Australia's government owned ABC, offers another story on prostitution:
Quote: "Sex work was one of the major ways poor women could earn a reasonable income in the 19th century. Especially unmarried women with babies."
Respectable people frowned on single mothers, who likely had no access to child care etc or welfare. So sex work may have been their only alternative.
Read the full story at: http://www.abc.net.au/news/2018-02-14/sex-work-in-19th-century-melbourne-what-rubbish-can-tell-us/9430592