How to decide whether to have an amnio?
August 15, 2011 2:15 PM   Subscribe

How to decide whether to have an amnio?

My husband and I need to decide whether to have an amnio. So far, my OB hasn't been willing to say anything other than the rates of miscarriage associated with amnios (and that their rates are standard), my results from the NT (so far about 1 in 5000 for Down syndrome and 1 in 9000 for trisomy 18), and that this is an elective procedure. We're still waiting for the latest round of results and that might impact our decision, but assuming we still have good results, we're really on the fence with regard to what to do.

(I feel like a terribly guilty about this, but we have definitively decided that I would have an abortion if the results were positive for a chromosomal abnormality.)

So a few questions:

1. If you don't mind sharing your own thought process, how did you decide whether to do the test? Particularly interested in people who knew they would have an abortion if the results were positive for a chromosomal abnormality).

2. Have you seen recent stats regarding whether amnios actually do increase the risk of miscarriage? I have been reading that roughly 1 in 300 women who have amnios have a miscarriage, but also that that is roughly the same stat for all women in the 2nd trimester, so possibly amnios aren't as likely to cause miscarriage as originally thought.

3. Does anyone know - are there other serious chromosomal abnormalities that amnios don't typically test for?

Any advice? We're wobbling back and forth on the fence and have no heads for statistics, so we're also a bit confused about what it all means and how likely we are to have a child with one of these problems based on the statistics we're getting.

I deeply apologize if I have offended anyone with inartful or ignorant terminology here. This is new territory to me!
posted by n'muakolo to Health & Fitness (24 answers total) 6 users marked this as a favorite
 
Is there any reason to have one?

- your age?
- family or ethnic history of disease?
posted by k8t at 2:37 PM on August 15, 2011


Um...your stats for women having miscarriages in their second trimester seem very off to me.

From your numbers you seem to be quite young, compared to the average Australian mum.

We had a risk for LittleTaff in 2006 of about 1 in 500. I was 36-ish. We had the doctor that brought nuchal translucency scans in to Australia.

His advice was that if the risk of Downs was greater than the risk of miscarriage then to have the amnio or cvs. So if we had a risk less than 1:300 to do it.

ToddlerTaff was born 2.3 years later and my risk was 1:3000 ish. We also did not fo the amnio.

We were told by our radiologist that there are hard and soft markers in the scan and that the soft markets, like the bridge of the nose, are not yet formally used as indicators. Bur that both of our babies had good statistics for both.

Naturally you're anxious. But your stats are marvelous and I would be delighted with them.

Talk more with the RADIOLOGIST if you have questions. The person who reads scans all the time. Also, if fit some reason you are still freaked out and go get the amnio, make fire the doctor doing it has statistics better than 1:300.

You're not a bad person for being prepared to terminate. It's a personal choice, and we wouldn't have tested if we weren't prepared to also. Or at least had enough facts to make an informed decision.

But your stats are fantastic, so I'm not sure why you're worried. Please talk to your doctor again.

Also, I'm happy to Memail with you if you want to have a chat about it all. It's so hard, and confusing.
posted by taff at 2:53 PM on August 15, 2011 [1 favorite]


Which you you rather live with, not having it and missing finding out your child had a chromosomal abnormality or having it, having a miscarriage and never knowing if it was the amnio or some other reason for the miscarriage? Are you in a high risk category?
posted by JohnnyGunn at 2:53 PM on August 15, 2011


We had an amnio 8 years ago, and it sounds like a very similar situation.

In our case, some suspicious things on the 24-week ultrasound prompted the OB to get a little more in the way of information. It turns out that the things (single 'markers' for Downs and Trisomy 18) were red herrings and nothing came of them. The sample was sent to a genetics lab and we waited for An Extremely Long Weekend to pass before we got the results (which, by the way, included the sex of the baby, so watch out if you're trying to stay surprised).
posted by jquinby at 2:54 PM on August 15, 2011


Those odds coming out of the NT sound good to me. I would not have further genetic testing, and I would likely have terminated a fetus with a chromosomal abnormality. (Mine were 1/9,000 for trisomy 21, something smaller for trisomy 18; both my OB and genetic counselor made it clear that those were excellent odds, and based on that result, I had no further testing.)

Here is one of my favorite ask.mefi posts about how to understand statistics.
posted by purpleclover at 2:54 PM on August 15, 2011 [1 favorite]


Did your doctor explain to you how very good your results are? You are well below the average risk for Downs (see for instance this BBC Health page with likelihoods for Downs). In fact, the chance that you would give birth to a baby with either abnormality is 0.02% for Downs and even less than that for Trisomy 18.

You could get unlucky still, of course (just like you could get unlucky and have a miscarriage or other complications), and I understand your worries. However, you would have to be very, very unlucky.

This is a decision only you can make - how much do you really, really want to be sure that you don't have a baby with these specific abnormalities? How much would the extra test do to make you feel better? How much would it increase your fears? (For what it's worth, since you did ask, my own thought process, with these results, would be, 'Glory, hallelujah! This is great news. No big needle for me.')
posted by brambory at 2:55 PM on August 15, 2011 [1 favorite]


I had both my children at a relatively young age (27 and 29), so I elected not to have amnio because maternal age didn't put them at a higher risk for Down's Syndrome.

Our family history was solid; no birth defects except on my husband's side in a very specific instance, attributable to a specific cause.

We had a higher-than-expected result for my youngest's AFP test, which are notoriously unreliable in any event, so we went to a specialist who was able to reassure us that his spinal chord and neural development was just fine.

So I chose not to have an amnio because there wasn't a compelling reason TO have one, and I would err on the side of caution when it comes to scary tests with big, scary needles, especially ones that have a 1 in 250 chance of resulting in miscarriage (the odds cited to us at the time). Now, the risk is estimated to actually be much lower.

That was my thought process. TL;DR answer: Don't have amnio unless you have an increased risk of complications or birth defects that balances out the miscarriage risk.
posted by misha at 2:58 PM on August 15, 2011


If your decision is based on those stats alone, I don't know why you would have one. My stats for Downs were one in 3000 and the doctor said the odds were so low they would never risk a potential miscarriage to investigate further. My friend on the other hand has just come back with 1:200 odds so they will be getting an amnio. Your doctor should be explaining the odds and advising you as to how they weigh up against complications with an amnio. I would ask further but based on what my doc told me, your figures are good. Are you missing some info out?
posted by Jubey at 2:58 PM on August 15, 2011


Response by poster: Thanks, all. No special reasons for us to be concerned. (Although I am 34, I believe my age is factored into the stats we're receiving.) We're just big worriers by nature. And we expect to only have 1 kid, and would like that one kid to be "healthy" if we can do anything reasonable about it. (I am already realizing we're in for a lifetime of worrying!)
posted by n'muakolo at 2:58 PM on August 15, 2011


To answer #1 (how'd you decide), for us it was... well I guess a cold-hearted, extremely logical discussion on what we gain by knowing. Ideally we'd like to say that we could love a child no matter what, but my spouse and I knew that while we could afford love, we couldn't afford anything else. We did not have the economic means nor the time needed to support a child that required extra care and attention, and we had little to no reasonable support from any close family. We also knew that given our age and family history, there were increased odds that something bad could be brewing.

You've already decided what to do if you found out there was something wrong with the fetus, and that's the same conclusion we came to. In that regard it was easier to make the decision to have an amnio. We felt that it would be better to know beforehand, so if in the event of a worst-case scenario we'd have time to prepare ourselves.

In the end I think it really depends on how you think you can handle the bad news. I am the type that likes to be as prepared as possible because I feel I can better manage things if/when it happens. I know that life will never play according to those rules, but I try where and whenever I can. My spouse is more or less the same, and I think we both felt that if something did go wrong, it would be easier for us to abort and recover then, rather than try to adapt later.

I don't really know about stats or what exactly an amnio can test for, but I can tell you that one of our close friends fell on the wrong side of those statistics and had a miscarriage because of it (something to do with an infection that resulted). Honestly that did factor into our decision and we really hemmed and hawed, but in the end we decided it was a risk we were willing to take, particularly in light of the other issues I mentioned above.

Granted, just because amnio and other tests come back normal doesn't mean everything will be hunky-dory. I just take it as an indication that things are going well and that the odds have shifted more in our favor. I'm sure there are still a number of things that can manifest later in life, and we will have to deal with that. However, by ruling out some of the bad things early on, we derived a small sense of comfort, and that made us feel a bit better about the prospective life ahead.
posted by CancerMan at 3:00 PM on August 15, 2011


We met with a genetic counselor who helped us understand the various risks. Can you find a genetic counselor to explain these things to you?

In the end, though our risks were relatively low (I would be 36 at delivery, but we had no history of genetic problems on either side), I still had amnio because my husband wanted to know for absolute sure and I didn't really feel strongly either way. Of course things were absolutely fine, but I still don't regret doing it. I would just make sure that the doctor drawing the sample was very experienced (you can ask about a specific doctor's history with complications).
posted by rabbitrabbit at 3:00 PM on August 15, 2011


I have been reading that roughly 1 in 300 women who have amnios have a miscarriage, but also that that is roughly the same stat for all women in the 2nd trimester, so possibly amnios aren't as likely to cause miscarriage as originally thought.

Yes, much lower: closer to 1 in 1600, according to recent research.
posted by misha at 3:01 PM on August 15, 2011


We declined the initial screening, essentially to avoid being in the situation you're in now - I'm assuming the numbers you have come from the quad screen or whatever it's called where you are.

While we would have aborted if we'd somehow gotten a confirmed major issue, the math we did indicated that for us (I'm 30) we had a higher chance of getting a false indication of a problem on the screening, going ahead with an amnio, and having a miscarriage of a healthy child, than having a child with a problem. Essentially, we're taking our 1/1,000 risk of downs rather than take the 1/100 risk of miscarriage, and we're ignoring the ways the screening might alter those numbers because we felt it was just so unreliable. I think if I'd been older and the risk of an abnormality closer to the risk of miscarriage our decision might have been different.

Honestly though, we also skipped the screening because there are so many problems it doesn't screen for, that we didn't feel it could give us peace of mind, just more stress, and I think a lot of this has to come down to what sort of risks and stresses you handle better, and to gut feelings. For you, I think it's probably down to whether you'd rather take the small risk of a surprise baby with a (findable by amnio) chromosome problem, or the higher but still small risk of losing a healthy pregnancy. I say do what you feel most comfortable with and what will let you enjoy the rest of your pregnancy, the risk is small either way.

Oh, and I think your point about miscarriage risk is fair, and it doesn't seem like anyone really knows what it actually is, but FWIW, the numbers we were told were more like 1/100, and that's with doctors at a big HMO who do the procedure a lot.
posted by crabintheocean at 3:05 PM on August 15, 2011


Agreeing with everyone above. I just had my first child at 40.

The one thing I wanted to point out - they tell you stay off your feet for a couple of days or whatever - I felt awful after my amnio and didn't feel "right" again for about 2 weeks. I was very surprised by this! I thought the amnio was going to be a cakewalk! The procedure itself went just fine, it was the "afterward" I wasn't prepared for.

I would still do another amnio. But there would have to be a very compelling reason to do so.

YMMV.
posted by jbenben at 3:10 PM on August 15, 2011


As others have said, you seem to be pretty low risk. My own risk was given as 1 in 1100 (i'm 37) and I didn't have an amnio, though to be fair I had pretty much decided that I would continue with the pregnancy regardless of the outcome. FWIW at the hospital I shall be giving birth in, you're considered high risk only when you have a 1 in 150 or greater risk.
posted by kumonoi at 3:18 PM on August 15, 2011


I am pregnant now, and had to make this decision a couple of months ago. At 36, I'm at Advanced maternal age, which made my initial odds for abnormalities higher than they ended up being after our NT results. After meeting with a genetic counselor we decided that we'd decide on amnio based on the NT results, which ended up being good enough that we felt an amnio wasn't necessary. I would have had an amnio had I felt uncomfortable with the results of the NT scan and the initial labs. And yes, we were prepared to terminate if the tests had picked up certain abnormalities.

Personally, with your NT results I would be foregoing the amnio. I know the odds are small that an amnio will result in miscarriage, but your odds post-NT are positive enough that I would not want to go through an invasive procedure that carries risks.
posted by DrGirlfriend at 3:34 PM on August 15, 2011


For us, we decided not to have one because we figured it wouldn't make any difference because we were committed to keep whatever we got. And later complications with the placenta in the 3rd trimester made us glad we did not do the amnio-draw because we would have always wondered and worried if that caused the complication. Then, yet another complication happened in the hours or minutes around the delivery, this time internal to the baby herself. As it was, there was lots of agonizing questions about possible causes, so I'm glad we had just one less thing to worry about.
posted by markhu at 3:51 PM on August 15, 2011


I had my first kid when I was 32 and the 2nd at 38. I had an amnio the first and CVS the second. I would have terminated for Downs. I didn't care about statistics or anyone's opinion except my husbands and mine. I don't have needle phobia, particularly, and it wasn't all that bad.
posted by Ideefixe at 3:53 PM on August 15, 2011


You've already decided that you would abort.

You've made the "hard" choice, now go ahead with the easy part (the diagnostics).
posted by pla at 4:01 PM on August 15, 2011 [1 favorite]


The miscarriage risk with amnio is quite dependent on the skill of the practitioner, from what I'm told, so if you do have it, find someone who does many of them. The more they do, they better they tend to be at it, so the lower the risk.
posted by Maias at 4:21 PM on August 15, 2011


Question #2 is the same one we had, namely, how do you determine the rate of CVS/amnio-caused abortion when you are ethically obligated to only screen women with an existing risk factor? Most studies compare CVS to amnio or compare two different sample methods, but they don't compare CVS/amnio to a null treatment group.

Our counselor cited a study (which I cannot find right now, of course) which claimed the elevated risk was pretty low compared to the baseline rate of spontaneous miscarriage.

As far as Q#1, we were both comfortable with abortion since we know that several of the chromosomal problems result in miserable, short, pain-filled lives for the resulting child. I've got a genetic disorder, and I'm fine with sparing any offspring the same misery if I can.
posted by benzenedream at 5:05 PM on August 15, 2011


I was in a similar situation, end of my first tri at my 35th birthday. My numbers also came back great and, well, I opted to roll the dice, hope everything continued to go well and did not do an amnio. My 8 month old is making a ruckus in the other room so I gotta go but everything turned out well. Good luck!
posted by amanda at 6:21 PM on August 15, 2011


Here's another way to look at the math. You essentially have two possible bad outcomes to your choice (ignoring all the other possible bad outcomes to pregnancy): a pregnancy with a chromosomal defect (and then an abortion), or losing a healthy pregnancy because of the amnio. By my math, one of these bad outcomes - losing the healthy pregnancy - is about 11x more likely than the other (1/300 vs 1/3,300ish). So the question becomes which bad outcome is worst to you, and possibly whether the least likely bad outcome seems 11x worse than the other.
posted by crabintheocean at 7:53 PM on August 15, 2011


I am currently 32 weeks pregnant with my first baby. After my NT scan and blood work at 13 weeks, I screened positive for Down syndrome due to a high HCG measurement - the odds they gave us were 1 in 279. We would have terminated if a chromosomal abnormality was confirmed through amnio.

We decided to go through with the amnio at 16 weeks. Our thought process was based on two factors: the risk of miscarriage at our hospital was very very low, around 1 in 1000; and I am the type of person that needs to know all possible information when making a decision. The amnio itself was no big deal - a little uncomfortable but not painful, and over very quickly. We only had to wait one day for the preliminary results, which were clear.

As for your question about amnios and miscarriage, our genetic counsellor gave us the stats of 1 in 1000 but said that there is no way to know whether miscarriages are actually caused by the amnio procedure itself. The statistic they report is the total of ALL miscarriages that occur in women who have had amnios at the hospital, regardless of whether it occurs the next day or not until 10 weeks later. I felt comfortable with the risk since it was so much lower than the risk of Downs.

I am really happy that I had the procedure done. It has given me a peace of mind that I would not have had without it, especially since my 20 week ultrasound showed a couple of "soft markers" for Down syndrome. Without the amnio, I would have been convinced the baby did have Downs.

That being said, your numbers are extremely good. In your situation I probably would not go through with an amnio. But either way, good luck with your decision and congrats on your pregnancy!
posted by barney_sap at 7:54 AM on August 16, 2011


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