Does a diagnostic ultrasound look for all birth defects? over 40 and having my first kiddo. will a diagnostic ultrasound at 22 weeks show all major forms of birth defect, or are there some that can only be detected by amnio or some other test?

Diagnostic : Diagnostic ultrasound is not 100% sensitive at identifying all major forms of birth defects, but it can identify many physical signs of various forms of birth defects. However, if the fetus has severe anatomical abnormalities, the ultrasound evaluation is very likely to accurately identify birth defects. Lets take the example of down's syndrome (trisomy 21). Most forms of down's syndrome demonstrate certain characteristic physical manifestations are usually detected on ultrasound. However, sometimes babies with down's syndrome can appear nearly normal even after birth; detecting these subtle abnormalities can be extremely difficult and occasionally impossible by ultrasound.

Yes and yes: As you get older, have more risk factors, or if something looks odd on the first ultrasound, a higher level ultrasound can be done to look for more advanced and subtle issues. Some genetic conditions, though, can only be found by sampling genetic material. An ultrasound at 22 weeks may not show a significant amount of smaller congenital defects but if something looks amiss, they may do one later.

Many undetectable: or missed. The accuracy is operator-specific, but even the most talented prenatal ultrasonologists, both Maternal-Fetal Medicine and Radiology specialists, will miss the diagnosis of Down in an affected pregnancy. You are entitled to have testing for Down by a maternal blood test for fetal DNA, 99.9% accurate, with results in 4 to 7 days. Your age-specific risk is 1/100. Get genetic counseling.