Transitions in infant feeding during the first year of life

To document ages at which transitions in infant feeding occur, to compare these transitions to literature reports from the 1970s and 80s, and to identify maternal characteristics related to the age of the infant when solid food was first introduced.

Ninety-eight mother/infant pairs (middle and upper socioeconomic status) participated in the longitudinal study. Using a randomized, incomplete block design, in-home interviews were conducted by trained personnel when infants were 2, 3, 4, 6, 8, 10, and 12 months of age; each mother/infant pair was seen four or five times. Information on food intake, including breast milk/formula, was collected at each interview. Means +/- SD and frequencies were calculated, and least squares analysis of variance was used to develop a predictive model related to the introduction of cereal.

Most mothers decided on the initial feeding mode (breastfeeding or formula) prior to pregnancy; 83% breastfed initially although most (76%) totally discontinued breastfeeding by 6 months. Infants' ages varied greatly when each of the seven categories of food was introduced, cereal was added to the infants' diets at a mean age of 3.8 +/- 1.4 (SD) months, juice 4.7 +/- 2.2, fruit 4.9 +/- 1.6, vegetables 5.2 +/- 1.3, mixed foods 7.8 +/- 2.1, table foods 8.2 +/- 2.1, and meat 8.2 +/- 2.1. The multivariate model explained 59% of the variability in ages of infants when cereal (generally the first solid food) was added. Significant variables (p < or = 0.05) were feeding mode, recommendation by the physician, and the interaction between feeding mode and education of the mother. Mother's employment and sibling rank of the infant contributed to the model (p = 0.06 and p = 0.09, respectively). Infants' age when cereal was added was not related to the variables of gender or birth weight.

The finding that the mothers' decision whether or not to breastfeed was made prior to conception supports the importance of population-based education aimed at women in the child-bearing years as well as patient instruction early in the pregnancy. However, the duration of breastfeeding was shorter than was reported in the 1980s. Infants varied greatly in ages when the seven categories of complementary foods were added to their diets. Although recommendations for delaying introduction of solid foods until the infant is 4 to 6 months of age have been in place for more than a decade, about half the mothers in this study did so earlier. Characteristics of mothers who introduced cereal earliest (i.e., mean age of infants < 4 months) were more likely to be formula feeding when cereal was added, to feed cereal via the bottle, to be primiparous, to be employed outside the home, and/or not to cite the physician as a source for guiding the infant's transition to supplemental food.