4th day without a bowel, she hasn't shown any signs of being uncomfortable...but I'm still worried that she might be too constipated...

What types of aids have the moms out there used that's been helpful? Does prune juice work?

Thanks so much for the response.

Just an update, after speaking with a few different moms, I realize I really shouldn't doubt my own instincts (although who am I to argue with a pediatrician right?) I know the standard is to feed rice cereal as a first food, but a part of me have always thought "Does it have to be? Can't I start with something a little different, like just go straight with veggies and fruits?" I took K off of grains and we jumped right into avocados, and she's doing fine now, regular, everyday!

I feed my little guy pureed prunes as well.  It's the only food so far he's made the "yuck face" on the first taste and actually cried for a moment too (we've introduced about 8 different foods so far).  Second taste went more smoothly and now he enjoys eating them. 
We still feed him cereal (either rice or oat) every morning and have found we need to keep giving him a tablespoon of prunes daily.

Those cereals are hard on baby's underdeveloped digestive systems! I know in Italy they do NOT start with rice cereal...I tried to give my son rice cereal for about a week then just switched to pureed veggies and fruits. He had less "issues" digesting those (even certain ones that aren't recommend until later, such as lentils, citrus fruits, etc) than with the rice cereal!!!