Many websites selling home fertility tests, also known as the "egg timer" test, directly to consumers are making misleading claims about their usefulness, a University of Sydney led study has found.

The findings are concerning to the researchers, as women may rely on website information to decide whether to have the test. They also may make decisions or plans to conceive or delay doing so, or seek potentially unnecessary fertility treatments such as IVF or egg freezing, on the basis of test results.

The study was published in JAMA Network Open, examined 27 websites selling the egg timer test directly to consumers online, from seven countries including Australia.

The egg timer test, known clinically as the anti-Mullerian hormone (AMH) test, measures the level of anti-Mullerian hormone in the blood. AMH is produced by follicles in the ovaries.

Three-quarters of the websites stated the test was a way of getting information about their fertility or likelihood of conceiving.

A majority of websites had information that was poor quality or made claims about the AMH test that are not supported by evidence, such as marketing the test as a reliable predictor of fertility. This is despite evidence showing the AMH test cannot reliably predict current or future fertility in the general population.

In addition, a majority of websites claimed that the test could indicate the onset of menopause or women at risk of premature menopause, although such estimates are considered to be unreliable.

The researchers are calling for more regulation and oversight on the marketing of home fertility tests. Currently direct to consumer AMH test marketing has minimal regulation.

"False and misleading claims about the usefulness of the AMH test undermine women's ability to make an informed decision," says co-author Dr. Rachel Thompson, from the Sydney School of Health Sciences Faculty of Medicine and Health.

"People may also be worried or reassured by the test results without basis and may change their reproductive plans and behavior as a result."

The analysis also found the amount and type of information provided on websites was highly inconsistent and varied greatly across each website.

Fewer than half of the websites included statements about the limitations of the AMH test.

Alexis Johnson, an author of the study and project officer in the Sydney School of Public Health, also pointed out that websites do not universally offer the option to speak to a doctor after the test.

"Only five of the 27 websites we reviewed—and only one of the three in Australia—include the option of a consultation with a physician after having the test," Johnson said.

The researchers say increasing public knowledge about fertility, including via fertility awareness campaigns, greater attention to reproductive health in routine health care, and addressing structural barriers to earlier childbearing are likely to be more effective in helping people to achieve their reproductive aspirations.