How accurate is a level 2 ultrasound at detecting certain birth defects or genetic abnormalities?

Question

AFP test came back positive for Down's syndrome. I know they are not very accurate. My question is...How accurate is the Level 2 ultrasound?

PS-I know the only 100% way to know for sure is the amnio.

Answer 1

The Level 2 U/S is pretty accurate. The technician or perinatologist, or whoever is conducting the U/S will spend at least an hour taking and re-taking measurements and noting any markers that might indicate a genetic problem.

I just went through this a month ago following a false positive on my AFP. After the ultrasound, the doctor said, "I can tell you with almost 100% certainty that your baby is fine." None of the markers for Downs were present during the ultrasound, and the growth matched up with the age, and everything looked good. But she also added that the only way to know 100% FOR SURE is to go ahead and do the amnio, which I did, and sure enough, everything is fine (knock on wood...).

Good luck. False positives on AFPs seem to be the norm, rather than the exception. You will be fine!