Sunday, October 28, 2012

31 Days of Awareness: Trisomy 18

Trisomy 18

Awareness Color: Light Blue
Awareness Month: March
Trisomy 18, also known as Edwards syndrome, is a condition which is caused by a error in cell division, known as meiotic disjunction.  Trisomy 18 occurs in about 1 out of every 2500 pregnancies in the United States, about 1 in 6000 live births.  The numbers of total births increase significantly when stillbirths are factored in that occur in the 2nd and 3rd trimesters of pregnancy. Unlike Down syndrome, which also is caused by a chromosomal defect, the developmental issues caused by Trisomy 18 are associated with medical complications that are more potentially life-threatening in the early months and years of life. 50% of babies who are carried to term will be stillborn, with baby boys having higher stillbirth rate than baby girls.


The genetic material from the extra eighteenth chromosome can cause a variety of problems with varying severity. Just as children with Down syndrome can range from mildly to severely affected, the same is true for children with Trisomy 18. This means that there is no hard and fast rule about what Trisomy 18 will mean for your child. However, statistics show that there is a high mortality rate for children with Trisomy 18 before or shortly after birth.
Typical characteristics of Trisomy 18 include:
  • Heart defects:
    • VSD (Ventricular Septal Defect): a hole between the lower chambers
    • ASD (Atrial Septal Defect): a hole between the upper chambers
    • Coarctation of the aorta: a narrowing of the exit vessel from the heart
  • Kidney problems
  • Part of the intestinal tract is outside the stomach (omphalocele)
  • The esophagus doesn’t connect to the stomach (esophageal artesia)
  • Excess amniotic fluid (polyhydramnios)
  • Clenched hands
  • Pocket of fluid on the brain (choroid plexus cysts)
  • Rocker bottom feet
  • Delayed growth
  • Small jaw (mycrognathia)
  • Small head (microcephaly)
  • Low-set ears
  • Strawberry-shaped head
  • Severe developmental delays
  • Umbilical or inguinal hernia
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