What IS the deal with all the prenatal tests for Down's syndrome?

Factual Questions
1

Yes, I have another pregnancy-related post. So be it. Being over 35 (as in, I’m 36), I’m considered “advanced maternal age.” This means my aging eggs are more likely to result in chromosomal abnormalities should they become fertilized. This is understood. What I don’t get is the “Oh noes! You’re old and need an extra half dozen tests to check for Down syndrome!”

I’ve had several extra tests, and all seem to be related to screening for Down’s. At 12 weeks, I had an ultrasound (called an NT–neuchal tube–ultrasound) where the tech measures the folds in the fetus’s neck as well as checking for neural tube defects. I had blood drawn then, and again at 16 weeks, to screen for just these problems as well as some other more routine checks. My OB said that the blood test in combination with the ultrasound is around 90% accurate in detecting Down’s; we felt that was sufficient a statistic, and the more invasive (though conclusive) amniocentesis was ruled out. No thanks, we’ll pass.

They asked us again at 16 weeks if we wanted the amnio. No thanks, we’ll pass. All the test results have shown all is well with our little one, so there is no concern.

Today I had another “special for old ladies” ultrasound at 20 weeks. Again they asked about the amnio–“Only way to be sure,” etc., even though the specialist had said everything test-wise (as well as on the ultrasound) looked fine. No thanks, we’ll pass. My thought is…the amnio will tell us for sure, but so will birth. But, jusssssst to be sure, I’m having a fetal echocardiogram at 23 weeks just to rule out Down syndrome, kinda for sure maybe. (Not definitive without the amnio, you know.) This is apparently all routine for us old moms.

I know they check for other defects and problems outside of Down’s, but I swear it’s the ONLY problem they seem to be looking for. I don’t understand why it matters so much to know NOW. In the earlier weeks, I know some may opt to abort (not what we would do with a Downs baby, but YMMV), but doing an abortion at 23 weeks does not seem routine (my understanding is OBs will do it up to 16 weeks). I understand the need to identify heart defects, but THIS much seems…odd.

Is there something about Downs we’re missing here? Our odds at my age are still about 1 in 350–certainly quite a bit shorter than the 1 in 1200 were I a decade younger, but still, that’s less than 0.3% chance.

Why so much effort screening for something when it is 99.7% likely things will be fine?

(FTR, baby boy #2 is jussssssst fine. Measuring fine, active, all things looking normal, ready to wrestle his VERY excited older brother.)

2

There’s a great tendency to do tests simply becuase they can be done. if you wouldn’t abort, and are happy to wait for the Big Day to find out for sure, then I can’t see any reason to have the amnio. And, given that it does have a certain morbidity, albeit a very low one, if you don’t need the amnio, then you need not to have it.

3

There are usually other issues that go with Down’s, such as heart defects, that are good to ID early on. If you had no insurance, there would likely be considerably fewer of these, but they would still perform some of them.

4

Actually even if the fluid tests positive for an extra 21st chromosome, the baby may not have it. I know of a little girl who has the same genetic disorder I have. Prenatal tests indicated she had it 100%. She was born. They tested her via blood…Didn’t find it. They tested her and tested her…and then FINALLY found one tiny abormal chromosome.

5

While knowing for sure can calm parental fears, a healthcare professional that goes on and on after you’ve said you’d be ok with the less invasive testing may just be practicing CYA.

6

Are you at a teaching hospital? They might just have a professor there who runs a Down study and is in need of subjects.

I’m 42, had my baby last year, and While I had lots of ultrasounds (which I liked very much) they didn’t push the amnio like they did with you. They were just looking for general problems. When my baby seemed to have a tiny kidney problem, they monitored that, and I got a few extra ultrasounds out of it, so I wasn’t complaining. But that clearly had a study aspect to it, as I was asked to fill in forms after the birth if everythign was okay, kidney wise, so they could correlate the ultrasound image of my baby’s kidneys with the presence of problems after birth. And that was done by an intern specializing in kidney problems in babies. So I guess kidneys was my teachings hospitals focus that year.

7

I would be very glad to be offered multiple tests for Downs syndrome at multiple stages so that I could abort ASAP if tests were positive. However, if you would not considering aborting, then you are correct in declining the amnio and additional tests.

8

nycea, the thing is, in some states abortion is not legal after 14 weeks. From what I just read, up to 24 weeks is legal in CA, where I am, although I think it’s difficult to find a practitioner who does it that late. When I was pregnant with my first and asked about the AFP testing (done at 14-16 weeks) and essentially what I do with the results, they said they do abort up through something like 18 weeks or so. So, what confuses me is, it seems, you’d be getting all this testing but then left with hands tied about what to do with the results. Although, are exceptions made?

I agree picunurse they’re probably just practicing CYA–just making absolutely sure I have been offered and I am certain about not doing the amnio. But it struck both hubby and I as odd that they keep making sure when our tests are all negative; baby boy #2 is doing great by all accounts. ::shrug:::

What I still do not understand is why there is so much energy focused on one possible problem that even with my increased odds is still an extremely remote possibility. Is Down’s that much more common than essentially everything ELSE that can go wrong?

9

Probably also because, even if they would not consider abortion, some parents would prefer to be warned in advance rather than having it come as a surprise, so that they can prepare themselves (and their family) for dealing with a Down’s baby.

10

Yep yep yep. The details are vague, but 12 years back friend was told that her baby had Trisomy 13, based on amnio.

As T13 is a pretty horrifying (and universally fatal) condition, they did ultrasounds to confirm - baby looked healthy enough but then sometimes it’s not obvious. So they did a combined fetal umbilical sampling, and repeat amnio.

The second amnio confirmed the first. The PUBS (umbilical blood) sample said “healthy baby”.

It was a pretty horrible time for them all, and I know they very seriously considered aborting at one point. They did not - and the baby was born perfectly healthy.

I forget the actual explanation, but it was something like a mosaic condition where the placenta was T13 and the baby was not, or it was a benign something-or-other with the baby (and the mother as well) that made the amnio give such results…

Weird though that the OP’s case they’re being SOOOOOO aggressive about pushing all the extra tests. The blood testing and ultrasound are pretty standard among people who are not having amnio, even among younger mothers, but the echocardiogram surely isn’t standard. Well, as others have noted, not unless you have insurance and doctors who are running scared for some reason!

11

Mama Zappa, the perinatologist told us yesterday the echo was standard when the mom is refusing amnio to rule out Down’s. (Down’s!Downs!Down’s!Down’s!Down’s!Down’s!Down’s!Down’s!..I swear, I just do not get it.)

Still seems like overkill, but whatever. Another opportunity to see the baby boy. BTW, saw my OB today, and he sees no reason for an amnio and agrees our littlest boy looks fine. All of this extra testing appears routine for an older mom, but reeeeeeeally…all of this? With my son, I had 2 ultrasounds and the AFP testing at 16 weeks, plus the standard glucose test (blech, that’s coming soon). With this one, it will total 3 ultrasounds + fetal echocardiogram, AFP testing at 12 and 16 weeks, and the glucose test.

12

It is probably in the insurance company’s financial interest not to add more Down syndrome kids to its insured population than required. Since the majority of people who do find out they are carrying a Down syndrome baby abort (Wikipedia says 90+%), the insurance company avoids the extra cost associated with that baby. The expenses that could be associated with a congenital heart defect are substantial. Looking here, half of Down syndrome babies have heart defects, and the recommended treatment is open heart surgery within the first 5-6 months. National Down Syndrome Society (NDSS)

Obviously there are a lot of ethical issues involved here. But it seems possible that offering a significant amount of testing could pay for itself from the insurance company’s perspective.

13

A perfect example of today’s throw away society…

14

Yeah, it’s totally like buying a new TV instead of having the old one fixed.

15

Moderator Note

ManicMan. Quit hijacking the thread. If you have a side comment, start a thread in the Pit or IMHO or MPSIMS.

samclem Moderator, General Questions.

Not a warning, just a note

16

Okay, first of all, it’s bugging me that I’ve been messing up the name of the condition. It is “Down syndrome,” not Down’s. There, the copy editor in me is satisfied.

Harriet the Spy, what you said makes sense; it seems that the insurance must have have some sort of financial investment in all this testing. It just seems to me the cost vs. reward is low. I have a 99.72% chance of NOT having a child with Down Syndrome, and all this testing just can’t be cheap. Then again, it must be pennies in comparison to a lifetime of health problems (and managed care), the least of which would be the common heart defects. Again, while it would not be reason for us to abort, I saw the “Termination Rates with Down Syndrome” article linked in the Wiki article after you mentioned it. 91-93% is surprisingly higher than I would have anticipated, but there it is in black and white.

I know the tests check for other things, but the emphasis on just one problem seems strange to me, especially since my ultrasound paperwork detailed problems in certain organs and some conditions (such as hydrocephalus) aren’t detectable prior to 28 weeks or so. Hmm, perhaps insurance sees it as “Well, that’s too late to abort” and so doesn’t go test-happy in seeking out those conditions.

Is Down syndrome that much more common than other possible abnormalities? Or just among the easiest to detect?

17

A child with special needs is a challenge no matter how you slice it. Having the information early enough to make an informed decision is something many (but not all) parents would find useful.

I also understand asking multiple times. The responsibilities of parenthood can sometimes drop down suddenly at week 20 when every thing was copacetic at week 12…YMMV

18

Actually not quite. T-13 has a high rate of morality but there are some kids alive with it. From what I recall, it’s not the existance of an extra chromsome that’s really worrisome…but rather the associated conditions that accompy the extra or missing chromosome. A lot of the medical stuff out there on chromosome disorders is very outdated or on the " most obvious" cases. Hell…a lot of parents get told that people with my syndrome are in a persistant vegatative state or are at best severely mentally retarded…Just really irritates me that docs tend to only tell abt the worst case scenerios.
As to the cite on Wikkipedia…that’s a toughie. Some Down’s babies die in utereo.

19

It may be that they are saying “Downs” because that is the trisonomy most people are familiar with, and, frankly, one of the least scary. The physician may be as concerned about detecting other chromosomal disorders, but assumes most patients only know about Downs and understand the idea of testing for Downs.

And it may just be that doctors really, really, really hate telling new mothers that their baby is dead, dying, or has Downs syndrome. It’s got to be easier to do at this stage.

20

Officially, no. In reality, yes, same as abortions were illegal in Spain when my aunt’s breast cancer was detected yet the doctors were scheduling her for one as phase one of her cancer treatment, without even asking whether she wanted it. “Illegal” isn’t the same as “not done.” (FTR, mother and now-adult youngest son are both in fine health)

No, but it’s something they can test for as well as something the patients will have heard of. There’s many other disorders (both genetic and teratogenic) for which they simply don’t have a test.

Down’s is one of the reasons for termination, in Spain; there are regions which haven’t seen a single person with Down’s born in years - and not because they aren’t getting bred.