text:  There's still a lot we don't know about the female menstrual cycle. In fact, last week, we revealed that menstrual products like tampons aren't even tested using menstrual blood, which has led to inaccurate absorbency claims. Dr. Sara Nasseri has been working to close this research gap. She's the CEO and founder of Quinn, a biotech company that's the first service to use a woman's period as a non-invasive blood test.