My poor breasts

Oddly enough, Gosia, my breasts are doing the exactly same thing (though
with less enthusiasm) now at nearly 37 weeks. It looks exactly as you
describe: pigment has flooded outside the line of the aureola onto the
surface of the breast itself. My 'linea negra' has also shown up just in the
last few days, as a dark smudge in what's left of my belly button. But not
very dark - I have very pale skin and even my freckles never get dark, so
none of this new pigmentation is dark.

Oddly even more, following your words, I am also very pale skin - a
natural blond-haired but those areolas are almost black. But no linea
negra at all.
Strange. Did you experience so big diameter increasing too?