For tens of thousands of New Zealanders, endometriosis and chronic pelvic pain are lived quietly - through cancelled plans, lost jobs and years of being told their pain is "normal".
Authors
- Jordan Tewhaiti-Smith
Research Fellow in Gynaecology, Medical Research Institute of New Zealand
- Mike Armour
Associate Professor at NICM Health Research Institute, Western Sydney University
Now, we have a clear picture of what that cost looks like in dollar terms. Our recently-published study - the first of its kind in New Zealand - estimates these conditions are costing NZ$22.6 billion annually.
Importantly, most of that burden does not sit in GP clinics or hospitals but shows up in people's working lives. In other words, the largest economic toll is not the price of treatment, but the price of being unable to work.
A hidden burden
Chronic pelvic pain (CPP) and endometriosis are separate yet tightly interlinked conditions that are widespread, disabling and routinely misunderstood.
CPP, sometimes also called persistent pelvic pain, is pain between the tummy button and the top of the legs that occurs on a regular basis for six months or more.
Around a quarter of women in New Zealand are likely to experience CPP, arising from a range of underlying conditions such as bladder pain syndrome and irritable bowel syndrome, and in some cases with no clear structural cause at all.
The most common underlying cause is the chronic inflammatory disease endometriosis. It affects about one in seven to one in ten women, girls and people presumed female at birth, during their reproductive years as well as an under-recognised number during and after menopause.
That makes it more prevalent than diabetes or heart disease. Its impacts extend far beyond pelvic or period pain, commonly including nausea, fatigue and profound disruption to daily life.
Yet endometriosis remains poorly understood and poorly treated. Decades of under-investment in research have left people waiting eight years or more for diagnosis, with only about a quarter satisfied with their treatment.
It is widely described as a "hidden" or "invisible" illness. Many people appear outwardly well, while enduring severe and persistent pain.
Gaps in education - among both the public and clinicians - combined with the lingering taboo around menstruation mean many grow up believing their symptoms are normal. Too often, it is dismissed as part of being a woman, or they are even advised to become pregnant as a supposed "cure".
Counting the true cost
To gain a deeper understanding of the economic cost, we drew on a survey developed by the World Endometriosis Research Foundation , which has been used in multiple countries including Australia.
However, this is the first time the data have been analysed using a detailed economic methodology designed to capture the true personal and societal costs of these conditions.
We applied international dollars (INT$), which adjust for differences in purchasing power between countries, allowing fair comparison of costs across health systems.
When projected over a 34.5-year working lifespan, lifetime per‑person losses exceeded INT$1.9 million for endometriosis and $1.5 million for CPP, highlighting the long‑term economic consequences of diagnostic delay and under‑treatment.
As with international research, we found most of the cost was not driven by medical care such as GP visits or procedures. Instead, it was lost productivity - driven by pain and fatigue - that dominated.
These productivity losses accounted for an estimated 65% of the total cost of endometriosis and 75% of the cost of chronic pelvic pain.
Another important finding was that applying diagnostic attribution substantially reshaped both per-person and national cost estimates, revealing that a large share of the economic burden previously attributed to non-specific pelvic pain is more accurately assigned to endometriosis.
By valuing productivity loss from the ground up, at the level of individual patients, we also found indirect labour costs were far higher than those reported in earlier "top-down" models, which systematically underestimate how profoundly these conditions disrupt working lives.
What should be done?
Improvements in diagnostic technology, including ultrasound, and in the expertise needed to diagnose and manage endometriosis, mean that certain forms of the disease can now be reliably identified on scans.
Providing wider access to this technology, and to practitioners experienced in improving outcomes for people with endometriosis and chronic pelvic pain - including specialist gynaecologists and multidisciplinary teams - could significantly reduce diagnostic delays and, in turn, healthcare costs.
In New Zealand, however, there are still many access issues that shape how people engage with healthcare for endometriosis and chronic pelvic pain. These inequities continue to have a negative impact on marginalised groups, including Māori and Pacific people.
Greater investment in support systems, particularly in the workplace, is also likely to substantially reduce the burden of these conditions.
Because most of the costs are related to reduced productivity and the need to take sick leave, relatively small changes - such as flexible working hours or the ability to work from home - could make a meaningful difference.
That said, these options will not suit everyone, especially people working in roles such as healthcare.
Finally, the development of a national action plan, underpinned by new and relevant research - similar to that introduced in Australia - has the potential to reshape experiences for people with endometriosis, including through the establishment of specialist pelvic pain clinics.
Jordan Tewhaiti-Smith is affiliated with the Medical Research Institute of New Zealand (working as a paid research fellow), and is the president of Specialty Trainees of New Zealand (junior doctors union).
Mike Armour receives funding from the Medical Research Futures Fund (MRFF) for research into endometriosis and diagnosis unrelated to this work.
