Heidi, I,too, would like more information and research to cite on the problems associated with mixing iron-fortified formula supplements with breastmilk in one feeding. I had heard that Abe Parvanta and Bo Lonnerdal are doing research in this area. Is it published yet? "The Breastfeeding Answer Book" has a few sentences on this topic (p. 515), as does "Breastfeeding and Human Lactation" (p. 115), but I would be interested in some recent studies to cite. This has wide implications. I had heard that WIC supplies mothers only with iron-fortified formula. Is that true? I am seeing mothers who are receiving iron-fortified formula at discharge from the hospital, and unsolicited from formula companies (delivered to their doors), and who are being advised to supplement breastfed (preemie or slow growth) babies with this after each feeding. If a baby is receiving iron-fortified ABM as well as breastmilk, how widely spaced should these be to minimize the detrimental effects? Should we try to get mothers to save up the pumped breastmilk to give it all in one feeding supplement, and then use all ABM in the next supplemental feeding, rather than mixing them? (My goal, of course, is to encourage all-breastmilk supplements, and eventually total feeding at the breast). Would 2 hours separation make any difference? Anne Altshuler, RN, MS, IBCLC and LLL leader in Madison, WI e-mail at: [log in to unmask]