Triploidy

When we first were given the diagnosis of triploidy, my husband and I tried to gather as much information as we could.  We found very little. It was through other family's blogs that I learned a little of what to expect during our pregnancy with Willow.  It is my hope that I can pass along the same information to help another family. 

Triploidy is an extremely rare chromosomal abnormality.  It is caused by the presence of a complete extra set of chromosomes.  It is suspected to occur in 1-2% of all pregnancies.

We had never heard of Triploidy before July 10, 2010.  The diagnosis devastated our entire family.  On July 7, 2010 we had visited a maternal fetal medicine specialist to have our anatomy scan.  We had already had an NT scan in June.  That sonogram and blood work did not reveal any concerns.  At the time our little one did measure one week behind.  The doctor had told us this was common and he was not concerned.  One month later, our world was forever changed.  During the anatomy scan the doctor started with our little ones' brain and noted that there was some fluid there.  He moved down to the face and said there wasn't a cleft lip and then moved to her hands.  He couldn't get a clear picture of her hands so he looked at her feet.  She had the cutest little feet and I remember the doctor saying it is definitely a girl!  He had thought the wee one was a girl at the last sonogram and I was beyond excited!   He went back to her hands and that is where he said he had some concerns.  He couldn't get her to open her hands and move her fingers individually.  He told us he thought her fingers were webbed. The doctor also took measurements on her stomach and femur.  Once again those she was measuring behind.  An amniocentesis was done and we had to wait 48 hours for the diagnosis.  The doctor had suspected trisomy 18, but we found out with one phone call that our little girl had triploidy. 
 To help understand triploidy, it helps to understand the make up of a healthy baby.  In a healthy baby, the baby gets 23 chromosomes from the mother and 23 chromosomes from the father.  They combine to give the baby 46 complete chromosomes. 


With triploidy, a baby inherits 46 chromosomes from one parent and 23 chromosomes from the other parent.  This give the baby a total of 69 chromosomes. This can occur in 2 different ways.  The most common occurance is the egg being fertilized by 2 sperms.  The other occurs when the egg does not divide properly. 

Triploidy1




Signs of Triploidy (from Healthline)
Not every fetus with triploidy will have all of these findings, but most will show some signs that can be detected by sonogram. Abnormal sonogram findings include:
  • severe early-onset intrauterine growth retardation (detected as early as 12–14 weeks)
  • brain abnormalities, including isolated ventriculomegaly (enlarged ventricles), Arnold-Chiari malformation, holoprosencephaly, and agenesis of the corpus callosum
  • cleft lip and possible cleft palate
  • limb abnormalities, such as clubfoot or syndactyly (webbing of the fingers and toes)
  • heart defects
  • kidney abnormalities
  • abdominal wall defects, such as an omphalocele (an opening in the abdominal wall, which causes the intestines to be located outside the body)
  • neural tube defects, such as spina bifida (an opening in the spinal cord)
  • oligohydramnios (a decrease amount of amniotic fluid)
  • placental abnormalities, including an enlarged placenta or a cystic placenta
The only way to diagnose triploidy is the a chromosome analysis (karyotype) completed.  This can be done through a Chorinic villi sampling (CVS) or through an amniocentesis. 
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In meeting with doctors and also reading as much as we could, we came to understand that triploidy is a random occurrence.  It does not have to do with the mother's age nor is it genetically inherited from either parent.  That being said I have read online of mothers that have had mulitple triploidy pregnancies. 

We are the 1-2% effected by triploidy.  Most triploidy pregnancies end in miscarriage during the first trimester.  According to the Healthline arcticle, only one in 10,000 infants is born with triploidy, and it is estimated that for every live-born infant with triploidy, 1,200 have been lost as miscarriages. Most infants with triploidy are either stillborn or die shortly after birth.  We feel blessed that Willow was born alive.  She lived for only minutes, but those few minutes mean the world to us. 
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