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Undiagnosed endometriosis is bad news for women doing fertility treatment

Lead researcher Dr. Katrina Moss breaks down what you need to know about a recent study that found women with a delayed endometriosis diagnosis were disadvantaged when undergoing fertility treatment.

Fast Facts

  • About 40% of women with endometriosis have infertility. Many of these women will need to use fertility treatments like IVF (in vitro fertilisation) and IUI (intrauterine insemination).
  • Fertility treatment is hard. It’s even harder if you have undiagnosed endometriosis. In our study, women whose endometriosis wasn’t diagnosed until after they started fertility treatment did more cycles, used more IUI instead of only IVF, and were less likely to report a birth (compared to women without endometriosis).
  • On the other hand, having a diagnosis of endometriosis levelled the playing field. Outcomes for women whose endometriosis was diagnosed before they started ART were no different to women without endometriosis.

What this research is about?

In Australia, 1 in 9 women have endometriosis. Of these, 40% have infertility and will need fertility treatment. This can include IVF and IUI, but recent clinical guidance recommends IVF instead of IUI for women with endometriosis.

This seems simple, but it can take up to 11 years to be diagnosed with endometriosis. Age is the most important factor for success in fertility treatment, which means that delayed diagnosis can reduce the likelihood of having children.

What did the researchers do?

We looked at whether the use and outcomes of ART were different for women with and without endometriosis. We also looked at whether the timing of the endometriosis diagnosis played a role. To do this we used data from on women born in 1973-1978 from the Australian Longitudinal Study on Women’s Health. This included self-reports via surveys, as well as linked administrative data on births, hospital admissions, medications (PBS) and medical treatment (MBS).

What did the research find?

Between 1993 and 2020, 1,322 women (9%) of the ALSWH cohort used ART. Of these, 35% had endometriosis, with two thirds diagnosed before they started ART and one third diagnosed after.

Compared to women without endometriosis, women who weren’t diagnosed with endometriosis until after they started ART had worse outcomes: they were 2.1 times more likely to use IUI rather than IVF only. They were also 4.1 times more likely to do a lot of ART cycles (11-36 cycles) instead of only 1-3 cycles. Finally, they were 33% less likely to report a birth (although we couldn’t link births directly with ART cycles).

For women diagnosed with endometriosis before their first ART, their use of IUI, the number of ART cycles and the likelihood of reporting a birth were the same as women without endometriosis.

How can you use the research?

It is essential to catch undiagnosed endometriosis before starting fertility treatment. Diagnostic surgery isn’t routinely conducted now because it can harm ART outcomes. However, imaging can be useful and endometriosis-related symptoms, such as severe period pain, heavy menstrual bleeding and back pain, can act as red flags for health professionals.

For women with endometriosis, the use if IUI might increase the time to pregnancy. Progressing straight to IVF could reduce the number of cycles and increase the odds of reporting a birth (although note that we couldn’t tie births to ART cycles in our research). It could also reduce the financial and psychological burden of fertility treatment.
Women with endometriosis are not disadvantaged during fertility treatment, as long as their endometriosis is diagnosed before they start and their treatment is adjusted accordingly.

Learn more

More information on endometriosis can be found at Jean Hailes (https://www.jeanhailes.org.au/health-a-z/endometriosis) or Endometriosis Australia (https://www.endometriosisaustralia.org/)


Dr Katrina Moss, The University of Queensland


Moss KM, Doust J, Homer H, Rowlands IJ, Hockey R, & Mishra GD. Delayed diagnosis of endometriosis disadvantages women in Assisted Reproductive Technology (ART) – a retrospective population linked data study. Human Reproduction. 2021. DOI: 10.1093/humrep/deab216.