WHAT IS ULTRASCREEN?
UltraScreen is a test
performed at 11 to 13 week 6 days which identifies fetuses (unborn babies) at
increased risk of having certain birth defects.
A blood test is combined with an ultrasound measurement to estimate your
specific risk for Down syndrome and trisomy 18. The blood drawn by fingerstick
or venipuncture is analyzed for two proteins called freeBeta-hCG
and PAPP-A which are
normally found in the blood of all pregnant women.
The ultrasound examines the baby’s neck, measuring the amount of fluid
accumulation behind the neck of the baby, called the nuchal translucency (NT). This
test is safe for you and your baby.
UltraScreen is the most accurate and
earliest prenatal screening test available.
The blood test alone (performed between 9-14 weeks) detects for 68% of Down
syndrome and 90% of trisomy 18 fetuses.
Combining
the blood test with the NT increases detection to
91% for Down syndrome, 97% for trisomy 18,
40% of heart defects, and some other birth defects.
WHAT ARE DOWN SYNDROME AND TRISOMY
18?
In each disorder the fetus
has an extra chromosome in each cell. The
extra chromosome causes birth defects and mental retardation.
The chance of having a baby with an extra chromosome increases with the
mother’s age.
WILL THE SCREENING TELL ME FOR
CERTAIN IF MY BABY HAS DOWN SYNDROME OR TRISOMY 18?
No.
This is not a diagnostic test. This screening test will ESTIMATE your risk for having
a fetus with a chromosomal abnormality.
WHO SHOULD BE OFFERED SCREENING?
Because most
babies with Down syndrome and trisomy 18 are born to women less than 35 at
delivery, UltraScreen is offered to all women who will be less than 35 and have
no family history of chromosomal abnormalities.
The
American
College
of Obstetricians
and Gynecologists (1994) and the
American
College
of Medical
Genetics (1993) recommend all women who will be 35 or older at
delivery or have a positive family history consider having amniocentesis or CVS
for prenatal chromosomal testing to diagnose 99.9% of all chromosomal
abnormalities. Screening is not a
substitute for amniocentesis because: 1) screening does not give a diagnosis,
2) screening estimates a risk for only 2 chromosomal abnormalities, 3)
screening will miss many of the hundreds of other types of chromosomal
abnormalities, 4) screening may falsely reassure some patients who still have an
increased chromosomal abnormality risk due to age.
WHAT IF MY SCREENING TEST SHOWS AN
INCREASED RISK?
It
does not
mean a chromosomal abnormality has been diagnosed; only that you may have an
increased risk of having a fetus with Down syndrome, and trisomy 18, or some
other chromosomal abnormalities. In most cases, the fetus does not have Down
syndrome or trisomy 18. Your
healthcare provider will offer you genetic counseling, and amniocentesis or
chorionic villus sampling (CVS) for chromosome testing to safely and accurately diagnose
your baby’s chromosomal make-up.
WHAT IF MY SCREENING TEST DOES NOT
SHOW AN INCREASED RISK?
This is good news,
however, first trimester screening cannot eliminate the risk for Down syndrome
or trisomy 18. They makeup only
about half
of all chromosomal abnormalities. First
trimester screening does not estimate a risk for the other half of chromosomal abnormalities and will not detect many of them.
WHAT OTHER TEST SHOULD I HAVE?
An alpha-fetoprotein (AFP)
test between 13-22 weeks is recommended to screen for 98%
of open spine and skull defects, and about 60%
of open abdomen defects. These birth
defects usually occur without a family history.
Your healthcare provider may discuss another ultrasound exam in the
second trimester. AFP testing is
available from GeneCare.
SHOULD I HAVE AN ADDITIONAL SECOND
TRIMESTER SCREENING FOR DOWN SYNDROME AND TRISOMY 18?
No.
A second chromosomal screening is not recommended.
Why? Because
the first trimester screen is more accurate and less likely to give a false risk
result. Any second screening is
unlikely to improve detection because most of the affected fetuses have been
found by first trimester screening.
If you do decide to have another
chromosomal screening, an AFP/freeBeta follow-up screening test has a higher
detection rate and a lower false positive rate (1-2%) than triple or quad
screening (7-14%).
IF I PLAN TO CONTINUE THE PREGNANCY
UNDER ANY CIRCUMSTANCE, SHOULD I HAVE SCREENING?
You will receive important
information about your baby, including identifying risks for birth defects and
mental retardation as well as some treatable problems like heart defects or
possible pregnancy complications. If
a birth defect is identified, your healthcare provider can discuss
options and provide support.
WHAT IS A GENETIC COUNSELOR?
A
genetic counselor provides information and support to families, individuals and
prospective parents. The genetic
counselor reviews your medical, family and/or pregnancy history, and your risk
factors. You can discuss genetic
testing options, any test results, and benefits of testing with a genetic
counselor.
SCHEDULE FOR PRENATAL TESTS
|
9w 0d -13w 6d |
1st trimester blood screen (freeBeta/PAPP-A) (24-84mm CRL). |
| 11w 0d -13w 6d |
Ultrasound NT measurement and blood tests (45-84mm
CRL). |
| 13w 4d -22w 3d |
AFP for spina bifida
|
| 13w 4d -22w 3d |
AFP/freeBeta screen, if 1st trimester screen not done.
|
| Amniocentesis, CVS, ultrasound, if indicated.
|
ULTRASCREEN
BENEFITS:
-
Gives you and your healthcare
provider earlier information to assist you in managing your pregnancy.
-
Detects more birth defects
than any second trimester screening.
-
Helps identify over 90% of
Down syndrome, 97% of trisomy 18, 40% of heart defects,
and some other birth defects.
-
Reduces mother’s anxiety
and unnecessary testing.
