Carmen Lorenzana - Your menstrual blood has a lot to say about your health

What comes up when you think about menstrual blood? Disgust? Curiosity? Fear? Shame? Pride?

Even though periods are a perfectly normal bodily function, many of us have experienced embarrassment and shame around them, and sadly, this stigma prevents us from accessing valuable information about our bodies. 

But did you know that your period can tell you a lot about your well-being?

Your period is a powerful feedback tool.

The length, amount, color, and texture of your period are important biomarkers that can offer clues to what’s going on in your body. This is why the American College of Obstetricians and Gynecologists (ACOG) has declared it as the 5th Vital Sign.

Knowing these signs is a right that you and all menstruators have! And today, I want to share some keys to understanding them. 

The lenght and amount of your period

In a healthy period, you should bleed from 3 to 7 days and lose between 25 and 80 ml of blood. Knowing how much you bleed can tell you if there is a hormonal imbalance:

  • Bleeding less than 25 ml or less than three days may indicate that your reproductive hormones are too low.
  • On the other hand, menstrual bleeds of more than 80 ml or more than seven days are known as menorrhagia, which can eventually lead to anemia. Heavy periods are associated with high estrogen levels, endometriosis, thyroid disorders, uterine fibroids, and other conditions.

To objectively measure how much you bleed, keep track of the size or volume of the menstrual product you use, how often you change it during the day, and how full it is when you change it. 

Here’s a guide to how much each menstrual product absorbs:

For pads and tampons:

  • Light flow – up to 3ml.
  • Medium flow – up to 5 ml.
  • Heavy flow – up to 8ml.
  • Super pads and tampons – up to 12 ml.

Menstrual cup: 

  • The menstrual cup has an average capacity of 30ml. Every brand is different, so check yours.

At the end of your period, add up your records, and voilà!

Of course, your estimation doesn’t have to be precise (it would be impossible!), But this will give you a close idea. If your menstrual product isn’t full to its max capacity, make an estimate. For instance, if I notice that only 1/3 of my cup was full, I’ll record 10 ml, etc.

The color of your menstrual blood

Your menstrual blood can range from bright red to brown or black during one cycle, and in most cases, that’s ok. Usually, it’s bright red on the first days, which is a sign of health. Then it may turn dark brown or black a few days into your period as older blood or parts of the uterine lining take longer to shed and oxidize.

Menstrual flow that looks diluted could be a sign of anemia or indicate low estrogen levels. At the same time, a grayish discharge could be a sign of an infection. If you experience any of this, book an appointment with your healthcare provider as soon as possible. 

The texture of your period

Your period is more than just blood; it also contains cervical mucus, vaginal discharge, and small pieces of endometrial tissue.

A healthy menstrual flow should be relatively liquid and without large clots. During your period, your body releases natural anticoagulants to thin your endometrium. However, a few clots may be present if you have heavy bleeding because the anticoagulants have not had time to do their job. Clots that look larger than a quarter (20mm or 0.75 in) may be worth investigating further, so talk to your medical practitioner if this is your case.

What about premenstrual spotting?

Sometimes it’s common to see dark or brown spots in the days before your period. 

According to Dr. Lara Briden in her amazing book Period Repair Manual, premenstrual spotting can indicate 3 things: 

  1. In most cases, it’s a sign that your body is not producing enough progesterone to maintain your uterine lining in place during the luteal (premenstrual) phase. As a result, the uterine lining starts to slowly shed earlier than expected. 
  2. It can also be a sign of an underlying thyroid problem. 
  3. It can indicate you’re having anovulatory cycles (quite common if you have PCOS).

Is this my period or just premenstrual spotting?

Remember, day one of your cycle is the first day of your period. Here we are considering the first day you have a full bleeding. If you have spotting, don’t mark it as the beginning of your new cycle; those days still belong to the premenstrual phase of your past cycle. 

In short: 

  • If you need to wear a pad, a tampon, a menstrual cup, etc. to manage your bleeding, it’s most probably day 1 of your cycle. 
  • If you can go through your day without using any menstrual product, or if you only need a pantyliner, that’s probably premenstrual spotting. 
  • Premenstrual spotting also looks darker than menstrual blood, and, in some cases, it can be brownish; this is because the blood is flowing slower and oxidizes in the air.
  • Tracking your Body Basal Temperature can also help you distinguish between premenstrual spotting and your period.

A menstrual cup can be your great ally

Carmen Lorenzana - Your menstrual blood has a lot to say about your health

Menstrual blood can be so unfamiliar that we’re used to getting rid of it right away. But by doing this, we miss out on priceless information about our health.

So here it is, yet another benefit of switching to a menstrual cup!

Every time you change your cup, take some time to carefully observe the color, consistency, and amount of period blood. You can even smell it and touch it if it feels good for you; there’s nothing dirty or unhygienic about it! And instead, you will learn a lot about your body and yourself.

Don’t forget to take notes of your observations and bring them with you next time you visit your OB-GYN.

Check my article How to choose the best menstrual cup to find the right fit for you.


Your period is a sign of health. Let’s end the stigma and normalize it.

New to Menstrual Cycle Awareness and not sure where to start? Download my free guide with 3 simple steps to get to know your cycle.

New to Menstrual Cycle Awareness and not sure where to start?

Download my free guide with 3 simple steps to get to know your cycle.

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