March is Trisomy Awareness Month. It is an opportunity to help people with Trisomy live full and meaningful lives, to raise awareness of this condition, and to support families affected by Trisomy.
What is Trisomy?
Most people have 46 chromosomes as part of their DNA. This is made of 23 sets of pairs. Some people have an extra chromosome in one of those pairs so they have 47 in total. This extra chromosome is called trisomy.
Each pair of chromosomes has a number and depending on which one is triplicated the diagnosis and prognosis will be different.
What are most common Trisomy conditions?
The most common trisomy conditions are is Trisomy 21, 18 and 13. .
Trisomy 21 or Down Syndrome is the most common. Trisomy 21 affects approximately 26 babies per 10,000 in Australia.
People with Trisomy 21 may have:
- some characteristic physical features
- some health and development challenges
- some level of intellectual disability
- most people with Down Syndrome today can expect to live into their 60's and achieve an independent and relatively successful life 
The next most common is Trisomy 18 or Edwards Syndrome. Trisomy 18 affects approximately 7 babies per 10,000. 
People with Trisomy 18 may have:
- a small head and facial features
- internal organs may have abnormalities
- intellectual disability
- many babies with trisomy 18 will not survive beyond the neonate period
- with medical care and support some people with Edwards Syndrome are living to their teens
The least common is Trisomy 13 or Patau’s syndrome. Trisomy 13 affects approximately 2.6 babies per 10,000.
People with Trisomy 13 may have:
- a small head and features
- an opening in the skull
- internal organs may have abnormalities
- many babies with trisomy 13 will not survive beyond the neonate period
- it is extremely rare but some children with Patau's Syndrome have lived to their teens
There are other even rarer trisomy chromosomes that usually result in first trimester miscarriages.
What causes Trisomy?
The extra chromosome occurs spontaneously at conception and is not preventable.
There is no known cause or cure for Trisomy.
We do know that advanced maternal age slightly increases the chances of it occurring . The likelihood of trisomy occurring in subsequent pregnancies is extremely rare.
Are there different degrees of Trisomy?
Yes, sometimes every cell in the body contains the extra chromosome this is called ‘full trisomy’. Trisomy can also be partial where only a part of the affected chromosome is triplicated. There is also mosaic trisomy which occurs when only some cells in the body contain a third chromosome.
Generally speaking, the more trisomy affected cells in the body the more pronounced abnormalities will be.
When is Trisomy diagnosed?
Trisomy may be suspected by information from the nuchal fold translucency ultrasound at approximately 12 weeks of pregnancy. This ultrasound measures the thickness of the back of your baby's neck. If the neck area is found to be thicker than normal this could possibly indicate trisomy particularly Down Syndrome. The results of the ultrasound and an accompanying blood test are given in odds, e.g your baby has a 1 in 1000 or 1 in 100 chance of having a trisomy condition.
It is important to note that nuchal fold results are NOT a diagnosis.
If your results come back with a high chance then further testing will be recommended. It is up to you and your partner if you wish to continue with further testing and receive a confirmed diagnosis. An amniocentesis or chorion villus sampling is often the next step for further investigation. These tests provide a definitive diagnosis. These tests do carry a small risk of causing a miscarriage, it is important to discuss the benefits and risks with your care provider.
There is also the genetic Harmony test which uses a blood test to check the foetus cells from the mothers blood. It is less invasive than an amniocentesis test and is also a definitive test however this is a private test not covered by Medicare and currently costs $450.
At other times it is not until birth that trisomy is diagnosed by a blood test which confirms the presence of the extra chromosome.
What do I do if my baby is affected a Trisomy condition?
It can be distressing to learn your baby either has or possibly has a trisomy condition. You may feel worried, sad, anger or shock at the diagnosis. This is normal and understandable. Many people are unaware of trisomy and the first time they learn of it is when they or family/friends encounter it. It is important that you seek support and information. Below are links to resources where you can find more information and support.
It can be reassuring to parents facing this situation to know they are not alone, many families before them have walked this path. Most people find it very beneficial to reach out and connect with other people who have been affected by trisomy.
Some people who receive a prenatal diagnosis of trisomy will opt to terminate the pregnancy. Other people will choose to carry the pregnancy to term.
There is no right or wrong decision, only you can make the right choice for you and your family.
As a doula my job is to provide non-judgemental support to families. I have experience supporting families through trisomy journeys and I know how helpful it can be to have someone to provide reassurance and comfort at times like this. If you live in the Illawarra area and would like to have a confidential chat about trisomy, please contact me anytime.
Current Facebook support groups and pages:
Trisomy SOFT Support Group Australia
Edwards Syndrome Families and Support
Down Syndrome Uprising
Down Syndrome Australia
There are also many public Facebook pages of families sharing their child's trisomy journey