We might think that “regular bowel movement” for our baby is the same as that for adults, which is usually once a day; however, our babies are not simply little adults. Their physiology is entirely different from ours, which means that what could be normal for adults may not necessarily be true for infants and children. Before diagnosing an infant or child as constipated, there are certain things we must consider like age, diet including source of milk (breastfeeding or formula feeding), and their normal bowel movement pattern. Real constipation occurs when the baby's stools cause significant difficulty and discomfort when being passed, because they are very dense and hard. This definition excludes the baby who has soft, easy-to-pass stools once a week, even if he seems to strain a lot in the process.
A common misconception about constipation concerns the use of iron as multivitamins or iron-fortified formula milk. This is probably because of the side effects of iron taken during pregnancy which causes constipation and dark-colored stools. However, the daily recommended dose of iron for adults is 18mg/day for non-pregnant females, and up to 27mg/day for pregnant women, which is over and beyond the dose for children. The usual dose of iron as multivitamin supplement for infants 0-6 months old is only 0.27mg/day and 11mg/day for babies 7-12 months old. While the content of iron is not the same for all formula milk, surely, it will follow the recommended daily dosages for it to be approved by the Bureau of Food and Drugs (BFAD).
Studies have shown that iron in formula milk does not actually cause constipation. Based on studies submitted to the American Academy of Pediatrics, babies who were given low-iron formula had the same rate of constipation as that of babies who were given high-iron formula; therefore, iron does NOT have a significant effect on constipation.