Menstrual Blood & Health - How to Read Your Period
Blood. It's a substance that runs through our veins, keeping us alive and functioning.
But somehow, the minute it’s coming out of a vagina, everyone loses their mind about it.
We’re taught from about the age of 11 to hide it, wrap it in toilet paper, and, for the love of God, don’t talk about it. Especially not in polite company. Especially not at work.
And so we grow up thinking periods are shameful.
In the best case, just an inconvenient mess. In the worst case, dirty and gross.
But here’s what no one told us growing up... your period isn’t an inconvenience, it’s actually a legit indicator of your internal health.
Aaaaaand it's officially considered your body’s fifth vital sign, I’m talking blood pressure, pulse, temp, and breathing.
Yep. Your period is diagnostic.
So let’s talk about what menstrual blood actually is, what it can tell you, and why some bloody brilliant people are finally doing something useful with it.
What Even is Menstrual Fluid?
Someone asked me this recently...
“I was listening to a podcast and they kept calling it menstrual fluid instead of blood, what’s the difference?”
Short answer... It’s not just blood.
It’s menstrual fluid, a rich, bioactive mix of blood, cervical mucus, endometrial tissue, immune cells, vaginal secretions, and yes, even stem cells.
And it’s wildly underrated.
But for decades, we’ve been told periods are... inconvenient at best, disgusting at worst.
And because of that, this monthly data from our bodies has been ignored, dismissed, or treated as TMI.
I Get Why You Might Think It’s Gross
We’ve all got at least one period horror story...
🩸 The horrified boyfriend when you woke up in a puddle of blood (get over it, childbirth is messier!).
🩸 The boy in PE chanting “eeewww gross” when you bled through your tiny hot pants (thanks, PE uniform of the 90s, for scarring me for life).
🩸 The co-worker who made that face when you walked to the bathroom with a tampon in your hand (oh riiight, I forgot, natural, non-optional bodily functions are so inappropriate for work).
🩸 The fact that, until very recently, period ads used blue liquid because red was apparently too “triggering.” Sure.
We’ve been conditioned to flinch.
Taught to hide it.
Wrap it.
Whisper about it in toilets.
But the truth is, menstrual fluid is fascinating AND important.
And I met some folks recently who are actually doing something with it.
BioGrad is on the case!
BioGrad is a UK-based medical research company that’s collecting menstrual fluid and using it for actual scientific research (I know, finally!).
I met with Claire Allerton and “Menstrual Dave” (yes, that’s what they actually call him), and they told me about the work they’re doing.
By using this bioactive brew of stem cells and important biomarkers, there’s growing evidence that it can help with...
- Fertility
- Immune health
- Hormonal disorders
- Even reducing the need for animal testing
It’s being studied for links to endometriosis, PCOS, chronic illness, and more.
And the best part?
You can donate your menstrual fluid, AND get paid for it.
Here’s how it works...
- You sign up
- They send you a collection kit (or invite you to a clinic)
- You donate
- Your sample helps real-life research, and you get cash
Finally, a way to make periods pay their rent.
👉 10 Myth-Busting Period Facts
But How Can You Use it to Inform Your Health?
Your menstrual fluid is like a window into your body's inner workings. Its appearance can tell you a lot about your overall health.
The colour, flow, texture, and symptoms that come with it can flag up issues like...
- Hormonal imbalance
- Thyroid dysfunction
- Iron deficiency
- PCOS or endo
- Stress
- Gut health
Conditions like endometriosis and PCOS often take years to diagnose, in part because we’re not taught what’s ‘normal’ to look for. But your period holds clues that, if better understood, could shorten that journey for so many.
Colour and Flow - What It Means
Have you ever noticed that your menstrual fluid's colour and flow change throughout your period?
This isn't just random. It’s your body’s way of talking to you.
Towards the beginning and end of your period, your menstrual fluid will appear brown or dark in colour, but by mid-flow, it should be a bright cherry red with a consistency similar to unset jelly.
- Pink or watery may indicate low estrogen or iron levels.
- Dark purple might indicate high estrogen or PCOS.
- Orange could indicate a vaginal infection.
- Grey or off-smelling = definitely time to see a doctor.
It’s not always easy to interpret, but once you start noticing patterns, you’ll know what’s 'normal' for you, and when something’s off.
Bonus Tip - Try a Menstrual Cup
If you want to better understand your period, this is one of the simplest ways in (I know it's not everyone's cup of tea).
Using a cup lets you see what’s actually going on. You notice volume, colour, texture, and that helps you start spotting patterns and changes.
Most importantly, once you get used to what it normally looks like, you can quickly spot abnormalities that might need further attention.
👉 The Truth About Menstrual Products & the Power of Your Period
What else should you be tracking?
It’s not just all about colour, other signs can give you useful intel too...
Cycle length
Anywhere from 21 to 35 can be 'normal' for you. What matters is consistency. If your cycle suddenly shortens or stretches out, that’s worth noting.
Period duration
A typical period lasts 3–7 days. Bleeding for longer might signal a hormonal imbalance, fibroids, or something else going on. Time to ask questions.
Volume
Most people lose around 30–40ml of blood during a period, that’s about 6 to 8 teaspoons, or roughly 5–10 fully soaked regular tampons across the whole bleed. Losing more than 80ml (closer to 16 tampons' worth) is considered a heavy period.
Lighter than 30ml could indicate low oestrogen or be thyroid-related.
More than 80ml might point to fibroids, endometriosis, or a hormonal imbalance. Equally, it might be a sign of flooding during perimenopause.
Clots
Small clots are normal, but big ones over 2cm (I know we don't always have a ruler to hand) might need a second look. However, if your flow is heavier, you might notice more clots, becuase your body might not have enough time to break them down.
Symptoms
Cramps, mood swings, fatigue, headaches, cravings, insomnia, and brain fog all matter.
These are data points.
Start tracking even a few of these in your notes app, a journal, or a period-tracking app, or use my very handy charting guide HERE.
Once you know your baseline, you’ll spot when something changes.
Understand the Wisdom of Your Body
So, you see, your period isn’t something to be ashamed of or hidden away. It’s a source of valuable information and data.
Your menstrual fluid is diagnostic, regenerative, and part of a monthly cycle your internal rhythm is set by.
And just like any other vital sign, your menstrual cycle speaks volumes about how your body is functioning.
So let’s embrace the magic of our menstrual fluid, decode its wisdom, and change the message for the next generation.
Let’s teach them to be curious about the information they have access to, so fewer people grow up struggling in shame and silence.
Curious about donating?
BioGrad’s study is live now, and they’re still recruiting. Click here to find out more.