What is trisomy 18 (Edwards syndrome)?

Individuals with trisomy 18 have an extra copy of chromosome 18 in the cells of the body. This extra genetic material causes changes in development of the embryo and fetus resulting in physical and developmental abnormalities.

Health problems are often life-threatening, including heart defects and breathing difficulties. Birth defects can occur in other organ systems as well, including the kidneys and the intestines. Miscarriages are common with affected pregnancies. The majority of babies with trisomy 18 die within the first year of life. Children with trisomy 18 that survive have severe intellectual disability.

How common is trisomy 18?

Trisomy 18 occurs in about 1 in 5000 live births. The condition is not related to race, nationality, religion or socioeconomic status. There is usually no family history of the condition.

How is trisomy 18 treated?

Treatment for trisomy 18 is supportive, meaning that the condition cannot be cured, and treatments are directed at managing complications. Common treatment measures include nutritional support, treatment of infections, and medications to manage heart failure.

Other names for
Trisomy 18

  • Edwards syndrome


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  • Jones, K. L. (Ed.). (2013). Smith’s recognizable patterns of human malformation (7th ed.). Philadelphia: Elsevier Inc.