DefinitionDown syndrome is a condition in which a baby is born with an extra chromosome. Chromosomes are small "packages" of genes in the body. They determine how a baby's body forms during pregnancy and how, as the baby grows in the womb and after birth, the baby's body functions. Normally, a baby is born with 46 chromosomes. Babies born with Down syndrome have an extra copy of one of these chromosomes. This extra copy changes the body's and brain's development and causes mental and physical problems for the baby. Prevalence of Down syndrome is calculated in two ways: 1) the number of live-born infants with Down syndrome to mothers less than 35 years of age per 10,000 live-born infants and 2) the number of live-born infants with Down syndrome to mothers 35 years of age or older per 10,000 live-born infants. (Live-born infants are the infants born with any evidence of life).
NumeratorNumber of live-born infants with Down syndrome to mothers in a given age group at delivery.
DenominatorTotal number of live-born infants to mothers in a given age group at delivery.
Data Interpretation IssuesIn January 2000, birth defects became a reportable condition in New Mexico; however, birth defects were collected prior to this date. The first year of consistent data is 1998. However, data for Down syndrome were not collected consistently until 2004. For Down syndrome data, the most recent year of analyzed data is 2011.
Data are collected on live births occurring in-state to NM residents. Therefore, live births that occur in NM among out-of-state residents are excluded.
Case finding/identification occurs through review of birth and death certificates, hospital discharge diagnoses, records from pediatric specialists and prenatal diagnostic providers.
Birth defect cases are ascertained up to age 4; however, the majority of diagnoses are made by age 1.
Why Is This Important?Birth defects pose a significant public health problem. One in 33 babies is born with a structural birth defect in the United States. Birth defects are a leading cause of infant mortality and responsible for considerable morbidity with enormous economic and social costs.
Usually, mental development and physical development are slower in people with Down syndrome than in those without it. Babies and adults with Down syndrome can have physical problems, as well as intellectual disabilities. Some physical problems associated with Down syndrome include:
-A birth defect of the heart
-Stomach problems, such as a blocked small intestine
-Celiac disease, a digestive disease that damages the small intestine so that nutrients from food are not absorbed well
-Problems with memory, concentration, and judgment, often called dementia
-Eye problems, such as cataracts or trouble seeing objects that are close by (far-sighted)
A person with Down syndrome can have an IQ in the mild-to-moderate range of intellectual disabilities. He or she also might have delayed language development and difficulties with physical coordination.
Other ObjectivesCDC Environmental Public Health Tracking, Nationally Consistent Data and Measures (EPHT NCDM)
How Do We Compare With the U.S.?The national prevalence of Down syndrome among births from 2004-2006 is 14.47 per 10,000 births (adjusted for maternal age). These data come from 14 birth defects surveillance programs: Arkansas, Arizona, California [8-county Central Valley], Colorado, Georgia [5-county metropolitan Atlanta], Illinois, Iowa, Kentucky, Massachusetts, North Carolina, Oklahoma, Puerto Rico, Texas, and Utah. For more information, please see: