In a groundbreaking study publishing on Monday the 7th of August 2023, scientists tested 21 different modern menstrual products, gauging absorbency and determining which products are most effective for heavy menstrual bleeding. The study marks a key development as it not only is the first-of-its-kind to examine such a broad spectrum of period products – from menstrual cups to tampons to period pants and more – but is also the first to run these absorbency tests using blood, not water. Yes, really. 

Let's dive into some of the key takeaways from the study and discuss what it means for managing and diagnosing heavy periods. 

What is heavy menstrual bleeding?

Up to one third of menstruating individuals are affected by heavy menstrual bleeding, or menorrhagia. But what actually classifies as heavy menstrual bleeding?

Generally, guidance on what classifies as a heavy period is based on how often you need to change or how quickly you bleed through your period products. 

In fact, the NHS claims that you may have menorrhagia if you:

• need to change your pad or tampon every 1 to 2 hours, or empty your menstrual cup more often than is recommended
• need to use 2 types of sanitary product together, such as a pad and a tampon
• have periods lasting more than 7 days
• pass blood clots larger than about 2.5cm (the size of a 10p coin)
• bleed through to your clothes or bedding
• avoid daily activities, like exercise, or take time off work because of your periods
• feel tired or short of breath a lot

How is heavy menstrual bleeding diagnosed?

As per the above, diagnosis for heavy periods is typically based on history taking - with patients reporting how quickly they bleed through their period products on any given day. 

Clinicians usually measure menstrual blood loss using the type, number, and fullness of period products per hour or day, and all medically-validated assessment tools are based on pads and tampons use. This becomes less helpful given more and more people are using alternative period products – like period pants and cups – to manage their flow. 

If you've ever bought a pair of 'heavy flow' period pants, put your wholehearted faith in them and been disappointment by how quickly you bled through, there's a reason why. Only the labeling of tampon absorbency is regulated – there are no structures in place to regulate the way alternative products label their absorbency levels. Tampons are regulated due to the risk of toxic shock syndrome, but there's no consistent regulation behind how absorbent other period products are reported to be. 

This creates further issues for people who are reporting their flow levels to their doctor. While the absorbency of a super tampon may be consistent across the board, they may bleed through different products with the same labelled absorbency at wildly different times. 

Blood is thicker than water.

You might be familiar with the old adage that blood is thicker than water. Despite this, up until DeLoughery's study, period product absorbency was tested with water or saline, and not blood. 

 DeLoughery's study used expired human packs red blood cells (RBCs) that could no longer be used for clinical purposes. RBCs are essentially what's left after plasma and platelets are removed from the blood. While the study noted that menstrual blood is likely to be more viscous than the RBCs, the researchers felt the red blood cells gave a more accurate measure than water or saline could. 

"We found that the product capacity labelling was discordant with our results—the majority of products reported that they had greater capacity than our testing found." said the researchers, "We suspect this is due to product testing with non-blood liquids, such as water or saline.”

Here are the key takeaways

1. The study revealed that in most cases, the period products were less absorbent than they claimed to be, reflecting the use of saline or water in testing and regulating their absorbency. 
2. Of the 21 products tested, Intimina's Ziggy Cup was proven to have the highest capacity, holding 80ml – this would be diagnostic of heavy bleeding. 
3. The considerable variation in absorbency in the products in the study highlighted the importance of the need for doctors to ask patients what types of products they use when diagnosing heavy bleeding. 
4. Further understanding of capacity of newer menstrual products can help clinicians better quantify menstrual blood loss, identify individuals who may benefit from additional evaluation, and monitor treatment.