S.T.
Itsacrazylifewith4 is right - as long as there's not a break in coverage that is longer than 63 days the new insurance plan can't exclude your pregnancy as a pre-ex condition. HIPAA is a federal law that became effective in the late 90's that was speciically targeted to address a situation like this. I know this becuase I am a consultant to employers regarding employe benefit plans and have been doing this for many many years.
You will need to show the new insurance company proof that you had coverage before - the old insurance company (or sometimes the former employer) will send you a "certificate of creditable coverage" also called a "HIPAA certificate". It will show how long the coverage has been in place and will list each covered family member by name. When you get that from the old company you send it to the new insurance company.
Many times the Human Resources departments at both companies can help speed the process by requesting it right away upon your husband's leaving the old employer and getting it submitted to the new company right away.
Finally - the last thing to consdier - if your doctor is now in your network and he's not in the network at the new company you can request a "transition of care" from the new insurance company. They don't have to offer it, and if you're still in the first trimester they don't usually approve it - but it's worth a try. WIth a transition of care the new insurance company calls your doctor who's not in their network and asks if the MD would accept from the insruance company, the same amount they would pay to their in-network MDs. If the doctor accepts, then the new insurance company would treat the doctor and the claims as if they were in-network. Of course, the best option is if your doctor is in both networks.
Anyway - congratulations on this new little blessing and stay well!