Synthroid & Birth Control: Understanding Thyroid Hormone Levels

Question
I take .175mg Synthroid daily and my TSH results stay around 1-2.  I feel healthy and well.  Three months ago, my doctor put me on Alesse birth control to help with periomenopause symptoms.  The paperwork with the pill says that it can impact thyroid test but it doesn't say how (at least not so I understand) I just had a thyroid test and my test result was very low (below 1) and now my doctor wants to reduce my synthroid.  When I asked both the lab and my doctor what the contraindication said, neither of them thought it made a difference.  Can anyone tell me if I just got a false reading on my TSH test or has the hormone medicine caused me to need a reduced level of synthroid.  Also does taking the Alesse with my Synthroid in the morning at the same time affect my absorption?  Again, the lab nor my doctor could answer that question.

Answer
Linda,

I have written extensively on NHRT with regard to sex hormones and thyroid.  Not a big fan of synthroid (or other synthetic hormones)... my approach is that of bioidentical T3 and T4 replacement.  The TSH is only good for diagnosing hypothyrodism, but is poor for micromanagement.  FreeT3 and FreeT4(fT4) should be used.  To answer your question about whether female sex hormones impact well they can.  Adding sex hormones to the picture can cause a complex system of hormone receptors to get shaken up.  Most often thyroid hormones must be INCREASED to solve this problem.  It has to do with binding proteins and free hormone levels.  Too complex to go into detail here.  So your TFT should be repeated two weeks after starting Alesse.  Also thyroid replacement (whether natural or synthetic) should be done on an empty stomach, only water.  No coffee no food, no supplements and no other medication for two hours after dosing.  You can read more on thyroid on my blog at www.docsaleeby.blogspot.com or for consultation with me on the phone www.saleeby.net

JP Saleeby, MD