NT test - technical details

Can someone help me interpret what my obst told me at yesterday's ultrasound?

I thought I was having an NT test. I'm sure that's what he told me a month ago. But the doctor didn't seem to measure the back of the neck. It seemed he measured the distance between two bright lines either side of the lower spine. He told me the distance was 1.6 and I should only worry about Downs Syndrome if the distance was greater than 3.

Yesterday I was thrilled to hear him say everything was fine, now I'm wondering if he did an NT test or something else. I got a printed report that said no abnormalities detected. And he said I will have more blood tests in a month. But I read that the blood test and the NT scan should only be a week apart.

Does anyone know enough technical details to put my mind at rest? (Flipping hormones - yesterday I was so happy and relieved, today I'm so worried.)

I'm in Vietnam, the obs is French and this is my first pregnancy so I'm really not sure what's going on.

Screening tests can be performed differently in different countries. It sounds like the blood tests might be what we call 2nd trimester screen. In Australia, women can have 1st trimester screening (NT measurement plus blood test) OR 2nd trimester screening which is a blood test only.

The second trimester screen gives you a risk figure for Trisomy 21, Trisomy 13/18 and also neural tube defects (like spina bifida).

In Australia, they like to do the NT with blood tests and give one risk figure for the pregnancy. So, you don't have both 1st & 2nd trimester screens, just one.

I'm not sure what they were measuring with the ultrasound. It's possible that it's another marker for chromosomal issues. Will try find out for you.

This might be silly question, but you weren't looking at baby upside down were you, and it could have been at the top of the spine not the bottom?

Hi Kate07,

These pictures are so blurry... I'm pretty sure I can see the head and an ear at one end. Now I've had a look at the pictures again, he measured in the mid-back section. It seems too low for the neck.

He poked and pushed until the baby flipped over so he could do the measurement. On the report it's called "neck brightness". I should have looked at this stuff before posting, just been worrying about it all day at work, jumped on the computer as soon as I got home.

Hi there GoingtobeinAsia,

The measurement of the Nucal Fold is at the back of the neck and to us it looks like the top of the spine. What you are describing and the measurement that the Dr quoted to you ARE the Nucal Fold. It is a thickening at the back of the neck.

I all sounds very good to me. Congratulations.

And if you are young, even in Australia, sometimes the NT scan is done without the bloods. The bloods just gives another level of information, its bloods, NT thickness and mothers age at conception that are done here most often - but again not all the time.

I would say it sounds like you have good cause to relax now!

Rachel

Hey Rachel and Kate07,

Thanks for your replies.

I'm 37 so I'm a bit worried about Downs Syndrome. The obst said everything looked fine, It just doesn't look like he was measuring anywhere near the neck!

I live next door to a Downs boy. He's the sweetest kid, bows very formally to me every time he sees me. I don't really know what I'd do if I found out our baby was Downs but I want to make sure all the tests are done properly.

I couldn't find info on another measure lower in the spine, i think you just have to assume that he was measuring the right thing and thankfully your results were good.

If the blood test the dr was talking about is for 2nd trimester screening, this will be another measure of your risk. I know this easier to say than to do but try not to worry too much.

I have spent a bit of time in Cambodia because friends lived there for awhile. I love it over there, the weather, the food, the people. Have never made it to Vietnam but it is on my list of places to go.

GoingtobeinAsia, sounds like you are really worried about the system over there and if you can trust it. Is that what you are worried about?

If I were in your shoes I would probably think about the following options;

1) go back to you Dr and ask for a discussion on your results and why bloods not taken into account,

2) get a second opinion, new Dr hopefully referred by a friend

3) think about getting a second opinion from your family Dr over in Oz, ring and ask their opinion

4) book in for an amnio to find out conclusively as that is what you would have done if the result were high risk (done between 15 and 16.5 weeks)

As you are 12 weeks now you have around a week to get another NT scan done with the bloods so it is possible. My OB asked me to get bloods exactly one week before the scan and that I should get scan done I think no later than 13 and a half weeks.

Some people who are low risk from thier NT scan still go on to have an amnio anyway as it is the only way of knowing the answer.

Sorry you are going through this stress.

Rachel