Problems of early infancy, formula changes, and mothers' beliefs about their infants.

Problems of early infancy are sometimes managed by changing an infant's formula from a cow milk formula to a soy protein or casein hydrolysate formula ("special formulas"). This study was designed to determine the frequency of formula changes, mothers' reports of problems that lead to such a change, and mothers' beliefs about the causes of these problems. Mothers of 189 breast-feeding (BF) and 184 formula-feeding (FF) infants were enrolled postpartum. Follow-up data were obtained by telephone interviews at 4 months. After starting a cow milk formula, 11% of the BF and 25% of the FF infants were given special formulas. Mothers frequently reported problems related to feeding, bowel movements, and crying behavior; 32% of infants with such problems were given special formulas. Excessive crying and colic were the most common problems leading to a formula change. When a formula was changed, mothers more frequently believed that the cause of the problem was intrinsic to the child (P less than 0.001) and that their infant had had a "disease or illness" (P less than 0.001). When formula changes occurred, 26% of mothers believed that their infants were allergic to cow milk. These beliefs may affect a mother's perceptions of her child's vulnerability.