Actually, it is surprising how often "fallen women" are mentioned in the Austen books - though always off stage (at least until they are "made an honest woman"). The two Elizas in Sense and Sensibility, the mother certainly suffering the terrible consequences of falling away from the middle-class protections, Lydia in "Pride and Prejudice", Maria in "Mansfield Park", Harriette's unnamed mother in "Emma" - all had unsanctified sex, and payed for it in various degrees. By comparison, in The Bronte sisters more famous books, "Jane Eyre" and "Wuthering Heights", the closest a woman comes to unmarried sex is in being in danger (and saved from) an unwitting bigamous marriage.
Mention of disgrace