The Maturation Index of Colostrum and Milk (MICAM): a measurement of breast milk maturation.

A biological marker, the Maturation Index of Colostrum and Milk (MICAM), was developed using filter paper chromatography. The MICAM consists of five patterns used to measure the individual rate of breast milk maturation among mothers. This article documents the biological basis of MICAM patterns as a gradual breakdown of an emulsion of breast milk that is dependent on the ratio of sterols plus phospholipids to fat content of the milk. Frequencies of MICAM patterns by day, timing of the milk collection, and inter-rater reliability are addressed and the construct validity is explored. This was a partial replication of the original tool development reported by Humenick in 1987. In both studies, the variables of timing of breast-feeding initiation, frequency, and cumulative length of breast-feeding episodes were significantly correlated as predictors of early milk maturation as measured by the MICAM. Milk maturation rate was also significantly correlated as a predictor of infant weight gain, weeks of sustained breast-feeding, and maternal-infant breast-feeding satisfaction. The MICAM can be used as a clinical screening tool to assess the progress of milk maturation in cases where breast-feeding has had a difficult or delayed initiation, and to evaluate interventions designed to support lactation.