Tuesday, March 10, 2015

Is ovarian reserve really declining in Indian women ?

Today's Times of India had an article about the high prevalence of low AMH levels in Indian women.  Are we really seeing an epidemic of low ovarian reserve ? Should young women start worrying and getting their AMH levels tested ?

The truth is that there have always been young women with poor ovarian reserve . Because the numbers of young women trying to have a baby is large , it's a mathematical certainty that some of them will have a low AMH level. However, in the past, we could not make the right diagnosis , and these women were often mis-labelled as having unexplained infertility. It's great that we have now have new and better diagnostic tools to test for ovarian reserve, but a diagnostic test should not be misused for screening. This creates all kinds of problems !

So why isn't a better diagnostic test an unmitigated blessing ?

Let's look at the second order consequences of the easy availability of these tests and the way they are being aggressively marketed. Because it's so easy to order these tests, even family doctors will start asking for them - just like they order tests for checking levels of Vit D and B12 routinely these days. In fact, lots of labs will also start offering them as part of the "Exceutive Health Checkup Plan" for women. Once the result comes back as low ( which it will in 5% of women, because this is how the normal range is defined), these poor women will then be referred to fertility specialists for further testing.

I guess I shouldn't be complaining ,because this means more work for me, but these tests will create lots of "worried well women". The truth is that doctors do not treat test results or lab reports - we treat human beings. Tests need to be interpreted in context, but this is too complex to explain in a newspaper article, which is why the message gets so garbled.The reporter is forced to oversimplify because of space constraints, which means the reader fails to understand the context of the study.

Personally, I believe the study was just an aggregation of the lab's test results performed over one year , and was quite pointless. Of course infertile women will have poor ovarian reserve - after all, that's one of the reasons they are infertile.The hidden agenda of the press release ( which described the "research study" done by the lab ) was to increase the lab's workload, and they will definitely succeed in doing this ! However, a lot of harm will be done by creating unnecessary anxiety in healthy young women, who will start obsessing about their "low AMH" levels. By creating these labels, the medical profession is doing a dis-service to our patients.

The big problem is innumeracy , and doctors are often not capable of interpreting the results of these studies properly.  Infertility specialists naively  support the flawed conclusions of the study , by  offering anecdotal evidence that they are seeing more young women with poor ovarian reserve. However, this is hardly surprising - after all, specialists are seeing only women with fertility problems. It doesn't make any logical sense to extrapolate this observation to the general population at large ( even though this does make for better headlines ) ! Thus, there will be lots of fertile women with low AMH levels, who do not even know they have a low AMH level because they have enough sense not to go to a doctor. Infertility specialists will never see these women, which is why they continue to have a distorted view of the clinical significance of a low AMH level. They will jump to the erroneous conclusion that low AMH = infertility because of poor ovarian reserve.

We need to understand that the predictive value of a positive result depends upon the " base rate" - the prevalence of poor ovarian reserve in the population being tested.  The implication of a low AMH in an infertile woman ( someone who has been trying for at least 1 year in her bedroom) is very different from finding a low AMH level in a woman who is unmarried ( whose low AMH level was detected during a "routine" health checkup). We cannot compare apples and oranges !

The problem seems be that doctors have created an epidemic of mislabelling. We have created lots of new diseases, such as prediabetes and prehypertension. " Pre-infertile" seems to be the new kid on the block !

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