World’s Largest Menstrual Fluid Biobank Targets Heavy Periods, Endometriosis and Fibroids

Researchers from the Universities of Bristol and Exeter are launching CycleTrack to study menstrual fluid and uncover biological clues behind heavy periods and other menstrual health problems.

Heavy periods can disrupt work, education, relationships and everyday life, yet many women wait years before they receive effective treatment.
A major new UK study is now asking whether menstrual fluid could hold the biological clues needed to understand why heavy bleeding happens and help women get answers sooner.

Why Are Heavy Periods Getting New Research Attention?

Heavy periods are often dismissed as something women simply have to live with. But heavy menstrual bleeding (HMB) can affect physical health, emotional wellbeing, education, work and everyday life.

Now, researchers from the University of Exeter and University of Bristol are launching CycleTrack, a major study designed to investigate what happens biologically during menstruation and why some women experience excessively heavy bleeding. The project aims to create one of the world’s largest menstrual fluid biobanks (1^✔ ✔Trusted Source
World’s largest menstrual fluid biobank will transform understanding of menstrual health

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The study is particularly important because researchers still do not fully understand the biological mechanisms responsible for heavy menstrual bleeding in many women.

What Is the CycleTrack Study?

CycleTrack will recruit thousands of participants from two established UK birth-cohort studies: Children of the 90s and Born in Bradford. Participants will track their health and menstrual symptoms using an app and detailed questionnaires.

They will record factors including:

• Menstrual symptoms
• Sleep
• Mood and energy levels
• Overall wellbeing
• Changes in their menstrual cycle

Participants will also collect menstrual fluid samples over three menstrual cycles using specially designed period pads. Researchers will then combine these biological samples with long-term health and genetic information already available through the cohort studies.

The goal is to identify biological signals that could distinguish different patterns of menstrual health and help researchers understand why heavy bleeding develops.

Can Menstrual Fluid Help Diagnose Heavy Periods?

Researchers hope it can eventually provide clues that are difficult to obtain through symptoms alone.

Heavy menstrual bleeding can occur with conditions such as fibroids, adenomyosis and endometriosis, but an underlying structural cause is not identified in around half of women with HMB, according to the wider Missed Vital Sign programme.

This creates a major diagnostic challenge. Women may know that their periods are unusually heavy, but there is currently no simple test that allows patients or primary-care clinicians to directly measure menstrual blood loss or determine its underlying cause.

The CycleTrack researchers hope menstrual fluid could contain measurable biological markers that help identify these differences earlier.

What Are the Symptoms of Heavy Menstrual Bleeding?

Heavy bleeding is more than simply having a “bad period.” Warning signs can include:

• Bleeding that lasts more than seven days
• Needing to change sanitary protection every one to two hours
• Passing large blood clots
• Fatigue or dizziness associated with iron deficiency
• Periods that interfere with school, work, social activities or everyday life

The wider Wellcome Leap programme estimates that HMB is reported by around one in three reproductive-aged women when they are directly asked about it, while the University of Bristol describes the condition as affecting up to 50% of women worldwide, depending on how it is measured.

Why Can Heavy Periods Cause Iron Deficiency?

Repeated heavy blood loss can gradually deplete the body’s iron stores. Iron deficiency may cause symptoms such as tiredness, shortness of breath and difficulty concentrating, and prolonged deficiency can progress to iron-deficiency anaemia.

This is one reason researchers want better ways to identify women whose menstrual blood loss is high enough to cause physical harm.

The Missed Vital Sign programme is specifically working toward tools that could identify women at risk of iron deficiency from menstrual blood loss much earlier. Its goal is to develop approaches that can identify women at risk within three months rather than three years.

Why Do Women Often Wait Years for Heavy Period Treatment?

Diagnosis can be delayed because heavy periods are frequently normalised by women themselves, while healthcare systems may lack simple tools to quantify menstrual blood loss.

The Wellcome Leap programme reports that women with HMB currently wait an average of five years for effective treatment. It also notes that self-perception of menstrual blood loss is not sufficiently accurate for reliably identifying the severity of bleeding.

This delay matters because symptoms can continue while the underlying consequences, including iron deficiency, accumulate.

The larger goal of the Missed Vital Sign programme is therefore ambitious: reduce the time from experiencing heavy menstrual bleeding to effective treatment from five years to five months.

Could the Study Help With Endometriosis and Fibroids?

Researchers hope the biological information generated by CycleTrack could improve understanding of conditions associated with abnormal menstrual patterns, including endometriosis and fibroids .

However, the study will not immediately provide a diagnostic test for these conditions. Instead, researchers will first look for biological patterns that could eventually lead to new diagnostic tools, risk prediction methods or more personalised treatments.

This distinction is important: CycleTrack is a research project, not yet a clinical test for heavy periods, endometriosis or fibroids.

When Will Researchers Have Results?

Sample collection is expected to continue through November 2027, with preliminary findings expected in early 2028.

Researchers hope that linking menstrual fluid with real-time symptoms and long-term health and genetic information will reveal patterns that would be difficult to identify from questionnaires or medical records alone.

If successful, the work could help move menstrual health from subjective symptom reporting toward more measurable, biologically informed diagnosis.

What Could This Mean for Women With Heavy Periods?

The immediate message is not that a new diagnostic test is already available. Rather, CycleTrack represents an attempt to fill one of the major gaps in women’s health research: understanding what menstrual fluid can reveal about a woman’s health.

Better biological markers could eventually help clinicians identify heavy menstrual bleeding earlier, detect women at risk of iron deficiency, distinguish underlying causes and choose treatments more precisely.

For millions of women who have been told that heavy bleeding is simply something they have to tolerate, that could eventually mean a much shorter path from symptoms to answers and effective treatment.

The goal is no longer simply to measure how much a woman bleeds, but to understand what her menstrual blood may be telling us about her health.

Reference:

1. World’s largest menstrual fluid biobank will transform understanding of menstrual health – (https://www.bristol.ac.uk/alspac/news/2026/menstrual-fluid-biobank.html)

Source-Medindia