Can amnio test identify spina bifida?

[Jbck]

Couple of sites I've found say it does but m/w says no. I was opting for it over CVS (I'm 42) as I'd rather have all possible outcomes in the one test. Is it possibly just spotted during the procedure as the baby is more developed? I'm all confused now.TIA

This from babycentre:

"What kinds of abnormalities can it detect?

The test can identify several hundred genetic disorders, including some of the most common. It can detect:

? Chromosomal disorders such as Down's syndrome,
trisomy 18, and Edward's syndrome

? Neural tube defects such as spina bifida and anencephaly.

Amniocentesis can also reveal whether the mother or baby is RH-negative, and whether the baby's lungs are mature enough for him to be born if a caesarean section is being considered. Amniocentesis doesn't detect every kind of abnormality, however -- for example, it can't tell you whether your baby has a cleft lip or palate."

I think your m/w is wrong - even before I searched I was sure it would.

As far as I know, an amnio will indicate a high risk of spina bifida or anencephaly if the AFP is measured and found to be at a very high level. This was routinely measured 10 or so years ago, but I'm not so sure that it is measured anymore (well, on the nhs anyway) - think they rely on ultrasound detection now.

Thanks Miaou I did another search myself & found the same thing, it was babycentre I first saw it on but wanted to check some other info. Apparently the amnio cannot give any indication of severity of SB but will detect it. I was sure I was right at the time but she was so quick to say no when I mentioned it I thought I'd got it wrong & didn't argue. Not like me

An amnio is just the taking of the fluid - like taking blood for a blood test. The doctor actually has to request what the amniotic fluid is tested for - eg. karyotyping to rule out common chromosome aneuploidies. If your midwive says that it won't detect spina bifida it may be because at that hospital the doctors do not ask for it to be tested. If you don't trust that midwife, ask another or a doctor, but don't assume that spina bifida will be ruled out just because babycentre says it can be detected.

eg. cystic fibrosis can be detected from a CVS or amnio - but for most people it isn't looked for..only if they have a family history of CF.

link{http://www.gla.ac.uk/medicalgenetics/nhs/biogenpopscreen.htm\here is some info}

What your midwife is probably meaning is that amnio is not usually performed to diagnose spinabifida because it is an invasive test that can cause miscarriage. SB is usually suspected with raised AFP blood test and confirmed by ultrasound scan.

If amniocenteseis is being performed to exclude as many abnormalities as possible, then SB may be one of them.

I think though that as you say, it is most often diagnosed visually on scan.

here

Thanks ladies, I'm certain that she meant it could not detect it from the rest of the convo.
I would ask much more at the hospital anyway & what abnormalities they'd be testing for either as routine or because of family history. I'm only 9 weeks so when I'm at my booking appt I'll check more. With DD I was quite a bit younger & had a detailed scan with no markers for any abnormalities, but this time I'm a bit more concerned

It used to be used to detect spina bifida and still is in some countries, but they now use a detailled anomaly scan because, in the case of a raised AFP blood test, there's a much higher risk of m/c with an amnio - I seem to remember them saying 10% rather than the usual 1%.

Plus all it would tell you is that there's a high AFP level in the amniotic fluid as well as in your bloodstream - not what's caused it, so it could be spina bifida (the more serios open types - the less serious types don't show up at all), or anencephaly, or a couple of conditions where the abdominal wall hasn't closed properly. They could check the AFP levels in the amnio sample if they were doing it anyway, but they'd be unlikely to advise an amnio to look for neural tube defects.

I had a raised AFP blood (triple) test and they then did lots of anomaly scans - I never had an amnio - they couldn't find anything wrong. With an anomaly scan they can tell you what the problem is, and there's obviously a big difference between a small abdominal wall defect that just needs fixing after birth (or as in our case an eye problem) and some of the other much more serious things that cause high AFP. With an amnio, all they can tell you is that it's high.

A raised AFP blood test result could be the result of any one of three things: the fetus is producing very large amount of AFP (dates wrong, twins, some anomalies etc), too much AFP is leaking out of the fetus into the amniotic fluid (anomalies including NTDs), or too much is going through the placenta into the mother's blood (placental problems). The latter problem wouldn't be picked up by an amnio so the blood test result is more useful as they can check all the possibilities - especially the risk of placental failure as the pregnancy progresses.

DS was born with an eye condition (cataracts) that probably caused the raised AFP. I'm very glad I didn't live in a country where I would have had an amnio for raised AFP as it could have led to me miscarrying DS.

I should also say that what AFP is, what it does and how it does it are very poorly understood (depite decades of research), so it would very difficult for a doctor to interpret anything useful from an amniotic level of AFP that seemed to 'disagree' with a blood test level - they would probably err on the side of caution and just check and plan for everything as they already do. That's probably why they wouldn't even offer to test for it even if you're having an amnio for other reasons. It's worth an ask though if you're having it anyway and you would really like to know.

I found that really useful, Crimplene - thanks! I was called back in because of raised AFP levels (mine was 2.55, apparently 2.5 is the highest normal level, not that that means much to me). I'm due back in to speak to a consultant the week after next, as the midwife has referred me on to consultant-led care. Am glad to hear all's well with your daughter now.

Hi Annie

I think AFP levels are usually given as multiples of the mean, that is, how many times the average level you have. Have you had a detailled anomaly scan yet? I was referred back for consultant-led care as well and I found it a bit of a rollercoaster ride, as once you have a raised AFP they never turn round and say 'OK, there's nothing wrong'; there's always something else too look for. Frankly, it is fairly likely that there is some kind of a problem, but how serious it might be, or whether there really is a problems at all is anyone's guess and they now will want to cover all possiblities with you.

I ended up taking control of the whole situation by having a home birth against their advice, as it was all getting too medical, and it worked for me and DS, but perhaps not for everyone in this situation. DS is fine, but will always have slightly dodgy eyesight(how bad, in the long run, we don't know yet).

I've been finding out a lot about AFP and have one or two contacts who are doing research in this area so if there's anything else I could help with, ask away.