I am probably the worst person to answer this because I am so laid back about the whole deal. I hate the several dozen appointments, the tests, the poking, the prodding, the "we just wanna check this". Drives me COMPLETELY insane. In turn, I drive them completely insane by the majority of the time, opting for the least invasive option every time. They wanted to do weekly BT for my anti-e, but I didn't see the point because the titer had been the same for 3 months. Was happy to agree with weekly US's to check the blood flow though. Cripes, Who wouldnt be?? You don't often get the option of seeing your bub every week for 12 weeks before he is born!

I'd be of the same opinion for this variance. They can screen with US and if it had anything to worry about, then I would considder the blood test. But if it won't change your mind at all, then its not something worth stressing yourself about during the pregnancy. Conversely, if you are now going to stress over it, agree to the US screen to set your mind at ease. Whatever will cause you the least worry in the long run is the barometer I use.