MATERNAL MILK SUPPLY INFANT

FACTORS AFFECTING THE MATERNAL MILK SUPPLY
True difficulties in the supplying of milk are most commonly related to the irregular or incomplete removal of milk. In the human mammary gland, lactation is under autocrine control in which the frequency and degree of milk removal appears to regulate an inhibitory peptide present in the milk. In other words, if the milk is not removed, this inhibitory peptide accumulates and subsequently decreases the synthesis of milk. If the milk is removed frequently, this inhibitory peptide does not accumulate, and milk synthesis increases.

Although most women are capable of producing more milk than their infants require, more than half of breastfeeding mothers perceive that their milk supply as inadequate. A mother may state that her milk is not in and that her infant is not getting enough milk. This misperception is most common during the immediate postpartum period. The neonate's requirements for fluid gradually increase over the first few days; ideally, the neonate frequently ingests milk in small volumes. As the baby's GI tract becomes more regulated and functional and as the stomach volume increases, the baby's milk intake increases.

The composition changes of the milk from colostrum to mature milk, which has a higher energy density (ie, caloric density) because of its higher fat content. Mothers should be encouraged to breastfeed at least 8-12 times during the immediate postpartum period to increase their milk supply. If a mother breastfeeds only 4-5 times during those early days, her milk production is delayed. Infrequent breastfeeding is associated with neonatal jaundice (referred to as breastfeeding jaundice or dehydration jaundice) and the early cessation of breastfeeding. Another perception of inadequate milk supply is related to the infant's growth spurts. During periods of enhanced growth, the infant may be more irritable and may seek the breast more often. These growth spurts usually resolve in about 1 week. Growth spurts should be explained to the mother to prevent undue stress or interruptions in breastfeeding.

Because the milk supply is directly related to its removal and ongoing synthesis, factors that hinder milk removal affect milk production. Factors that could disrupt the complete removal of milk are numerous (see Recognition and Management of Common Breastfeeding Problems). For example,
stress and fatigue in both parents may have an impact on the mother's milk production. Evaluating for these risk factors in the mother-infant dyad is essential to ensure that the milk supply is sufficient and that breastfeeding difficulties are not perpetuated.

If an infant is ill, a mother typically uses a breast pump to remove and store her milk. Premature infants who are first learning to breastfeed may be ineffective at milk removal. Some infants have neurologic disabilities or suck-swallow incoordination (common among premature infants born at <33 wk of gestation). In those situations, a mother may need to pump her breasts after breastfeeding to maintain adequate lactation while her infant learns to breastfeed more effectively. By facilitating complete removal of the milk by using a pump, the mother's supply remains abundant and thus easier for the infant to consume. Marianne Neifert, MD, uses this simile: "With an increase in a mother's milk supply, feeding is like drinking from a fire hydrant; the infant cannot miss."

In summary, factors affecting maternal milk supply include the following: (1) irregular or incomplete milk removal, (2) growth spurts (The infant's demand and maternal supply can change. The milk supply should normalize within 1-2 days.), (3) maternal fatigue and stress, and (4) the infant's medical condition (eg, prematurity, neurologic injury).