Human Milk Flow

Abstract

AND BETTY NIMS DETROIT Though many rational theories have been advanced on the subject, it is not known whether nervous, chemical or glandular agents operate to start the flow of milk. Even seemingly convincing experimental evidences are contradictory concerning the causes of the hypertrophy of the mammary glands during pregnancy and their secretory activity immediately after parturition. There is a general opinion that nervous shock, certain psychic states caused by the presence or absence of the suckling reflex and the emotional status and environment of the mother affect the flow of milk. The perturbation accompanying these factors is evidently not a direct nervous mechanism, since it has been shown experimentally that the severance of the spinal cord in woman 1 and in other mammals 2 and of the nerves supplying the mammary glands 3 causes no untoward influence on the secretory activity of the glands. This evidence is further substantiated by the results of an experiment in which two mammary glands of a guinea-pig were transplanted into the skin back of the ear of a sister animal.4 A few months later, the experimental animal conceived and bore young, and the two mammae in their new environment were seen to function normally, i. e., they became

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

“…In a large study of 200 women who expressed milk manually for 24 h, the volume ranged from 0.8 to 1.8 liters for a mean daily loss of 400 mg calcium (582,584). Individual women were identified who had sustained production of up to 3 liters of milk per day during 6 -12 mo of lactation (419,583,838); analysis of their milk revealed daily calcium losses of 500-1,200 mg (419, 838). However, manual expression of milk can yield much greater volumes than a suckling baby demands, thereby overestimating milk production.…”

“…However, this should be mitigated by the infant consuming solid foods by 6 mo of age and a reduction in the amount of milk produced. On the other hand, a professional "wet nurse" can have high volumes of milk output that are sustained for long intervals (419,583,838), so ongoing bone loss seems inevitable. However, no bone density data have been reported for such women.…”

“…Women who nurse twins and triplets can have, respectively, more than double and triple the milk output of women nursing singletons (233,792). Individual cases of women nursing singletons have documented milk output of up to 2.4 -3.1 liters per day that was sustained for more than 12 mo of lactation (583,838). The composition of milk is similar between women with average and high outputs (233,792), and so producing more milk will cause greater maternal losses of calcium.…”

Trace Element and Mineral Nutrition During Lactation

“…There is substantial evidence that infant demand is the major regulatory factor for volume of milk secreted during lactation. Studies of early investigators (4) indicate that wet nurses could secrete greater than 3,000 mL/d and mothers of twins and triplets are reported to secrete 2,000 to 3,000 mL/d by nursing about 12-15 times per day (5). Thus, the average quantity of milk secreted by lactating women for a normal single infant is far less than maternal capacity for milk production.…”

Human Milk: Nutritional Aspects of a Dynamic Food

“…When mothers secrete a milk with a low energy density, increased suckling by their infants stimulates an increase in milk secretion. In the early studies of Macy et al [9], wet nurses were reported to secrete 13,000 g/day, and mothers who exclusively nurse twins or triplets can produce 2,000-3,000 g/day by nursing about 15 times/day [10]. Thus, the human potential for milk production is far greater than the average demand of a thriving single infant.…”