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 About birth defects
- A birth defect is an abnormality of body structure, function or chemistry present at birth that results in physical or mental disabilities.
- Birth defects are the leading cause of death in the first year of life.
- There are thousands of possible types of birth defects, with health consequences that range from mild to life threatening.
- Down syndrome and cleft lip or cleft palate are the most common birth defects in the United States. About 5,500 babies are born each year with Down Syndrome, and about 6,800 with a cleft lip or palate.
Causes of birth defects
The causes of many birth defects are still unknown. Those with known causes can be divided into these types:
- Single-gene: birth defects that can be inherited from just one gene from one or both parents.
- Chromosomal: caused by abnormalities in entire chromosomes (groups of genes), or having too few or too many of a certain chromosome.
- Environmental: caused by factors such as alcohol or chemicals that come from outside the developing child's body.
- Multi-factor: caused by a combination of several of the above.
Single-gene birth defects
- Every human being has about 20,000 genes that direct the growth and development of our bodies. Each child gets half its genes from each parent.
- A child inherits a genetic disease when one or both parents parent pass along a faulty gene.
- Some defects can be caused by just one gene from one parent. An example is achondroplasia, a form of dwarfism.
- Other defects can only be inherited when both parents have an abnormality in the same gene and pass it on to the child. The parents can be perfectly healthy, and unaware that they carry such a defect. Cystic fibrosis is an example of this.
Chromosomal birth defects
- Abnormalities in the child's chromosomes, usually caused from an error when an egg or sperm cell was developing, produce chromosomal birth defects.
- The result can be too few or too many chromosomes, or broken or rearranged chromosomes. This causes disruptions in the normal development of the child.
- Down syndrome is caused by a chromosomal birth defect.
Environmental birth defects
- Environmental birth defects are caused by factors that are not inherited. Instead, they are present in the mother's body and reach the baby as it develops during pregnancy.
- Alcohol, certain drugs and medications, infection, and exposure to certain chemicals can cause such defects in the unborn child.
- Fetal alcohol syndrome is one example of an environmental birth defect.
Some birth defects can be prevented.
- Environmental birth defects can be prevented by avoiding their causes. This includes avoiding alcohol, or ensuring proper nutrition during pregnancy.
- Inherited birth defects can be prevented by identifying them in the parents before a baby is conceived.
- It's vital to visit your doctor before you become pregnant in order to identify and treat conditions that can pose a risk in pregnancy.
- A doctor can give advice on the lifestyle factors before and during pregnancy that can contribute to or reduce the risk of birth defects.
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