Is Your Oestrogen Under Replaced?

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Oestrogen absorption and requirements vary between individuals. On commencement of HRT, usually the lowest dose is used either transdermal or oral and this is then adjusted upwards depending upon symptom response and absorption. Because of the huge variation in absorption (10-90% between individuals) some patients may seem to be on an adequate dose of oestrogen but in fact, continue to experience severe symptoms. This can be a concern because of impaired quality of life and the danger then of attributing residual symptoms to other causes which can lead to an inappropriate referral and extra medications for the individual’s symptoms. Symptoms can include:

•  Vasomotor/Adrenaline – panic attacks, sweating, anxiety resulting in inappropriate anxiolytic medication
• Sleep disturbance/ Fatigue – prescribed sleeping tablets, multivitamins, iron supplements
• Low mood – negative thoughts, loss of confidence resulting in appropriate antidepressants
• Heart racing, sweating, chest pains attributed to cardiovascular issues - prescribed cardiac medication such as betablockers 
• Joint pains /collagen weakening attributed to arthritis – prescribed anti-inflammatory medication such as NSAID’s, methotrexate and occasionally even steroids which will impact firstly on bone generation or see questionnaire on website

Therefore, it is clearly important to assess the symptoms but if in doubt, an FSH blood test (not oestradiol as this fluctuates too much to be representative) will give a more accurate indicator as to whether the oestrogen absorption is adequate. In some cases, due to poor absorption, higher doses need to be used to achieve optimal symptom relief. By definition, this therefore does not increase any theoretical extra risk as the blood levels themselves are not high, it is simply that the dose required to achieve adequate levels is higher. This occasionally may mean that two types of oestrogen may require to be used such as oral as well as transdermal.

As above, it is important that if you wish to assess the amount of oestrogen in your bloodstream, you only check an FSH blood test (Follicle Stimulating Hormone) not oestradiol. Oestradiol levels are only relevant to the use of transdermal oestrogen and even then, blood levels can fluctuate hugely particularly after application of gel or spray and so this is only a snapshot of the blood level at that time and can cause confusion. Oral oestrogen converts mostly to oestrone in the gut wall and liver and this cannot be measured. Therefore, checking oestradiol levels is not relevant and should not be encouraged. It would be similar to a one-off check of a thyroxine level for monitoring thyroid replacement instead of checking a TSH or a one-off glucose estimation for monitoring response to anti-diabetic medication instead of HbA1c. The FSH should be less than 5-10IU/L to indicate best absorption into the bloodstream irrespective of dose and route of administration. Even if higher doses or several types of oestrogen are required to be used, because of the huge variations of absorption, the FSH may still be high and symptoms continuing due to absorption variation and you will then need to adjust your dose or type of oestrogen. 

Please remember that absorption varies depending upon timing of the cycle and other factors such as gut health, batches of medication and skin factors such as sweating, skin irritation etc. The aim therefore is to achieve steady blood levels within the correct range irrespective of dose and type of oestrogen even if different types of oestrogen need to be used to achieve this (see symptom questionnaire).