How is she feeling? if she feels fine it very well may be that nothing will have to be done.
I would suspect she is VERY tired. However it is also not uncommon for pregnant women to be very tired even when everything is perfect.
But as you point out her FT3 is BELOW range. And her FT4 is only 17% of the range. Generally the target many people have found to feel well is where the FT3 is in the upper 1/3 of the range (66.7%) and the FT4 is in the MIDDLE of the range (50%). Your wife is significantly below both of those levels.
Understand also that perfectly functioning people can often feel well low in the ranges. The 66% and 50% mentioned above is really more appropriate for people who have been diagnosed or have a known low thyroid issue. These folks seem to need a little extra higher levels than a truly "normal" person.
You may want to talk to the Dr about getting a starter dose of thyroid medication. Most likely a T4 medication such as synthroid or a generic equal. But don't be surprised with a "normal" TSH value of 2 a Dr may not be inclined to prescribe a thing.
If you dn't already know, T4 is converted by the body into T3. Both T3 & T4 can be either "free" or they can become attached to a protein. Once the hormone attaches to a protein it becomes biologicaly inactive (useless). So your body will only convert the free T4 into T3. But that T3 either remains free or becomes attached. Your body's cells ONLY use the free unattached T3 hormone.
So really what I'm saying is that if there is one thing to test and monitor since it is the only thing your body uses at the end result is Free T3. Then it may make sense to raise the FT3 level up.
More FT3 can be made by either taking a T4 medication and letting the body convert it naturally into FT3. This is the most common way. Or you can directly take T3 but this is less common at least to start. They can also be used in combination.
Not sure if this gave you the answer you were looking for but hopefully you got some insight.
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