The concept can certainly be dated as early as 1978, with the first mention of Eccentrica Gallumbits, the triple-breasted whore of Eroticon Six in the Hitch-Hiker's Guide to the Galaxy .
scifi.stackexchange.com/users/23/Mike Scott
Aelita: Queen of Mars , a 1924 Russian silent film directed by Yakov Protazanov.
Nothing direct, but perhaps the different environment of mars has allowed females to develop a third breast as highlighted in the costume of the leading lady, Yuliya Solntseva
scifi.stackexchange.com/users/54148/user54148
There have been a number of multiply-breasted female characters seen in science-fiction and horror films.
Be warned, NSFW links below... Four -breasted characters are seen in; Earth Girls are Easy (1989)
The Warrior and the Sorceress (1984) Six -breasted character are seen in Necropolis (1987)
Star Wars : Return of the Jedi (1984)
However, he first appearance of a three -breasted character seems to be Star Trek 5:
The Final Frontier
from 1989, released over a year before Total Recall.
A cat-like alien woman with three breasts is seen in the cantina scene on Nimbus III.
There's an even earlier match for a three-breasted character in the Sci-horror film " Vicious Lips " from 1986.
A band finally gets the opportunity for that breakthrough gig if they can make it to an "in" club on another planet.
They encounter a variety of strange aliens .... UPDATE
I've found an even earlier match in the Sci-smut thriller Galaxina from 1980.
Our (ahem)
heroes visit an alien brothel where they encounter many attractive alien females:
scifi.stackexchange.com/users/20774/Valorum
It is too in the Volume 1 (1962-1965) of « Little Annie Fanny » in the story from december 1964 called « Astronaut Annie » published originally in Playboy.
scifi.stackexchange.com/users/124958/Patou
If you can speak Italian this is from the '60s: http://it.wikipedia.org/wiki/Pupazza_frascatana
La leggenda legata alla pupazza vuole che rappresenti una mammana, una balia che teneva a custodia
i bambini delle donne impegnate nella vendemmia.
Questa mammana era in grado di ammansire
anche
i bambini più agitati e capricciosi: a differenza delle sue colleghe, infatti,
li imboniva allattandoli ad un seno finto
con del buon vino di Frascati.
Così, il dolce raffigura una donna con tre seni, due per il latte e uno per il vino.
La leggenda, nata negli anni sessanta, oltre a legarsi goliardicamente alla viticoltura, una delle maggiori realtà produttive frascatane, si è diffusa in pochi anni come patrimonio iconografico locale.
Sul territorio italiano si
producono altri dolci detti pupazze, ma la pupazza frascatana è l'unica pupazza a rappresentare la figura femminile con tre seni.
"
This describes a mythical midwife who uses he three breasts, of which dispense milk and one of which dispenses wine, to soothe children.
scifi.stackexchange.com/users/15652/Maurizio In denmark
I am trying to figure out who implemented the first three-breasted character, as seen in  Total Recall  (1990).  I know someone who says there was such a character in the original  Battlestar Galactica  series but he has no proof to back up his claim.  Does anyone know anything about that, or of any other instances where it might have first happened?
Who first implemented the three-breasted character?
scifi.stackexchange.com
<history-of><characters><total-recall>
scifi.stackexchange.com/questions/17770
scifi.stackexchange.com/users/6694/kcwebz
There have been a number of multiple-breasted female characters seen in science-fiction and horror films.  This can  be dated as early as Aelita: Queen of Mars , a 1924  Russian silent film  directed by Yakov Protazanov.  This was also seen in 1978, with the first mention of  Eccentrica Gallumbits, the triple-breasted whore of Eroticon Six  in the  Hitch-Hiker's Guide to the Galaxy . The concept was first introduced in a film by Protazanov as early as 1978.
The concept was first introduced in a film by Protazanov as early as 1978. There has been several instances of mutiple-breasted characters.