Nancy E. Wight MD, FAAP, IBCLC wrote:

> Iron in vitamins or formula does NOT cause constipation.  There are
several
> good research studies to show this.
And Anne Cook wrote:
I've seen this information mentioned in formula company literature, and in
WIC
information, but this seems to contradict *years* of anecdotal evidence to
the
contrary.  If iron supplements in adults cause constipation (and they do!),
why
wouldn't there be a similar effect on infants?

Not only do the studies show that the iron does not cause the problem, but
I too have lots of experience with babies and formula.   Since I work for
WIC, I unfortunately have more experience with formula than Breastfeeding!
  What I find is that moms assume that iron is causing the constipation,
and after several weeks they change to low iron, this is about the same
time that the baby's GI system gains a little maturity, and the problem
often gradually resolves on its own.
        For babies less than one month, I recommend the addition of 2-3 oz of
water mixed into the formula by 1/2 oz/bottle, not given directly.   The
proteins in ABM are larger than in brmilk and require more water to be
broken down, and the additional water does the trick.  Many moms find that
if they change to soy ABM, the problem is resolved---it doesn't advertise
on the label, but has the same fortification with iron that ABM with iron
has!
        There have been a few babies in my experience who are sensitive to the
iron, and those can be corrected by mixing low-iron ABM with iron fortified
ABM.
           Incidentally, iron does not cause constipation for me (and some
other women I've counseled)  but diarrhea!
Of course, the real resolution to this problem is give them breastmilk!
Michelle Scott, RD,MA,IBCLC in beautiful NH where the xc skiing was perfect
last weekend at Great Glen,NH