Low TSH levels???

Tricia • Love my perfect little family!💕5yo son💕2yo daughter💕Just had TWINS💕

Has anyone else been told their TSH levels are too low? I was told it can happen when carrying twins/multiples, and I'm just looking for ease of mind. My OB ordered them to be checked with my 1st trimester labs, and we just received the results. He said I will be monitored closely with additional thyroid labs, but should I be more concerned?

I don't have any history of thyroid problems prior to pregnancy. Could the pregnancy be what has caused this to happen?