mall
October 26, 2009, 12:12pm
26
Hi mall,
The nucal sac is on the back of the baby’s neck. It goes away as the baby develops but its measured early in pregnancy because downs syndrome babies usually have a very large nucal sac. So they measure it and give you the odds of whether the baby has downs or not. So this, too is unreliable but much more reliable than the blood test for markers. The estimation of the babys age and therefore the due date is very accurate though.
A CVS test (Chorionic Villi Sampling) is done at week 10 or 11. They insert a catheter through the cervix and remove a tiny sample of the placenta to do genetic testing. Amnio is done around week 18, they insert a needle through the abdomen and remove a sample of amniotic fluid to do the genetic testing. These tests are accurate to test for a number of genetic problems. CVS is slightly more risky than amnio but depends on how experienced and skilled the doctor is.
I dont know the details of the diabetes tests. I had them done in the second trimester and in two of my pregnancies, I had a second test in the third trimester because my results were borderline. I dont think it matters much if you have it done a week or two early but not sure…there isnt risk associated with the test so you could always have it repeated if you have a concern.
thx MO3 for such a detailed reply (hugs). as far as my knowledge goes not alot of preg women are asked to go for CVS or aminotic testing unless asked by doc i guess. maybe becus its a bit risky like u said. needless to say how its done sounds equally scarrrrrrry. what do u think abt it Sahar?? ill ask doc to check for downs syndrome (by checkin the nucal sac rite - ultrascan?)