Dr. Marjorie Greenfield
Specializing in pregnancy and birth.
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 Ask Dr. Greenfield
Neck Thickness Seen on Ultrasound & Fear of Down Syndrome | | | QUESTION | | | Dear Dr. Greenfield:
I had an ultrasound at 10 weeks due to a previous cone biopsy. Although they found my cervix to be in good shape, they told me they were concerned because of a measurement of the back of the baby's neck was enlarged, which could be a sign of Down syndrome. I have never heard of this before and it has left me very concerned. I'm 33 years old and this is my third child. What are my chances of this being a Down syndrome baby? I cannot have CVS done because of my cervix, but to wait until I'm sixteen weeks for an amnio will make me a nervous wreck. I cannot find any information about this enlarged neck diagnosis in any prenatal books. Do you have and information on it and should I really be that concerned. I will have follow up ultrasounds every three weeks because of my cervix, but what if this continues to show on them?— Ty's Mom | | | ANSWER |
March 12, 2002 | | | Dear Ty's Mom,
Within the past few years, ultrasound findings or markers have been identified that are associated with Down syndrome and other chromosomal problems. These include nuchal (neck skin) thickness, sometimes referred to as a measurement of nuchal translucency. In about a third of the cases in which thick neck skin is found, the baby is totally normal and healthy. The other two thirds of the time, thick neck skin is evidence of Down syndrome or other abnormalities of the fetus. Some of these abnormalities are minor. There are no ultrasound findings that tell you for sure that the fetus has Down syndrome, and conversely, a perfectly "normal" ultrasound study does not guarantee a chromosomally normal newborn.
In order to understand what this means for you, you should speak with a genetics counselor. Your doctor can give you a referral to your local genetic counseling service. In addition to the ultrasound study, your blood can be tested between the 11th and 14th week of your pregnancy for markers that can help to screen your baby for Down syndrome. The genetics counselor can then factor in your age, the ultrasound findings, the blood screening result, your family history and any other risk factors, and provide you with an assessment of your personal risk of having a baby with Down syndrome.
Once this testing has been concluded, you can make your decisions based on true risk, instead of the anxiety that has been building ever since the "ultrasound marker" was identified. You will probably be surprised to learn how low your risk actually is. If you decide that you want genetic sampling on the fetus, you may want to get more information about all the possibilities in order to make the decisions that will be best for you and for your family. Some doctors do CVS trans-abdominally, which might be an option for you. Your doctor or the genetics counselor can tell you which diagnostic procedures are available in your area.
Waiting even a week for this kind of information during pregnancy is torture, so you need to get data and try to keep perspective on your real level of risk. It is almost certainly a lot lower than you fear. Good luck to you.
— by Marjorie Greenfield, M.D. |
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