False Negative possibility?

[PenelopeParker]

A quick background, I'm 30, and due to male factor infertility, we got pregnant with IVF.  Since my husband was born with a heart defect, the doc recommended we have the quad scan, which leads me to my question...

I hear all the time of the false positive rate with the quad screen, when it comes back positive and then there are no other markers and the baby is born without any abnormalities.  But I was curious if anyone has been given a "negative" reading, and then later things show up on the ultrasounds?  Based on the quad screen we were told we had a 1:900 chance for downs, and then 1:5000 for tri 18/13.  But then they discovered a choroid plexus cyst at the 20 week ultrasound (which the doctor said could change my odds), and as of yesterday at 32 weeks they found fluid on his kidneys, which is a second soft marker.  The doctor didn't seem too overly concerned since the baby is growing ahead of schedule and no other markers were found.  We're trying not to freak out about it, but after everything we went through to get pregnant it's just so hard.  Anyone in this situation?

[lydia307]

Hi Sandi,

I am 44 years old and 14 weeks pregnant.
I had a nuchal measurement which came out normal at 2.4. Unfortunately, the blood test of HCG which twice higher than normal(2.01), the placenta papp was normal at 1 mom. The NHS hospital contacted me to say that I was high risk of having a baby with Downs syndrome (1 in 70) and that they were suggesting that I do the amnio to have an accurate test for down's syndrome. They also advised that if I wanted to have an informed decision I could do another scan privately to test for 2 additional markers (presence of nasal bone and for abnormality of heart flow of the baby, which I did yesterday. The gynecologist who performed the scan could see the nasal bone but said that the heart flow was abnormal. He also did another nuchal measurement and found it to be high 3.5! He told me that I was 1 in 2 of having a baby with down syndrome..I feel totally confused now that I had 2 different nuchal measurements , the NHS was normal and the one at the private clinic was high...I feel that the existence of the nasal bone is a good hope...?? as to his nuchal measurement maybe he was wrong? Although he said he did it 3 times, but when I did it I was 14 weeks pregnant and when I did it at NHS I was 13 weeks and 4 days pregnant, does it make any difference?? As to high HCG, I feel it is linked to the pregnancy symptoms..I had terrible nausea for the last 2 months, being unwell every day, unable to work...etc..could it be high because of high pregnancy hormones??? Now I am feeling confused about all these results and still have to decide if I will have to do the CVS or amnio..bearing in mind the 1 in 100 chances of miscarriage...It is my first baby and my fertility tests showed that I had a low count of ovules which might make it harder for me to conceive again?? but who knows.... If you have any comments or advice please write to me as I am really sad and confused. I am very happy for your healthy baby..Lydia

[bbunting1]

To answer your question but not to scare you. I am 36 yrs old...just barely turned 36 when I conceived. I had all the genetic screenings during my pregnancy and was not worried b/c all the test came back normal. I even had 5 ultra sounds and not once did anyone even think of any abnormalities.

I went into labor almost 3 weeks early...and when my baby was born instead of being overwhelmed with joy...I was like.."somethings wrong...what's wrong with his eyes?" My babies doc ordered a karyotype test and sure enough...positive for trisomy 21 or down syndrome.

I was devistated...I cried everyday. I was broken. NOW...he is almost 4 weeks old and so beautiful! He is a blessing! I wouldn't change a thing.

My advice is to do some research on downs...talk to parents of children with downs....don't research on the internet...the internet always gives worst case.

Yes...false negatives can happen. It is rare. Just call your local down syndrome support group and talk to them...that is your best resource.

[Dragon1973]

Hello Penlopeparker & naynay363,

I am one of those women.  I had no markers show up on my initial tests, the blood works and IPS (integrated Prenatal screening) tests came back normal.  My baby's NT (Nuchal translucency scan) came back in normal range.  But for my age of 35 at the time, I still opted to have an Amnio because I was a need to know type of person.  So to my shock, and everyone else's, when our son's result came back albeit 1:385 initial maternal odds, as that very 1, (he had Ds) I could not believe it was true.  All the prior testing, all the prior screening - negative.  But here was this amnio showing 100% without a doubt that he had Down syndrome!

Now, I wanted my son no matter what, and it didn't change my mind about having him.  It just gave me the time to prepare and learn everything I could - and what a shock and wonderful surprise to learn that Ds wasn't what I and everyone thought it was going to be.  Our son is what everyone who knows him would call "typical".  He is as normal (a word we don't like to use) as they come.

From this I have learned, numbers are just that... numbers.  There are false positives and false negatives.  Odds and statistics are just numbers and unless you have definitive testing such as Amnio, CVS or PUBS, there is no way to know for sure.  My experience has allowed me to become a parent guide, an author and group creator and leader.  I have so much information and resource to pass on to anyone who is interested.  I have created websites and references to help people from the beginning of pregnancy, through prenatal testing to after birth.
I have references posted in my blog: www.welcometoourhouse-myjournal.blogspot.com and am working on a brand new reference website.  I have publised books and articles to help people and hopefully provide them with the hope and answers that they are looking for.

I have been there myself when it comes to the confusion of testing and statistics and odds.  If you have any questions with respect to the results or process of your testing, I can help.  Please feel free to message me directly at anytime.  I am here to help and pass on any guidance to those in this often scary and quite confusing situation.  

In addition to anything I have mentioned, please keep in mind, that while I or others may have extensive knowledge in many areas, you should always seek professional medical advice from your own physician, as it pertains to medical conditions or concerns.

Good luck, and if you have any other questions that I can help you with, please feel free to message me directly.

Sincerely,
Sandi (Dragon1973)
MedHelp Genetics Community Leader;
Children - Special Needs Community Leader;
Down syndrome Community Leader & Ds Group Forum Founder/Moderator;
MTHFR Group Forum Founder/Moderator;
Pregnancy: June 2011 Community Leader

[naynay363]

hello, and I feel your pain and frustration. Im 29 years old and  now 29 weeks pregnant, my wife and I also went thru a clinic but had a donor.   when I was 17 weeks pregnant, i was told from the beginning that my odds of having a downs baby is 1:170. Heartbreaking news! The level 2 ultrasound after that (actually 2 of them between 18 and 22 weeks) didn't show any markers. But ----- i will tell you, that after knowing people with worse odds, researching, and talking to dr's ----that the false postive rate for this test is ridiculous!!!! Some Drs offices' don't even offer that test because of the high false positive rate. just keep hoping and praying that everything is ok.....but either way im' sure we will be fine.