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Ask Dr.M.D.Mazumdar, MD Your Own Question
Dr.M.D.Mazumdar, MD
Dr.M.D.Mazumdar, MD, Doctor (MD)
Category: Health
Satisfied Customers: 9030
Experience:  Twenty years experience in active private practice
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I had my anatomy scan at 21 weeks. They have found that I

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I had my anatomy scan at 21 weeks. They have found that I have a SUA ( single umbilical artery). The doctor doing the scan was a maternal fetal meds doctor so he then switched to a level 2 US. He said that I had no other markers for downs and that my case was isolated. I haven't had any testing such as the marterni21, harmony etc. The baby had a nuchal fold of 5.7mm and he said anything below 6 is good. I am now hearing that less than 5 is what they are using now. Which is it? Also, what are my odds truly of having a downs baby with the 2 vessel cord? I hope I am making sense.

Welcome and thank you for your question. I am Dr.Mazumdar and I hope I'm able to help you with your medical problem today.

- Did you get an ultrasound earlier - at around 13 weeks?

- Did you get a Triple test?
Customer: replied 3 years ago.

NO I didn't get either and now regret it. I have 2 other children and never had any problems. My insurance wouldn't pay for the tests so I skipped them.

Thank you for the added information.

Your doctor is right though - a nuchal thickness of less than 6 mm in the second trimester is normal and reduces the risks of a Down's syndrome. 6mm is still the standard cut-off point, not 5 mm.

About 1 in 500 pregnancies have a single umbilical artery with no other abdnormality.

But there is a risk of having a fetal abnormality , usually in the renal, cardiovascular, gastrointestinal systems - but these would have been picked up in the 2D ultrasound, if present.

There is also a risk of a chromosomal abnormality like Down's.

Since the nuchal thickness is normal, the chances of a Down's is less. But 5.7 is too close to 6 mm and it would be better to get a repeat scan. An amniocentesis may be necessary if the nuchal thickness is around 6mm in the second scan.

Please take a second opinion form another fetal medicine specialist.

I hope this helps.

Customer: replied 3 years ago.

I will have monthly scans from here on out. So would they be able to catch it later and if so I could then do an amnio?

Any anatomical problem will be caught in the coming ultrasounds.

Amniocentesis is usually performed between 14 and 20 weeks. If you wish to get one, you will have to ask your doctor and plan for it now.
Customer: replied 3 years ago.

I was already 21 weeks at my US. The Maternal fetal meds doctor said that the risk of amnio out weighed the problem. He didn't seemed concerned by the 5.7 mm at all. He said that anything below 6 was good at this point. He said now we just have to watch for iugr. I just wish I had a more definitive answer. I guess at this point, I wont have one till birth. In your experience have you ever seen a baby have downs that had no other markers than the SUA and had below a 6mm nuchal fold?

DOwn's usually produces definite markers like the nuchal fold thickness. It is unlikely that a baby with only one marker like a sinlge umbilical artery (SUA) will have Downs. SUA can occur in many normal pregnancies.
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