Thyroid levels

I did my two betas and they’re both positive! My doctor also checked my thyroid levels and said she’ll likely suggest a synthroid medication if TSH levels are elevated. She mentioned throughout first trimester the recommended level is under 2.5.

Has anyone taken this before? Is this normal? Is there risks? I’m asking because I haven’t taken this in my prior pregnancy (non IVF) and this was never tested.

TIA!