Information brochure
Prenatal Testing of
the unborn child
| Contents
Introduction
4
General information
5
The different tests
6
Chromosomes and DNA
11
Chromosome and DNA-examination
15
Indications for the different tests
16
The procedures: Chorion villus sampling and Amniocentesis
19
Important information about Chorion villus sampling and
23
Amniocentesis
The procedure: Advanced ultrasound examination (GUO I&II) 26
Glossary
28
Important telephone numbers
29
Additional information
30
Addendum
31
Colophon
32
3
| Introduction
Most children are born healthy. However, a small proportion is born with
chromosomal and or physical congenital abnormalities. In a number of
cases it is possible to detect these abnormalities in the early stages of
pregnancy.
In this brochure you will find information about the different tests and the
way they are carried out here in our hospital. This gives you an overview of
the different types of tests, what they involve and which abnormalities can
be detected.
If however, after reading this brochure, you still have questions, you can
make an appointment to see a gynaecologist. The relevant telephone
numbers can be found at the back of this book.
4
| General information
During the pregnancy it is possible to detect a certain number of abnormalities,
for example Down syndrome. However, not all abnormalities can be detected.
There always remains a small risk that the baby is born with a detectable or
not detectable abnormality in spite of all the available tests. Most congenital
and or hereditary illnesses are discovered after the baby is born. If there
are certain known congenital or hereditary illnesses in your family it is
advisable to first visit a geneticist. The geneticist will then evaluate the
hereditary illness and its relationship to you as parents, to your unborn
child and future (pregnancies) children. A consultation by the geneticist
should preferably take place before a new pregnancy commences. There are
different ways of identifying abnormalities by the unborn child: with
screening or diagnostic tests. Screening tests involve examinations that
determine whether or not there is an increased risk or risk that your unborn
child has a certain abnormality.
For these tests there are separate brochures available. The brochures over
“Screening for Down syndrome” and “The structural ultrasound examination”
are available at the obstetric outpatients or can be downloaded via our
website www.vumc.nl/rpcs
This brochure focusses mainly on the diagnostic tests. Diagnostic tests are
used to obtain a definite answer as to whether the unborn child has a certain
abnormality or not.
In many of the cases the test will come back normal, that is to say, without
any evidence of a certain abnormality. If however an abnormality is found,
this will be explained to you as well as the consequences for you and the
unborn child. As the Dutch law stands (at the time of writing this brochure)
it is possible to terminate the pregnancy, after discussing this with your
gynaecologist, on the grounds of the test results, up until 23 full weeks of
pregnancy. There is, by Dutch law, a compulsory 5 day period, beginning
on the first day of the consultation over a termination, which you have to
comply to. This compulsory period gives you time to fully consider the
situation and your eventual decision.
A “normal” prenatal test result means that the abnormality that was being
looked for with the test is not present. It is important to realise that there is
always the possibility that the child will be born with an abnormality that
you have not tested for.
5
| The different tests
Prenatale screening
Every pregnant woman who wishes information about prenatal screening
qualifies for a first-trimester combined test and a structural anomaly scan.
The first-trimester combined test
The first-trimester combined test gives an indication as to whether you
are carrying a child with an increased risk of Down syndrome, Edwards
syndrome or Patau syndrome.
The test is comprised of two parts:
1. Blood test by the mother, between the 9th and 14th week of pregnancy
whereby two substances are examined. Namely a hormone called
human choriongonodotrofine (hCG) and a protein called pregnancy
associated plasma protein-A (PAPP-A).
2. Measurement of the skin fold, which every child has at this time, in the
region of the unborn child’s neck (nuchal translucency or NT). This
measurement is conducted by means of an ultrasound scan between
the 11th and 14th week of pregnancy.
If after the test there is an increased risk of Down syndrome, Edwards
syndrome or Patau syndrome (risk≥1:200) you can make an appointment
for a consultation with the obstetric outpatients department.
The results of the blood test and nuchal scan, combined with the age of
the mother and the exact stage of the pregnancy are combined and used
in determining the risk of the child being born with Down syndrome,
Edwards syndrome or Patau syndrome.
If the results of the first-trimester combined test show that there is an
increased of Down syndrome, Edwards syndrome and or Patau syndrome
(risk ≥1:200) you can then make an appointment with the out-patients
department of obstetrics and gynaecology to discus the test results. See
list of telephone numbers at the back of this brochure. During this
consultation you can ask questions about the test results and their
consequences. Options for further examination will also be discussed with
you.
*
he duration of the pregnancy is determined during an early ultrasound examination (around
T
11 weeks) whereby the crown rump length (CRL) of the foetus is measured.
6
Non-invasive prenatal testing (NIPT)
Pregnant women with an increased risk by the first trimester combined
test, may if they wish, take part in the TRIDENT study. This TRIDENT study
is the forerunner to the introduction of the NIPT test in the Netherlands.
The NIPT involves a blood test by the mother, as from 10 weeks of
pregnancy. This blood is tested in the laboratory for Down syndrome
(trisomy 21), Edwards syndrome (trisomy 18) and Patau syndrome
(trisomy 13). The test results can be normal or abnormal. The test accuracy
is not 100%. By an abnormal test result there is a small chance that your
baby does not have a trisomy. Further examination is therefore necessary.
By a normal test result is the chance that your baby does have a trisomy
so small, that further examination is not advised.
This scientific study ensures that fewer women in the future will be
referred for a chorionic villus sampling or amniocentesis.
For whom is the NIPT intended?
Only women who have a had a “high risk” result from the combined test
are allowed to take part in the TRIDENT study. One exception is if there is
a medical indication for trisomy. In this case the women can take part
directly in the study by contacting the outpatient department in the VUmc.
A previous combination test is not necessary.
For whom is the NIPT not intended?
Excluded are women whereby a nuchal translucency (NT) measurement is
equal to or more than 3.5mm. Also multiple (twins and triplets)
pregnancies are excluded. Pregnant women under 18 years of age are
also excluded. Pregnant women who do not conform to the strict
inclusion conditions cannot have a NIPT test here in the Netherlands. NIPT
is also not possible even if the women is prepared to pay the costs. NIPT results
The test results are available between 10-15 work days (2-3 weeks) after
the blood reaches the laboratory. You will be informed of the test results
via the telephone. Also a letter will be sent to you to confirm the results.
7
Cost
In 2014 all pregnant women who take part in the TRIDENT, irrespective of
their age, are exempt from any costs.
If you need more information please contact www.meerovernipt.nl or
contact the nurse assistant, outpatients department. Relevant telephone
numbers are to be found at the back of this brochure.
The structural anomaly scan
The structural anomaly scan, also known as ‘SEO’ is performed between
18-22 weeks of the pregnancy. The optimal time for this examination is
19 weeks of pregnancy. The primary indication for this scan is to look for
signs of an open back (spina bifida) or an open skull (anencephaly). By a
defect in the neural tube is the development of the spinal column and or
the skull abnormal. By a spina bifida there is a disruption of the fusion of
the spinal column whereby the spinal cord is exposed. Children with a
spina bifida are usually physically handicapped and sometimes mentally
handicapped. Children with an “open skull” usually die shortly after birth.
The risk of having a child with a neural tube defect is 1:1000. This means
of every 1000 children born 1 has a neural tube defect. This risk does not
increase with increasing maternal age. The risk increases if there is a
history of close family members with a neural tube defect. Taking Folic
acid 8 weeks before and 10 weeks after conception reduces the risk of
having a child with a neural tube defect. The preference for identifying a
neural tube defect is the ultrasound examination. In some certain
circumstances the levels of alpha-fetoprotein (AFP) can be measured by
doing an amniocentesis.
The structural anomaly scan is a reliable method of identifying other
congenital defects. Every pregnant woman qualifies for a structural
anomaly scan. However if you have an increased risk of having a child
with a congenital defect you qualify for an advanced ultrasound
examination (GUO) which can only be done in a hospital.
If you are considering having prenatal tests done, you will beforehand
have an informative consultation with your general practioner, your
midwife or else your gynaecologist. You can also choose to have a
consultation here in the hospital. See the telephone numbers in the back
8
of this brochure.
Specific information over the above examinations is also to be found in
the brochures “Information over the screening for Down syndrome” and
“Information about the structural ultrasound examination”, published by
the RIVM (Dutch Ministry of Health). You can visit the websites www.rivm.
nl and www.vumc.nl/rcps and download the relevant information. On the
website www.vumc.nl/rcps is a list of all the centres that have a contract
with the regional centre for prenatal screening (RCPS) with regard to giving
information over prenatal screening and performing the first-trimester
combined test and the structural anomaly scan.
Diagnostische testen
The chorionic villus sampling
This test is used to check the baby’s chromosomes. It may also be used,
in a number of specific indications, to determine changes in the baby’s
DNA. The test can be performed from the beginning of the 11th week of
pregnancy and involves taking a small sample of the chorionic villi from
the placenta. The chorionic villi are part of the developing placenta
(afterbirth). The chorionic villi have the same chromosomal structure as
the unborn child.
The amniocentesis
This test is used to check the baby’s chromosomes. It may also be used,
in a number of specific indications, to determine changes in the baby’s
DNA, neural tube defects (open back or open head) or for the detection
of certain metabolic disorders. The test can be performed from the
beginning of the 16th week of pregnancy. With this examination any
chromosomal abnormality, alterations in the DNA or metabolic disorders
can be traced by examining the fetal cells in the amniotic fluid. Neural
tube defects can sometimes be identified by an increased level of alphafetoprotein (AFP) in the amniotic fluid. However, a rise in the level of
these proteins can be caused by other conditions as well. The AFP is only
examined in specific cases.
9
The advanced ultrasound examination
This test can detect congenital abnormalities by the baby. The optimal
time for this examination is 18-21 weeks of pregnancy. The advanced
ultrasound examination is only performed in specific indications.
10
| Chromosomen en DNA
What are chromosomes; what is DNA?
The human body is made up of individual units called cells. Your body
and that of your unborn child (fetus) has many different kinds of cells,
such as skin cells, kidney cells, heart cells and blood cells. Chromosomes
are found in the nucleus of every cell. The genetic information is stored in
DNA. Segments of DNA in specific patterns are called genes. Your genes
make you who you are. Chromosomes carry all the information used to
help a cell grow, thrive and reproduce. Chromosomes also tell us what
sex we are and whether we carry a specific genetic condition.
Humans have 46 chromosomes (23 pairs of chromosomes) 22 pairs of
numbered chromosomes, called autosomes, and one pair of sex
chromosomes, X and Y. Each parent contributes one chromosome to each
pair so that offspring get half of their chromosomes from their mother
and half from their father.
Fig. 1
Photograph of Chromosomes arranged in pairs.
11
The most common chromosomal abnormalities
Down syndrome
Down syndrome (trisomy 21) is a congenital disorder caused by the
presence of an extra chromosome 21. In people with Down syndrome, each
cell has not two but three copies of chromosome 21. This extra
chromosome 21 is responsible for the distinguishing features of Down
syndrome. In most cases (95%) there are three separate copies of
chromosome 21 present. That means that in every cell there are 47 instead
of 46 chromosomes. This extra chromosome is formed when a fault occurs
during cell division by the egg cell or sperm cell. In a small number of cases
(5%) the extra chromosome is attached to another chromosome. This is
called “translocation”. If Down syndrome is as a result of translocation then
there is a higher risk that future pregnancies and family members will be
affected.
Children with Down syndrome are characterised by a number of distinctive
physical features. These features can vary in severity. For example;
flattening of the back of head, slanting of the eyes and often a skin fold by
the inner part of the eyelid. There is also mental impairment and a delay in
motor development. A large proportion of the children have also other
physical abnormalities. Almost half of the children who have Down
syndrome are born with a heart defect. In many of the cases this defect is
operable. Other common problems include; ear problems, eye problems,
thyroid problems and gastrointestinal disorders.
Edwards syndrome
Edwards syndrome (trisomy 18) is a congenital disorder caused by the
presence of an extra chromosome18. Trisomy 18 is caused by the
presence of three- as opposed to two- copies of chromosome 18 in the
unborn child’s cells. Infants born with Edwards syndrome can have a wide
variety of severe physical and mental conditions. Quite often the baby has
a small face, low set malformed ears, abnormally small jaw, cleft lip/
palate, clenched fists and club feet. The brain is often underdeveloped.
The children have frequently a low birth weight; before birth the unborn
12
child shows signs of growth restriction. More than 90% have a structural
heart defect. Spina bifida, kidney and intestinal malformations are also
common. The syndrome has a very low rate of survival, the infant often
dies during the pregnancy. The infants, who do survive, live only for a few
days. Approximately 5% of the infants survive the first year of life. Survival
to adulthood is extremely rare. All surviving children have a severe form
of mental retardation.
Patau syndrome
Patau syndrome (trisomy 13) is a congenital disorder caused by the
presence of an extra chromosome 13. The extra chromosome disrupts
(early in the pregnancy) the normal course of development of the face.
This can result in a cleft lip/palate. The eyes can be small and set close
together: sometimes the eyes are not fully developed. Often there is
developmental failure in the front part of the brain. The infant may also
have an extra little finger/toe. Frequently the feet have an abnormal form.
Not all the infants have these specific features and the severity can vary.
The syndrome has a very low rate of survival. Often the infant dies during
the pregnancy. Approximately 5% of the infants born with Patau syndrome
live longer than 6 months. Survival to adulthood is extremely rare. All
surviving children have severe physical disorders and the future for these
children is somber.
What is the likelihood of having a child with a chromosomal
disorder?
The likelihood of having a child with a chromosomal disorder increases with
the mother’s age (see table1). The most common chromosomal disorder is
Down syndrome (trisomie 21).
13
Table 1
This table shows the risk of carrying a baby with one of the most common chromosomal
abnormalities per 10.000 live births at different maternal ages:
Age of the mother in years
Trisomie 21
(Down syndrome)
Trisomie 18
(Edwards syndrome)
Trisomie 13
(Patau syndrome) 15 - 19
8
0.6
0.3
20 - 24
8
0.7
0.4
25 - 29
9
0.9
0.5
30 - 34
14 1.5
0.7
35 - 39
50 4
2
40 - 44
170 15
6
14
| Chromosome- and DNAexamination
Chromosome examination
There are three different methods to examine the chromosomes, the
“Quick test” known as QF-PCR (quantitative fluorescent polymerase chain
reaction), the culture method and the array-method.
The quick test QF-PCR is a specific examination for the chromosomes 21,
18, 13 and the sex (X en Y) chromosomes. The remaining chromosomes
are not examined. This examination is extremely accurate when
determining if the child has Down syndrome (an extra chromosome 21),
Edwards syndrome (an extra chromosome 18) or Patua syndrome (an
extra chromosome 13). Sometimes the extracted material has traces of
material from the mother. This is not always visible at the time of the
procedure. If this is the case, the test cannot be done because it is not
possible to distinguish between material from the child and that from the
mother. If this is so you will receive a telephone call from us within 2 days
after the procedure. The culture method will then be started whereby the
shape and number of all the chromosomes in the cultivated cells will be
analyzed. This is called ‘karyotyping’. This method is used only in specific
indications together with the QF-PCR test. Sometimes it is necessary, as a
result of the tests, to test your blood and that of your partner.
By the array-method all the chromosomes are examined for small
chromosomal changes (too much or too little chromosome material)
which cannot be detected by the first two methods. For more information
over the array-method we refer you to the website www.vumc.nl/rcps
DNA-examination
For certain indications a DNA examination can be carried out. If a family is
known to carry a particular disease, for example cystic fibrosis, muscular
disease, metabolic disease or blood disease, then it is possible to look in
detail at specific changes in the DNA. These changes are not visible with
the QF-PCR test or the culture method.
15
| For whom is the test?
QF-PCR
Indications for examination of the chromosomes using the QF-PCR test on
the material collected during amniocenteses or a chorionic villus sampling
are:
• Pregnant women who are 36 years or older in the 18th week of the
pregnancy;
• Pregnant women, by whom DNA-examination or metabolic examination
is being performed, whereby the possibility exists that a chromosomal
examination may also be necessary.
• Parents who have gender associated diseases within the family;
• Pregnant women who have undergone an I.C.S.I. treatment to become
pregnant;
• Pregnant women whereby an abnormality has been found by their child
during an ultrasound examination.
Culture method
Sometimes the QF-PCR test is combined with the culture method for
examination of the chromosomes using the QF-PCR test on the material
collected during amniocenteses or a chorionic villus sampling. Indications
are:
• Parents who have already had a child with an abnormal chromosomal
pattern;
• Parents who have themselves an abnormal chromosomal pattern
(chromosome variant for example translocation).
DNA-examination
For DNA examination by means of a chorionic villus sampling or
amniocenteses the indications are:
• Parents whose offspring have an increased risk of inheriting a certain
disease that can be traced by DNA-examination.
• Pregnant women whereby a specific abnormality has been found by
their child during an ultrasound examination.
16
Before DNA-examination is done it is usual for the parents to visit the
geneticist to asses the medical background of the family in relation to a
particular disease.
The Advanced Ultrasound examination (GUO)
There are two categories of indications for this examination:
Parents with an increased risk of having a child with a congenital
abnormality
• Parents who have had a previous child with congenital abnormalities that
were not detectable by a chorionic villus sampling or amniocenteses but
only by ultrasound
• Parents who have themselves a congenital abnormality
• Family members with a congenital abnormality (brother/sister/parents of the couple)
• If the pregnant women has insulin dependant diabetes
• If the pregnant women uses anti-epileptic medicine
• Pregnant women who have undergone an I.C.S.I. treatment to become
pregnant
• If the pregnant women uses medicines that are known to have a
dangerous effect on the unborn child
• If the pregnant women uses ‘hard drugs’
• Other reasons for example: Exposures to radiation or chemotherapy,
positive thyroid antibodies, monochorionic twins and inter marriage (for
example marriage between a nephew and niece).
A pregnant woman where there is a suspicion that the child has an
abnormality
• A second opinion: where there is suspicion of an abnormality as a result
of an ultrasound examination in another centre
• If the growth of the child is less than the expected size for the dates
• If the growth of the child is more than the expected size for the dates
• If there is a reduced amount of amniotic fluid
• If there is an increased amount of amniotic fluid
17
• Heart rhythm irregularities by the child
• Other reasons, for example certain infections by the mother that can
have possible effects on the unborn child
18
| How the chorionic villus sampling and the amniocenteses are performed
The chorionic villus sampling
The chorionic villus sampling can be done from the 11th week of pregnancy.
There is a small amount of tissue removed from the placenta.
Figuur 2. Sketch of Chorion villus sampling via the abdominal wall
The examination itself
The chorionic villus sampling test can be done in two ways.
• Via the vagina (trans vaginal)
• Via the abdominal wall (trans abdominal)
Via de vagina
For this examination we use a gynecological chair with leg/foot supports.
After disinfection of the genital area a sterile speculum is introduced into
the vagina. Under ultrasound control a sterile slender forceps is
introduced into the cervix (mouth of the uterus) and along the inside wall
of the uterus into the placenta. When the forceps are in place a small
amount of placental tissue is removed. The amniotic sac is not entered
and therefore the child cannot be damaged.
Usually 20-50 milligrams of tissue is removed which is approximately a
thousandth of the volume of the tissue in the whole placenta. Sometimes
the amount of tissue removed is insufficient. If that is so then a second
sample will be taken (in the same sitting). If after a third sample there is
still insufficient tissue then the examination is stopped. It is then wiser to
wait a few weeks and perform an amniocentesis.
19
Most women experience a “menstruation/period like” pain that should
disappear soon after the procedure is finished. The pain is usually not
very severe. The procedure takes approximately 10-15 minutes.
After the procedure most women experience some blood loss. This may
take the form of a blood clot. The blood almost always comes from the
cervix (mouth of the uterus), which when it is touched, bleeds quite
easily during pregnancy. You should not worry about this. The blood loss
usually stops 12-24 hours after the procedure. A pinkish discharge may
be present for up to 3-4 weeks after the procedure. This is no cause for
concern.
Via the abdomen
The abdomen is first disinfected and then covered with a sterile sheet.
The ultrasound probe is also covered with a sterile sheath. After
disinfection of the abdomen, a fine (hollow) needle is inserted, under
ultrasound control, through the abdominal wall, through the wall of the
uterus and into the placenta. By small ‘up and down’ movements of the
needle some tissue is removed from the placenta which is then sucked
up through the needle into a syringe. The amniotic sac is not entered and
therefore the child cannot be damaged. This part of the procedure
usually takes no longer than a minute. Although you will be aware of
what is happening, most women describe the procedure as being
uncomfortable rather than painful, and similar to period (menstruation)
pains. In approximately 10% of the cases insufficient tissue is collected
and the procedure has to be repeated (in the same sitting). There should
be no amniotic fluid or blood loss. However, you may experience some
discomfort of the abdomen.
Sometimes the examination is not successful. This can occur if the
appropriate position to remove some tissue form the placenta cannot be
reached or that the test cannot be properly carried out in the laboratory.
In these situations an amniocentesis will be carried out at a later date.
20
The Amniocenteses
Fig. 3
Sketch of amniocentesis via the abdominal wall
The amniocentesis can be done from the 16th week of pregnancy. The
amniocentesis takes place through the abdominal wall. The mother lies
on her back on the examination table and with ultrasound the position of
the baby and the distribution of the amniotic fluid is assessed. The
abdomen is first disinfected and then covered with a sterile sheet. The
ultrasound probe is also covered with a sterile sheath. After disinfection
of the abdomen, a fine (hollow) needle is inserted, under ultrasound
control, through the abdominal wall, through the wall of the uterus and
into the amniotic fluid. The ultrasound is used continually during the
examination to assist the doctor during the procedure.
As the needle is pushed through the abdominal wall you may experience
a quick/slight stabbing pain. When the needle has passed the abdominal
wall into the amniotic sac most women describe this part of the
procedure as uncomfortable rather than painful. Through the hollow
needle approximately 20 cc of amniotic fluid is then drawn up into a
syringe. This takes approximately 20-30 seconds. 20cc is approximately
10% of the total amount of amniotic fluid. The removal of this amount of
fluid has no effect on the baby and will be regenerated within a few days.
After the examination, you may experience a “menstruation/period like”
pain. This feeling can last between a few hours and a couple of days.
These symptoms’ should disappear within a few days. Experiencing pain
21
after the procedure does not have any correlation with a miscarriage.
Very occasionally there is insufficient amniotic fluid removed during the
examination. Depending on the situation, the examination may be
repeated straight away or postponed for a week.
Multiple pregnancies
In case of multiple pregnancies the preference for invasive diagnostic
testing is amniocentesis. Although only one of the children has an
increased risk for a chromosomal abnormality or a structural abnormality,
we advise to perform karyotyping of all children. Despite the careful
management during the procedure, it might be possible that not always
material is collected from all children, but that due to the direction and
position of the membranes material is mistakenly taken twice from one
child.
22
| Important information with
reference to the chorionic villus
sampling and the amniocenteses
Prior to the examination
In the weeks prior to the test you will have had consultations with one or
more of the following; your doctor, midwife, gynecologist or geneticist.
Here you will receive the relevant information and also have the
opportunity to ask questions. Afterwards, if you have decided to do the
test, an appointment will be made for you.
Blood type
It is important to know what blood type and rhesus antibody factor you
have, so you are asked to bring that with you on the day of the test.
If your rhesus factor is negative then you will receive, on the day of the
examination, an injection of “Anti-D” to prevent you making anti-bodies
which may react with the baby’s blood cells.
The risks
After the examination there is a small risk of a miscarriage. With chorionic
villus sampling (C.V.S.) the risk is approximately 0.5% (5 in 1000). This
means that if by 1000 pregnancies a C.V.S is done approximately 5 will
end in a miscarriage as a result of the test. However 995 pregnancies
should continue normally. The rate seems to be the same for both transcervical C.V.S. and trans-abdominal C.V.S. By the amniocenteses the risk
is approximately 0.3% (3 in 1000). This means that if by 1000 pregnancies
amniocenteses is done approximately 3 will end in as miscarriage as a
result of the test. However 997 pregnancies will continue normally.
Lifestyle after the test
After the chorionic villus sampling or amniocenteses you may go home.
You are advised to take it easy and not work for the rest of the day.
By heavy blood loss and or loss of amniotic fluid, fever or extreme pain
always contact the out-patients department of obstetrics. In the evening,
night or weekend then contact the duty gynecologist. See the telephone
numbers at the back of this brochure.
23
After the test
After the chorionic villus sampling: 7 to 10 days after the test an
ultrasound examination is planned.
After the amniocenteses: check the baby’s heart beat. This can be done
during your next visit by the midwife or the gynecologist.
The test results
The QF-PCR test (quick test): the results usually take between 2-5 working
days.
The culture method: the results usually take 2 weeks for a chorionic villus
sampling and 3 weeks for amniocenteses.
The DNA examination: the results usually take between 2-5 weeks.
The risk that the examination fails is higher by placental tissue than by
amniotic fluid.
You will receive the test results via the telephone. That is why we notify
the relevant telephone numbers where we can contact you. A written test
result will be sent to the person who controls you during the pregnancy
(general practioner, midwife or gynecologist).
If the test results show the baby has a genetic condition then the
gynecologist and or the geneticist will discuss with you what this means
and how this will affect your baby. Also they will talk about your options
and the possibility of terminating the pregnancy. There is, by Dutch law,
a compulsory 5 day period, beginning on the first day of the consultation
over a termination, which you have to comply to. This compulsory period
gives you time to fully consider the situation and your eventual decision.
Before 12 weeks of pregnancy curettage (operative emptying of the uterus)
can be performed. This takes place in the short stay unit and you will
usually be able to return home the same or the next day. However, in
many cases the test results will be available later than 12 weeks of
pregnancy and therefore too late for curettage. In this case termination
of the pregnancy will take another form. This involves inducing a
premature labor with the use of medication. Pregnancy induction can, in
some situations, be used before 12 weeks of pregnancy. The birth will
then follow via the normal way (vaginal delivery).
24
Storage of the genetic material
Genetic material will be stored so that at a later date additional tests can
be made. However, there is no guarantee that the amount of material
stored, is sufficient for further testing. Sometimes new material has to be
obtained.
The costs
If the chorion villus sampling, amniocentesis, chromosome examination
or DNA-examination is as a result of a medical indication then your
insurance will cover the costs (see Indications for prenatal examination/
prenatal diagnostic tests). Policies and policy conditions can vary per
insurance company. It is therefore advisable to refer to them before you
have the examination.
Appointments
If you have an indication for this test and decide to have the test then in
most cases your specialist will make the relevant appointments for you.
The appointments for the pre-test consultation and the test itself will be
made via the outpatients department for obstetrics and gynecology.
If you independently think that you have an indication or wish to have
this test you can contact our department via the telephone numbers at
the back of this brochure.
25
| The advanced ultrasound
examination (GUO)
An ultrasound examination makes it possible to see the unborn baby within
the mother’s uterus. Some external abnormalities, for example a neural
tube defect and severe deformities of the arms or legs can be clearly
identified using ultrasound. Certain abnormalities of the baby’s organs, for
example the heart, kidney and brain, can also be visualized using
ultrasound. This examination can find many congenital abnormalities by the
baby but not all abnormalities can be visualized with ultrasound.
The optimal time for this examination is 18-21 weeks of pregnancy. This
examination is done by a specially trained doctor, sonographer or
gynecologist. The GUO examination is a more detailed examination than
the structural anomaly scan (18-21weeks) which every pregnant woman is
entitled to. The indications for a GUO can be found in a previous section of
this brochure.
Fig. 4
Ultrasound photograph of the foetal heart
The report
During or immediately after the examination the results of the examination
will be explained to you and your partner. If an abnormality is found then
the necessary appointments (chorionic villus sampling, amniocentesis,
MRI or ultrasound) will be made and a written report will be sent to your
own specialist (midwife, general practioner or gynecologist).
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The costs
It is always advisable to contact your insurance company with reference to
reimbursement of the costs of these extra examinations as they can vary
from company to company.
The indications for a GUO in the VUmc can be found in a previous section
of this brochure.
Appointments for a GUO
In most cases the relevant appointments will be made by your specialist
or by your midwife. The appointment will then be made at the out-patients
department for obstetrics and gynecology.
If you independently think that you have an indication for this examination
it is advisable to first contact our out-patients department via the telephone
numbers at the back of this brochure.
Registration of the results of the pregnancy
To check and maintain the quality of our tests we ask all participants of
prenatal testing to kindly fill in a short questionnaire about the results
and outcome of your pregnancy.
All your information will be treated confidentially
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| Word list
Alpha-foetal protein
Anencephaly
Chorion tissue
Chromosome
DNA
Ultrasound
Folic Acid
Geneticist
Placenta
Rhesus factor
Spina Bifida
Duration of pregnancy
CRL
A protein produced by the baby
Abnormality of the skull (open head)
Tissue from the placenta
The carrier of the features that make us who
we are. In other words, your genes.
Chromosomes make us female or male, give us
our bodily characteristics, our characteristic
features and sometimes also a predisposition
for certain diseases.
DioxyriboNucleicAcid. Is the foundation of the
chromosomes.
An examination using high frequency sound
waves to visualise the child in the uterus.
A vitamin from the “B-complex” group
A doctor specialised in hereditary diseases
Afterbirth
Blood group factor
Open back
Is determined during an early ultrasound
examination (ideally around the 11 week)
whereby the crown rump length of the foetus
is measured.
Crown Rump length. The duration of the
pregnancy is determined during an early
ultrasound examination (around 11 weeks)
whereby the crown rump length (CRL) of the
foetus is measured.
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| Important telephone numbers
Appointments Out-patients department obstetrics and gynaecology
(020) 444 1190
Consultation by nursing assistant
(020) 444 0090
Information and test results. Bureau Prenatal screening and
diagnostic
(020) 444 3234 or (20) 444 3235 (daily 09.00-16.00)
Duty doctor or midwife (evening, night and weekends)
(020) 444 4444 and ask for tracer 6105
Delivery rooms VUmc
(020) 444 4822
Out patient department of Genetics
(020) 444 0150
Chromosome Laboratory
(020) 444 0746
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| Addresses and websites
The Regional centre for prenatal screening and diagnostic
www.vumc.nl/rcps
Gynaecology and obstetrics, out-patients and ward VUmc
www.vumc.nl/afdelingen/verloskundegynaecologie/Verlos/
Eurogentest
www.eurogentest.org
Erfocentrum
www.erfelijkheid.nl
Antenatal results and choices
www.arc-uk.org
The Genetic Interest Trust
www.gig.org.uk
The Rare Chromosome Disorder Group
www.rarechromo.org
RIVM. RIVM is the Dutch National Institute for Public Health and the
Environment.
www.rivm.nl/zwangerschapsscreening en www.rivm.nl/20wekenecho
Recommended Down syndrome sites on the internet
www.ds-health.com/ds_sites.htm
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| Addendum
There is always the possibility that not all the material, which has been
removed during the test, will be used. Usually this residual material is
destroyed. However, sometimes this residual material is used by the
laboratory themselves. For example for quality checks, calibrating
equipment or for the further development of new tests. The residual
material is always used anonymously. If you object to us using the material
in this way please make a point of letting your specialist know. Not
indicating or making us aware of your objection implicates that you accept
the use of the material for other purposes.
This procedure is conform the ‘Code goed gedrag’ (Code of good
behaviour) from the Dutch Federation of University Medical Centres.
Dr. C.J. Bax, gynecologist and perinatoloog
Mw. drs S.L. Bhola, geneticist
Prof. dr. H. Meijers, cytogeneticist
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Publisher
VUmc©
VUmc®
september 2014
De Boelelaan 1117
www.VUmc.nl
Postbus 7057
1007 MB Amsterdam
306104/E
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