Objective: To evaluate the growth of exclusively breastfed infants from birth to 6 months of life.Methods: This was a longitudinal study of 184 children who received primary care at a public institution (Exclusive Breastfeeding Stimulation Program, PROAME) in Belém, state of Pará, Brazil, between February 2000 and January 2001. A total of 102 children completed the study. All were born at full term with a birth weight greater than or equal to 2,500 g. No events were recorded during the neonatal period and the infants were exclusively breastfed, on demand, since their birth. The infants were followed up monthly, and the weight and length measured at birth and at the end of the first, fourth and sixth months of life were compared to the 50th percentile line of the NCHS growth charts and to other previous studies of Brazilian children who were exclusively breastfed.Results: Growth was adequate for all the children, who doubled their weight before the fourth month of life. Despite a slow-down in weight and height gain after the fourth month, the weight averages at 6 months were greater than the standards used for comparison. Conclusions:The average weight of these exclusively breastfed children was above the 50th percentile of the NCHS curve at 6 months, thus confirming the nutritional advantages of breast milk, especially when the mothers receive guidance regarding the appropriate techniques for breastfeeding.

Conflict of interest: noneObjective: The objective was to determine the prevalence of iron deficiency and iron deficiency anemia among exclusively breastfed infants from one to six months of life and to identify associated risk factors. Methods: This is a cohort study of the hemoglobin and serum ferritin levels of 102 healthy full-term infants, weighing more than 2500 grams (5.5 pounds) at birth, evaluated for growth development and supported to promote exclusive breastfeeding. Hemoglobin and ferritin levels were measured in the first, fourth, and sixth months of life. The hemoglobin and ferritin levels of the mothers were also measured in the first month postpartum. Results: At four months, 5.7% presented iron deficiency and 3.4% had iron deficiency anemia. At six months, the percentage of children with iron deficiency increased more than four times, reaching 26.1%, while iron deficiency anemia was present in 23.9% of the infants studied. Iron deficiency at six months of age was significantly correlated to growth velocity. Conclusion: According to the results of this study, exclusive breastfeeding protects infants from iron deficiency and iron deficiency anemia for the first four months of life. After this age, in accordance with the literature, the findings of this study demonstrated an increase in anemia and iron deficiency rates, adding to evidence that supports the monitoring of iron levels in exclusively breastfed children presenting higher weight gains beginning at four months of age.