“I don’t get it” said one of my fertility clients one day – ”every time I get a new blood test my levels are more or less normal – they can’t find anything wrong – yet I feel sh*te and still can’t get pregnant!!”

Yes indeed it’s complicated, many factors can be conspiring together to keep your fertility system under par, but one issue that really hits me is the routine over reliance on ‘average’ levels of hormones from blood tests.

The reference ranges for various hormones like estrogen, FSH, LH and progesterone are worked out using a hodge podge of averages across the population, yet everybody in the lab testing world knows there is no such thing as an average person, and despite this we still try to get people to have average ‘normal’ levels.  Sure there is some wiggle room built in to accommodate different kinds of people, but this only makes it harder for an individual to know what their hormone reading actually means to them.  Are they fine or in need of a raise – or do they need a bit less than that?

The problem with this is twofold;

• Your ideal level of any given hormone may be different from the average (it often is!)
• The way hormone levels are detected in blood tests doesn’t really tell you what’s going on inside your body – meaning in your cells!

I’m not saying that average values from blood tests are pointless – they can tell you if a serious disease is afoot, sure – but most people are not in this category!  Instead I’m saying they’re useless for helping you tweak your body to make things better.  They are a holdover from the old way of doing things, and we all know how long it takes to stop doing old things and start doing new things.  All of us – right?  We all find it hard to change old habits so I guess we can’t exactly get off complaining about the medical system and how it’s stuck in the mud, when we can’t do it ourselves!

Anyway – here’s the science bit if you want it:

Hormones travel around the blood in two ways – ‘bound’ or ‘free’ – meaning they are either bound to carrier proteins or they are not.  My analogy for this is they are either getting carried around the blood in submarines, or they are swimming around on their own!  Typically over 95% are contained in the submarines, and the rest are swimming around freely.  The purpose of the submarines is to deliver the hormones to where they need to go in your body – the submarine delivers them to your tissues, then they get out of the submarine and go into your tissues – where they do their thing.

When you measure estrogen from a blood test for example, the number you see represents the combined total amount of estrogen, meaning the quantity of estrogen in the submarines plus the small bit of extra estrogen that is swimming around ‘free’.

Now here’s the clincher – only the free stuff can do anything – only the free estrogen can go into your cells and make them do something that estrogen makes them do.

Estrogen for example makes your womb lining grow in preparation for pregnancy, but only free estrogen can do this, not estrogen bound to a carrier protein (not the estrogen in the submarines).

Blood tests tell you your total estrogen level – but your moods and womb lining and skin and all the stuff estrogen affects is only affected by the free estrogen – yet blood tests don’t measure free estrogen, they measure ‘bound’ estrogen and then use the result as a proxy to determine how your body is getting on.

This is a bit like knowing somebody is wealthy because they own shares in google, and then assuming they can easily buy the next round of drinks, without realising they only have 2 euro in their pocket at that moment and can’t actually buy anything.

Yet that’s the way the medical system has evolved to view hormone levels, they comment on your overall wealth without knowing your immediate liquidity status, they even prescribe treatments based on these readings, often ignoring how a person is feeling – when how you ‘feel’ is directly related to your free hormone levels.

Is there a way to tell how much free estrogen (or progesterone…or LH or FSH for that matter) you have floating around your blood?  The answer is yes – you can get this information in saliva tests, because all the hormone in saliva is in the free state (it has to leave the submarine to get into your saliva), and reference ranges have been worked out which are not generic average ranges but rather ranges based on what healthy people have, therefore they offer decent targets to aim at.

Why don’t doctors use these?  Old ways are slow to change – there’s a double message here for all of us I guess!

Brendan