Libby French always knew she wanted to have children, and at 27, she thought it wise to investigate her fertility.
"My mother went through menopause fairly early in life [and] I had acne and extremely painful periods, which I thought may indicate hormonal changes or imbalances," 29-year-old Libby from Bundaberg says.
Libby's GP recommended she take an AMH test, also known as the egg timer test.
It measures the level of anti-Müllerian hormone (AMH) in a woman's blood to estimate her ovarian reserve.
Libby's AMH came back as "low".
"My GP instructed [the result] was low for my age and that she wouldn't recommend putting off having a baby."
It sent Libby into a panic.
"I was devastated, anxious, and felt like the timing to have a baby was out of my control."
But the test is not a reliable predictor of fertility, says Tessa Copp, a researcher in public health at the University of Sydney.
Her work focuses on the inappropriate medicalisation of women's reproductive health.
She told ABC podcast Ladies, We Need to Talk, some fertility clinics are marketing the AMH test as an empowering way for women to safeguard their fertility, and says "it's quite misleading".
The AMH test and its intended purpose
The AMH test is a blood test that "can give an indication" of the number of eggs left in a woman's ovaries, explains Dr Copp.
"It doesn't give an indication of egg quality, and it's not predictive of fertility … and it should not be used to inform your reproductive potential."
She points to research showing women with high or low AMH levels of the same age have roughly the same chance of getting pregnant.
"You only need one egg [to fall pregnant]."
The test can be helpful used in the right context, however.
"It's useful in IVF or when undergoing egg freezing, as it can give an indication of how many eggs might be retrieved in an egg stimulated cycle," Dr Copp says.
"This guesstimate can be useful in setting expectations about how many egg collection cycles you might need."
Jenny Doust is a GP and clinical epidemiologist at the University of Queensland, and has a specific interest in women's health and diagnostic test evaluation.
She says the test's intended purpose is for specialists to work out how to "program a woman's fertility treatment", for example, measuring potential risk of ovarian hyperstimulation syndrome.
Professor Doust says relying on AMH results as a marker for fertility may mean other problems are missed.
"Lots of people with low AMH will have no problem getting pregnant, and lots of people with high AMH can have major problems getting pregnant for other reasons."
Dr Copp says marketing language used by some fertility clinics is misleading women.
"We're seeing lots of companies using feminist slogans or sayings to market the AMH test. Things like, 'Be proactive about your fertility', 'You deserve to know your reproductive potential', 'Own your fertility', 'Knowledge is power'."
'High-stakes decisions based off test results'
Libby took her GP's advice and began trying for a baby with her fiancé immediately.
But as her anxiety grew, she decided to reach out to a gynaecologist to gather more information.
Libby says her gynaecologist suspected she had endometriosis, and referred her to a fertility specialist.
After surgery to remove what was later confirmed as the disease, Libby says the specialist recommended she begin IVF right away.
"I struggled with not being in control," Libby says of the IVF process.
"Every round you lose a little more hope of what you thought your life would look like with a baby, but you have no other choice but to keep pushing through to at least feel like you're working towards your dream."
Dr Copp says because there is no reliable test of fertility other than "trying to get pregnant when you are ready", she understands why women would be tempted to rely on the AMH test.
"In theory, it sounds great, but it just doesn't play out in reality.
"The worry is that women are getting it thinking it's indicative of their fertility, and they're making high-stakes decisions based off this test result."
She says for people like Libby, receiving a low result may cause "needless anxiety and fear".
"Which may press you to have a baby before you're ready or pay thousands of dollars to freeze your eggs."
And for those who receive a high result, Dr Copp says they may be "falsely reassured" about delaying pregnancy.
'I may have frozen my eggs sooner'
Marissa Jacques from the Gold Coast/Yugambeh Language Region is someone who thought a high AMH result would buy her more time.
At 34 she was single, but knew she wanted to have kids one day.
A Google search led her to the AMH test. She says the specialist she saw said her result was "above average".
"I was like, great. Fabulous … I've got a little bit more time," Marissa says.
"He even went as far to say casually that, right up until you're 40, you should be well and truly fine.
"Unfortunately for me, I used that casual comment … as a basis for decision making."
At 36, Marissa still hadn't met anyone and was again worried about her chances of starting a family.
She explored freezing her eggs, and through testing was surprised to learn she had stage 3 endometriosis.
"I wasn't prepared for it. I literally went in to freeze some eggs, and then I had to deal with that first."
Having surgery for her endometriosis meant she was 38 by the time she was able to begin the egg freezing process.
After three rounds, she got 12 eggs total. Marissa says she was hoping for a lot more.
It cost her $30,000, and by the end of the third round, Marissa says she was emotionally and physically drained.
Now 39, Marissa says she wishes her gynaecologist never made the comment about her having plenty of time.
"If [that comment] wasn't made, I may have done [egg freezing] sooner. I may have collected more eggs. And I may have given myself a better chance at a live birth."
'I've seen women take money out of superannuation'
Professor Doust says misleading marketing is playing on women's existing anxieties around being able to have children.
She says women need "unbiased and personalised information" when considering egg freezing or IVF.
"These things cost a lot of money. I've seen women take money out of superannuation to pay for them."
Professor Doust recommends people curious about fertility visit Your Fertility, established by the federal government and now run by the Victorian Assisted Reproductive Treatment Authority (VARTA), as a starting point for unbiased information.
Libby and her fiancé conceived naturally while taking a short break from the IVF process.
She is currently in her third trimester.
Despite the controversy around the AMH test and the stress it caused her, Libby says she doesn't regret taking it, as it kick-started investigations into her fertility.
"The AMH test provided me with the information to decide my future.
"If I hadn't had the test, I believe I may not have been able to have my own biological children if I had waited and didn't start trying for a baby."
