Ovarian reserve testing: Should it be used as a decision making tool?

There is increased concern regarding delaying parenthood and age-related fertility decline, particularly for women, throughout the US and UK. Although current clinical science has yet to reveal a single true 'fertility test' for women, many interested in having biological children are seeking a definitive guide as to whether they can delay pregnancy or should be concerned. 

Age is the single best predictor of whether a woman will be able to conceive or not. Every woman is born with a limited supply of eggs - all the eggs she will have in her lifetime are contained in her ovaries from birth. A collection of tests typically, used prior to assisted reproductive technologies like in vitro fertilisation (IVF), can provide a snapshot into a woman's remaining pool of eggs, called 'ovarian reserve'. These tests, however, are not predictive of natural fertility, that is, the likelihood a woman could conceive spontaneously without medical interventions, but rather help clinicians tailor regimens for ovarian stimulation and predict the success of egg retrievals for IVF or egg freezing. 

Alarmingly, despite a lack of clinical evidence, one of these measures, a blood test for antimüllerian hormone (AMH), has been highlighted in the media as a possible fertility test for the general population. 

A woman's remaining egg pool secretes AMH - higher levels may indicate a greater quantity of eggs left, however, this number alone does not provide information about a woman's ability to conceive spontaneously. AMH level does not give insight into the quality of a woman's eggs, and only a single healthy egg is required for conception. 

Furthermore, an AMH test cannot be used to reassure a woman she will not experience infertility or that she can delay motherhood without concern. A hormone test cannot detect conditions such as endometriosis or physical issues such as a blocked fallopian tube, which can impact fertility. A one-time AMH test is not a good predictor of spontaneous conception or how long it will take to get pregnant, nor is it useful in accurately predicting the onset of menopause.

Professional practice societies in the United States, including the American College of Obstetricians and Gynaecologists and the American Society for Reproductive Medicine, have cautioned against the use of AMH testing in the general population without a diagnosis of infertility. Their opinion paper written by the American College of Obstetricians and Gynaecologists can be viewed here. 

In the US and UK, private fertility clinics often offer more comprehensive measures of reproductive hormones in addition to AMH level, including follicle stimulating hormone (FSH), oestradiol (E2), thyroid panels, combined with an ultrasound of the ovaries to visualise and count developing egg follicles (antral follicle count) during the menstrual cycle to assess any abnormalities. 

While more comprehensive, and likely to provide a more complete picture of ovarian reserve leading to tailored follow-up counselling, these fertility MOTs are largely unnecessary in otherwise healthy women without a history of infertility. 

None of these tests provide any concrete guidance about the next steps a woman can take in family planning, unless she has attempted to conceive for several months. Even for women considering egg freezing, ovarian reserve testing focused on AMH level offers minimal guidance as patients with the lowest AMH will have the poorest outcomes when trying to freeze eggs. The decision to pursue egg freezing must be separated from assessing ovarian reserve. 

In summary, older women with average or robust ovarian reserve measures may mistakenly assume they are not at risk for age related fertility decline and forgo egg freezing or reconsidering their family planning timeline. Similarly, a low AMH level or other test result can cause alarm or unnecessary anxiety for patients who may not actually have any issues conceiving.

It is critical for women to fully understand the limitations of these so called fertility tests; that they do not predict fertility or time to conception and are primarily useful for women already diagnosed with infertility. All women deserve comprehensive counselling about age-related fertility decline and family planning, as well as follow-up care options including fertility preservation through egg freezing. However, using ovarian reserve testing as a decision-making tool is inappropriate and is not supported by the most up-to-date research and best practice guidelines.