Trisomy 13 and trisomy 18 are problems with genes that cause serious birth defects and health problems.


Chromosomes carry our unique DNA. Infants born with trisomy 13 or 18 have 3 chromosomes where there should only be 2.

Risk Factors

There are no known risk factors.


Most children will have some, but not all of these symptoms.

Trisomy 13:

Cleft Lip
Cleft lip
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Trisomy 18:

  • Periods of not breathing
  • Arms and legs in a bent position
  • A vertical slit in the upper lip
  • An abnormal opening in the roof of the mouth
  • Clenched hands and overlapping fingers
  • Abnormal hands and feet
  • Eye problems
  • Feeding problems
  • Hearing loss
  • Low birth weight
  • Low-set ears that may be unusual in shape
  • Problems learning
  • Small head, with the back of the head larger
  • Small mouth and jaw
  • Webbed neck


These problems can be found both before and after a child is born. Tests may be:

Before birth:

  • Pictures may be taken of your baby. This can be done with ultrasound .
  • Amniocentesis to test the fluid in your uterus.
  • Chorionic villus sampling (CVS) to test cells from the placenta.

After birth:

  • Your doctor will check your baby's health. This can be done with a physical exam.
  • A chromosome analysis may be done using a blood sample.


There is no treatment or cure. Most babies have severe physical problems. It is treated by making the child comfortable, rather than prolonging life. Talk to your doctor about whether life-prolonging measures are right for your child.

Children who survive infancy may need:

  • Surgery to correct physical problems
  • Speech therapy
  • Physical therapy
  • Other types of developmental therapy


There are no known ways to prevent trisomy 13 or trisomy 18. After these disorders are diagnosed, parents can decide whether to continue or terminate the pregnancy. Parents who are concerned should talk to a genetic counselor when deciding to have children.

Revision Information

  • Reviewer: EBSCO Medical Review BoardKari Kassir, MD
  • Review Date: 03/2019 -
  • Update Date: 04/09/2019 -