Consider the period. Lukewarm uterine jus. Bloody snot that smells of womb silt, lumpy with gobbets of dead endometrium that has been the weft of life for about a lunar month. For all the hymning and humming and hawing, it indicates the failure of conception.
Repugnance is a sort of aesthetic judgement. That menstrual blood has been the object of revulsion, not mere sensory dislike, not ‘animal-reminder’ disgust, is perhaps on account of the idea that it issues forth from a sphincterless, incontinent ostium, located between the plumbing for faeces and urine. And that the said blood carries in it the curdled pickings of tissue debris and some imagined putrefaction and contamination. It is a visceral disgust that predates the germ theory of disease, and is based on a knowing that precedes rational thought. It never needed a manifesto or a plebiscite or a sub-committee to manifest itself. It’s from the time of the early carriers of faith, when they lived in a state of fear and benightedness, whose nature, according to the medieval Jewish philosopher Maimonides, was the nature of mute animals; when they believed that in the savannah and the desert and the forest and the night sky were hidden benevolent and evil spirits; before they knew what a gamete was, or a blastocyst, or the endometrial lining.
Waxing Sapphic Gently 
