Its normal for a breastfed baby to poop after every feed, its normal for a breastfed baby to not poop for up to 14 days. And of course anything in between.
I would say its the meds.... Breastmilk is a natural antacid, so nursing her in a more upright position should provide her more relief than any medication. Most peds are really dumb on breastfeeding and are quick to dole out medications. Nurse her in a semi-upright position and keep her semi-upright for about 15 minutes or more after her feed, and that should allow the breastmilk to soothe her tummy and not allow the acid to flux up and cause her pain.
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Just editing to post some websites to prove my point about breastmilk being a natural antacid, since apparently some don't believe that.... AND I never said breastmilk would make it go away, I said its a natural antacid...therefore HELPING the reflux. Meds don't make reflux go away either, and in fact most new studies show it doens't help at all. Besides, I'd rather use a natural antacid like breastmilk on my baby than any medication.
http://www.kellymom.com/babyconcerns/reflux.html
**GERD may cause babies to either undereat (if they associate feeding with the after-feeding pain, or if it hurts to swallow) or overeat (because sucking keeps the stomach contents down in the stomach and because mother’s milk is a natural antacid).**
http://www.infantrefluxdisease.com/is-baby-getting-enough...
**Some breastfed babies, after the first three to four weeks of life, may suddenly change their stool pattern from many each day, to one every three days or even less. Some babies have gone as long as 15 days or more without a bowel movement. As long as the baby is otherwise well, and the stool is the usual pasty or soft, yellow movement, this is not constipation and is of no concern. No treatment is necessary or desirable, because no treatment is necessary or desirable for something that is normal.**
http://infantrefluxdisease.com/breastfeeding-baby-with-re...
**Breastfed babies with reflux and GERD generally seem to cope better than those who are formula fed. Perhaps this is because they get more comfort from the closeness that nursing provides over bottle feeding or because breast milk acts as a natural antacid**
**It's certainly no secret, breastfeeding is best for baby, but that's particularly true for babies with reflux.**
**Breast milk is digested twice as fast as formula, this is beneficial for babies with reflux because the faster food moves out of the stomach, the less chance it has of being refluxed.
Breast milk, particularly the proteins, are more hypoallergenic than formula, especially cow's milk based formula. Reflux can—in some cases—be aggravated by milk or food allergies so providing the most hypoallergenic possibility is extremely beneficial.**
http://infantrefluxdisease.com/breastfeeding-reflux.php
**Babies with reflux can take two completely different approaches to mealtime. Some become frequent and aggressive feeders, guzzling fast and demanding more. These babies seem to get relief from the natural antacid effects of the milk**