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1. Saint L, Maggiore P. Hartmann PE. Yield and nutrient content of milk in eight women breastfeeding twins and one woman breastfeeding triplets. Br J Nutr 1986;56: 49-58.
2. Renner E, Schaafsma G. Scott KJ. Micronutrients in milk. In: Renner E, ed. Micronutrients in milk and milk-based food products. New York: Elsevier Science Publishers, 1989:1-70.
3. Institute of Medicine (US). Subcommittee on Nutrition During Lactation, Committee on Nutritional Status During Pregnancy and Lactation, Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. "Milk composition" nutrition during lactation. Washington, DC: National Academy Press, 1991: 113-52.
4. Gallagher W. The motherless child. The Sciences 1992; 32(July/August):12-5.
5. Philipp E, Setchell M, Ginsburg M, eds. Scientific foundations of obstetrics and gynaecology. 4th ed. Oxford: Butterworth-Heinemann, 1991.
6. Russo J, Russo IH. Development of the human mammary gland. In: Neville MC, Daniel CW, eds. The mammary gland: development, regulation and function. New York: Plenum Press, 1987:67-93.
7. Dawson EK. A histological study of the normal mamma in relation to tumour growth: I. Early development to maturity. Edinb Med J 1934;41:653-82.
8. Cowie AT, Forsyth IA, Hart IC. Hormonal control of lactation. (Monographs of Endocrinology 15). Berlin: Springer-Verlag, 1980.
9. Vorherr H. The breast: morphology, physiology and lactation. New York: Academic Press, 1974.
10. McKiernan JF, Hull D. Breast development in the newborn. Arch Dis Child 1981;56:525-9.
11. Ayalah D, Weinstock IJ, eds. Breasts: women speak about their breasts and their lives. London: Hutchinson, 1980.
12. Hartmann PE. The breast and breastfeeding. In: Philipp E, Setchell M, Ginsburg M, eds. Scientific foundations of obstetrics and gynaecology. 4th ed. Oxford: Butterworth-Heinemann, 1991 :378-90.
13. Milligan D, Drife JO, Short RV. Changes in breast volume during normal menstrual cycle and after oral contraceptives. BMJ 1975;4:494-6.
14. Dawson EK. A histological study of the normal mamma in relation to tumour growth: II. The mature gland in pregnancy and lactation. Edinb Med J 1935;42:569-98, 633-66.
15. Salazar H. Tobon H. Morphologic changes of the mammary gland during development, pregnancy and lactation. In: Josimovich JB, Reynolds M, Cobo E, eds. Lactogenic hormones, fetal nutrition, and lactation. New York: John Wiley & Sons, 1974:221-77.
16. Parker CR Jr. The endocrinology of pregnancy. In: Carr BR, Blackwell RE, eds. Textbook of reproductive medicine. Norwalk, Conn, USA: Appleton and Lange, 1993:1740.
17. Lyons WR. Hormonal synergism in mammary growth. Proc R Soc Lond 1958;149:303-25.
18. Dilley WG, Kister SJ. In vitro stimulation of human breast tissue by human prolactin. J Natl Cancer Inst 1975;55:35-6.
19. Stampfer M, Hallowes RC, Hackett AJ. Growth of normal human mammary cells in culture. In Vitro 1980;16: 415-25.
20. Strum JM, Hillman EA. Human breast epithelium in organ culture: effect of hormones on growth and morphology. In Vitro 1981;17:33-43.
21. Klevjer-Anderson P. Buehring GC. Effect of hormones on growth rates of malignant and nonmalignant human mammary epithelia in cell culture. In Vitro 1980;16: 491 -501.
22. Plaut KI. Role of epidermal growth factor and transforming growth factors in mammary development and lactation. J Anim Sci 1992;76:1526-38.
23. Hurley WL, Doane RM, O'Day-Bowman MB, Winn RJ, Mojonnier LE, Sherwood OD. Effect of relaxin on mammary development in ovariectomized pregnant gilts. Endocrinology 1991;128:1285-90.
24. Jhappan C, Geiser AG, Kordon EC, Bagheri D, Hennighausen L, Roberts AB, Smith GH, Merlino G. Targeting expression of a transforming growth factor b1 transgene to the pregnant mammary gland inhibits alveolar development and lactation. Eur Mol Biol Organ J 1993;12:183545.
25. Plaut KI, Ikeda M, Vonderhaar BK. Role of growth hormone and insulin-like growth factor-1 in mammary development. Endocrinology 1993;133:1843-8.
26. Hytten FE. Clinical and chemical studies in human lactation: VI. The functional capacity of the breast. BMJ 1954;April 17:912-5.
27. Daly SEJ, Kent JC, Huynh DQ, Owens RA, Alexander BF, Ng KC, Hartmann PE. The determination of short term breast volume changes and the rate of synthesis of human milk using computerized breast measurement. Exp Physiol 1992;77:79-87.
28. Cox DB, Kent JC, Owens RA, Hartmann PE. Mammary morphological and functional changes during pregnancy in women. Proc Aust Soc Reprod Biol 1994;26:47.
29. Ostrom KM. A review of the hormone prolactin during lactation. Prog Food Nutr Sci 1990;14:1-44.
30. Arthur PG, Kent JC, Potter JM, Hartmann PE. Lactose in blood in nonpregnant, pregnant, and lactating women. J Pediatr Gastroenterol Nutr 1991;13:254-9.
31. Flynn FV, Harper C, de Mayo P. Lactosuria and glycosuria in pregnancy and the puerperium. Lancet 1953; ii(October 3):698704.
32. Nicholas KR, Hartmann PE. Progesterone control of the initiation of lactose synthesis in the rat. Aust J Biol Sci 1981;34:435-43.
33. Hartmann PE, Trevethan P. Shelton JN. Progesterone and oestrogen and the initiation of lactation in ewes. J Endocrinol 1973;59:249-59.
34. Hartmann PE, Whitely JL, Willcox DL. Lactose in plasma during lactogenesis, established lactation and weaning in sows. J Physiol 1984;347:453-63.
35. Whitely JL, Hartmann PE, Willcox DL, Bryant-Greenwood GD, Greenwood FC. Initiation of parturition and lactation in the sow: effects of delaying parturition with medroxyprogesterone acetate. J Endocrinol 1990;124: 475-84.
36. Hartmann PE. Changes in the composition and yield of the mammary secretion of cows during the initiation of lactation. J Endocrinol 1973;59:23147.
37. Peaker M, Linzell JL. Citrate in milk: a harbinger of lactogenesis. Nature 1975;253:464.
38. Chilvers CED, McPherson K, Peto J. Pike MC, Vessey MP. Breast feeding and the risk of breast cancer in young women. BMJ 1993;307:17-20.
39. Anderson GH. The effect of prematurity on milk composition and its physiological basis. Fed Proc 1984;43: 243842.
40. Kuhn NJ. Progesterone withdrawal as the lactogenic trigger in the rat. J Endocrinol 1969;44:39-54.
41. Kulski JK, Smith M, Hartmann PE. Perinatal concentrations of progesterone, lactose and a-lactalbumin in the mammary secretion of women. J Endocrinol 1977; 74:509-10.
42. Kulski JK, Smith M, Hartmann PE. Normal and caesarean section delivery and the initiation of lactation in women. Aust J Exp Biol Med Sci 1981;59:405-12.
43. Neifert MR, McDonough SL, Neville MC. Failure of lactogenesis associated with placental retention. Am J Obstet Gynecol 1981;140:477-8.
44. Kulski JK, Hartmann PE, Martin JD, Smith M. Effects of bromocriptine mesylate on the composition of the mammary secretion in non-breast-feeding women. Obstet Gynecol 1978;52:38-42.
45. Arthur PG, Kent JC, Hartmann PE. Milk lactose, citrate and glucose as markers of lactogenesis in normal and diabetic women. J Pediatr Gastroenterol Nutr 1989;9: 488-96.
46. Neubauer SH, Ferns AM, Chase CG, Fanelli J, Thompson CA, Lammi-Keefe CJ, Clark RM, Jensen RG, Bendel RB, Green KW. Delayed lactogenesis in women with insulin-dependent diabetes mellitus. Am J Clin Nutr 1993;58:54-60.
47. Arthur PG, Kent JC, Hartmann PE. Metabolites of lactose synthesis in milk from diabetic and non-diabetic women during lactogenesis II. J Pediatr Gastroenterol Nutr 1994;19:100-8.
48. Lawrence RA. Breastfeeding: guide for the medical profession. St Louis, Mo, USA: CV Mosby, 1980:121-3.
49. Hwang P, Guyda H, Friesen H. A radioimmunoassay for human prolactin. Proc Natl Acad Sci USA 1971; 68:1902-6.
50. Peaker M, Wilde CJ. Milk secretion: autocrine control. News Physiol Sci 1987;2:124-6.
51. Sosa R, Klaus M, Urrutia JJ. Feed the nursing mother, thereby the infant. J Pediatr 1976;88:668-70.
52. Prentice AM, Paul A, Prentice A, Black A, Cole T, Whitehead RG. Cross-cultural differences in lactational performance. In: Hamosh M, Goldman AS, eds. Human lactation 2: maternal and environmental factors. New York: Plenum Press, 1986:1344.
53. Hartmann PE, Sherriff J, Kent JC. Maternal nutrition and milk synthesis. Proc Nutr Soc 1995;54:379-89.
54. Wickes IG. A history of infant feeding. Part III: Eighteenth and nineteenth century writers. Part IV: Nineteenth century continued. Part V: Nineteenth century concluded and twentieth century. Arch Dis Child 1953; 28:33240, 416-22, 495-501.
55. Matterson N. Is he biting again? Woodend, Australia: Marion Books, 1984.
56. Lilburne AM, Oates RK, Thompson S. Tong L. Infant feeding in Sydney: a survey of mothers who bottle feed. Aust Paediatr J 1988;24:49-54.
57. Hartmann PE, Saint L. Measurement of milk yield in women. l Pediatr Gastroenterol Nutr 1984;3:2704.
58. Arthur PG, Hartmann PE, Smith M. Measurement of the milk intake of breast-fed infants. J Pediatr Gastroenterol Nutr 1987;6:758-63.
59. Woolridge MW, Butte N. Dewey KG, Ferris AM, Garza C, Keller RP. Methods for the measurement of milk volume intake of the breast-fed infant. In: Jensen RG, Neville MC, eds. Human lactation: milk components and methodologies. New York: Plenum Press, 1985:5-21.
60. Daly SEJ, Owens RA, Hartmann PE. The short-term synthesis and infant-regulated removal of milk in lactating women. Exp Physiol 1993;78:209-20.
61. Daly SEJ, Hartmann PE. Infant demand and milk supply. Part 2: The short-term control of milk synthesis in lactating women. J Hum Lact 1995;11:27-37.
62. Cox DB, Hartmann PE. Plasma prolactin and milk synthesis in women. Neuroendocrinology 1993;58(suppl 1) 47.
63. Daly SEJ, DiRosso A, Owens RA, Hartmann PE. Degree of breast emptying explains changes in the fat content, but not fatty acid composition, of human milk. Exp Physiol 1993;78:741-55.
64. Heesom KJ, Souza PFA, Ilic V, Williamson DH. Chain-length dependency of interactions of medium chain fatty acids with glucose metabolism in acini isolated from lactating rat mammary glands. Biochem J 1992;281 :273-8.
65. Hartmann PE, Atwood CS, Cox DB, Daly SEJ. Endocrine and autocrine strategies for the control of lactation in women and sows. In: Wilde CJ, Peaker M, Knight DH, eds. Intercellular signalling in the mammary gland. New York: Plenum Press, 1994:203-25.
66. Graber RG, Sumida C, Nunez EA. Fatty acids and cell signal transduction. J Lipid Mediat Cell Signal 1994;9: 91-116.
67. Molenaar AJ, Davis SR, Wilkins RJ. Expression of a-lactalbumin, a-S1-casein, and lactoferrin genes is heterogeneous in sheep and cattle mammary tissue. J Histochem Cytochem 1992;40:611-8.
68. Hartmann PE, Rattigan S. Saint L, Supriyana O. Variation in the yield and composition of human milk. Oxford Rev Reprod Biol 1985;7:118-67.
The two women you showed us both produced more milk from the right breast than the left. Is this usual, and is it related to which breast the baby is put to first at a feeding?
I think that perhaps two-thirds of women are uneven in the milk production between their left and right breasts, but it doesn't necessarily mean they are consistently higher in the right breast. We found that some women changed from one lactation to the next, so most milk production in one lactation is in the right breast, and in the next it's in the left breast, so there is a fairly random distribution between breasts. Some people think it has to do with the handedness of mothers. We haven't looked at that, but certainly it can change during subsequent lactations. It seems to me to relate to a behavioural characteristic in animals, which is teat order. There is evidence from Sweden, I believe, that indicates that when babies are put on their mother's abdomen, they make their way up to the breast. They also tend to associate with the breast that they attach to first. This observation would be consistent with observations of the establishment of teat order in other mammals.
I was particularly interested in your observation that fat content increases as the breast is emptied. Does that mean it is better for a woman to empty one breast before transferring the baby to the other?
This is an interesting situation, and one has to be very careful in responding, because how it is applied in practice can be quite misleading. The breast has regular mechanisms that can cope with most patterns of feeding. So far, our results indicate that it doesn't much matter how the breast is emptied; the baby will get the same amount of energy over a 24-hour period. One-sided feeding has only been recommended for women with oversupply problems. For normal feeding it is reasonable to finish one breast before offering the other.
Back to milk production. Presumably, in the case of twins, both breasts can operate to full capacity if they are emptied at the same rate?
That is correct. Our studies suggest there is additional capacity. I think mothers in Western societies have to down-regulate their physiological capacity to produce milk to their babies' requirements. We can look at the endocrine system as setting the upper limits of the mother's milk production capacity and the autocrine mechanism as then cutting it down to the actual needs of the baby. With twins the mother sustains a higher level of production that perhaps approximates the breasts' maximum capacity. We studied a woman who fully breastfed triplets for two and a half months, so the breast has enormous capacity.
You didn't mention the relationship of oxytocin to storage capacity. It seems that much of the milk won't come out without oxytocin release. Is that true? There is very little information on that.
Residual milk, in my opinion, has done more to confuse our understanding of lactation than just about any other concept. This is because it is based on the very unnatural situation of the dairy cow. The suckling situation is totally different. Oxytocin is obviously required for milk ejection, but the amount of milk that is taken depends on the baby's appetite, not what the mother has available. So in mothers with high storage capacity, there is enormous variation between the storage capacity and the amount of milk that the baby might take at any one time.
But if the mother didn't release oxytocin at all, would that dramatically reduce the amount of milk the baby could get?
Yes, it certainly can be a problem. We don't notice it particularly in women who are breastfeeding. It is often a problem for mothers who are expressing milk. If they don't get a let-down, they can have a great decrease in milk production.
It is very important to look at milk production from individual breasts, which relates to Dr. McLaren's first question. We did an initial study in Oxford on six mothers to determine if the interval between feedings was correlated with the amount of milk the baby took. If you combine the production of both breasts, there's no relationship. If you split the intake from the left and the right breasts, there is a very tight coupling. That is, the gap between feeds determines how much the baby takes from a breast. For the other breast, there is no such relationship. It was clear women showed "breastedness" in the same way they show handedness, but it wasn't linked to handedness, because we had five "left breasted" mothers and one "right-breasted" mother, but they were all right-handed.
So it's not clear what the relationship is. It was almost as if the control mechanisms were located in one side, as in true handedness. When we moved to Bristol, we studied 20 more mothers and found no such relationship. We found the relationship was with the first breast to be offered, which confused us somewhat. Therefore, we didn't publish the results.
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