The Wet Nurse's Tale by Erica Eisdorfer

Susan Rose is not your average Victorian heroine. She's promiscuous, lovable, plump, and scheming. Luckily for Susan, her big heart is covered by an equally big bosom, and her bosom is her fortune- for Susan becomes a professional wet nurse, like her mother before her, and she makes it her business to know all the intrigues and scandals that the upper crust would prefer to keep to themselves.

When her own child is caught up in a family scandal, Susan must use all of her street smarts to rescue her baby from the powerful mistress of the house. The scheme she weaves is bold and daring, and could spell ruin if she fails-but Susan Rose has no intention of failing.