National Statistical

Utilising data to better understand women’s health is a key government priority. The Women’s Health Strategy for England has outlined the existing evidence gaps and demonstrated that more research is needed. With that in mind, the ONS has carried out the first population-level study of its kind to explore the characteristics of women with an endometriosis diagnosis in England.  Here, Dr Isobel Ward explains the research and why it is so important. 

Women make up 51% of the population, and despite on average living longer than men, women spend a significantly greater proportion of their lives in ill health and disability when compared with men. Investing in women’s health research has been identified by the government as essential to reduce disparities in women’s health across England.    

Why is this analysis important? 

Endometriosis is a common gynaecological condition which has debilitating impacts across many domains, including physical, psychological, social and economic. Endometriosis is characterised by endometrial tissue, similar to the lining of the uterus, growing in other places, such as the ovaries and fallopian tubes. Media stories have highlighted the devastating impact the condition can have.  

Our Characteristics of women with an endometriosis diagnosis in England: 27 March 2011 to 31 December 2021 release adds new evidence to our understanding of endometriosis, giving healthcare planners and policy makers vital greater insight to support women’s health. To date there has been no population level analysis of the characteristics of women with endometriosis in England. With a study group of more than 24 million women, we used 2011 Census data linked to Hospital Episode Statistics (HES), to identify women who had a diagnosis of endometriosis in an NHS hospital in England between 2011 to 2021. Our work utilises the gold-standard 2011 Census self-reported demographic information to estimate which groups of women were most likely to receive an endometriosis diagnosis. Critically, this research makes use of anonymised administrative data, which is already collected, to improve women’s health outcomes. This aligns with one of the objectives outlined in the 10-year implementation plan in the Women’s Health Strategy. 

As part of our work, we spoke to women affected by the condition:  

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“This analysis is important to me because greater understanding of the characteristics of women with endometriosis is urgently needed. The impact of endometriosis can affect every area of life and receiving my diagnosis was a huge relief because my pain and symptoms finally made sense. Everyone living with endometriosis should be able to access a diagnosis, support, and treatment that works for them. Research is key to improving outcomes for the endometriosis community.”

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“This ONS work will increase awareness of the social and economic impact of endometriosis.” 

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What do our results show? 

Using 2011 Census data linked to hospital records from 2011 to 2021, we estimate the prevalence of endometriosis diagnosis to be approximately 2% of reproductive age women in our linked population (which is likely an underestimate of the true prevalence as many women will not have a diagnosis) and the average age at diagnosis was 35 years. 

Differences in the likelihood of having an endometriosis diagnosis by sociodemographic characteristic reflect differences in the probability of having endometriosis, as well as the probability of receiving a diagnosis in an NHS hospital. 

Women living in the most and least deprived areas were least likely to have an endometriosis diagnosis, possibly reflecting lower access to healthcare services in the most deprived group and more use of private healthcare in the least deprived group. 

The likelihood of receiving an endometriosis diagnosis was highest in the “White British”, “Black Caribbean”, and “Mixed White and Black Caribbean” ethnic groups, and lowest in the “Chinese”, “Arab”, and “Black African” ethnic groups. Women self-reporting to be in bad health, or disabled, were more likely to have had an endometriosis diagnosis compared those in very good health or non-disabled women, respectively.  

Overall, our results demonstrate significant sociodemographic differences between groups of women receiving an endometriosis diagnosis in England.  

What is next?

This, and future work, will provide important information to gynaecologists, clinicians and other allied health professionals, as well as policy makers to illustrate the prevalence of endometriosis and the groups most affected.  

We’ve received funding for this work, as well as a series of other analyses, from the UK Government’s Labour Markets Evaluation and Pilots Fund (2024 to 2025). We will be publishing the next piece of work in this package of research in January 2025, where we have evaluated the impact of endometriosis on labour market outcomes for women in England. Furthermore, we are working with academic partners to explore presentations of endometriosis in primary care, as well as the broader socioeconomic ramifications of the condition.