What is Trisomy 18/Edwards Syndrome?

Trisomy 18 / Edwards Syndrome

Trisomy 18 / Edwards Syndrome is a rare, genetic disorder caused by the presence of 3 copies of all or part of chromosome 18.

Every cell in your body contains 23 pairs of chromosomes, 46 in total, half from your mother and half from your father. A Trisomy 18 baby has 47 chromosomes, instead of the usual 46, this affects the babies development in utero. It is a random condition and very rarely inherited from either of the parents (higher in partial trisomy). It is usually an error in cell division and there is no way to predict, treat or avoid it.

Trisomy 18 is the second most common trisomy, the first being Downs Syndrome (Trisomy 21) and the third being Patau Syndrome (Trisomy 13). About 1 in 1500 pregnancies is diagnosed with Edwards Syndrome and about 1 in 5000 make it to birth, with girls having a higher chance of survival according to some. Most pregnancies end in miscarriage in the first or second trimester, and babies who make it to birth have a high chance of being stillborn or dying shortly after, though this can often be increased due to a lack of medical intervention. (In pregnancies diagnosed at 12 weeks this is around 70%) The longer the pregnancy the continues, the higher the chance of your baby being born alive.

It is often referred to as ‘Not compatible with life.’ This is an outdated medical opinion, the correct term for Trisomy 18 is ‘Life-limiting’. Devastatingly, most babies will die during their first year of life, with around 5-10% making it past their first birthday. (I was also told by a Trisomy specialist that if Amber made it past her first month she would have a 40% chance of making it to her first birthday.) The most recent research shows survival rates at 13.5% at 1 year old and 12.3% at 5 years old. Medical interventions also increase the chances of life. It can be difficult to predict how many children would survive if all pregnancies continued, due to the severity of Trisomy 18, many families choose TFMR (termination for medical reasons). It is a heartbreaking, life-changing, traumatic experience and it is certainly one of the hardest decisions anyone has to make. There should never be any judgement on the choices that are made during this time, it is unimaginably difficult and almost impossible. It took me 5 weeks of intensive research to decide conclusively that I would let Amber guide me and that I would fight for her chance at life.

There are 3 types of Trisomy

Full Trisomy is the most common, this affects every cell in the body and the effects from this can often be more severe.

Mosaic Trisomy, where only some of the cells in the body contain the extra chromosome. The severity of mosaicism is dependent on the type and number of these cells. This occurs in about 5% of cases.

Partial Trisomy (translocation trisomy) is the most rare of all. The affected cells contain a section of the extra chromosome instead of the full copy. Again, severity is dependent upon which part of the chromosome is translocated.

Both mosaic and partial trisomy can lead to much less severe affects but this is not guaranteed. Nor is it absolute that a baby with full trisomy will not survive or be more affected. There is a large variety of conditions associated with Trisomy 18 and all our children are unique and should be treated accordingly.

You can be screened during pregnancy for Downs, Edwards and Patau syndromes, through ultrasound scans/blood tests, these are not conclusive and may only suggest an issue. If they do you will be offered diagnostic testing, CVS (chorionic villus sampling, this takes a sample of cells from the placenta and is not routinely offered unless potential problems detected during initial antenatal screening. CVS is done around 11-14 weeks and are around 99% conclusive) and amniocentesis (a sample of amniotic fluid is tested. This is usually done around 15-20 weeks but can also be performed later in pregnancy. It is 98-99% conclusive.) Initial results are within 3 working days but secondary results can take up to 3 weeks.

Trisomy 18 is a complex diagnosis and the symptoms are wide ranging, from physical characteristics to severe and life threatening medical complications. Babies may have a combination of some/all of the following. (I will label next to those relevant to Amber and place a * next to those that were detected whilst I was pregnant with her)

Indicators may be

Small strawberry shaped skull with prominent occiput

Small mouth/jaw

Wide set eyes

Clenched fists/overlapping fingers (this is very commonly spotted in scans) Amber*

Rockerbottom feet

Short breastbone

Cleft lip/palate

Webbing between 2nd/3rd toes Amber

Lowset ears

Choroid plexus cysts (not problematic themselves but commonly a marker during scans) Amber*

(During pregnancy) Polyhydramnios (excess amniotic fluid) Amber*

(During pregnancy) Intrauterine growth restriction Amber*

(During pregnancy) Single umbilical artery (cord should have 2 arteries and 1 vein) Amber*

Low birth weight Amber (4Ibs 11)

Medical complications may be:

Congenital Heart Defects (VSD/ASD/PDA) About 90% of T18 babies will have a CHD Amber* (I only knew about the VSD whilst pregnant)

Abnormalities with other organs including kidneys/liver

Gastrointestinal conditions (Oesophageal Atresia/tracheoesophageal fistula/omphalocele)

Feeding difficulties Amber (it was discovered she had a bowel malrotation at 6 weeks old)

Respiratory conditions (apnoea – sometimes central, often obstructive) Amber, mild obstructive apnoea



All children will be affected by growth delays, learning difficulties and developmental delays.

I personally refused amniocentesis when offered it initially after my dating scan at 12 weeks, everything looked good on my first scan and having already had two miscarriages I wasn’t prepared to risk another. Also, I had never heard of Edwards (or Patau) syndrome, I didn’t know anything about them and certainly wasn’t aware of their severity. I think like most mothers (parents) Downs syndrome was the one everyone knows about, for me Downs was never an issue. I used to teach children with Downs riding and stable management and never saw it as something to be particularly concerned about.

It was at my anomaly scan where the sonographer thought Amber may perhaps have a small VSD (ventricular septal defect) but wasn’t absolutely certain. From some angles her heart looked fine, so I was sent to Glasgow for her to be checked by a cardiologist at fetal medicine.

It was at this next scan, when I was exactly 20 weeks pregnant that other indicators were picked up. She had a large VSD, a choroid plexus cyst, clenched fists, a single umbilical artery and I had polyhydramnios. When told their suspicions of either Edwards or Patau I was told ‘Not compatible with life’ and my heart and world shattered. I had an amniocentesis that day to confirm diagnosis. By the time I received initial results 3 days later I was certain that she had Trisomy 18/Edwards syndrome due to the presence of the cyst and clenched fists, both very common T18 symptoms. I got the full results 3 weeks later where I was told she had Full Trisomy 18, though I insisted on a retest once she was born as they only checked 30 cells.

I want to raise awareness of Edwards syndrome for many reasons, in memory of my beautiful, brave daughter, to help other families and also to try and change minds about this diagnosis.

It is not acceptable that families are still being told that it is incompatible with life. Once I started researching Trisomy 18 I found many, incredible children who HAVE survived. Who live or have lived happy lives. Children whose families have fought for them and children who have proven medical opinion wrong.

Families should instead always be told that Trisomy 18 is ‘life limiting’. I was incredibly fortunate in both mine and Ambers medical teams. They were all understanding, open and fought for my little girl with everything in their power. They treated her as an individual, not on the basis of her diagnosis. I was so very lucky and am so very grateful. I have met some amazing people on Ambers journey.

Others are not so lucky however, I have read awful stories of families having to fight during pregnancy for interventions. Of families being told there is no hope. Of families having to fight to get treatments even after their baby is born and beyond as they grow and survive.

This shouldn’t be the case. Though a complex and serious diagnosis our children deserve a chance and their families deserve to be listened to and shouldn’t have to battle for every treatment. I would wish that everyone could have the experience that Amber and I had with our doctors, nurses and other specialists because they were, honestly fantastic.

Though shattered by her loss, I have no regrets. Amber brought with her such joy, hope and love. We had 12 wonderful (though often exhausting, complicated and scary) weeks together. I love her beyond measure and she knows she is loved. I would do it all again without question. She is my daughter and her life matters.

The Trisomy community I have become part of is one full of love and compassion.

Our children matter.

Leave a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s