DefinitionNumber of children born with Down syndrome per 10,000 live births to women residing in New Jersey in a specified time interval.
NumeratorNumber of children born with Down syndrome among live births to women residing in New Jersey in a specified time interval.
DenominatorCount of all live births to women residing in New Jersey in a specified time interval.
Why Is This Important?Trisomy 21 (Down syndrome) is a chromosomal abnormality characterized by the presence of an extra copy of the 21st chromosome. Down syndrome is the most frequent genetic condition of childhood associated with mental retardation.
Maternal age is a major risk factor that increases the chance of conceiving a baby with Down syndrome. At maternal age 20 to 24, the probability of conceiving a child with Down Syndrome is 1 in 1,562; at age 35 to 39 the probability increases to 1 in 214; and above age 45 the probability increases to 1 in 19. However, though the probability of a child being born with Down syndrome increases with maternal age, approximately 80% of children with Down syndrome are born to women under the age of 35. There are currently no known environmental factors that are associated with developing Down syndrome.