From http://middle-earth.xenite.org/2011/12/16/what-are-the-roles-of-women-in-tolkien/ (the author, Michael Martinez, is a Tolkien scholar known for very thorough digging through Tolkien material for analysis like this). Emphasis mine:
The Hobbit — There are no active female roles in The Hobbit. Published in 1937, this children’s story was essentially composed for J.R.R. Tolkien’s sons and although he expanded the original tale for publication he did not add any speaking female roles to the story. Nor did he add female characters in the two subsequent major revisions of the story that were published in 1950 (the Second Edition, which incorporated theoretical changes Tolkien had suggested to his publisher in 1947) and 1965 (the Third Edition, which was rushed into publication to address a copyright dispute). That said, there are three female characters who are mentioned in The Hobbit: Bilbo’s mother Belladonna Took, the unnamed mother of Fili and Kili, and the unnamed wife of Girion of Dale.
All three women serve a similar purpose in the story: their roles are to provide connections between major characters in the story and their predecessors. Through Belladonna Bilbo is connected to the Old Took, Gandalf’s friend; through their mother Fili and Kili are connected to Thorin, Thrain, and Thror; and through Girion’s wife Bard is connected to the ancient kings of Dale. These references to women in The Hobbit unfortunately set a precedent in the publication history that is hard for Tolkien to overcome.
As a side note, while the mother of Fili and Kili wasn't named in The Hobbit, she was named in LOTR, in Appendix A, part 3 (Durin's Folk):
Dís was the daughter of Thráin II. She is the only dwarf-woman named in these histories. It was said by Gimli that there are few dwarf-women, probably no more than a third of the whole people. They seldom walk abroad except at great need, They are in voice and appearance, and in garb if they must go on a journey, so like to the dwarf-men that the eyes and ears of other peoples cannot tell them apart. This has given rise to the foolish opinion among Men that there are no dwarf-women, and that the Dwarves 'grow out of stone'.
It is because of the fewness of women among them that the kind of the Dwarves increases slowly, and is in peril when they have no secure dwellings. For Dwarves take only one wife or husband each in their lives, and are jealous, as in all matters of their rights. The number of dwarf-men that marry is actually less than one-third. For not all the women take husbands: some desire none; some desire one that they cannot get, and so will have no other. As for the men, very many also do not desire marriage, being engrossed in their crafts.