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Scary 1st Trimester Screen - Amnio? CVS? Neither?

Aug 2011

I am 35 and in the 12th week of my second pregnancy. I had a first-trimester screen today, and had normal results for the nuchal fold scan and one of the blood tests. The kicker was the PAPP-A blood test, which was .13 MoM. This is very low, apparently. The overall Down Syndrome risk calculation the genticists run came up with a risk of having a Down Syndrome baby of 1/39, which seems incredibly high to me, given the nuchal test was normal. The perinatologist recommended an amniocentisis or a CVS. We have no family history of any genetic disorders, and the twins from my first pregnancy are healthy and happy.

I have been reading a ton about the PAPP-A results, their reliability, how different factors can affect them (including IVF, which we did and which has been found to be a factor in low PAPP-A levels). Also, the doctor never even mentioned the host of other issues I read about that could come along with low PAPP-A, including low birth weight, interuterine growth restriction, and other things. So even if the amnio/CVS come back negative, we still could have problems with this pregnancy.

Has anyone ever experienced a normal nuchal result, but bad blood test results? Had a low PAPP-A? Should we do a CVS or the amnio? Should I get a second opinion? I'm so confused, we have only a short window to decide, and there are so many factors to consider...I personally don't think I'd want to terminate this pregnancy if there is anything wrong, but my husband emphatically disagrees with me (I recognize this is a whole advice topic on its own). Anon


I was pregnant at age 39 and was over 40 when my son was born. I had a CVS done around 10 weeks. I would recommend it; it was a great relief to get happy results. I feel that I could not have waited for the amnio. Email me if you'd like me to discuss the CVS further. It was a breeze!
I was 43 when I was pregnant with our first and only daughter (a natural pregnancy after I'd completely given up on IVF, IUI, etc.). I had a normal nuchal fold test but based on results from one of the blood tests, the geneticists calculated that we had a 1 in 7 chance of a Down's pregnancy--much higher than the standard calculated risk even for my age. We did an amnio and that was normal (although as you have pointed out that does not necessarily mean all is OK; amnio only tests for a very limited range of chromosomal defects). So we proceeded, still with tremendous anxiety. We now have a lovely, healthy, normal daughter about to enter 3rd grade. Likely you will be fine also. Remember that based on the odds you were given (1 in 39), you can look at the flip side: you have a 38/39 chance of everything being OK. Understanding the Anxiety
Hi -- Sorry you're in this position. We were in the exact same boat with our first child over 3 years ago. Normal nuchal measurements, really low Papp-A, with the calculations showing us with a much higher risk of Trisomy 13 and 18. Unlike your situation, neither of us were conflicted about what we would so if the baby turned out to have Trisomy 13 or 18, as these are lethal genetic defects, so it may not be exactly the same. However, we decided to get a CVS (which has a cut-off of 13 weeks, so if you want one, you have to do it FAST!) and I'm so glad we did because it was so reassuring and allowed us to relax and enjoy the pregnancy rather than living under this anxious cloud. In the right hands (we went to SF Perinatology -- they are beyond expert!), CVS has a very low pregnancy loss rate. Newer research shows it to be equivalent to amnio in terms of risk of loss. The risk of loss was much lower than the risk of having a baby with a trisomy, so it made a lot of sense to us to have it done.

The other stuff you read online, about potential pre-term labor, etc, you should know has very little evidence to back it up. Our midwife told us there was really no evidence about what a low Papp-A means in light of normal CVS results, but because Papp-A was a placental hormone, some people thought it might signal some kind of inadequacy with the placenta, and cause the placenta to crap out early. So the standard procedure is to put women on a regimen of weekly NSTs (non-invasive testing) after 32 weeks. But there's really no evidence that this helps. I found the weekly testing incredibly annoying (because it was time-consuming) and ended up having a healthy baby boy at 41 weeks with a very large placenta if I remember correctly. So in our case, the whole fear about placental insufficiency seemed unfounded and just another thing to worry about.

This time we skipped the first trimester screen altogether and just got the CVS. I didn't want to mess around with all of that other stuff. Sympathetic


First, you are right to have some doubts about the test results since the blood test (quad marker test) can be influenced by many things (i.e. incorrect conception date etc...but you should be sure about that with IVF); also I'm a scientist and labtests can give you a false result at times - maybe ask to repeat the blood test (not sure if the time window has passed for that but maybe they still have the blood and can do the Papp determination again?);

But in any case, all those tests give you are probabilities, diagnosis is only possible with Amnio/CVS. CVS is riskier but can be done earlier. Both carry a significant risk of you losing the baby just due to the procedure. So you have to weigh that risk (which seems to me exacerbated here bc of difficulty conceiving) with how much you want to make sure that you don't give birth to a child with Down syndrome.

You mentioned you would like to have the child even if it's handicapped - then I wouldn't do neither CVS or Amnio and just try to forget about the results. It's 98% likely that your baby is perfectly fine according to the nrs. you quoted.

Also, I wouldn't be pushed by the husband on this - you are the mom and we moms have the right to protect our babies. anon


I also had a normal nuchal fold measurement but a very low PAPP-A test, which made my risk of DS very high. We chose to have an early amnio at 16 weeks and everything was normal chromosomally. However, my pregnancy became very complicated around 20 weeks with hypertension, pre- eclampsia and ultimately HELLP syndrome. My previous pregnancies were healthy and uncomplicated, with a normal PAPP-A each time. I have since seen women with abnormal PAPP-A numbers and complications, some with IUGR, some with hypertension and pre-eclampsia, others with minor fetal abnormalities. I have also seen plenty of cases without any complications of having a low PAPP-A. Many OBs like to monitor women with more frequent ultrasounds if you have a low PAPP-A to check fetal growth, along with regular visits with blood pressure and urine protein monitoring. Whether you choose CVS or amnio is a personal decision, but just be aware that you may be at higher risk of other complications because of your numbers. In my case, I was induced only a couple weeks early, and fortunately my baby was okay. Good luck, and I hope that you are able to get some clarity around this issue. Been there
I had a similar experience during my first pregnancy: PAPP-A was extremely low, while beta hCG and the NT measurement were both normal. As a result, the combined first trimester screen put me at a 1/74 risk for Down's syndrome (I was 37). Actual values were as follows (in case it is helpful): PAPP-A: 0.21 MoM (0.5th percentile); beta hCG: 0.89 MoM (50th percentile); NT: 1.1 mm (an excellent measurement). Your PAPP-A result is obviously a little lower than mine was, but at 0.5th percentile, mine was clearly in the extreme low range. In light of those results I scheduled an immediate CVS. However, due to a structural problem with the uterus I ended up having an amniocentesis instead at 16 weeks. During the 4 week wait period I did a lot of research on the topic - as well as a lot of worrying. I was nervous about the 1/74 risk of Down's, as well as the host of other problems that, according to the literature, can be associated with low PAPP-A levels even in the absence of a chromosomal abnormality, i.e., IUGR, low birth weight, problems with placental function, etc.. The amniocentesis came back normal. Later in the pregnancy it was discovered that I had placenta previa (most likely the reason for the low PAPP-A). Despite this, I had a perfectly healthy baby - and no major problems due to the previa, though I did end up requiring a c-section.

I am not sure how exactly you could benefit from a second opinion. It sounds like what you need is to be matched with a good genetic counselor who will be able to go over the results and options with you (I take it you didn't get much help from the perinatologist). That said, the blood tests are nothing more than a screen, based on which you were advised to consider further testing. I don't think you will get a different opinion anywhere. These physicians are pressed for time, and honestly, when it comes to the various details and statistics, a good genetic counselor may actually know more, or at lest be able to deliver more to you. However, I don't think anyone out there will advise you not to pursue additional testing - simply because you screened positive (based on your ''numbers''). Keep in mind though, that these numbers are derived from a computer-generated algorithm that incorporates your age, along with other factors (I believe in most clinics ''positive'' means anything greater than 1/100). Of course, whether you choose to follow that recommendation or not is a personal decision that is entirely up to you.

If you do decide to pursue further testing, I highly recommend DR. James Goldberg of SF Perinatal. He is the absolute best - exceptionally skilled, experienced, considerate, and makes you feel very comfortable. I cannot say enough wonderful things about him. I have had two amniocenteses with him and had an excellent experience both times. CVS v. amnio - both provide the same information. The main advantage of CVS is that it's done earlier in the pregnancy, so you get information about a month sooner. Previously it was reported to carry a slightly greater risk than amnio, but I believe that estimate has changed and now both are considered equally safe. Rarely, a CVS either cannot be performed or results are inconclusive, in which case an amniocentesis really is the only option. I personally think that both are very safe procedures, especially if performed by a skilled physician, and I wouldn't think twice if faced with the decision again. Incidentally, my second pregnancy screening test put me at a very low risk, and I still decided to have an amniocentesis because for me, knowledge is key. But everyone is different, and you need to decide what is right for you. If I were in your position though, I would probably go for CVS.

That other issue you alluded to is a really tough one - I'm sure many couples don't discuss these things in advance because they are so unpleasant to think about. Unfortunately, I don't have any advise on that one, but I will say that some women may chose to have amniocentesis strictly because they want to ''know'', period. Both amniocentesis and CVS can be used to detect a multitude of conditions other than the major chromosomal abnormalities that are routinely screened for via bloodwork in the first trimester. Some need to be specified, but others (chromosomal) can be detected as part of the standard karyotype. Reduced PAPP-A levels are relevant only in the risk assessment for Down's and Trisomies 13 &18 (though the last two are typically associated with abnormal hCG levels in addition).

Bottom line - only you can decide. But it sounds like you could benefit from some counseling to help with the decision. Finally, you are hearing from someone who had an exceptionally low PAPP-A and perfectly normal outcome (my son will be 3 next month and is absolutely healthy). Best of luck to you. I am happy to discuss this with you further if you would like (just ask the moderator for my email). -Monica


Alternative to Amnio/CVS: Blood Based Screening

April 2011

I am 38 years old, 12 weeks pregnant, and a family member just told me they read about some ''brand new'' (not sure what exactly that means) alternative to amniocentesis/ CVS: it is a non-invasive genetic test that scans the fetus' DNA through the mother's blood--it's called Blood Based Genetic Screening. So it is a simple blood draw and then computer technology somehow separates the baby's genetic material from the mother, just like amnio but without any associated risks. This is different, I believe, from the blood drawn in the 1st/2nd trimester that's part of the Triple Screen. Has anyone else heard of this/done this yet?? I would love an alternative to amnio with just the same diagnostic accuracy. Hopeful


Dear Hopeful - Although there have been some major advances in blood-based prenatal testing, and this approach may eventually replace amnio/CVS, it hasn't yet become cost-effective or robust enough to use in the clinic. There are companies that will do blood-based paternity testing, but for more comprehensive prenatal analysis, I believe that CVS or amnio are still the only options. I've had both (amnio first pregnancy, CVS with a second, twin pregnancy) and although they involve some short-term pain, for us it was well worth it to know that everything was okay (I was 43 during my second pregnancy). The risk of infection or miscarriage is very small with experienced doctors. 3 healthy boys
Hi! I really, really understand your interest in this! It is true that tests like the one you described have been under development for a few years by a few different groups (see e.g. http://fcmb.dk/ for one of them). I heard from someone at UCB that these tests are about one year away from being on the market. You should ask your ob/gyn though, it is possible that there is a test on the market already (but keep in mind that even if it, it will be very new, possibly still needing some fine tuning...). Anon
I am a nurse-midwife and have never heard of this. The best non-invasive test that I know of is the combined nuchal translucency (via ultrasound) and maternal blood test. The nuchal translucency has to be done before 14 wks 2 days, and the blood draw before 13 wks 6 days. CNM
I saw an article about that too, but I am not sure the test is in use yet, and I am not sure if it can detect anything other than Down Syndrome... See NYT article link below: http://www.nytimes.com/2008/10/07/health/research/07down.html?pagewanted=2 And the company: http://www.sequenom.com/home/products---services/diagnostics/prenatal- diagnostics/fetal-nucleic-acid-technology/ Andrea
I believe you are referring to Fully Integrated Screening. This is a three part test involving two blood draws for you and an ultrasound of the baby's nuchal translucency (back of the neck). The first blood draw occurs now (approx 12 weeks), as does the ultrasound. You are then given a preliminary result. The second blood draw occurs between 15-20 weeks, and provides you with your final result. This testing is similar to the ''triple screen'' you mention, but about 10% more sensitive. In other words, it is non invasive and provides quite good information, but not as much accuracy as the CVS or Amnio. (Quick summary of the choices: the ''triple screen'' -- now actually called ''quad screen'' -- is 80% sensitive, the fully integrated screen is 90% sensitive, and the cvs/Amnio is 99% sensitive. Sensitivity refers to true positives. This means, for example that Fully Integrated Screening picks up 90% of the babies who have a chromosomal abnormality.)

By State law, all women in California are offered Fully integrated Screening. Of course, you can decline in favor of no testing or cvs/Amnio. Your Ob-Gyn should be able to discuss all of this with you in depth, or refer you to a Genetic counselor, if you have more involved questions. In the end, the decision is not only technical, but emotional. Usually, one choice just ''feels better'' than the others. Good Luck Local Ob-Gyn Nurse Practitioner


I know of several technologies that have been developed for testing fetal DNA in maternal blood, including one developed by Stanford Professor Stephen Quake. That technology is being developed by a company called Artemis Health. The company has not yet received FDA approval for the test, so it is not yet available. http://news.sciencemag.org/sciencenow/2008/10/06-03.html These technologies are coming, but not likely for a year or two more. - Biotech dad
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