Confusing NT scan result. Help!

Hi Everyone, I am new to Twinstuff. I had my NT scan last week which showed one baby is low risk and the other is high risk. I know the risks of having an amnio with twins and the docs don't seem very keen anyway. I just wondered if anyone else has been in this situation and what did you do? I have been back and forth so many times with my decision I am making myself dizzy!

Thanks :unknw:

 

First, welcome to TS and Congratulations on your Twin Pregnancy!

How far along are you? What is your Dr thinking your baby is at high risk for? Is it something that is detected via Amnio could be helped? Is there any way that you can get a second opinion? Best of luck to you and your little one's! :hug:

 

Hi Kyrstyn,

The NT scan is for Down's syndrome and the amnio is the only way to confirm. The chance of miscarrying twins following amnio is 2-3% so it is a difficult decision.

I am now 13 weeks and 3 days so running out of time for re-scan. I have had a breezy pregnancy so far so this worry is spoiling it!

 

I guess you have to ask yourself, if the amnio came back positive would you be willing to terminate at this point? If the answer is no, then I probably wouldn't do it because its not going to change the outcome, and therefore wouldn't be worth the risk. For us, we never did any of the testing (other than u/s) because not only is there a lot of false positives in those tests (especially in twin pregnancies), but we were not going to terminate regardless of health issues.

I know this must be a very hard decision for you!! Good Luck! :hug:

 

I had something similar happen to me. Personally, I'm not scared of an amnio and have had it 3 times with this pregnancy. Once to check for chromosomal abnormalities and once to check for infection since I went into PTL. The amnio is absolutely not the reason I went into PTL since I had it over a month before I went into PTL. The miscarriage rates are much lower if you have an experienced doctor w/ a great track record.

I completely disagree with the statement about termination/amnio. One doesn't necessarily have to do with the other although if termination was a factor, I respect that too. We didn't want to terminate but went ahead with the amnio because we wanted to be prepared as much as possible before the babies were born. As a result of the testing, we discovered issues with what is most likely twin B's placenta that put us at extremely high risk for preemies so I will be delivering at a hospital with a level 3 NICU. (We would have probably done this anyway with the PTL issues but now we have all the specialists in place to deal with whatever issues.)

Just for the sake of full disclosure, my amnio came back normal but the cgh array which was performed with the amniotic fluid came back with extra info. The amnio is limited in what can be tested for but there are more tests available which weren't available even a year ago (which is a good and bad thing). Feel free to PM if you want more information but it's really a personal and possibly financial decision which only you and your husband can make.

Edit - I hit reply to early...not to easy to type while on bed rest!

 

Hi and welcome to Twinstuff. :welcome:


I agree with Kyrstyn, would you make any decisions based on the result of the amnio? I personally would not do an amnio, for me it would not matter what the result was.

Just to let you know as well, my cousin's DS was very high risk for Down's Syndrome, he had 3 soft markers and her blood test numbers were high as well. Her OB told her to prepare herself for it. When he was born 3.5 years ago, he did not have Down's Syndrome or anything else. So everything from the u/s to the blood tests were inaccurate. Just something to keep in mind.

 

Remember amino have a high rate of false positive and twins have a higher rate. I've seen several singleton moms have aminos and been told they were mot likely having a down syndrome child and the babe be perfectly norm

 

It was more the difference in their nuchal measurements that have me confused. Has anyone else had such wildly differing results from nuchal transluscency scans? Mine are di-di twins so I expected them to be slightly different but not so much that I would be left wondering what it all means.

 

This is incorrect information.

I generally do not like medical talk from non medical people because a n=1 study like "my cousin had high risk but a normal child" is not proof of anything statistically. I don't even medical talk myself much (I do not give real advice just explain things and send people to see their doctor) because I could be anyone without any medical background lying online and you would believe me blindly just because I say I am a dr. That is behaviour that should be discouraged by any and all medical people out there.

Now about the statement I quoted: amnios do not have high rates of false positives at all, amnios have a tiny tiny rate of false positives (usually because it is done by a bad lab tech, in our lab it has NEVER happened in my years of working there). Screening for risk, such as alpha fetoprotein in maternal blood (and NT scans are often added to the screening to give a more accurate risk assesment) do not give a yes or a no. It gives a risk 1 in 3897 for instance or 1 in 12. That means that out of all women who are your age, have the exact same numbers as you in the maternal blood (and in case it is added have the same exact NT scan numbers) 1 out of 3897 (or 1 in 12) will have a child with down syndrome and 3896 (or 11) will have children without Down syndrome. This does not mean healthy, just without Down syndrome.
In twin pregnancies the maternal blood test does not work because both embryos are putting protein in the maternal blood flow so how do we know how much which multiple is putting out? There is no way currently of knowing. So instead most pregnancies are offered NT scans and risk assessment is done via maternal age and NT scan only. This is less determinative, so the false positive rate is higher than if it is assessed via all the blood markers you can do with singleton pregnancies. What the poster of the absurd quote above meant probably is that the risk assessment is not as accurate in twins due to this.

Amnios however are absolutely almost always correct. If the amnio says there is Down syndrome, that child will have Down syndrome. I would also say that if you would never terminate the pregnancy, not even terminate the affected foetus, then you are risking losing both just to know and be prepared. Through the screening you know that possibly one of your twins has a problem, you are already "prepared", do you need to know it exactly? Would you hate the rest of your pregnancy, be worried constantly and just be completely unhappy? Because your happiness is also important. So ask for genetic counselling or for your GYN to counsel you on the risk he has assessed you for, if it is huge (like 1 in 3) or just bigger than usual (1 in 150 for isntance). Then make an informed choice depending on you, your family, your situation.

I hope this helped. And please when you know nothing about something or misunderstand yourself, refrain from giving advice to others! It is just really confusing to the expecting mom.
Millie

 

I did the NT scan with my boys, and was blown away by the result. I got the call at work-that Nicholas(baby A) was fine-low low risk. Then I was told that Anthony(baby B) was at high risk-he was a 1 in 49 chance(which sounds scarier than the 2% chance it really was.

I opted not to do any further testing, unless the 20 week u/s showed more markers for Down Syndrome. Well-it was shown that he had a short femur-another soft marker for Down Syndrome. However-dh is Italian, and not the tallest-so I tried to chalk it up to genetics-and the Dr. there that day said he may have as well. So-we left that u/s with less answers, but we didn't do any more testing in terms of CVS or amnio(the CVS would have had to be done long before the 20 week u/s).

You do what makes you feel comfortable with! We also met with a genetics counselor right after we got the results too.

 

My twins came back with divergent results after the NT scan too. Baby A had an average or better than average result, and Baby B had about a 1 in 70 chance of down syndrome. We immediately recieved a ton of genetic counselling (like 6 hours!). It helped immensely with our decision to go ahead of the amnio. They had tons of info about the accuracy and risks of amnio at our hospital, the significance of having identical twins with divergent NT readings, etc. If you haven't had one on one counselling yet - get it. They even arranged an early anatomy scan (15.5 weeks) with a specialist skilled in looking for early soft markers of down syndrome.

After all the counselling and follow up ultrasound, I decided to go ahead with the amnio, because it is a diagnostic test. I think we had it done at 16 weeks. Test results came back fine - no down syndrome or other major chromosonal abnormalities.

Incidentally - termination was never really a concern for us. I wanted to know so that my family and I could be as prepared as possible to love and support our baby(ies) from the moment they were born. I don't know much about raising children affected by down syndrome, but I suspect there is a lot to learn, and a huge supportive community that we could have tapped into while still pregnant. I didn't want to be naive about this stuff. That's why I did the amnio.

Other factors that went into my decision to do the amnio - the genectics people were able to tell me that the pregnancy loss statistics following amnios may be a bit outdated and include all losses following amnios (i.e. including those losses that would have happened anyway); my hospital had a very good record re safe amnios; and we were able to take a sample from only one amniotic sack, theorectically reducing the pregnancy loss risk (this isn't always possible or advisable).

Good luck with your decision and make sure you ask oodles of questions about this decision at your doctors/genetic counsellors/ hospital. They have the most accurate info for your situation. It wasn't an easy decision for us, but I'm very satisfied with the advice we recieved from our hospital and my ultimate decision to go ahead.