When Jess Taylor was diagnosed with endometriosis at 20, she was worried becoming a mother might not happen for her.
Ms Taylor was told by specialists she would be "very unlikely" to conceive naturally.
"The grief you go through is significant," she says.
"You think 'my body as a woman is built to grow babies', and now I'm being told that I can't do that — that is very overwhelming."
Ms Taylor, who has since become a mum, says her experiences inspired her to help other women navigate the disease, including its impact on fertility. She took on the job of CEO for QENDO, an organisation advocating for people with endometriosis and other pelvic-health-related conditions.
It's estimated one in seven people assigned female at birth have endometriosis.
We explain why the disease can make it hard to get pregnant, and how prevalent infertility is for people with the condition.
How endometriosis impacts fertility
It's not always known how endometriosis is impacting someone's fertility, explains Katrina Moss, a public health researcher at the University of Queensland, with an interest in reproductive health and assisted reproductive technology.
But Dr Moss says there are several ways the disease can hinder natural conception, such as inflammation impacting endometrial receptivity (a process that provides the embryo the opportunity to attach, invade, and develop), as well as egg formation and ovulation.
Inflammation in the pelvic cavity can also alter interactions between sperm and egg, she says.
Endometriosis can block the fallopian tubes, and impact the hormonal balance of the ovaries.
Ms Taylor says where someone's lesions are may determine if their fertility is impacted.
"If they have endo lesions across their ovaries or fallopian tubes, then they may have a more increased chance of fertility issues."
Dr Moss says surgery to remove endometrial lesions on the ovaries can affect ovarian reserve (the quantity and quality of eggs remaining in a person's ovaries) and response to ovarian stimulation in fertility treatment.
Prevalence of infertility in people with endometriosis
Most people with endometriosis won't have trouble conceiving, says Dr Moss.
"It's around 40 per cent of women with endometriosis who will have trouble conceiving, that means 60 per cent won't.".
However stats can be "tricky", she explains, because most of the data is based on people who have an endometriosis diagnosis.
"But we know a lot more women have endo [who are undiagnosed]," she says, adding a diagnosis can take a long time (about seven years on average).
Dr Moss works on the Australian Longitudinal Study for Women's Health, and as part of that followed a cohort of Australia women for more than 25 years.
She has mainly worked with the group born between 1973 and 1978, who are now in their mid to late 40s.
"It's a good cohort to look at because we've got really good survey data, and we know they are at the end of their reproductive years," she says.
One study that involved 8,241 of those women found 12 per cent had endometriosis. Of the women who were diagnosed with the disease, 47 per cent said they had trouble trying to conceive. It was 67 per cent for women who had both endometriosis and PCOS.
For those without either condition, 23 per cent said they have trouble trying to conceive.
"If we look at women with endo, their difficulty conceiving is twice the rate of people without either, so it's definitely elevated," Dr Moss says.
Ms Taylor says the most accepted rate of infertility in people with endometriosis is 30 to 50 per cent.
Some researchers say the rate is lower.
For example, a 2018 study from Kate Young at the Queensland University of Technology says research with larger samples typically finds about 10 to 15 per cent of women diagnosed with endometriosis are also diagnosed with infertility.
Does treatment for endometriosis improve fertility?
Treatment for endometriosis is multi-disciplinary. What treatment someone has, and results they get when trying to address infertility will be very individual, says Ms Taylor.
"It really comes down to where the lesions in the body are.
"A lot of women find they do go have a laparoscopy, remove some scar tissue or adhesions and … find they can conceive naturally after that."
For women who find sexual intercourse painful, a pelvic health physio may also help with trying to conceive, Ms Taylor says as another example.
"It's just so individualised."
'Early diagnosis is key'
For those who do have trouble conceiving due to endometriosis, Dr Moss says, "early diagnosis is the key."
Her research found women with undiagnosed endometriosis had reduced chances of a live birth when undergoing IVF.
"[We found] people who had undiagnosed endometriosis were disadvantaged during fertility treatment.
"People who knew about their endo followed a different treatment path: they did fewer cycles and were more likely to go straight to IVF rather than starting with IUI [intrauterine insemination], which may be more effective for women with endometriosis."
She says the study showed people who knew about their endometriosis before fertility treatment had the same success rate as people with other causes of infertility.
"It was only late diagnosis that caused disadvantage."
But Dr Moss says it's important to remember fertility treatment doesn't work for everyone.
"I can't stress this enough, because most of the stories we see about IVF are the happy ones where people got their baby.
"In our study, one in four women under 35 and one in two women aged 35 and over [from the whole sample] stopped fertility treatment without having a baby."
Dr Moss, who has endometriosis, knows that pain intimately.
"We struggled with fertility … we did about 13 cycles and it didn't work for us.
"And it was honestly the hardest thing I've ever done."
This is general information only. For personal advice, you should see a qualified medical practitioner.
