So-called 'fertility MoT' tests gauge a women's ovarian reserve – how many eggs she has in her ovaries – by measuring biomarkers in blood or urine. But a new study of 750 women aged 30 to 44 suggests that the number of eggs a women has does not reflect how likely or easily she will get pregnant, at least in the short-term.
'Women are already using these as fertility tests. Over the years, they've worked their way into being in the mainstream without evidence,' study author Dr Anne Steiner at the University of North Carolina in Chapel Hill told STAT.
The study followed older women, with no history of infertility, who had been trying to get pregnant for at least three months. Women with biomarker levels of inhibin B, anti-Müllerian hormone (AMH) and follicle stimulating hormone, indicating low egg reserves, were no more or less likely to get pregnant than those with results suggesting normal egg reserves, six months and 12 months later.
Many fertility clinics routinely offer AMH tests on the assumption that 'women with a lower ovarian reserve would be less likely to respond to treatment', according to a statement from the US National Institutes of Health, which funded the study. The work was published in JAMA.
'Many more women are concerned about having their first child when older than was the case for previous generations, leading to pressure to seek "fertility tests",' said Professor Richard Anderson of the University of Edinburgh. 'This paper, confirming smaller earlier studies, shows that we do not have such a thing.'
He added: 'The most important test is whether a woman is ovulating, i.e. whether she is releasing an egg every month, rather than how many eggs she might have in reserve.'
Other experts agreed; Dr Channa Jayasena of Imperial College London told the UK newspaper the Daily Telegraph: 'Hormone levels change with time, so taking a snapshot today tells us very little about what women's fertility will be like tomorrow.'
He added: 'This study tells us that measuring these hormones to predict fertility in potentially worried and vulnerable women is wrong, and should be stopped.'
Dr Steiner concurred, telling STAT: 'Women with low values [for their ovarian reserves] are going to have unnecessary anxiety, and women with high values may be incorrectly reassured.'
She also noted that women should not use such tests to decide whether or not to freeze their eggs.