Tuesday, September 11th, 2007
Twelfth Week Ultrasound Update: Nuchal Translucency, Autism and Zombies
There is only good news coming out of our twelfth week ultrasound.
Brief history: My wife contracted Fifth Disease around the time we discovered she was pregnant, saddling us with a 15 percent chance of miscarriage.
Yesterday we drove 4.5 hours to the Prenatal Diagnosis, Reproductive Genetics Unit of the University of California at San Francisco (actually located in Santa Rosa, Calif.).
We had an ultrasound to measure nuchal (neck) translucency, a pocket of fluid behind the baby’s neck. If the pocket was greater than 3mm, it would be abnormal.
In our situation, it might indicate fetal hydrops, a build-up of fluid in the baby that would likely result in death this early in the pregnancy. Other parents with risk factors often use this test to look for increased chance of Down syndrome and two other genetic anomalies.
Our baby’s nuchal translucency was a safe, normal 1.7mm. Yay!
Our geneticist assessed our family history and factored it with the results of a blood test to give us more good news.
The before screening risk for a generic 33-year-old woman:
Our updated risk after screening:
- 1 in 7,961 for Trisomy 21 (Down syndrome)
- 1 in greater than 10,000 for Trisomy 13/18 (Patau and Edwards syndrome)
Doctors love graphs. Here is a bar graph we were given.
Here is a chart I made that better explains the situation.
The most interesting point of the ultrasound was when we asked to hear the baby’s heartbeat so that we could record it and play it back later for our 3-year-old daughter. (She went to preschool that day, then stayed with a friend.)
We were told UCSF is not using its doppler (a motion/sound reading device) at this time. It seems that an in-progress study is looking at the possibility that certain types of high-power dopplers might contribute to autism. In the meantime, UCSF is playing it safe. I’m not sure of what use this information is; I’m just putting it out there.
My wife, a nurse, is quick to caution that there are many types of dopplers, and you shouldn’t confuse a shovel with a forklift.
The freakiest part of the visit was seeing the 3-D ultrasound. They call it 4-D, but come on, what does an ultrasound image have to do with space-time theory? Yeah, that’s what I thought you’d say.
I’m not a big fan of 3-D in utero images because the babies always look bubbled, unnatural and generally grotesque. And yet, I was surprised when our 3-D baby appeared on the computer screen looking like a zombie with its brain eaten out.
Here is something no one tells you about a 12-week-old baby. The bones of its skull are still forming. Its head is wide open like a wineglass.
Sure, there is skin covering the head, but it’s the equivalent of plastic wrap on a Tupperware bowl. The ultrasound looks right through it to show you an image that looks like your baby’s head has exploded. And due to the bubbly nature of the imagery, the baby’s arms looked like flippers and when viewed in motion he looked downright scary, like Village of the Damned scary.
The ultrasound technician thought the image was “cool,” but after seeing a million in utero babies, she’s probably talking about the baby’s position and the degree of detail in the photo.
“Uhh, could you print me a 2-D image, too? Thanks.”
But to recap, the baby appears fine. We’ll get another ultrasound later as a final confirmation that will inspect the baby’s developed organs and also tell us its gender. And then, I think, we need to hold a baby naming contest with a cool prize.