2. Early Detection depends upon the severity and the nature of mental retardation:

many genetic abnormalities can be identified before birth. Some of the methods of identifying
include: amniocentesis,fetoscopy,chronic villus sampling, sonography, and blood screening
tests,

some conditions like Down's syndrome, microcephaly(small head circumference) can be
identified at birth.

after birth if the growth and the developmental milestones are delayed and there is presence of
neurological signs and symptoms, identification of mental retardation can be made with fair
degree of certainity within one year.

in case having mild delays of development, assessment of intellectual functioning becomes
crusial tool for diagnosis which can be performed with reliability by the age of 3 to 5 years.