S.B.
Dear T.,
Congratulations on your pregnancy!
I'm a licensed insurance agent and my advice is to definitely speak with Aetna Member Services. The number is on your ID card. Have a list of questions prepared ahead of time and document your conversation. I would definitely let them know that you are pregnant and that you need to clarify your maternity benefits, if there are any restrictions on providers you can see such as in-network as opposed to out-of-network, and if you need referrals, etc. It's best to find all of that out now.
As for the blood work, I don't see why it would be necessary to repeat the same tests. You can have your results forwarded to your new physician. Keep in mind that insurance policies pay for benefits covered and for things that are deemed "medically necessary". Unless the lab botched the tests or something, it wouldn't be necessary to repeat the blood work due to switching doctors. Doctors are pretty savvy about these things. They know they need to submit diagnosis codes and procedure codes in order to request tests and submit to insurance. Start with your insurance company first. If you don't have an Evidence of Coverage booklet that outlines your benefits, rights and responsibilities, request one.
Best of wishes to you!