USG can diagnose all except:
D i.e. Down's Syndrome In anencephaly, absece of vault. In NTD, presence of meningo-myelocoel & In placenta pre location of placenta seen by USG confirms the diagnosis. Although on prenatal U/S increased nuchal fold thickness, and reduced length of femur & humerus are suggestive of Down's syndrome but the diagnosis is confirmed by chromosomal study (trisomy of 21st autosome) either by amniocentesis or chronic villous sampling.
Anencephaly
Neural tube defect
Placenta pre
Down's syndrome