Apple hasn’t given details about the new HealthKit metrics just yet, but looking at a screenshot of the Health app displayed in the WWDC Keynote speech, you can see where the app displays, “Light” — meaning the severity of the menstruation.
This is critical for a condition called Menorrhagia. Where the menstruation cycle can be abnormally heavy or prolonged. This can be caused by a variety of pathologies such as Fibroids or Endometriosis, but the diagnosis only comes after close monitoring of the cycle. This is a feature Family physicians and Gynecologists could utilize when making the diagnosis.