If you were pregnant this year (because I think the plan might have changed within the past year or two) and were under 35, was your NT scan covered? I am finding unclear & inconsistent information out there, and so far the customer service has not been entirely helpful.
Re: Insurance - anyone have fed BCBS basic?
TTC #2: BFP 12/17/11, m/c 1/7/12 and D&C 1/12/12
baby blog/cooking blog

I am currently pregnant and have fed BCBS basic. For the entire pregnancy, I had a co-pay at my first visit to confirm pregnancy, will have a $150 copay for the hospital stay, and will have to pay a copay for the baby's circumcision. That's it.
I am 35, but I don't think they had to code it special or anything to get coverage. I don't know if it matters where I went for the NT scan though. I did it at GIVF in Merrifield, which is just treated like a specialist's office. I'm not sure if they would treat it differently if it was done at a hospital outpatient facility. (I know my ENT office visits are treated differently because it is billed by Johns Hopkins hospital instead of a regular physician service.)
I had an NT scan. I also had the basic blood screening to see if I'm a carrier for cystic fibrosis and a few other things. No charge.
I also have BCBS Basic. I had my NT scan in May, and both the blood tests and the sonogram were 100% covered. I tried to verify that they would be beforehand and found it virtually impossible -- BCBS would only tell me that they would cover it if it was "medically necessary routine maternity care" without telling me what that encompassed. I spoke to my doctor's billing office (Reiter Hill) and they told me that the sonogram, at least, was coded as a routine maternity sonogram so that it should be covered -- and it was. I also did the sequential blood screen at 16 weeks, and that was 100% covered also.
If you are worried, you may try talking to your doctor's billing office. There are so many feds around here that I am sure they routinely deal with BCBS and may be able to offer you some reassurance.