Gehrung considers that in healthy young girls amorous sensations are normal during menstruation, and in some women persist, during this period, throughout life. More usually, however, as menstrual period after menstrual period recurs, without the natural interruption of pregnancy, the feeling abates, and gives place to sensations of discomfort or pain. He ascribes this to the vital tissues being sapped of more blood than can be replaced in the intervals. "The vital powers, being thus kept in abeyance, the amative sensations are either not developed, or destroyed. This, superadded by the usual moral and religious teachings, is amply sufficient, by degrees, to extinguish or prevent such feelings with the great majority. The sequestration as 'unclean,' of women during their catamenial period, as practiced in olden times, had the same tendency." (E. C. Gehrung, "The Status of Menstruation," Transactions American Gynecology Society, 1901, p. 48.)
It is possible there may be an element of truth in this belief. Diday, of Lyons, found that chronic urethorrhœa is an occasional result of intercourse during menstruation. Raciborski (Traité de la Menstruation, 1868, p. 12), who also paid attention to this point, while confirming Diday, came to the conclusion that some special conditions must be present on one or both sides.
See, e.g., Ballantyne, "Teratogenesis," Transactions of the Edinburgh Obstetrical Society, 1896, vol. xxi, pp. 324-25.