Disease is another factor. STDs can result in infertility; gonorrhea and syphilis were rampant in some communities of prostitutes, in various times and places. Pelvic inflammatory disease (PID) seems to have been much more common in both married women and prostitutes, 1875-1915, than it is today, judging from medical literature of the time. It is also a cause of infertility.
Prostitutes in modern areas where condom use is virtually unknown (parts of sub-Saharan Africa, for example) sometimes become infertile early in their working lives.