Edwards syndrome (trisomy 18) is a genetic condition that causes physical growth delays during fetal development. Life expectancy for children diagnosed with Edwards syndrome is short due to several life-threatening complications of the condition. Children who survive past their first year may face severe intellectual challenges.
Edwards syndrome, also known as trisomy 18, is a very severe genetic condition that affects how your child’s body develops and grows. Children diagnosed with trisomy 18 have a low birth weight, multiple birth defects and defining physical characteristics.
Edwards syndrome (trisomy 18) can affect anyone. The condition occurs when a person has an extra copy of chromosome 18, which is random and unpredictable. The likelihood that a parent will have a child with Edwards syndrome (trisomy 18) increases with maternal age at the time of pregnancy. If a parent had a child with Edwards syndrome (trisomy 18) and becomes pregnant again, it’s unlikely they’ll have another child diagnosed with the same condition (no more than 1%).
Edwards syndrome (trisomy 18) occurs in an estimated 1 out of every 5,000 to 6,000 live births. The condition is more common during pregnancy (1 out of every 2,500 pregnancies), but most (at least 95%) fetuses don’t survive full term due to complications from the diagnosis, so pregnancies can end in miscarriage or babies are stillborn.
John Hilton Edwards, et al., discovered Edwards syndrome (trisomy 18) in 1960 after researching a newborn with multiple congenital complications and issues with cognitive development. They reported their discovery and identified the condition as the result of a third cell attaching to a pair of chromosomes at chromosome 18 (trisomy 18).
Symptoms of Edwards syndrome (trisomy 18) typically include poor growth before and after birth, multiple birth defects and severe developmental delays or learning problems. Symptoms are present during pregnancy and after your child is born.
Your healthcare provider will look for signs of Edwards syndrome (trisomy 18) during a prenatal ultrasound, including:
An Edwards syndrome diagnosis can result in a live birth, but trisomy 18 most often causes a miscarriage during the first three months of pregnancy or the baby is stillborn.
After your baby is born, your child likely has physical characteristics of Edwards syndrome (trisomy 18), including:
Because children diagnosed with Edwards syndrome (trisomy 18) have underdeveloped bodies, the side effects of the condition have serious and often life-threatening consequences, including:
Issues relating to the heart affect nearly 90% of children diagnosed with Edwards syndrome (trisomy 18) and are the leading cause of premature death among infants who have the condition, next to respiratory failure.
Having three copies of chromosome 18 instead of the typical two causes Edwards syndrome (trisomy 18).
All humans have 46 chromosomes that divide into 23 pairs. Chromosomes carry your DNA in cells, which tells your body how to form and function as its instruction manual. You receive one set of chromosomes from each of your parents.
When cells form, they start in reproductive organs as one fertilized cell (sperm in males and eggs in females). Cells divide (meiosis) to create pairs by copying themselves. The cell’s copy contains half the amount of DNA as the original cell, 23 chromosomes from 46, and each chromosome pair has a number.
During egg and sperm formation when chromosome pairs are supposed to divide, there’s a chance that a chromosome pair will not divide (as if they are too sticky) and both copies will be included in the egg or sperm. When fertilization happens, those two copies join one from the other parent so the result is three copies in total. The incorrect number of chromosomes is unpredictable and random and isn’t the result of something the parents did before or during pregnancy.
When a third copy of a cell joins a pair, a trisomy occurs. Trisomy means “three bodies.” If someone receives an Edwards syndrome diagnosis, they have a third copy of chromosome 18 in their cells.
Diagnosis of Edwards syndrome (trisomy 18) begins during pregnancy, and confirmation of the diagnosis occurs either before or after your baby is born. Your healthcare provider will look for signs of Edwards syndrome (trisomy 18) during a routine ultrasound screening, including fetal activity, the amniotic fluid surrounding your fetus and the size of your placenta. If signs of a genetic condition are present, your healthcare provider may offer additional testing for confirmation.
During pregnancy, your healthcare provider will offer different tests to determine the diagnosis of your child if they show symptoms of Edwards syndrome (trisomy 18). These tests include:
After your child is born, your healthcare provider will examine your child’s heart via ultrasound to identify and treat any heart-related conditions as a result of their diagnosis.
Often, the condition is so severe that babies who survive being born are treated with comfort care. But treatment for Edwards syndrome (trisomy 18) is unique for each child, based on the severity of their diagnosis. There’s no cure for Edwards syndrome (trisomy 18).
Treatment for Edwards syndrome (trisomy 18) might include:
Edwards syndrome (trisomy 18) is the result of a genetic mutation and there’s no way to prevent the condition. However, if you qualify for a combination of genetic testing and in vitro fertilization (preimplantation genetic testing), you can significantly reduce the chance of having a child with Edwards syndrome (trisomy 18). If you plan on becoming pregnant and want to understand your risk of having a child with a genetic condition, talk with your healthcare provider about genetic testing.
There’s no cure for Edwards syndrome (trisomy 18). Almost all pregnancies end in miscarriage or stillbirth. Of those pregnancies surviving into the third trimester, nearly 40% of babies diagnosed with Edwards syndrome (trisomy 18) don’t survive during labor, and nearly one-third of the surviving babies deliver preterm.
The survival rate varies for babies born with Edwards syndrome (trisomy 18):
Children born with Edwards syndrome (trisomy 18) will need specialized care to address their unique symptoms immediately after they are born. The survival rate is low, especially if your child has delayed organ development or a congenital heart condition. Out of the 10% who survive past their first birthday, children go on to live fulfilling lives with significant support from their family and caretakers, as most never learn to walk or talk.
One of the side effects of having a child with Edwards syndrome (trisomy 18) is a risk of miscarriage or a loss of pregnancy. If you’re pregnant, contact your healthcare provider if you experience any symptoms of a miscarriage, including:
If your child born with Edwards syndrome (trisomy 18) has any of the following symptoms, take them to the emergency room or call 911 immediately:
A note from Cleveland Clinic
An Edwards syndrome (trisomy 18) diagnosis might be overwhelming due to the severe complications that arise from the condition. Your healthcare provider will support you and your family along the journey, helping you navigate your child’s diagnosis or coping with loss. If you plan on becoming pregnant, discuss genetic testing with your healthcare provider to identify your risk of having a child with a genetic condition.
Last reviewed by a Cleveland Clinic medical professional on 12/13/2021.
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