Engelska
Information about diagnostic tests
Most children are born healthy
Most children are born healthy, but one to two per
cent of all newborn children have some kind of
serious inherent abnormality, for example mal­for­ma­
tion or chromosomal abnormalities. Diagnostic
testing is the common name for examinations (includ­
ing ultrasound) which can be carried out in order to
find out if the fetus has any sort of malfor­ma­tion or
chromosomal abnormality. Modern screening dis­cov­
ers around half of all malformations. It is important to
know that screening cannot give definite answers to
everything and that there is no guarantee the child
will be healthy.
All screenings are voluntary.
Ultrasound screening is carried out during
pregnancy weeks 16–20
The ultrasound screening is offered to all pregnant
women. It is carried out between weeks 16-20, it is not
painful and does not carry any known risks.
The aim is
•
to find out the expected delivery date
•
to see if there is more than one fetus
•
discover if there is any serious malformation of
the fetus.
The ultrasound examination shows a full image of the
child. The width of the head and the width of the
femur are measured to get the expected delivery date.
The examination can also highlight the discovery of
some more serious malformations, for example,
mye­locele and abdominal wall rupture as well as a
number of abnormalities in the skeleton or internal
organs. If a serious abnormality is discovered the
woman is offered an amniocentesis or a placenta test.
(See below.)
35 years or older at the time of delivery
Increased age in pregnant women raises the probability
of certain chromosomal abnormalities. The most
com­mon chromosomal abnormality is Down's syn­
drome. The probability of a 35 year-old woman expect­
ing a child with Down's syndrome is approx. 0.4%. If
the woman is over 40 the probability has increased to
1.4%.
Results of the chromosomes of the child can only be
determined by an amniocentesis or a placenta test. As
both the amniocentesis or placenta test carry a risk of
miscarriage screening is first offered to find out if there
is a high risk that the fetus has Down's syndrome. The
screening is known as CUB.
CUB (Combined Ultrasound and Biochemical)
Screening is offered to women 35 years old or over at
the time of delivery and is carried out between 11-14
weeks of pregnancy. The aim is to calculate the possi­
bility of the fetus having Down's syndrome (trisomy 21)
or two other more serious chromosomal abnormalities
(trisomy 13 and 18).
The CUB screening consists of an ultrasound screening
combined with a biochemical test. The results of the
biochemical test and ultrasound determine the possi­
bility of the fetus having Down's syndrome (trisomy 21)
or two other more uncommon chromosomal abnor­
malities (trisomy 13 and 18).
Engelska
What is the procedure?
The biochemical test can be taken from week 9 but no
later than 5 days before the ultrasound screening. The
CUB screening can be carried out between 11-14 weeks
of pregnancy. The ultrasound screening takes the meas­
ure­ment of the fluid which gathers at the back of the
fetus' neck (Nuchal translucency). By combining the age
of the mother, the measurement of the fluid at the back
of the fetus' neck and the results of the biochemical test
the probability of the fetus having Down's syn­drome
can be determined.
How do I get the results?
In connection with the ultrasound screening the woman
is informed of the fetus having either a high probability
or a low probability of chromosomal abnormalities.
Most are given a result of low probability.
• If the probability is assessed as low no further
screenings are offered.
• If the probability is assessed as high the woman is
offered an amniocentesis or a placenta test.
If a woman has already reached a decision to have an
amniocentesis there is no point in taking a CUB
screening.
Amniocentesis
This test can not be carried out before 14-15 weeks of
pregnancy. First an ultrasound screening is given to see
the fetus and determine how long into the pregnancy
the woman is. Then a needle is inserted into the uterus
and a small quantity of fluid is taken. The sample is then
sent for a chromosomal analysis. It is important to know
that the the amniocentesis procedure might cause a
miscarriage, figures show one miscarriage per 100-200
samples.
Placenta test
The test cannot be taken before 10-11 weeks of preg­
nancy. This test also begins with an ultrasound screen­
ing. When the fetus has been seen and it has been
assessed how far the pregnancy has come a needle is
inserted into the placenta and a small sample of pla­
centa is taken. The sample is then sent for a chromo­so­
mal analysis. The placenta test might also cause a
mis­carriage, figures show one miscarriage per 100-200
samples.
www.vardguiden.se with individual e-services.
General information and health care advice
tel 08-320 100, in Arabic 08-528 528 38,
in Bosnian/Serbian/Croatian 08-528 528 96.
Results and answers
Women who have undergone an amniocentesis or
placenta test due to their age or concern over Down's
syndrome are first offered what is known as a fast
analysis of the test. This means that after only a week
you can get a definite decision regarding Down's
syndrome and the decision regarding the other most
common chromosomal abnormalities can be given
within seven days. You may also find out the gender of
the child.
If there are hereditary chromosomal abnormalities or if
the amniocentesis has been carried out because of an
abnormality being discovered during the ultrasound
screening full chromosome mapping is recommended.
This means it takes three weeks to get the test results.
Take time to contemplate before making your
decision about a diagnostic test
Visit the midwife and doctor at MVC to ask questions
and to gain more information about the screenings and
the abnormalities that may be discovered. If you wish to
abstain from the diagnostic test but would prefer to
know the expected delivery date and if there is more
than one fetus you can take this up with the midwife or
doctor at MVC.
Support and help
If it appears that the fetus has some sort of illness or
malformation you will receive all necessary support and
help.
Do you wish to know more?
Read more about pregnancy, different tests and screen­
ing at www.vardguiden.se/gravid
Updated 12-06-2009
The MÖSAM group (including the maternity care
chief physician and coordinating midwives) in
collaboration with the diagnostic test unit at the
gynecological centre in Stockholm county and
the Department of Clinical Genetics, Karolinska
University Hospital.