Trisomy 18 (Edwards Syndrome)
Content reviewed against published NIH, March of Dimes guidelines
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If your baby has been diagnosed with or you suspect trisomy 18 (edwards syndrome), here is what the evidence says.
The short answer
Trisomy 18 (Edwards syndrome) is a chromosomal condition caused by an extra copy of chromosome 18, occurring in about 1 in 5,000 live births. It causes serious medical complications including heart defects, organ abnormalities, and severe developmental delays. While trisomy 18 is a life-limiting condition, each baby is an individual. Families are supported in making care decisions that align with their values, and many find profound meaning in the time they have with their child.
Key takeaways
- Trisomy 18 (Edwards syndrome) is a chromosomal condition caused by an extra copy of chromosome 18, occurring in about 1 in 5,000 live births. It causes serious medical complications including heart defects, organ abnormalities, and severe developmental delays. While trisomy 18 is a life-limiting condition, each baby is an individual. Families are supported in making care decisions that align with their values, and many find profound meaning in the time they have with their child.
- Usually normal when: Prenatal screening suggested trisomy 18 risk but diagnostic testing (amniocentesis) came back normal — false positives do occur
- Call your doctor if: Your baby with trisomy 18 is in respiratory distress, has a blue or gray color, or appears to be in significant discomfort
- Varies by age — see the age-by-age breakdown below
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By Age
What to expect by age
0-3 months
Trisomy 18 is often diagnosed prenatally through screening tests and confirmed by amniocentesis or CVS. Babies born with trisomy 18 typically have low birth weight, a small head, clenched fists with overlapping fingers, heart defects (present in over 90%), and other organ abnormalities. Medical care in the newborn period focuses on comfort and quality of life. Some families choose comfort care only, while others pursue medical interventions. There is no single right approach — decisions should be guided by your family's values and the medical team's guidance.
3-6 months
About 40-60% of babies with full trisomy 18 survive beyond the first month, and about 5-10% survive their first year. Babies who survive often have significant medical needs including feeding support (often tube feeding), cardiac management, and respiratory support. Despite the challenges, many parents describe this time as precious. Palliative care teams can help manage symptoms and support quality of life for both the baby and the family.
6-12 months
Babies with trisomy 18 who survive to this age often show slow development and may achieve some social milestones like smiling and recognizing caregivers. Medical management continues to focus on comfort and treating symptoms. Some families choose interventions such as cardiac surgery, which can extend life in select cases. Support organizations for trisomy 18 families can connect you with other families who understand your experience.
12 months+
A small percentage of children with trisomy 18 survive beyond their first birthday, and some live for several years, particularly those with mosaic trisomy 18 (where only some cells have the extra chromosome). These children have significant developmental delays but can form bonds with their families and respond to love and stimulation. Ongoing care involves a multidisciplinary team focused on comfort, quality of life, and family support.
What Should You Do?
When to take action
- Prenatal screening suggested trisomy 18 risk but diagnostic testing (amniocentesis) came back normal — false positives do occur
- Your baby was evaluated for trisomy 18 features but genetic testing confirmed normal chromosomes
- Your baby with mosaic trisomy 18 has some features but is more mildly affected than full trisomy 18
- Your baby with trisomy 18 is stable, comfortable, and responsive to your care and presence
- You received a prenatal screening result indicating increased risk for trisomy 18 and want to discuss diagnostic testing options
- Your baby has been diagnosed with trisomy 18 and you want to discuss care options and goals
- Your baby with trisomy 18 has changes in their comfort or medical status
- Your baby with trisomy 18 is in respiratory distress, has a blue or gray color, or appears to be in significant discomfort
- Your baby with trisomy 18 has stopped feeding, is unresponsive, or you have concerns about imminent decline — contact your palliative care or medical team immediately
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Trisomy 18 (Edwards Syndrome).
Things to mention
- You received a prenatal screening result indicating increased risk for trisomy 18 and want to discuss diagnostic testing options
- Your baby has been diagnosed with trisomy 18 and you want to discuss care options and goals
- Your baby with trisomy 18 has changes in their comfort or medical status
Observations to share
- You received a prenatal screening result indicating increased risk for trisomy 18 and want to discuss diagnostic testing options
- Your baby has been diagnosed with trisomy 18 and you want to discuss care options and goals
- Your baby with trisomy 18 has changes in their comfort or medical status
Urgent signs to report immediately
- Your baby with trisomy 18 is in respiratory distress, has a blue or gray color, or appears to be in significant discomfort
- Your baby with trisomy 18 has stopped feeding, is unresponsive, or you have concerns about imminent decline — contact your palliative care or medical team immediately
My notes
From ismybabyalright.com — free, evidence-based baby health guides
Related Resources
Frequently asked questions
Is trisomy 18 (edwards syndrome) normal?
When should I call the doctor about trisomy 18 (edwards syndrome)?
When is trisomy 18 (edwards syndrome) normal?
What causes trisomy 18 (edwards syndrome)?
What should I mention to my pediatrician about trisomy 18 (edwards syndrome)?
Is trisomy 18 (edwards syndrome) normal at 0-3 months?
Is trisomy 18 (edwards syndrome) normal at 3-6 months?
Should I go to the ER for trisomy 18 (edwards syndrome)?
Does trisomy 18 (edwards syndrome) go away on its own?
References
- [1]National Library of Medicine. Trisomy 18. MedlinePlus Genetics, 2023. NIH
- [2]March of Dimes. Trisomy 18. March of Dimes, 2023. March of Dimes
All content follows our editorial policy and is reviewed against published clinical guidelines.
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Related Resources
Bottom line
Most cases of trisomy 18 (edwards syndrome) are normal. Talk to your pediatrician if your baby with trisomy 18 is in respiratory distress, has a blue or gray color, or appears to be in significant discomfort.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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