It is mentioned in the Encyclopedia of Prostitution and Sex Work Vol 2 ISBN 0-313-32970-2 Pub 2006 Greenwood Press
SEAMSTRESSES. "Seamstress" was a euphemism for "prostitute" in census records and other documents of the 19th century in the United States. Historical documentation showing several "seamstresses" sharing common living quarters may generally be assumed to represent a brothel. Whether this occupation was reported by prostitutes or supplied by census enumerators and other officials remains speculative, although potential reasons for both are easily understood.
Legitimate uses of the term should not be confused with the codified use. Other historical and modern euphemisms exist, including laundressess and actressess.
New Essays on Poe's Major Tales by Kenneth Silverman, Cambridge University Press 1993 also states:
Terms like "shopgirl" and "seamstress" were mid-century euphemisms for
women whose chief source of income was their bodies.
This website also discusses the issue with reference to an older work by Charles Horne
In John Cleland's Fanny Hill Mrs Cole's establishment poses as a
"millinery shop". A milliner's or mantua-maker's establishment was
often likened to a house of prostitution, probably an accurate public
A good many of the fallen women whose bastard children were put into
the Foundling Hospital were seamstresses. Millinery and dressmaking
were a kind of introduction to the prostitute's trade. What trial
records show is that when prostitutes were brought into court (usually
for stealing a gentleman's watch while his trousers were down), they
would describe themselves as apprentices to a mantua-maker, or as
being at one time a mantua-marker before they were led astray. A
character witness for a prostitute will commonly be a mantua-maker,
but I think many judges and juries realized that this mantua-maker
acted as the "aunt" at the head of a small-time ring of streetwalkers.
The professional mantua-maker often took in lodgers to supplement her
income, and the real situation, often as not, is that she would have a
few girl "apprentices" who mended stolen clothes and made new clothes
from stolen textiles while they are not otherwise engaged picking up
men in the street and bringing them to their mistress's upstairs
rooms. It was not uncommon for a gentleman to go into a milliner's
shop and have sex with one of the girls then and there. Though
dressmaking could of course involve a high degree of professional
skill, it also provided good cover for both prostitution and fencing
stolen goods. Very large quantities of linen and silk, plus ribbons
and lace etc., were regularly stolen from warehouses, and found their
way to mantua-makers, milliners, and tailors. Tailors and milliners
often acted as pawnbrokers, which to a great extent meant dealing in
stolen goods. They operated on the boundary between the underworld and
the respectable world.
The occupation of millinery or mantua-making was widely regarded as
just a cover for prostitution. Charles Horne in Serious Thoughts on
the Miseries of Seduction and Prostitution (1783) warned parents not
to allow their daughters to become milliners, mantua-makers, or
workers in the various clothes trades because they were "actually
seminaries of prostitution".