nuchal fold test necessary?

---isn't the false positive rate fairly high?
I.e., the probability that the baby does not have Downs, given that the test
is positive, is pretty high.

The combined nuchal lucency and maternal blood test has sensitivity
and specificity both in the high 90's. False positives are quite rare
with this test. The vast majority of women who get these tests have
negative results and normal babies.

I had this test. My result is considered positive. My age related
risk is 1 in 48. The result I received listed my risk, based on
freeBeta, PAPP-A, nuchal translucency and maternal age as 1 in 43.
So, even though I have a positive result, I still, according to their
numbers I should have a better than 97% chance of having a baby
without Down Syndrome.

In the past, I have only had ultrasounds in emergencies and with 2 of
my 3 children I did not have any ultrasounds. I avoid the doppler. I
will not risk an amniocentesis. Now, I have to decide whether or not
to have a 20 week ultrasound, based on these results and whether to
travel to a city where I could have a high resolution ultrasound. I'm
not sure that having the nuchal translucency was the right decision
for me. If the results had been 1 in 5 or 1 in 2, I would have gone
for the high resolution ultrasound, since there would be a higher
chance of the baby needing care after birth that can't be obtained in
local hospitals. Now, I'm not sure what to do.

--Betsy

What is to prevent someone for filing the something
ahead of time, regardless of whether or not there is an
advance diagnosis, specifying under what conditions they
are interested in aggressive treatment?

OK, here's how your scenario would play out:

Baby is born, doesn't transition well, needs resuscitation in the
delivery room. Has some physical exam findings that could be related
to a syndrome, but nobody is able to make a definitive diagnosis.
Imaging is done, cells are sent for karotype, and in the meantime the
baby is on a ventilator. The baby is on a ventilator at this time
because the diagnosis is not known, therefore the prognosis is not
known. We don't know if this is a lethal anomaly, or if it is a
survivable anomaly like trisomy 21 but requires some newborn intensive
care. This goes on for two or three days. The baby dies. The karotype
comes back at three or four days later, and you find out the baby had
trisomy 13; a lethal anomaly.

If you had known ahead of time, you would have known that intervention
was pointless and could have opted for a compassionate care plan
instead.

Since you didn't know, you lost the opportunity to spend quality non-
medical time with your child.

I'm not sure what you are getting at with your advance directive
specifying conditions. "Don't resuscitate my baby if it has any
dysmorphic features?" Without a diagnosis, you do not know what the
baby's prognosis is and you don't have any basis for the decision to
withhold treatment.

Regarding quality/extensiveness of ultrasound screening:
I don't know what is available or routine in your community. In my
area, a routine midtrimester screening exam will be performed usually
in the OB's office by a sonographer overseen by the OB. This is the
same person who spends most of his/her time doing hysterectomies and
bladder suspensions and normal deliveries and seeing women in the
office for hormone replacement. Out of maybe 30 minutes exam time,
perhaps 5 minutes of that will be spent on the fetal heart, generating
4 or 5 different anatomical views.
In my community, if a baby is known to have Down syndrome and the
parents want to continue, the anatomic survey will be performed in a
tertiary fetal diagnostic center. In addition to the 30-40 minute
anatomic survey, the baby will have a specialized exam for the heart -
usually at about 22-24 weeks (slightly later, to be able to visualize
the heart when it is larger and easier to see). Both of these exams
will be overseen by a perinataologist.
If I was a parent of a T21 baby and wanted the baby to survive, I
would certainly be a great deal more comfortable with the second
scenario.

alath wrote:
What is to prevent someone for filing the something
ahead of time, regardless of whether or not there is an
advance diagnosis, specifying under what conditions they
are interested in aggressive treatment?

OK, here's how your scenario would play out:

Baby is born, doesn't transition well, needs resuscitation in the
delivery room. Has some physical exam findings that could be related
to a syndrome, but nobody is able to make a definitive diagnosis.
Imaging is done, cells are sent for karotype, and in the meantime the
baby is on a ventilator. The baby is on a ventilator at this time
because the diagnosis is not known, therefore the prognosis is not
known. We don't know if this is a lethal anomaly, or if it is a
survivable anomaly like trisomy 21 but requires some newborn intensive
care. This goes on for two or three days. The baby dies. The karotype
comes back at three or four days later, and you find out the baby had
trisomy 13; a lethal anomaly.

If you had known ahead of time, you would have known that intervention
was pointless and could have opted for a compassionate care plan
instead.

Since you didn't know, you lost the opportunity to spend quality non-
medical time with your child.

I'm not sure what you are getting at with your advance directive
specifying conditions. "Don't resuscitate my baby if it has any
dysmorphic features?" Without a diagnosis, you do not know what the
baby's prognosis is and you don't have any basis for the decision to
withhold treatment.

OK, I can see that point if it is too difficult to
fairly quickly ascertain survivability.

Regarding quality/extensiveness of ultrasound screening:
I don't know what is available or routine in your community. In my
area, a routine midtrimester screening exam will be performed usually
in the OB's office by a sonographer overseen by the OB.

I have no idea what is common elsewhere, but I can't
think of the last person I know *here* (i.e., where I live)
who had their routine midtrimester screening at their doctor's
office. It certainly could happen here. Goodness knows that
I have met only a small fraction of pregnant women around here ;-)
It's just that all the ones I *do* know seem to go to the lab
and report that the exams are closer to an hour in length.
This is a fairly densely populated area with a lot of medical
facilities, which I'm sure makes a difference.

This is the
same person who spends most of his/her time doing hysterectomies and
bladder suspensions and normal deliveries and seeing women in the
office for hormone replacement. Out of maybe 30 minutes exam time,
perhaps 5 minutes of that will be spent on the fetal heart, generating
4 or 5 different anatomical views.
In my community, if a baby is known to have Down syndrome and the
parents want to continue, the anatomic survey will be performed in a
tertiary fetal diagnostic center. In addition to the 30-40 minute
anatomic survey, the baby will have a specialized exam for the heart -
usually at about 22-24 weeks (slightly later, to be able to visualize
the heart when it is larger and easier to see). Both of these exams
will be overseen by a perinataologist.
If I was a parent of a T21 baby and wanted the baby to survive, I
would certainly be a great deal more comfortable with the second
scenario.

And that's exactly the sort of thing that makes
women feel like it's irresponsible of them not to have all
the tests done. For ever test, there's some situation that
could occur where the test could have made the difference.
But the question, to me, is to put things in a broader
context. What are the possible downsides of the test?
How often does it *actually* make a difference? What are
the alternatives? What are the odds? What impact will
the information have? Which can you live with, the very
small chance that the baby will need the immediate, highly
specialized care, or the very small chance of a miscarriage
from an amnio to confirm the diagnosis, the months of
uncertainty with a suspicion but without a definitive diagnosis?
None of those are easy choices, and I think different
people find comfort along different paths. Even when you
ask folks who've *been* through having a baby with a lethal
anomaly, staggeringly high numbers (to me, anyway--it usually
seems to be about 50 percent) say they would *not* have
prenatal testing in a future pregnancy. I'm not sure even
I understand that, but they of all people have a right to
that decision (in my opinion).
Anyway, I'm just arguing that these are complicated
decisions that come down to more than just the numbers. At
the same time, I think the first trimester screening pretty
much beats the pants off the second trimester screening, and
thus has fewer downsides making it a better choice for many
who do want to be screened.

Best wishes,
Ericka

I have no idea what is common elsewhere, but I can't
think of the last person I know *here* (i.e., where I live)
who had their routine midtrimester screening at their doctor's
office. It certainly could happen here. Goodness knows that
I have met only a small fraction of pregnant women around here ;-)
It's just that all the ones I *do* know seem to go to the lab
and report that the exams are closer to an hour in length.
This is a fairly densely populated area with a lot of medical
facilities, which I'm sure makes a difference.

In my experience, what you describe is unusual, with nationalised health
care in the UK, even though there is variety from trust to trust
(healthcare in a given are is managed by a trust, though they do keep
restructuring and changing names!), within one trust, things should be
pretty consistent, so one example tells you how the whole trust does it
rather than that particular doctor or midwife and it really does seem to
be that routine 20ish week ultrasound is the 20-30 minute version, with
a longer or more specific one only carried out if any additional risk
factors present, so friends who had a baby with a more minor heart
defect that hadn't been picked up, then had an extra ultrasound overseen
by the relevant specialist.

I can only speak for one hospital in Korea, but that also seemed to be a
20-30min ultrasound, we did end up with one heading towards an hour and
only realised later this was as soft markers for downs were found so
they were checking everything very thoroughly, we knew something was
going on as a whole series of doctors were called in, who's
conversations we couldn't understand. I feel as if I should be angry we
weren't informed, but in many ways I'm glad that we weren't, we'd
decided against routine ultrasound, but ended up with some 2nd trimester
issues (turned out to be my kidneys) and thus had an ultrasound, had we
been confronted with the information, it would have really thrown us, as
it was info we'd never expected to have to deal with. As it was, they
took appropriate action from the finding of the soft markers and we
weren't worried.

Cheers
Anne

Ericka wrote:

I have no idea what is common elsewhere, but I can't
think of the last person I know *here* (i.e., where I live)
who had their routine midtrimester screening at their doctor's
office. It certainly could happen here. Goodness knows that
I have met only a small fraction of pregnant women around here ;-)
It's just that all the ones I *do* know seem to go to the lab
and report that the exams are closer to an hour in length.
This is a fairly densely populated area with a lot of medical
facilities, which I'm sure makes a difference.

For this pregnancy I have been seen at a military hospital. For my "big"
ultrasound, I was sent to radiology where a tech spent about 45 minutes looking
at and measuring every single body part, including internal organs. The
ultrasound was then reviewed by a radiologist and the results were sent to
the OB. Anectdotally, I've not heard of someone having their OB actually
do the midtrimester screening themselves.

FWIW, I had the midtrimester screening done because I had declined all other
testing (nuchal fold, AFP/triple screen, etc). I wouldn't have terminated
under any circumstances, but if there were physical abnormalities that could
interfere with a vaginal delivery I wanted to know. I can't say what I would
have done if they had found soft markers for DS or other genetic problems.

When I was about 7-ish weeks pregnant I had an ultrasound due to possible
miscarriage, and that was done in the OB clinic by a PA, but just to look
for a heartbeat and measure the size.

--Jodi
34-ish weeks w/babe #1

P.S. Ericka, thank you for taking the time to comment on that other article
I posted (about induction lowering c/s rates). I was offline for awhile
and when I came back it appeared that my newsreader had eaten the thread!
But luckily I had read your response and really appreciated your input.

Anyway, I'm just arguing that these are complicated
decisions that come down to more than just the numbers.

I agree that the realities are always more complicated than what we
think of ahead of time. I definitely do reject the oversimple "do
every test because that's what's best for the baby," or "more
information is always better," or "do all the tests and let the
professionals sort out what they mean: they know best." These are all
dangerous oversimplifications. Most people can adopt them and get away
with it, but every once in a while it could put them in a situation
they don't want to be.

What started me on this was an echo of another equally misleading
oversimplification, and one that is often repeated: "if you wouldn't
do an amnio or wouldn't terminate, there is no reason to do
screening." This is an equally dangerous oversimplification. And
again, in most cases, it's an oversimplification that you can get away
with. But every once in a while, it could put you in a situation where
you don't want to be.

It's never simple. Accepting a test is never simple. Declining a test
is never simple. These are always highly complex decisions with many
possible consequences. In most cases, mom and baby will both be fine
no matter what choices are made - so any discussion of testing or not
testing is always a discussion of rare unlikely events coming together
in complicated and often unforeseen ways.

One way to go at these decisions - not the best way, perhaps, and
certainly not the only way - is to consider what for you is the most
undesirable outcome and take that possibility off the table. Some of
my worst possible outcomes involve my baby dying in strangers' arms in
the midst of some invasive procedure because we don't know what's
going on and don't realize when it is time to say "quit." I have been
there when this happens, and it's bad enough as a provider. I don't
want to go anywhere near the parent end of this scenario. If my baby
has 25 minutes to live, I want to know that and make sure those 25
minutes are spent in the way that's best for my baby and my family.
That's what's important to me.

The original question was, "is there any reason to do this test, if
you wouldn't terminate?" I suggested some possibilities. I didn't say
"yes, for these reasons the test is mandatory and everyone should have
it." Instead, I said "here are some scenarios where it could make a
difference."

Whether we are considering scenarios where doing a test leads to some
undesirable situation, or those where declining a test leads to some
undesirable situation, it is up to the individual to determine which
of those scenarios is most meaningful (positively or negatively) to
them. Nor is relative incidence or likelihood the most salient factor,
because outcomes whether positive or negative do not all have equal
desirability or undesirability. If I wear my helmet every time I ride
my bike there is a 100% likelihood that I will experience helmet
related inconveniences, like getting my hair messed up. The chances
that I will have an accident such that my helmet saves my brain are by
comparison vanishingly remote. I'm still wearing my helmet, because to
me the inconvenices of wearing the helmet, though highly likely to
occur, are trivial compared to the consequences of a closed head
injury, however unlikely. It's not the relative likelihood of the
various outcomes, it's how I personally weigh the value of the
outcomes.

So, no, I'm not advocating that everyone should have first trimester
screening. It's far too much a complex and individual decision for
that.

Nor should anyone else suggest "if you wouldn't terminate, there's no
reason to screen." It's far too much a complex and individual decision
for that, too.

What, for you, is the downside of the specialized ultrasound?

You hinted at the upside - potentially detecting a condition
foreknowledge of which could lead to better treatment and possibly a
better outcome for your baby.

So far, the only downside I'm hearing is having to drive to another
town for the scan. Are there other downsides you're trying to balance
here?

at and measuring every single body part, including internal organs. The
ultrasound was then reviewed by a radiologist and the results were sent to
the OB.

Now that is a real rarity. The last prenatal diagnosis conference I
went to, one of the presenters asked for a show of hands by specialty.
Almost everyone was from the MFM/perinatal side. Only a tiny handful
were radiologists.

Anectdotally, I've not heard of someone having their OB actually
do the midtrimester screening themselves.

Most OBs certainly do not perform the exam themselves. In many cases
however it is the OB who signs off on the results. If we are talking
about a generalist OB, some are qualified for this but most frankly
are not. ACOG does not have standards for ultrasound in the education
of OB-Gyn residents. Maternal-fetal subspecialists do get a great deal
of specialty training in ultrasound and, generally, are probably best
qualified to supervise fetal sonography and pronounce on the
significance of the results. I've never worked in any system or
community where most people's routine midtrimester screening scans
were supervised by perinatologists (MFM), though. In the US, most
insurance carriers won't approve a perinatologist visit unless there
is an abnormal finding or a high risk diagnosis.

One way to go at these decisions - not the best way, perhaps, and
certainly not the only way - is to consider what for you is the most
undesirable outcome and take that possibility off the table. Some of
my worst possible outcomes involve my baby dying in strangers' arms in
the midst of some invasive procedure because we don't know what's
going on and don't realize when it is time to say "quit." I have been
there when this happens, and it's bad enough as a provider. I don't
want to go anywhere near the parent end of this scenario. If my baby
has 25 minutes to live, I want to know that and make sure those 25
minutes are spent in the way that's best for my baby and my family.
That's what's important to me.

I think you have to put this kind of thing in the light of article such
as http://news.bbc.co.uk/1/hi/health/6948015.stm, I wish it included a
figure for the total number of downs babies, whether born or aborted,
versus the number of healthy babies miscarried due to tests, rather than
the number of live born downs babies, but either way, 3200 babies dieing
due to testing is an awful lot and that's the problem with prenatal
testing, it's stepping down the line to a test that carries a risk of
miscarriage and if you start, how do you know when to stop - I can see
your reasoning for knowing, even when you wouldn't terminate, but that
can leave a lot of parents stuck at the point knowing there is some
physical abnormality, with results from other tests not coming back at a
comparable risk to that of miscarriage from amniocentesis.

There is also the argument that the medical profession doesn't really
know for sure what the outcomes would be if some of the considered fatal
karotypes actually were aggressively treated as a baby with normal
genetics would be, though good outcomes are sufficiently rare, that it's
not a big factor.

Cheers
Anne

alath wrote:
[...]
In my community, if a baby is known to have Down syndrome and the
parents want to continue, the anatomic survey will be performed in a
tertiary fetal diagnostic center. In addition to the 30-40 minute
anatomic survey, the baby will have a specialized exam for the heart -
usually at about 22-24 weeks (slightly later, to be able to visualize
the heart when it is larger and easier to see). Both of these exams
will be overseen by a perinataologist.
If I was a parent of a T21 baby and wanted the baby to survive, I
would certainly be a great deal more comfortable with the second
scenario.

My understanding - which could very well be wrong - has been that if a
heart defect (or any other defect) isn't major enough to show up on an
18 - 20 week scan, then it is probably not going to be major enough to
cause the baby to go straight into a life-or-death scenario where
minutes count without some sort of indication or warning postnatally.
I'm curious - how often would you say such a case happens? I'm not
trying to disagree with you - I'm honestly curious.

BTW, what you said about the lethal genetic abnormalities was
thought-provoking and something I hadn't considered. Thank you.


All the best,

Sarah
--
http://www.goodenoughmummy.typepad.com

"That which can be destroyed by the truth, should be" - P. C. Hodgell