NORMAL BREAST DEVELOPMENT

EMBRYOLOGY

Breasts begin developing in the embryo about 7–8 weeks after conception,
consisting only of a thickening or ridge of tissue.

From    weeks   12–16,  tiny    groupings   of  cells   begin   to  branch  out,    laying  the

foundation  for future  ducts   and milk-producing  glands. Other   tissues develop

into    muscle  cells   that    will    form    the nipple  (the    protruding  point   of  the breast)

and areola  (the    darkened    tissue  surrounding the nipple).

In  the later   stages  of  pregnancy,  maternal    hormones    cause   fetal   breast  cells   to

organize    into    branching,  tube-like   structures, thus    forming the milk    ducts.  In

the final   8   weeks,  lobules (milk-producing glands) mature  and actually    begin

to  secrete a   liquid  substance   called  colostrum.

In  both    female  and male    newborns,   swellings   underneath  the nipples and

areolae can easily  be  felt,   and a   clear   liquid  discharge   (colostrum) can be  seen.