Fasting and thyroid

I had an appointment with my primary doctor last week and because of some things I’ve had going on, she wanted to do some blood work, including a test of my thyroid hormone levels. I got a call Friday from the nurse that one of the hormones (I forgot whether it was T3 or T4) was just a little bit low, not much. The other hormone was in normal range, but on the low end. She said with the one only being a little low, my doctor didn’t want to prescribe anything yet. She wants to recheck my levels this week.

The office has a lab in house, so they just did my blood work right after I saw the doctor. They didn’t ask anything about when the last time was that I ate. I have been doing intermittent fasting as part of my diet/exercise routine because I am working on toning up now after losing all the weight from my last baby. I was still fasting when they took my blood. I do remember when I was researching the best way to intermittently fast that if you have hypothyroidism, it is best to get direction from your doctor before adding any fasting into your routine. What I’m wondering is - could the intermittent fasting have contributed to the levels being low last week? I really can’t find any information as to whether fasting actually lowers your thyroid levels, all I see is stuff telling people to check with their doctor before fasting if they’ve already been diagnosed with hypothyroidism.

I know this isn’t a medical forum and I am going to ask my doctor about this when I go back in on Friday to talk to her and have the blood work repeated. I’m also going to call and ask the nurse if I should be eating before hand or not. I just thought I’d see if anyone has insight on it because I’m a little nervous about it coming back low again. I thought your thyroid was supposed to be able to maintain normal levels of hormones regardless of outside factors like that if it’s functioning properly.