Hearing the words Edwards syndrome during pregnancy can feel like the ground shifts slightly. One scan, one blood report, one careful sentence from your doctor, and suddenly you are thinking about chromosomes, survival, and decisions you never expected to face. Many parents want straight answers: What exactly is Edwards syndrome? How sure is the test? What can be done for the baby during pregnancy, at birth, and afterwards? And, just as importantly, what choices are truly available in India, with your family, your beliefs, and your medical realities?
Edwards syndrome: what it means in simple medical terms
What Edwards syndrome is (trisomy 18, explained)
Edwards syndrome is a genetic condition where a baby has three copies of chromosome 18 instead of the usual two. Chromosomes are DNA packages present in almost every cell. When there is extra chromosome 18 material, many genes are present in extra copies, and that can disturb foetal development across multiple organs (heart, brain, kidneys, digestive tract, and the musculoskeletal system).
There is no treatment that can remove the extra chromosome. Care therefore focuses on:
- the baby’s comfort and stability,
- treatment of specific complications where possible,
- and aligning medical steps with the family’s goals.
Edwards syndrome vs trisomy 18 vs T18
You may hear “Edwards syndrome”, “trisomy 18”, or “T18”. All point to the same diagnosis: extra chromosome 18 material.
Doctors may also mention a karyotype result (a chromosome map), for example:
- 47,XX,+18
- 47,XY,+18
Screening result or confirmed diagnosis? This changes the entire conversation
The most stressful phase for many families is the “in-between”: a report suggests Edwards syndrome, but you are not yet sure whether it is a risk estimate or a confirmed diagnosis.
- Screening tests estimate probability (they do not confirm): ultrasound markers, maternal blood tests, cfDNA/NIPT.
- Diagnostic tests confirm: CVS or amniocentesis with chromosome analysis.
If you are sitting with a positive NIPT report, you may be thinking: Is this final? Not necessarily. Confirmation is usually the next step if you want certainty.
Types of trisomy 18: full, mosaic, partial
Edwards syndrome can present differently depending on the chromosome pattern.
- Full (complete) trisomy 18: almost all cells have an extra chromosome 18. Most common, usually most severe.
- Mosaic trisomy 18: some cells have the extra chromosome, others do not. Severity can be variable (it depends on which tissues are affected and the proportion of trisomic cells).
- Partial (segmental) trisomy 18: only a segment of chromosome 18 is duplicated, sometimes due to an unbalanced translocation. Outcomes depend on the size and location of the duplicated segment.
Why a confirmed Edwards syndrome diagnosis matters for pregnancy and newborn care
A confirmed Edwards syndrome diagnosis helps your team anticipate likely pregnancy issues such as:
- IUGR (intrauterine growth restriction)
- polyhydramnios (excess amniotic fluid)
- congenital heart defects
It also helps with practical planning:
- where to deliver (centre with NICU or not),
- who should be present (neonatology, paediatric cardiology),
- what level of newborn care matches your family’s values.
Genetics, causes, and risk factors
Extra chromosome 18: aneuploidy and gene dosage
Trisomy 18 is an aneuploidy (an atypical chromosome number). The extra chromosome changes gene dosage (meaning many genes are present in extra copies). This alters development across several body systems, which is why Edwards syndrome is not limited to a single organ.
How it happens: nondisjunction and early cell-division errors
Most full trisomy 18 cases happen due to nondisjunction, when chromosome 18 does not separate properly as an egg is formed (less commonly during sperm formation). The extra chromosome is often maternal in origin, and population risk increases with maternal age.
Mosaic trisomy 18 usually results from an error after fertilisation during early cell division, creating a mix of typical and trisomic cells.
Partial trisomy 18 and translocations: when parental karyotype may be advised
Partial trisomy 18 can be associated with translocations.
- An unbalanced translocation means extra genetic material is present.
- A parent can sometimes carry a balanced translocation (no symptoms) yet have a higher chance of pregnancies with unbalanced chromosome patterns.
If partial Edwards syndrome is found, your doctor may discuss karyotyping of parents to clarify recurrence risk.
Maternal age and chance biology
Maternal age is a well-known risk factor, with a clearer rise from around 35 years. Still, Edwards syndrome can occur at any age, most families have no prior history.
Recurrence risk for a future pregnancy
After a pregnancy with full trisomy 18, recurrence risk is often quoted around 1% (plus the baseline age-related risk). If a translocation is identified, the risk can be higher, and genetics counselling becomes especially helpful.
How common is Edwards syndrome?
At conception, trisomy 18 is often estimated around 1 in 2,500 pregnancies. Live-birth prevalence is lower (commonly around 1 in 6,000 to 1 in 8,000), because many affected pregnancies end in miscarriage or stillbirth, and some families choose to end the pregnancy after diagnosis depending on personal circumstances and legal framework.
Numbers can support counselling, but they cannot predict an individual baby’s journey.
Prenatal screening and diagnostic tests for Edwards syndrome
First-trimester combined screening and second-trimester quad screen
- First-trimester combined screening (10-14 weeks): nuchal translucency + maternal serum markers (PAPP-A, free beta-hCG). It gives a risk estimate.
- Second-trimester quad screen: also a risk estimate, can miss cases.
NIPT/cfDNA: excellent screening, not confirmation
cfDNA/NIPT can be done from around 10 weeks and is very sensitive for Edwards syndrome, yet it remains screening.
False results can occur due to:
- low foetal fraction,
- placental mosaicism (placenta and foetus differ),
- rare maternal factors.
A positive NIPT is commonly followed by a diagnostic test if the family wants certainty.
Diagnostic testing: CVS and amniocentesis
- CVS (chorionic villus sampling): usually 10-13 weeks, samples placental tissue, earlier answer.
- Amniocentesis: from about 15 weeks, analyses foetal cells from amniotic fluid.
Both can confirm Edwards syndrome with chromosome testing.
Karyotype, FISH, and chromosomal microarray (CMA)
- Karyotype: confirms trisomy 18 and helps identify full, mosaic, or translocation-associated patterns.
- FISH: faster preliminary result, usually followed by full confirmation.
- CMA (chromosomal microarray): higher-resolution mapping, can be useful in partial trisomy 18.
Diagnosis after birth
Sometimes Edwards syndrome is suspected after delivery based on physical findings and organ involvement. Confirmation is done with chromosome testing from a blood sample, followed by genetics counselling to clarify type and recurrence risk.
Ultrasound findings that can suggest Edwards syndrome
Why one sign alone is not enough
Ultrasound markers can raise suspicion, but no single sign confirms Edwards syndrome. Doctors interpret the overall pattern.
Findings that may raise suspicion
Possible prenatal findings include:
- IUGR
- polyhydramnios
- heart anomalies
- clenched hands with overlapping fingers
- omphalocele in some pregnancies
Signs and symptoms of Edwards syndrome after birth
What may be seen in a newborn
Many babies are small at birth and may have hypotonia (low muscle tone). Feeding can be difficult (weak suck, easy fatigue, poor coordination of suck-swallow-breathe). Respiratory fragility may be present right from the start.
Facial features can include micrognathia (small jaw), low-set ears, and microcephaly (small head).
Heart defects
Congenital heart disease is common in Edwards syndrome. Examples include:
- VSD (ventricular septal defect)
- ASD (atrial septal defect)
- PDA (patent ductus arteriosus)
These can contribute to breathlessness, fatigue during feeding, and poor growth.
Neurologic involvement and breathing challenges
Neurologic differences are common and, in full trisomy 18, development is usually profoundly affected. Possible findings include:
- brain anomalies (for example, agenesis of corpus callosum)
- apnoeas (pauses in breathing)
- seizures in some babies
Limb findings
A classic feature is clenched fists with overlapping fingers. Clubfoot, rocker-bottom feet, stiffness, and contractures may occur.
Kidney and digestive concerns
Kidney anomalies may include hydronephrosis or horseshoe kidney, with increased risk of urinary infections.
Digestive and feeding issues can include reflux, constipation, aspiration risk, and sometimes major malformations like oesophageal atresia or tracheo-oesophageal fistula.
Mosaic and partial forms: sometimes a different picture
Mosaic or partial Edwards syndrome may present with subtler or mixed signs (perhaps a heart defect dominates, or feeding difficulty persists over months). Some children are recognised later.
Pregnancy care and planning after a prenatal diagnosis
Monitoring during pregnancy
Care often includes:
- detailed anomaly scan,
- serial growth scans,
- monitoring amniotic fluid,
- foetal echocardiography if heart disease is suspected.
Birth planning: aligning medical steps with family goals
A written plan can be helpful, especially when multiple teams are involved. It may include:
- place of birth and NICU availability,
- immediate newborn measures (skin-to-skin, warmth, comfort care, resuscitation choices),
- symptom relief priorities,
- family wishes and rituals.
Vaginal birth versus caesarean depends on obstetric factors and agreed care goals.
Treatment and care for babies and children
Care goals: no cure, still active and meaningful care
There is no curative treatment for trisomy 18. Care for Edwards syndrome often focuses on comfort, preventing avoidable complications (infection, undernutrition), and choosing interventions that feel proportionate for the baby and family.
Shared decision-making in the newborn period
Different approaches may be considered:
- full intensive care,
- limited interventions,
- comfort-focused care.
These are not one-time decisions. Plans can evolve depending on how the baby responds.
Feeding and nutrition support
Feeding support may include:
- paced oral feeding with positioning,
- nasogastric tube feeds,
- gastrostomy when longer-term support is desired and fits the care plan.
The aim is adequate calories and reduced aspiration risk.
Breathing support
Depending on needs and goals, support may include oxygen, non-invasive ventilation (CPAP), or invasive ventilation. Respiratory infections are a common concern and need early attention.
Coordinated follow-up
Ongoing care may involve paediatrics plus cardiology, pulmonology, neurology, gastroenterology, genetics, rehabilitation therapies, social work, and psychological support.
Paediatric palliative care: comfort, symptom control, planning
Paediatric palliative care supports:
- pain and distress control,
- breathlessness management,
- feeding comfort,
- anticipatory guidance and family support.
It can be provided alongside other treatments.
Prognosis and life expectancy
What the numbers say, and what they cannot say
In full trisomy 18, many pregnancies end in foetal loss, and many live-born babies die in the neonatal period. Across published summaries, around 5-10% of live-born infants with full Edwards syndrome reach one year, with variation based on medical problems and the level of interventions chosen.
Group statistics cannot predict one baby’s individual course.
What often influences outcomes
Factors commonly include:
- severity of heart defects,
- respiratory failure and apnoeas,
- infections,
- feeding difficulty and aspiration,
- prematurity.
Quality of life: decisions that are revisited over time
Families and teams often focus on proportional care (reducing discomfort, supporting bonding, and re-evaluating interventions as the baby’s condition changes).
To remember
- Edwards syndrome (trisomy 18) is caused by extra chromosome 18 material and may be full, mosaic, or partial.
- Screening tests estimate risk, CVS or amniocentesis confirms Edwards syndrome and clarifies the type.
- Ultrasound may show IUGR, polyhydramnios, heart anomalies, clenched hands, and sometimes omphalocele.
- Babies may face heart disease, breathing instability, apnoeas, feeding and swallowing difficulty, neurologic involvement, kidney anomalies, and digestive problems.
- There is no cure for Edwards syndrome, care focuses on comfort, preventing avoidable complications, and shared decisions that match family goals.
- A coordinated medical team, including paediatric palliative care, can support both symptom relief and difficult decisions. Parents can download the Heloa app for personalised guidance and free child health questionnaires.
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