isolated nuchal thickness and normal pregnancy

Does anyone know the risk of having a child with Down Syndrome with
isolated increased nuchal thickness (7 mm) at 24 weeks gestation? No
age risks or family history of genetic defects.

Anyone experience having this U/S result, but in the end turned out to
have a normal baby?

I'm not able to help you with the risk of Down Syndrome (although you
probably could google it) as you need to use the nuchal fold measurement in
conjunction with age factors also. But I wanted to say that the Nuchal fold
test is only a good diagnostic tool if done during the period of 12-14 weeks
with 13 weeks being preferable.

As the baby gets older the fold can increase with the size of the baby but
not necessarily increase the risk of the syndrome.

5mm is the maximum measurement they like to see at 13 weeks, but as I said
with a bigger baby the thickness can be much more but not necessarily
indicate a problem.

I'm sorry I can't be more help.
Take care

--
Pip

My premmies :
Abby - 6 months old and too laid back to roll over
Jasmine - 3 1/2 and I'm going to change her name to "Devils Child"


--
"Sandra" wrote in message
ups.com...
Does anyone know the risk of having a child with Down Syndrome with
isolated increased nuchal thickness (7 mm) at 24 weeks gestation? No
age risks or family history of genetic defects.

Anyone experience having this U/S result, but in the end turned out to
have a normal baby?

My understanding is that the nuchal fold test is done at a very specific
time -- between 10-14 weeks. At that time, it should be under 3mm, maybe
1-2 or something like that. So a measurement of 7mm at that age would be a
very bad thing. But at 24 weeks? I don't know. Did they say what they
felt it should be? I really don't know what to tell you except that I've
never heard of this test being done so late in the pregnancy, and it would
be logical to me that the reason for that is that by mid-pregnancy there are
lots of variations that come into play based on individual size, genetics,
and growth. Good luck.
--

Jamie
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"Sandra" wrote in message
ups.com...
Does anyone know the risk of having a child with Down Syndrome with
isolated increased nuchal thickness (7 mm) at 24 weeks gestation? No
age risks or family history of genetic defects.

Anyone experience having this U/S result, but in the end turned out to
have a normal baby?

"Sandra" wrote in message
ups.com...
Does anyone know the risk of having a child with Down Syndrome with
isolated increased nuchal thickness (7 mm) at 24 weeks gestation? No
age risks or family history of genetic defects.

Anyone experience having this U/S result, but in the end turned out to
have a normal baby?


Hmmm, that's an unusual time to have the nuchal fold test, as others have
stated. I did find this reference:
http://www.greenjournal.org/cgi/cont...tract/85/1/103
which looked at 18-24 weeks, and found that 8.5% of chromosomally normal
fetuses had a thickness of over 6mm, while 38% of those with trisomy 21
(Downs) had a thickness over 6mm. I start to get confused about the rest of
the statistics (pg brain!)...maybe Ericka can translate?
Based on your result, I would assume that you were offered amnio to look for
chromosomal abnormalities and perhaps a fetal echocardiogram?
This is an abstract about increased nuchal fold in the second trimester with
normal karyotype. You'd have to pay to get the full article.
http://tinyurl.com/83t9y

My understanding is that increased nuchal fold can indicate chromosomal
abnormalities, heart defects, or neural tube defects. However, it can also
occur in healthy fetuses, so it's an indicator, not a diagnostic tool. Your
risk of a problem goes down with every normal test result (ie normal amnio,
no other problems noted on ultrasound, normal fetal echo, etc) if you choose
to have testing. If you weren't referred to a genetic counselor, you might
want to consider asking for a referral. He/She may be able to give you more
specific risk figures based on your situation.

Good luck,
Amy

Some of the above replies make a common mistake - confusing the nuchal
thickness (or nuchal skin fold) with the nuchal lucency (or nuchal
translucency) test.

The nuchal lucency test is newer, more in the news these days, is done
earlier in pregnancy (late first trimester), and is sometimes done in
combination with maternal blood tests.

The nuchal skin fold measurement is done later in pregnancy - Beryl
Benacerraf was one of the early pioneers in this research and she
specified 15-20 weeks gestation and a .5 cutoff value. Others have gone
up to 22-24 weeks, with different cutoff values. In Benacerraf's
original series the positive predictive value of an increased nuchal
skin fold was 69% i.e; 69% of the babies with this finding did have
Down syndrome. Please note however that Sandra describes a later
gestation measurement and Benacerraf's numbers probably would not
apply.

Peter Callen at UCSF published maternal age-specific odds of fetal Down
syndrome during the second trimester based on ultrasound findings. To
quote the exact number I would need to know maternal age - Sandra just
said "no age risks" which I take to mean maternal age less than 35,
although even at ages less than 35 the risk of Down syndrome is still
associated with maternal age.

Callen's numbers show the following combinations of maternal age,
ultrasound finding, and Down syndrome risk (DSR):

Age 25 - pre-ultrasound DSR 1:1040 - DSR with normal u/s 1:1733 - DSR
with increased nuchal thickness 1:56

Age 30 - pre-ultrasound DSR 1:690 - DSR with normal u/s 1:1150 - DSR
with increased nuchal thickness 1:37

It's going to be hard to be sure of your exact odds Sandra because
these research protocols all have slightly different criteria for when
the measurement is done and technically how it is done, and I don't
know how the measurement was done by your providers.

Another variable I don't know is the technical quality of the
ultrasound you had done. The nuchal skin fold measurement is
technically difficult because it depends on the flexion or extension of
the baby's neck and the angle the picture is taken from. Also, anytime
you are evaluating the prognosis of an "isolated finding" there is a
concern about the quality of the scan because of the possibility of a
significant finding that may have been missed. We have a range of
possibilities here from a nuchal fold measurement done incorrectly and
no real increase in risk at all, to a "noticed" increased nuchal
measurement and an "unnoticed" heart defect or CNS anomaly, which would
increase the risk dramatically.

So basically I have given you a bunch of information but I still have
no real answers for you. I'm sure you are worried, and unfortunately, I
have to agree there is some diagnostic basis for your concern in
addition to the emotional turmoil I'm sure you're going through.

From a medical standpoint, the finding does increase your risk to the
point where most providers would offer a genetic amnio, but if you are
now greater than 24 weeks that may not make much sense.

One noninvasive and potentially helpful thing would be to have a fetal
echocardiogram - a detailed ultrasound focusing just on the baby's
heart. The incidence of heart problems in Down syndrome babies is very
high. This study definitely should be done in a perinatologist's,
pediatric cardiologist's, or antenatal diagnostic center (not in your
obstetrician's office). If there is a structural heart problem, that
would reflect an increased DSR. If present, having the prenatal
diagnosis of a heart problem could help your providers plan for the
care of your baby after birth. If the echo is totally normal, that
could increase your confidence that the nuchal skin fold finding is
truly "isolated."

Sorry you are going through this - I know it must be terribly
difficult. You will be in the thoughts and prayers of many mkp'ers.

"Sandra" wrote in message
ups.com...
Does anyone know the risk of having a child with Down Syndrome with
isolated increased nuchal thickness (7 mm) at 24 weeks gestation? No
age risks or family history of genetic defects.

Anyone experience having this U/S result, but in the end turned out to
have a normal baby?


We didn't measure nuchal fold, but Downs is not the only issue that can
cause nuchal thickening. There are many, many different chromosomal
disorders which can have similar effects, ranging from tiny deletions of one
segment of one chromosome which have little impact on up to full trisomy or
monosomy of a chromosome. And of course, it's in the range of "normal kids
get it too".

When my dd was born with slightly wide-spaced eyes, slightly low ears,
inward curving fifth fingers and a slight epicanthal fold, Downs was my
first thought, but it ended up being a partial deletion (partial monosomy)
rather than a full or partial trisomy, on a completely different chromosome
(and one where we have no clue in the long run how strongly it will affect
her). There's this assumption people make that Downs is the "only"
chromosomal issue that might crop up, and it's just not.

IMO, the hardest parts thus far have been the time between the test results
and "clarification of diagnosis." Very stressful, cried a lot, the whole
works. Now it's mostly just who she is, though I always have it in the back
of my mind when considering developmental issues, it's not something I
"worry" about on a minute-to-minute basis. More like on a week to week
basis.

Jenrose

Thank you alath for your reply. I agree that there are a number of
variables to consider. I am 27 years old, and did have a prior U/S at
10 weeks with normal results. No increased nuchal lucency was seen at
that time, although they did mention that the head was difficult to
visualize. I agree that there could be reporting error too as they
gave me a range of the nuchal thickness being 1-7mm instead of "1-6 mm"
as they've quoted me. Everything else in the U/S report was normal
including gestational age and size. No other "soft" signs were seen.

Amniocentesis was offered, but at this point, the result would not
influence my decision to keep my baby. As well, I'm not keen at
placing my baby at risk for our own self-assurance.

I was wondering if you had the reference to Dr. Callen's paper that you
had quoted. The literature is a bit confusing, and the patient
population that's studied didn't really apply to my situation. What
made me worried was one paper that quoted a specificity of 0-2% for a
positive result.. which I guess equates roughly to 1:56 chance given a
positive result.

I'm hoping that maybe there was some error in measurement and also
because the U/S was performed later in my pregnancy. I understand that
nuchal thickness continues to increase during the growth of the fetus?

I thank you all for your support. This is our first baby, and I think
we're extra paranoid about every little thing.