Human milk is nature's ideal diet for infants. When breastfeeding goes well, a baby will consume adequate quantities of human milk to meet all her nutrient requirements for about six months of life. Breastfed babies grow rapidly in the early weeks and months of life, putting on weight at least as fast as bottle-fed babies. Once a mother's milk comes in abundantly, her breastfed baby should start gaining about one ounce each day, or one and a half to two pounds each month, for approximately the first three months. Most babies double their birth weight at about four and a half months of age. Their early rapid weight gain pattern gradually tapers off (or else we'd all eventually be as big as elephants!). Babies don't triple their birth weight until about one year, and they quadruple it around age two. After the first three to four months, breastfed infants may gain weight less rapidly than bottle-fed babies during the remainder of the first year. The differences in growth patterns of breastfed and bottle-fed infants can give the false impression that an older breastfed baby's growth is faltering when it might actually be normal. I need to emphasize, however, that "faltering" growth in a breastfed infant during the first three to four months should not be considered normal. Early difficulties gaining weight probably reflect unresolved breastfeeding problems that should not be ignored.
Vitamin and Mineral Supplements
In the past, physicians routinely prescribed vitamin and mineral supplements for breastfed infants. Not only was this practice costly and usually unnecessary, but it also undermined women's confidence by implying that their milk was deficient. I recall being confused about why my first baby, Peter, required supplemental vitamins and iron if my milk was supposed to be "perfect nutrition." "How did babies in ancient times thrive without such supplements?" I wondered. Ironically, formula-fed babies don't require extra vitamins and minerals because formulas are fortified with them. Expectant and new parents can get the wrong message that breast milk is less nutritious than artificial baby milk if supplements are given to breastfed infants and not to formula-fed babies. Let me review the current recommendations for supplementation of healthy breastfed infants.
The milk produced by a well-nourished woman has ample amounts of vitamins. However, poorly nourished women with vitamin deficiencies will produce milk that is deficient in vitamins. A few cases of vitamin-deficient milk and poor infant growth have been linked to a strict vegetarian diet in lactating mothers who weren't taking vitamin supplements.
Human milk is relatively low in vitamin D, but this vitamin is synthesized in the skin in ample amounts if a person is exposed to sunlight. Dark-skinned individuals require more sunlight exposure than light-skinned persons. Vitamin D deficiency can cause rickets (softening of the bones producing bowing of the legs and other bone deformities). A few cases of rickets have occurred in exclusively breastfed babies. The babies in whom rickets occurred were at particular risk because they were dark-skinned and received very little sun exposure. To prevent any chance of rickets, some physicians prescribe multivitamin drops for all breastfed infants instead of singling out those who get little sunshine exposure. Multivitamin preparations are used for this purpose because they actually are cheaper and more accessible than plain vitamin D.
Vitamin and/or mineral supplements may be required for premature infants and those with special health problems. Ordinarily, no vitamin or mineral supplements are necessary for healthy, breastfed infants of well-nourished mothers. Nevertheless, some doctors routinely prescribe liquid multivitamin preparations for breastfed infants "just in case." This practice probably does no harm beyond the added expense and hassle of trying to get your baby to take the vitamins. However, a few mothers report that their infants react adversely to vitamin preparations, either refusing them or acting fussy afterward. If that is the case with your baby, ask your doctor whether a valid indication exists for prescribing the supplements.