Tuesday, April 5, 2011

Baby Update!

Tomorrow I'm 13 weeks pregnant! We went to our OB last Thursday for the Nuchal Transluceny test.  This prenatal test (also called the NT or nuchal fold scan) can help assess our baby's risk of having Down syndrome (DS) (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13),  as well as major congenital heart problems.
 Trisomy 18 and trisomy 13 are genetic disorders that include a combination of birth defects including severe mental retardation, as well as health problems involving nearly every organ system in the body. Unfortunately, 90 percent of babies born with trisomy 18 or 13 die by age 1. It is important to note that 5 to 10 percent of babies with trisomy 18 or 13 do survive the first year of life. Therefore, these disorders are not universally fatal and, in the absence of any immediate life-threatening problems, accurate predictions of life expectancy are difficult to make. There are a few reports of babies with trisomy 18 or 13 surviving to their teens, however, this is unusual.

The NT test uses ultrasound to measure the clear (translucent) space in the tissue at the back of the developing baby's neck. Babies with abnormalities tend to accumulate more fluid at the back of their neck during the first trimester, causing this clear space to be larger than average. 
The NT scan must be done when you're between 11 and 14 weeks pregnant. (The last day you can have it done is the day you turn 13 weeks and 6 days pregnant.) We did it in combination with a blood test in what's known as first-trimester combined screening.
Like other screening tests, an NT scan won't give us a diagnosis. But it can assess our baby's risk for certain problems.
The sonographer first confirmed our baby's gestational age by measuring him from crown to rump to see if he's about the size he should be for his age. Our little alien was tracking right on schedule at 12 weeks, 4 days.  Based on our last sonogram it should be at 12 weeks, 5 days; but the OB was not worried about a single day discrepancy.  Then the tech positions the sensor, called the transducer, over my abdomen so that our baby's nuchal fold area shows up on the monitor and measures the thickness of it on the screen with calipers.Our OB was looking for 3cm or less measurement and our baby was 1cm!

Another item they look for is whether or not there is a nasal bone present. A nasal bone is a good indicator that all is well.  Our little one looked like an alien, but did have a nasal bone!
Our baby's chances of having a chromosomal abnormality are determined by the nuchal fold measurement, our age, and our baby's gestational age. Since we had the combined screening, the blood test results were also be factored in.

Our age is factored in because although anyone can have a baby with a chromosomal abnormality, the risk increases as you age. For example, your likelihood of carrying a baby with Down syndrome ranges from about 1 in 1,295 at age 20 to about 1 in 82 at age 40.  Both Juan and I are in the "increased risk range" with me at 35 and Juan at 50, so I have been very worried about the results of this test.

Our results were screen NEGATIVE!!!!

What does that mean?
Our odds for having a baby with DS were 1:250 prior to the screening; and are now 1:3118.
Our odds for having a baby with Trisomy 18 or 13 were 1:450 prior to the screening; and are now 1:9000.

Although a normal screening result (screen negative) isn't a guarantee that our baby has normal chromosomes, but it does suggest that a problem is unlikely.

Overall, this is VERY POSITIVE news and we are very thankful to God!  It seems we are hurdling each new step like pros.

Now for the big reveal!

I told you our baby looks like an alien!  :)


Becky Dunham said...

Yay! So glad all is going well! Amazing how those tests work. When i had my babies (my youngest is 13), i don't think they had the nuchal cord test. that is a fairly new procoedure, at least I have only recently begun to hear about them as a medical transcriptionist :) I love the alien pics! My niece is due in June and we just watched a video of her ultrasound and it is just amazing :) So glad you are keeping us posted!

Denise said...

Wonderful news Jessica!!!! So so happy for you!!!

Jolanda said...

Hi sweetie,my baby's also lookded like aliens...but as you know...it are sweeties now...so don't worry!!
Have a nice day,enjoy your pregnancy...
I'm so happy that everything is fine!!

Carolina said...

You need to scrap baby's first pics!!!! It's such a relief every time baby's checked and eveything's fine! Say hi to the little alien from me!