'It's a very unique biological specimen': What menstrual blood can reveal about your health

Similarly, Berlin-based startup theblood is currently validating a test kit to help predict endometriosis, early menopause, PCOS, and fertility issues. They've also previously demonstrated in a small study that vitamin A and D levels in menstrual blood correspond to those measured in blood throughout the body, albeit at consistently lower levels.

"Our goal is for women to have quicker access to diagnosis, better treatment, and better prevention," says Isabelle Guenou, who co-founded theblood in 2022. Growing up, Guenou suffered badly from endometriosis, which took eight years to diagnose, and underwent several surgeries for it.

Menstrual blood can even indicate the type of toxins one is exposed to, according to a small 2022 study by Metz which detected phenols, parabens, phthalates, and other environmental pollutants in the menstrual blood of four volunteers. 

The menstrual revolution      

Despite this progress, much about menstrual blood remains a mystery. The biggest one, many researchers agree, is that we haven't yet identified all the components present and how these can change rapidly during menstruation.    

Research is nascent, largely because of cultural stigmas that surround the topic, even today, when we call menstruation numerous unflattering euphemisms, like the Curse, Satan's Waterfall, Alarmstufe Rot ("Code Red Alarm"), Les Ragnagnas ("Grumbling"), and Kommunister i lysthuset ("Communists in the gazebo").