Genetic Testing

So as you know I am considered Advanced Maternal Age for being 33 and pregnant with twins.  We opted for a test called a NT scan or nuchal translucency.  This includes bloodwork and an ultrasound.  In the ultrasound they measure the thickness of the skin on the back of the neck, which is a marker for chromosomal abnormalities.  I had the bloodwork done two weeks ago and the ultrasound was this past Wednesday.

I love looking at them in ultrasound.  Especially now that they are moving around.  I drank a glass of orange juice before the appointment to make sure they were awake.  They looked great!  Their measurements were for Baby A 2.3mm and Baby B 1.8mm.  Both within normal range though they called Baby A "high normal".

The genetic counselor came in after reviewing the bloodwork and the ultrasound and said "I'm sorry it's bad news."

I immediately went into panic mode.  Not my babies!  This can't be happening to us...

She went on to tell me the my PAPP-A and Free B HCG levels were extremely low.  This increases the risk of chromosomal abnormalities.  Low PAPP-A can also indicate placental issues further along in the pregnancy. 

She told me that Baby A had a 1 in 11 chance of Trisomy 13 or 18, and a 1 in 464 of Downs Syndrome.  (I'll explain this in a moment)

Baby B has a 1 in 54 chance of Trisomy 13 or 18 and a 1 in 5,000 chance of Downs Syndrome.

There are three main Trisomy diagnosis...Trisomy 21 is Downs Syndrome.  Trisomy 13 and 18 are more severe. 

Trisomy 13 (also called Patau syndrome) is a genetic disorder in which a person has three copies of genetic material from chromosome 13, instead of the usual two copies.  This can cause severe mental retardation, birth defects and heart problems.  More than 80% of children with trisomy 13 die in the first year.

Trisomy 18 is a genetic disorder in which a person has a third copy of material from chromosome 18, instead of the usual two copies.  Trisomy 18 is a somewhat common syndrome. It is three times more common in girls than boys.  Again severe mental retardation, heart defects and other birth defects are common.  Half of infants with this condition do not survive beyond the first week of life. Some children have survived to the teenage years, but with serious medical and developmental problems.

Obviously I am scared to death.  But before you all start to feel bad here is the upside.  Twin blood tests are notorious for coming back with wonky results.  They are many times inaccurate.  IVF can also throw off bloodwork.  More than likely I may end up with a placental issue later in the pregnancy due to the low PAPP-A levels.  These could include interuterine growth restriction, preeclampsia and placental degradation.  Thankfully we know about it early so my high risk OB can keep a close eye on the placenta in the second and third trimester.

So after all this I decided (since Todd was in Florida for business) that I was going to go with the less invasive course of action.  There is a blood test that has come out in the last year called MaterniT21.  It tests for the big three Trisomies with very high accuracy.  I went over to the hospital next door and had the lab draw a couple vials of blood.  They told me I should have the results within the next two weeks.

After doing further research and speaking with come people that have been through something similar we aren't really worrying about anything.  The chances of either baby actually having T13 or T18 is very slim.  The chances of both of them being affected is astronomically small.  If for some reason the test comes back positive, it won't tell us if one or both is affected.  We would then need to do an amniocentesis on each baby to determine which one is affected.

But again, we aren't going to worry ourselves to death for the next couple of weeks.  We can't change what is going to happen, only move forward and do what's best.

And because they looked great in the ultrasound I'm really thinking they are just fine.  They had no physical indications of any issues.  So all in all I think everything is going to be just fine.  I just want my story to be out there in cases someone else goes through the same thing.