[A study on immunoglobulin A in human milk. Relationship between the amount of IgA and perinatal factors including food intake].

The concentrations of IgA in human milk on the 5th or 6th day after delivery were measured in 117 women who delivered maturely, and the amount of IgA per 24 hours was calculated by multiplying the IgA concentration by the total milk volume of the same day. The relationship between the amount of IgA and perinatal factors, including food intake during the latter half of the pregnancy, were investigated. Subjects were divided into three groups (little, moderate, much) by the amount of IgA per 24 hrs and quantification theory II statistical analysis was applied to discriminate among the three groups using 13 factors concerning the perinatal period and food intake as explanatory variables. 1. The ratio of correct classification into the three groups was relatively high, suggesting that there is a relation between the amount of IgA in milk and perinatal and food intake factors. 2. Among the perinatal factors, the age, the gestation period and the number of experienced deliveries were effective for the amount of IgA. The obtained results showed that women 20-29 years old who had the first delivery after 38-40 weeks of gestation were liable to have the greatest amount of IgA in milk. 3. The amount of IgA of the women who ate less in the latter period of pregnancy compared with pre-pregnancy, or had a "less frequent intake of protein" was liable to be the greatest, and that of women with a "large volume" or "frequent protein intake" was liable to be greater than that of those with "the same volume" or "moderately frequent protein intake." The amount of IgA of the women with a "frequent intake of salted dried fish" was the greatest. The fact that the amounts of IgA of the women who "ate less" or had a "less frequent intake of protein" were liable to be the greatest was considered to show that toxemia or the tendency to near abortion or preterm delivery greatly affected the amount of IgA.