even though risk increases with maternal age, if we consider 100 down syndrome babies, most of them will have younger mothers. thats because older mothers dont give birth as often as younger ones!
the middle two can be offered to those in 2nd trimester
integrated test isnt offered but naturally if tests done in both trimesters
first trimester screening is better than the qaudruple screening
The advantage of the above is that its one test before doing an invasive test. So just to make sure before doing an invasive test.
check the distance of the gap there and also whether the nasal bone is present.
It forms a part of the routine anomaly scan.
but if suspect, must go for an invasive text...in which case nipt can help form an addiitonal step in downs syndrome and turners because invasive caries risk
For cardiac anomalies must do a fetal targetted sonagraphy ,,, including a fetal echo to check for abnormalaties. !!! Can do targetted and detailed sonography for the fetus!!!!!!!!!
Even mri!?
cystic hygroma is the swelling behind the neck....not the same as NT...its a big swelling if present.
in low resource setting in first trimester only dating scan is done and detailed anomaly scan isnt done. But in second trimester anomaly scan is done.
And usually will pick gross anomalies easily....and for that amniocentesis is done directly
But then there are other soft markers that wont indicate fully but reasons for suspicion.
If present then calls for invasive amniocetesis scan but now NIPT forms one additional non invasive ste to be done before taking this step for soft markers.
If SUA and GCA no need non invasive testing...can directy go for amnicentesis and karyotuping.
Before 18 weeks the cord is very thin...so hazardous to sample the vein from it.
There is hazard so thats why in certain circumstances the non invasice test can be done before this is tried...but in other circumstanecs no use because quiet certain like in gca
chorionic villus sampling and stuff is done under ultrasound guidance to avoid pricking the fetus
CVS can be done by both the abdomen and the vaginal/cervix route ...no one is better than the other. depends on the expertise.
Since trophoblast is rapidly deviding can get results of karyotype in 48 to 72 hours. Another advantage.
Cant do CVS before 10 weeks becaue of limp reduction defects!
in amnocentesis have to centrifuge the amniotic fluid and then make it cultured because these cells are differienciated and hence take more time ot be grown and hence needs to be cultured so takes 7 to 10 days.
Why UA cannot be sampled? Because can undergospasm and die
Why sampled near the placental insertion = because in other areas its more wobbly wobbly and hence hard to take unlike near the placenta where it is fixed.
Because of these reasons cordocentesis has an inherently high risk of fetal loss.
cordocentesis is also done in rh negative mothers under certain circumstances
what type of invasive test that is done depends on the age of the fetus in weeks....so depends on when the anomaly is detected and that will guide what invasive test is needed.
Diagnosis vs screening (test of diagnosis and test of screening : Triple test is a screening test while amniocentesis and karyotyping is a diagnosis test) so choose accordingly
above depends on the age of the fetus
niptt cannot do kayrotyping..it uses a different modality of testing!
diagnosing neural tube defect ⇒ 1. Ultrasound scan 2. MS-AFP 3. AF ach esterase (but this is invasive test but best marker for open NTD)
for prior affected child - no need to go for screening first since screening itself can be unreliable - false negative and positive so instead directly go for invasive confirmatory testing.
if either of the parent is carrying a translocation then no chance of a normal off spring ⇒ either will get downs or if the other non chomosmy gets inherited then monosomy 21 which will abort.
MUST BEGIN WITH SOonography because most of the conditions that incease MS AFP can be detected by simple ultrasound.
which can also diagnose multiple pregnancy, iud and confirm g age...can screen out all of these....so this first.
but the tbalet available in the market is 5mg. so all women take anyway but what stated here is the recommended dosages.
anecephaly is an anomaly that can even be detected in the dating scan as well!!
no fetal ptuitary and thats why these signs
prenatal screening
