Trisomy 18: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Trisomy 18?
A team usually cares for babies with trisomy 18. It often includes a neonatologist, a doctor who treats newborns, and a medical geneticist, a doctor who treats inherited conditions. Heart doctors and other specialists may join the team. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is trisomy 18?
Trisomy 18, also called Edwards syndrome, is a chromosome condition. A person with trisomy 18 has three copies of chromosome 18 in their cells instead of the usual two. The extra material disrupts normal development. It is linked with problems in many parts of the body.
There are three types. Full trisomy 18 is the most common and most serious type. In mosaic trisomy 18, only some cells have the extra chromosome, and symptoms may be less serious. Partial trisomy 18, in which only part of the extra chromosome is present, is very rare and may also have less serious symptoms.
Symptoms
Newborns with trisomy 18 can have some or all of the following signs:
- Low birth weight and slow growth before birth.
- Heart defects, which are problems with how the heart formed.
- A small, abnormally shaped head and a small jaw and mouth.
- Clenched fists with overlapping fingers.
- Low-set ears and a cleft lip or palate, which is an opening in the lip or the roof of the mouth.
- Club foot or feet with a rounded bottom, called rocker-bottom feet.
- Kidney, spine, and digestion problems.
- Hernias, which are bulges of tissue through a weak spot in the body wall.
Each person with trisomy 18 is different. Everyone with trisomy 18 has some level of learning disability. Other problems can include hearing loss, vision problems, feeding problems, heart failure, and seizures.
Causes and who gets it
Trisomy 18 happens by chance. It is not linked to anything you did before or during pregnancy. Most cases are not inherited, which means they are not passed down in a family. They come from random events when eggs and sperm form. Women of any age can have a child with trisomy 18, but the chance goes up as a woman gets older. Partial trisomy 18 can be inherited. A parent can carry a rearrangement between chromosome 18 and another chromosome, with no extra material and no signs of the condition.
How doctors diagnose it
Trisomy 18 is usually screened for in pregnancy. Screening shows the chance that a baby has the condition. A common first test combines a blood test and an ultrasound scan, which is a picture made with sound waves. If screening finds something, you may be sent to a specialist for more scans and tests. These include non-invasive prenatal testing, amniocentesis, or chorionic villus sampling. Amniocentesis and chorionic villus sampling can tell you if your baby definitely has the condition. After birth, doctors look at the baby's features and do chromosome studies. These studies can show whether the extra chromosome is in every cell or only some cells.
Treatment
There is no cure for trisomy 18. Treatments and support can help children have the best possible quality of life. Many kinds of health professionals may be involved, and they help make a care plan. Care may include:
- Regular monitoring and treatment, including surgery, for heart, breathing, and digestive problems.
- Physical therapy, occupational therapy, and speech therapy.
- Pain control and palliative care, which is care that eases hard symptoms, for more severe symptoms.
Support groups, such as the Support Organization for Trisomy 18, 13 and Related Disorders, can also help families.
When to see a doctor
Call 911 or go to the emergency room if a child with trisomy 18 has severe trouble breathing or stops breathing, has blue or grey skin, or cannot be woken up or is not alert.
Genetic counseling can help families understand the condition and the chance of it happening again. There is also a small increased chance of trisomy 18 if you have already had a pregnancy or baby with it.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can help with follow-up visits, answer family questions, and coordinate care with specialists such as geneticists and heart doctors. They do not replace the hospital team that cares for a newborn.
Common questions
Is trisomy 18 inherited?
Most cases are not inherited. They come from random events when eggs and sperm form. Partial trisomy 18 can be inherited from a parent who carries a rearrangement of chromosome 18 called a balanced translocation.
Can trisomy 18 be cured?
No, there is no cure for trisomy 18. Treatments and support can help children have the best possible quality of life.
How long do children with trisomy 18 live?
Many babies with trisomy 18 die before birth or within their first month. Nine out of ten children die by 1 year of age, and 5 to 10 percent live past the first year. Babies with mosaic or partial trisomy 18 may have fewer health symptoms, and some grow up to be adults.
Can trisomy 18 be prevented?
No, it is not possible to prevent trisomy 18. It happens by chance and is not linked to anything you did before or during pregnancy.
Sources
- MedlinePlus Genetics - Trisomy 18
- NHS - Edwards' syndrome (trisomy 18)
- MedlinePlus - Trisomy 18 (Medical Encyclopedia)
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
