Low T3 affect fertility?

[librarygirl2]

Hi folks,

I've been on Tirosint 50 mcg. and just got my labs:
TSH .73
FT4: 1.5 (0.8-1.8)
FT3: 2.5 (2.3-4.2)

Since I switched last month to Tirosint (yes, I can stay on it longer than 10 days which I couldn't do before) I haven't had my period yet and I know for sure I am not pregnant.  

I have been trying to conceive for 7 months with good FT4 numbers but basement-level FT3s.  Would the lower FT3 hinder my ability to get pregnant?  I cannot find any research on this.

Thanks

[librarygirl2]

Thanks gimel!

[gimel]

The simple answer is yes, it can.  When a patient is hypo, getting pregnant and having a successful pregnancy is difficult.  If you want a reference for this I will have to look around, but there are many references available about the problem.  

When you look at this list of typical hypo symptoms you will find among many others, irregular menstrual cycles and trouble conceiving a baby.  Symptoms are the best indicator of thyroid status.  
http://thyroid.about.com/cs/basics_starthere/a/hypochecklist.htm

Based on knowledge of only a few symptoms and your FT3 result that is in the low end of the range, I'd say that you are hypothyroid.  FT3 is the most important thyroid hormone because it largely regulates metabolism and many other body functions.  Studies have also shown that FT3 correlated best with hypo symptoms, while FT4 and TSH did not correlate very well at all.

A good thyroid doctor will treat a patient clinically by testing and adjusting FT3 and FT4 as necessary to relieve symptoms, without being constrained by resultant TSH levels. Symptom relief should be all important, not test results.  Test results are valuable mainly as indicators during diagnosis and afterward to monitor FT3 and FT4 levels as meds are increased toward achieving symptom relief.  You can get some good information about clinical treatment in this link.  

http://hormonerestoration.com/files/ThyroidPMD.pdf

Thyroid patients taking T4 meds frequently find that their FT4 level will increase adequately, but due to lack of conversion of T4 to T3, their FT3 levels lags behind, like yours.  FT3 results that fall in the lower end of the range are frequently not adequate to relieve symptoms.  Many members report that symptom relief for them required that FT3 was adjusted into the upper part of its range and FT4 adjusted to at least midpoint of its range.  Since your FT4 is already at midpoint, just increasing your Tirosint is not going to do it for you.  You need to either add a source of T3 to your meds, or switch to a T4/T3 combo type med.  So you need to discuss this with your doctor and see what transpires.