Or any formula for that matter. It looks like Cookie Crumb is going to have to go to formula full time (he’s four months). We tried Enfamil at first but it seemed to cause a lot of gas and exacerbated his acid reflux. He’s been on Nestle Soy formula for about 6 days, and it seems to be going well so far. I’ve been mixing in a teaspoon or so of prune juice with each bottle to ease constipation but he still seems a bit backed up. 
Any thoughts/advice?
All three Hallkids were on soy formula. When HallGirl 1 had stopped breastfeeding (horrible experience, another thread), the ped put her one milk based formula. She would projectile vomit after every (and I mean every) feeding, so we quickly switched to soy based formula, and she did fine. When Hallgirl 2 was born (no breastfeeding this time), she “had difficulty” with her first bottle and I immedately demanded soy based formula for her in the nursery, which based on HallGirl 1’s history, they did. No problems there.
After Hallboy stopped breastfeeding (better experience, still another thread), I didn’t even try milk based formula, but put him on soy.
The only difference I saw between the milk and the soy formulas was the smell if/when they spit up. Soy reeked. However, it was a small trade off for a baby who was gaining weight and wasn’t screaming because of gas pains.
I don’t know a damn thing about formula but -
Cookie Crumb! That’s so clever! I love it!
Define “backed up”. Constipation in babies before they’re on solids is not defined by time between poops but by the consistency of the poops. WhyBaby poops no more than once a week, and her pediatrician sez she doesn’t care how long the time span is, if it’s soft when it comes out, fine. Some babies just don’t poop very much.
If, on the other hand, it’s bloody, black, white or pebbley, we’re to call the pediatrician immediately.
As for which formula - eh. Whatever makes your baby gain weight and hopefully spit up less. They’re all pretty nutritionally equivalent (though most doctors want them on iron-fortefied). Every baby has his favorite. I assume you’re doing the other reflux things - small meals more often, lots of breaks to burp (really to slow down the eating) and keep him upright for 1/2 an hour after each meal (front carriers are your friend!)
We had to put WhyBaby on Zantac a week ago, but frankly I’ve seen no difference at all. But she doesn’t seem too upset with the fountains of milk gushing out her nose and mouth - she always wants more when she’s done spewing. So we’re just keeping lots of cloths handy and watching her weight closely.
Well, I’m actually defining constipation by the distress he seems to be in until he goes, which is about once a day. He goes through about two hours of gyrations and, ultimately, crying fits and then messes his shorts and he’s OK. I just came back from the pediatrician du jour and she didn’t think the prune juice was really necessary or likely to help, so I’ll cut that out despite the fact I pretty much hated her and all her theories.
He’s also on Zantac and I have seen an improvement but really think there’s been more of an improvement with the soy formula (pediatrican said she doesn’t think that should make any difference either but I know there is a difference).
Of course, she did a master’s thesis on colic and spent most of the appointment telling me that he wasn’t gassy, just mad.
Yes, we have an appointment with a new pediatrician next week. 
Have you tried formula that isn’t fortified with iron? I remember how my prenatals would back me up and they’re mainly iron pills.
My son will have screaming fits almost nightly when his tummy hurts from gas build up. A lot of times if I push his legs into him tummy it helps push it out and he feels better. I’ve also heard of parents taking the thermometer and taking the temp to get things moving. It might be worth a shot. As long as you don’t put it in too far I don’t see the harm in it.
My mother said that it was a good thing my youngest brother was the last child. After discovering he was mildly allergic to can milk, she began feeding him soy milk. Uopon the first diaper change, she threw away the cloth diaper. She said the thought of cleaning it after smelling it the first time put her off washing them. My brother was the child who was weaned the fastest. 
Son of Stonebow was exclusively breastfed until age 9 months. Then we weaned to a soy formula, and he drank the soy formula until he was just a little over 12 months old. We never had a bit of trouble, and despite some of the soy horrors that you can read on the internet, he’s a healthy, well-adjusted child.