Breast volume and milk production during extended lactation in women.
Quantitative measurements were made of relative breast volume and milk production from 1 month of lactation until 3 months after weaning, and the storage capacity of the breasts was calculated. The increase in breast tissue volume from before conception until 1 month of lactation was maintained for the first 6 months of lactation (means+/-S.E.M.) (190.3+/-13.1 ml, number of breasts, nb = 46). During this period of exclusive breast-feeding, 24 h milk production from each breast remained relatively constant (453.6+/-201 g, nb = 48), and storage capacity was 209.9+/-11.0 ml (nb = 46). After 6 months, breast volume, milk production and storage capacity all decreased. There was a relationship between 24 h milk production and the storage capacity of the breasts, and these both appeared to be responding to infant demand for milk. At 15 months of lactation, the 24 h milk production of each breast was substantial (208.0+/-56.7 g, nb = 6), even though the breasts had returned to preconception size. This was associated with an apparent increased efficiency of the breast (milk production per unit breast tissue) after 6 months, which may have been due to redistribution of tissues within the breast. The possible causes of the decrease in breast volume are discussed.
Kent
J C
JC
Department of Biochemistry, The University of Western Australia, Nedlands, WA 6907, Australia. jkent@cyllene.uwa.edu.au
Mitoulas
L
L
Cox
D B
DB
Owens
R A
RA
Hartmann
P E
PE
D000328:Adult; D001835:Body Weight / Q000502:physiology; D001940:Breast / Q000033:anatomy & histology* / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation / Q000502:physiology*; D008895:Milk, Human / Q000502:physiology; D013997:Time Factors
D005227:Fatty Acids