Tests during pregnancy:Amniocentesis

How is an amniocentesis performed and what are the risks involved?

What is amniocentesis?
Amniocentesis, or amnio, is a prenatal test in which a needle is inserted into a woman's abdomen to remove a portion of the amniotic fluid. This is usually done in conjunction with an ultrasound test so that the doctor can see where he is putting the needle to avoid harming the fetus. By performing biochemical tests and by examining the fetal cells in this amniotic fluid, it is possible to detect certain disabilities.

What can it detect?
One of the main uses of amniocentesis is to detect chromosomal abnormalities. With amniocentesis, it is possible to reconstruct the chariotype of an individual, i.e. map his or her chromosomes. This allows the detection of trisomies (extra chromosomes), monosomies (missing chromosomes), and other structural defects in the chromosomes.

The amniotic fluid can also be tested for levels of AFAFP, acetylcholinesterase (AChe), and hemoglobin F. It is possible to detect neural tube defects, including anencephaly, spina bifida, and meningomyelocele (though the use of amniocentesis to detect neural tube defects has been mostly superceded by a combination of the AFP test and high resolution detailed ultrasound).
It is also possible to detect about 70 metabolic disorders. The tests for metabolic disorders, however, are only done if family history warrants, and will not be done for women being referred for amnio due to age or results on the AFP test or Down's screen. If there is no history of genetic disease in the family, a genetic analysis will not be performed, only a chromosomal analysis. What can an amnio not detect
Amniocentesis will not guarantee you a normal child. It cannot detect most non-chromosomal genetic defects, nor can it detect defects of body structure, such as harelip, cleft palate, congenital heart disease, hypospadias, pyloric stenosis, clubfoot or congenital hip dislocation. Defects caused by exposure to toxic substances will also not be detected by amnio.

What are the risks of amnio?
The main risk of amnio is that it may increase the chance of miscarriage. (1 in 270 in 1996) Different sources disagree on how much. The risk of miscarriage for pregnancies from 16 weeks on is 3% normally, and that amnio increases that risk by 0.5%. Blatt says that the most common figure given is 0.5%, but that some sources cite 1% to 1.5%, and Rothman gives a 3 in 1000 risk that an amnio will result in miscarriage.

After the test, you may experience cramping, fever and chills, vaginal bleeding or leaking amniotic fluid. Call the doctor if these are severe or persist. Under what circumstances is amnio usually given?
Amniocentesis is recommended when the risk of a disability detectable by amnio is judged to be greater than the risk from amniocentesis. People for whom amniocentesis is likely to be recommended include:

• women with an abnormal result on the AFP or Down's screen which is not explained by ultrasound
• women with a previous child with a disability which amnio can detect
• women who have had three or more miscarriages
• carriers for conditions which can be detected,
• carriers of sex-linked conditions such as hemophilia,
• pregnancies in which one of the parents is known to have rearranged chromosomes,
• women with ultrasound results showing a fetal anomaly compatible with a chromosomal abnormality,
• advanced age. (chromosomal abnormalities are more common in older women.)

How early can an amnio be done?
Amniocentesis is most commonly done between the sixteenth and eighteenth week of pregnancy. In some places, it is experimentally offered as early as twelve weeks.

Late amniocentesis is often done in the third trimester to determine fetal lung maturity if early delivery is indicated.

After the amnio is done, it takes two to four weeks to get the results.



Comments: Tests during pregnancy - Amniocentesis

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saintsigma - 646 days ago.
hi Razon 13, how is your result? I went for the Amnio test 2 days ago. I was so terrified for the result which i haveto wait for 2-3 weeks...Just hope for the best will happen...

Razon13 - 696 days ago.
Well, had my amniocentesis done yesterday and it went just fine did not hurt at all just a little prick in the tummy (doctor told me to rest for 48 hours so being spoilt by hubby a bit)..very glad it's over now just have to wait for results!! and begins the waiting game.. saw my baby boy on the U/S he is doing fine his heartbeat is good and when I got home I felt him move around a bit which is a great feeling after such a prodedure!!

v.moore21377@yahoo.com - 705 days ago.
Razon, I am 37 weeks pregnant now and also 34 years old. My test came back with the exact same odds. My genetic counselor advised I skip the amnio since the odds equal out to just a 1 percent chance. Don't sorry, those are great odds.

Razon13 - 705 days ago.
I am 19 weeks and just had my results back from my AFP test..they show some abnormality and a 1:111 chance of DS so I have been advised by my doctor to do the amniocentesis test just to make sure all is well!! They say it's quite common for someone my age, 34 to have abnormalities and it's my 1st preganancy. So I am getting it done next week!! so fingers crossed all goes well!!. (All my friends have had it done so I am not to worried)

tkdmommy - 752 days ago.
I just wanted to clarify something re: amnio - someone said it is mandatory for women over 35 in Canada. This is not true. It is mandatory for doctors to advise you of your right to prenatal screening (IPS), as 'older' mothers-to-be may be more at risk for having babies with certain conditions. If you do not decide to have the screening done, no big deal. I had it done with my latest pregnancy and had a risk of 1:8 of having a child with DS. Met with a genetic counsellor who laid out my options; again - totally optional. I opted for having an amnio and had one yesterday. Yes, it was nerve wracking, and yes, it hurt, but I'd rather be prepared either way so I can either breathe a sigh of relief if everything is ok, or can research and prepare myself if it is not. Good luck to anyone who is having one - it is over very quickly and then you can rest with your feet up and hopefully not stress out TOO much while waiting for results! Cheers!

sarcanrus - 859 days ago.
Hello all. I am curious if anyone has had an amnio for praternity reasons? I know that it can be an added risk, but so is stress. I am curious about the process and what the testing for the father is as well. If anyone has any input, please let me know. I am a 32 year old woman, and have wanted children for a long time now, I am a bit shocked at the circumstance I find myself in, but all in all, I AM HAVING A BABY and am elated! Thank you for any information you have.

agustinagf - 1037 days ago.
Hi girls! I am so happy I found this section! In Canada the test is required for women over 35 years old. I'm 35, so I will need to take it. I am terrified, afraid of needles, worried, etc... you know the feeling... so it makes me feel better that I am not alone and that the test is not as bad as it is in my head! I still have to wait - I'm only 12 weeks pregnant - but it's good to have information in advance. Thank you for being there!

2inoctober - 1108 days ago.
Just had my amnio done last week and got the results back: healthy baby girl! Huge sigh of relief. Anyway, I had an amnio with my son, but I did not remember how painful it really was. Luckily, it's only for a moment - just did a lot of deep breathing and thinking about calm wonderful things. :) Good luck to all the pregnant mommies getting this test done.

Cindie - 1134 days ago.
Hey ladies, for those of you who come across this page and have questions about actually HAVING the amnio feel free to message me. I have 2 wonderful baby boys and had an amniocentesis with each pregnancy. I have an extremely rare skin disorder that can be passed on to any baby I have and it's a %50 chance. My first son has the skin disorder but ALSO has Down Syndrome. I found out at 17w. Termination wasn't for me and I am prolife. BUT I don't judge those who choose to terminate. My 2nd son is healthy and doesn't have the skin disorder. I had the amnios because babies with this rare skin disorder (EHK or Epidermolytic Hyperkeratosis) are born with ripped up skin and a Csection is the best option so they don't get really bad infections. The amnio IS uncomfortable and a bit painful but it is over really quick, within a couple minutes. You can get your FISH results within a week to 10 days and full results can take up to 8 weeks depending on what they're looking for. The amnio IS %99.9 accurate.

blessedagainwith10 - 1207 days ago.
mom of 7 - I don't get it? What do you mean you have no choice?? Are you a surrogate carrying someone elses babies??

mom of 7 plus 2 - 1208 days ago.
I am PG with twins and have to have a Amiuno. I don't want to but I dont have a chosse. I am 40 years old. I have had 9 kids and this is my 2nd PG with twins. I had my own twins at 38 weeks. And did no extra testing. But these are not mine so I dont have a say so. Belive it or not I hate needles after all those kids I hate needles. Has anyone had one done carring twins? If so let me know how it went. Thanks

ejsontheway - 1221 days ago.
Has anyone had amnio to test for lung maturity? And if so, how long did it take for the results?

myst - 1229 days ago.
Terrifying decision to do the amnio. I had no morning sickeness with surprise pregnancy so missed the CVS and NT test windows. So Amnio was only choice. Though I am terrified of needles I toughed this out - was not super painful - just anxiety and bit of cramping as needle went through. 16 day wait for results was awful, but I had my test in middle of Xmas holidays. All was well, so now I can relax and enjoy!

scared n single - 1271 days ago.
My doc wants to do an amnio in a week to check on lung development. I am 35 weeks pregnant and TERRIFIED doesnt even come close to describing how im feeling. Please please let me know if possible what the test actually is liike. Thanks in advance!

chucklebuns - 1322 days ago.
I had an amnio on Monday, got the first results 24hrs early on the Wednesday; All clear, and now I'm waiting for the final results which takes 3 weeks, really freakin out now as I have no idea what the chances are of having an all clear for the first and a problem with the second.....

lora030185 - 1338 days ago.
will that needle not burst the sac

lora030185 - 1338 days ago.
will that needle not burst the sac

misslynnz - 1357 days ago.
My baby is healthy! He is 9 months old. Because I was 37 the Doctors suggested I do the CVS test. It came back abnormal with Tetrapolidy. They told me my baby would not live because he had 92 chromosomes. They suggested I do the amino, it came back abnormal. Well, I had faith. . . and I have a healthy baby boy. Good thing I did not listen to the 'false positive' results. If you get bad news. . . remember it could be a 'false postive' like in my pregnancy. My prayers are with you.

Chrisplus2 - 1365 days ago.
I had the amino done because my triple test came back with increased risk of Down's, 1:118, since I am 38 years old I went ahead and had it done. the procedure was essential painless and very quick, they had drawn the fluid within 2 minutes or so. All in all a quick and easy test. I paid extra for the FISH test and had the results wuthin 3 days, all normal. Puh, what a relief and blessing.

mjb - 1475 days ago.
I just got back from having an amino. Not exactly text book. The needle went in and that was fine but then they had to go around a membrane and that was really uncomfortable and it took a long time!

misimis1 - 1547 days ago.
Ok - Not to scare anyone about this test but they all aren't this easy and painless. I had this test done Wednesday at 10:30am I am 20 weeks preg., I was told that it only hurts if your uterus contracts and I would be able to drive myself home. Well during the test she was correct she stuck the needle in and it felt as if I was getting my blood drawn, then the doc says ok the sharp part is out and I thought wow that didn't hurt much at all, well as I was finishing this thought in my head the pain comes, the doc explains I'm having a contraction and it's normal and it's almost over, then it's over and I thought yeah that hurt, then she reaches to takeout the cathetor and I start screaming don't take it out, another contraction has just started. So my Amnio test was very painful, however, that's not the part I want to share with you. I get in my car to leave and I feel like I absolutely can't drive. I stay there cussing up a storm screaming and tensing every muscle in my body over and over again. Call the doc, they say it's normal and don't be alarmed I will probably cramp more than other women because my test wasn't as textbook as most. So, I wait longer and decide I might be able to drive now. In short I make it about 5 - 6 minutes away and this horrific pain comes back. I pull over into the gas station and wait for 1hr 1/2. My friend brings to my attention these aren't cramps they are full contractions, so I start breathing and trying (Trying) to relax my muscles. Every time one contraction was over my body would shake with muscle spasms and pain from pushing my back into my seat with such force. Again, I am 20 weeks and know nothing about breathing and relaxing myself and my baby for this kind of pain. The contractions lasted until 2:30pm regularly every 10-12 minutes, and finally made it home and was in bed for two days, the only relief I can get is in a warm bath 3 to 4 times a day. Again, not to worry anyone but my experience was horrific and people should be prepared for the worst case senario, thank goodness I didn’t have anything to do for a few days.

miraclemomy - 1559 days ago.
I had amniocentesis when I was 22 weeks pregnant .Doctor told me that ultrasound showed a shadow on the heart of the baby which can be one of the signs of ds. Fish test came back normal after 24hrs and confirmed by the full results after two weeks.

katie-d - 1609 days ago.
i had an amnio at 20 weeks because my screen came back 1/75 for downs (i am 38). it was SO scary having it done. but it didn't really hurt. it was a little uncomfortable, and i cried the entire time, but not because it hurt but because i felt terrible guilt over putting my baby at risk just so i could know if she was perfect or not. it was an AWFUL feeling, but i had to know. i paid extra for the FISH results and got them the next day. luckily all was well, chromosonally. it is really not a bad procedure i didn't think, the mental anguish you go through is WAY worse than the physical. orse than the physical. good luck to everyone.

sherrylong - 1619 days ago.
ok, ladies I finally found this page that explains the amnio. I have to have an amnio on Tuesday to find out if my little one's lungs are mature enough to have her on the 26th. I am chicken about needles I need to know those of you have had it does it hurt, did you look and was anyone as far along as I am??? 37 weeks. I am very nervous.

2ndtime mom - 1628 days ago.
I had my amnio last wed.Starting to get worried about the results.i wish i could stop thinking about it!!!How soon do you get the results?the doc who performed the test daid 12-14 days but my reg doc said they will call in one week?

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