Jennifer,

The short answer is "It depends". One source describes it as a "dynamic
process".

Literature on breast surgery frequently speaks of the breast as "a
cutaneous envelope" that contains different percentages of different
types of tissue at different times in life.

Fatty and connective tissue serve in part to "hold space" for the
development of new ductal and glandular tissue. As glandular tissue
develops, nature temporarily removes fat and connective tissue from the
envelope.

After weaning, but before a new pregnancy, glandular and ductal tissue
undergo regression; the longer the interval, the more regression. Fat and
connective tissue are redeposited as glandular tissue regresses.

Each of these processes takes time (some development occurs monthly,
during part of the menstrual cycle, and during pregnancy, the process
takes about 3-4 1/2 months ). I have heard in the past that rapid weaning
often results in saggier breasts, which makes sense in light of the above
physiology.

The onset of a new pregnancy with a new placenta (whose size and
efficiency might be quite a bit different from previous ones), brings a
new surge of placental hormones to stimulate regeneration of ductal and
glandular tissue, which includes four different types (or degrees) of
lobular development. (As Cathy Fetherston related so well in the
archives, the process resembles the arrival and departure of leaves on a
deciduous tree.)

Russo J, Russo IH. Development of the Human Mammary Gland In: The Mammary
Gland, Development, Regulation, and Function ed. by Neville MC, Daniels
CW 1987 Plenum Press, NY. pp 67-93.

On P. 89, a very interesting table of pie charts illustrates the average
% of breast volume components of a total of 14 women at various stages in
their reproductive lives.

Another interesting article includes information on
fat storage in gluteal areas in pregnancy vs. during lactation.

Kreisberg RA, Clues to disease from location of body fat, Contemporary
OB/GYN Sept. 1987 pp 134-144.

Can you tell I've finally begun to make progress with filing my
references (with helpful advice from Chris Mulford)!

Jean
**************
K. Jean Cotterman RNC, IBCLC
Dayton, Ohio USA

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