From Gould and Pyle's Anomalies and Curiosities of Medicine
http://etext.lib.virginia.edu/toc/modeng/public/GouAnom.html

The perverted appetites and peculiar longings of pregnant women furnish curious matter for discussion. From the earliest times there are many such records. Borellus cites an instance, and there are many others, of pregnant women eating excrement with apparent relish. Tulpius, Sennert, Langius, van Swieten, à Castro, and several others report depraved appetites. Several writers have seen avidity for human flesh in such females. Fournier knew a woman with an appetite for the blood of her husband. She gently cut him while he lay asleep by her side and sucked blood from the wounds -- a modern ``Succubus.'' Paré mentions the perverted appetites of pregnant women, and says that they have been known to eat plaster, ashes, dirt, charcoal, flour, salt, spices, to drink pure vinegar, and to indulge in all forms of debauchery. Plot *[637] gives the case of a woman who would gnaw and eat all the linen off her bed. Hufeland's Journal *[452] records the history of a case of a woman of thirty-two, who had been married ten years, who acquired a strong taste for charcoal, and was ravenous for it. It seemed to cheer her and to cure a supposed dyspepsia. She devoured enormous quantities, preferring hard-wood charcoal. Bruyesinus *[228] speaks of a woman who had a most perverted appetite for her own milk, and constantly drained her breasts; Krafft-Ebing cites a similar case. Another case *[280] is that of a pregnant woman who had a desire for hot and pungent articles of food, and who in a short time devoured a pound of pepper. Scheidemantel cites a
-81-case in which the perverted appetite, originating in pregnancy, became permanent, but this is not the experience of most observers. The pregnant wife of a farmer in Hassfort-on-the-Main ate the excrement of her husband.