First Ultrasound/ Low TSH

Today I went for my first ultrasound! I was suppose to be 9 weeks and 6 days but baby measured further along. Baby measured 10 weeks and 4 days with a heart rate of 169! They changed my due date from July 10th to July 5th! All of my labs from last week are normal except my TSH. It is low for first trimester pregnancy. My TSH last Monday was 0.18 and the normal is 0.26- 2.66. The doctor hasn’t said anything so I’m not going to worry unless I get a call. Everything else looks great so far. Did anyone else have low TSH in their first trimester?