Hi mama! Congrats sa baby number 2! Ay, ang low TSH during pregnancy is actually something na kailangan talaga ng close monitoring with your OB or endocrinologist, hindi ko ma-confirm kung marami pang may same situation, pero alam ko it's more common than you'd think, especially sa second pregnancies. The good news is na your doctor can manage it properly throughout your pregnancy, so don't worry too much! Have you already scheduled a follow-up with your OB about this, or is this your first time knowing about the low TSH? They'll likely want to check again in a few weeks to see kung paano ito mag-progress. You're doing great by staying on top of your prenatal care!