A bit of Googling brings up plenty of discussion on the subject, including this well-argued thread:
http://www.british-ge...ndex.php/t-14150.html
However this thread cites a specific source (the philanthropist Charles Booth), possibly adding some verisimilitude to the theory:
"According to Charles Booth, in almost all cases prostitution was not seen as a permanent way of life. To some it was a temporary or occasional employment, as Booth described it for East End tailoresses or dressmakers 'who return to their trade in busy times'. Though disease and mortality would overtake the unfortunate, it was a less hazardous profession than many of its alternatives."
http://www.rootschat....92299.msg1749271.html
Chris