LineVoltageHalogen wrote:
Greetings All, my wife and I are in our 18th week and we just got back
the results of our Maternal Serum Test. The doc says we have a
slightly higher risk than normal for downs, 1/129 to be exact. First
off we conceived via IVF (third attempt was the charm) and we had PDG
on the embryos (8 went out for testing 6 came back bad, two good and
they were transferred). The two embryos that came back were supposedly
genetically perfect, no indicator of trisomy 21 or any other
abnormality for that matter. So now we are terrified not knowing what
it going on with our little bundle of joy. What are the odds that PGD
would miss trisomy 21 and then having the embryo implant? We are in
the process of scheduling a level II ultrasound and I guess from there
we have the option of amnio if that test comes back demonstrating one
or more markers. I have been doing a bunch of reading and it seems
that the tri-test in far from perfect and that there are many reasons
why any of the three tests would come back out of the expected range.
It should be noted that they were only supposed to test the AFP
(protein) and they goofed up and tested the other two items (hcg,
estrosis?) as well. My wife was also doing a glucose test that day as
well. I understand that we won't know until we have further testing
but I guess that I am just looking for some uplifting stories that will
at least make me feel that the maternal serum test is simply wrong and
the PGD testing was right.

The PGD testing is more specific than the triple
screen. It's not so much that the triple screen isn't perfect
as it is that the triple screen is designed to be just that--
a *screening* test. It simply identifies a pool of candidates
for further testing. A substantial majority of those who
have a postive screen have perfectly normal babies. The
goal of the test isn't to identify babies with trisomy 21.
The goal is to eliminate those who are very unlikely to
have trisomy 21 (who therefore won't benefit as much from
invasive testing that poses a risk to the pregnancy), but
the price of that is that many women with perfectly healthy
babies end up in the higher risk pool for further screening.
Even without the PGD testing, the odds would be very
much in your favor. Even the results returned say that you
have a better than 99 percent chance of having a baby without
Downs Syndrome. Add in the PGD, and odds are extremely good
that the baby does not have Downs Syndrome.

Best wishes,
Ericka