developmental psychology

1. CHORIONIC VILLUS
SAMPLING (CVS)
{WHAT IT IS; HOW THE PROCEDURE IS PERFORMED; WHY IT IS
PERFORMED; THE PROS AND CONS ASSOCIATED WITH IT; THE ETHICAL
ISSUES SURROUNDING ITS APPLICATION}

2. Introduction
• Karyotyping is the process of pairing and ordering all the
chromosomes of an organism, providing a genome-wide snapshot of
an individual’s chromosomes.
• Karyotypes are a source of diagnostic information for specific birth
defects and genetic disorders that reveal characteristic structural
features for each chromosome.
• With Chorionic Villus Sampling, a small sample of chorion cells are
collected for karyotyping.

3. CHORIONIC VILLUS
SAMPLING (CVS)
• *The chorion is a membrane that
develops around an embryo, and part of
it is used to form the placenta.*
• CVS is a prenatal test that involves taking
a sample of cells- chorionic villi- which are
removed from the placenta for testing.
• The chorionic villi are wispy projections of
placental tissue that share the baby’s
genetic makeup (the placenta provides
oxygen and nutrients to the growing baby
and removes waste products from the
baby’s blood).

4. HOW CVS IS PERFORMED
• During the test, a small sample of cells is removed from the placenta using 1 of 2 methods, under the
continuous guidance of an ultrasound scan to make sure nothing enters the amniotic sac or touches the
baby:
1. Transabdominal CVS- your tummy is cleaned with antiseptic before a local anaesthetic injection is used to
numb the area; a hypodermic needle is inserted through the skin into the womb and guided to the
placenta using an image on the ultrasound scan; a syringe is attached to the needle which takes a sample
of cells from the chorionic villi; after the sample is removed, so is the needle.
2. Transcervical CVS- a sample from the chorionic villi is collected through the neck of the womb(cervix); a
thin tube attached to a syringe is, or small forceps, are inserted through the vagina and cervix and guided
towards the placenta using the ultrasound scan
• The test usually takes about 10 minutes, although the whole consultation may take about 30 minutes.
• The test can be done as early as 10 weeks of pregnancy, but generally it is done between the 11th and 14th
weeks of pregnancy.
* In the case of multiple pregnancies (twins or more), you may need a separate procedure for each foetus.*

5. CVS PROCEDURES

6. WHEN CVS IS OFFERED
• CVS is not routinely offered in pregnancy. It’s only offered if there’s a
high chance a baby could have a genetic or chromosomal condition.
• This could be because :
1. An antenatal screening test has suggested a baby may be born with
a condition such as Down syndrome, Edward’s syndrome or Patau’s
syndrome.
2. A mother has had a previous pregnancy affected by a genetic
condition.
3. There is family history of a genetic condition such as sickle cell
disease, cystic fibrosis or muscular dystrophy.

7. BENEFITS OF CVS
• Accurate results- you can rely on CVS results to make important healthcare
decisions. There is approximately 98% accuracy in diagnosing Down
syndrome and some other conditions associated with gross chromosomal
abnormalities.
• Critical information- you may face a higher risk of having a baby with a
genetic disorder or other problem and it is best to know what is going on
with the foetus as soon as possible. Having this information can help
parents make the best healthcare decisions such as to prepare for any
special treatment a baby may need immediately after birth, or the decision
to terminate the pregnancy.
• Quick results- the results are usually available within a few days after the
test; at most 2 weeks later.

8. RISKS/CONS OF CVS
• The procedure is invasive and uncomfortable as a tube or needle has to be
inserted into the cervix to reach the placenta.
• After the procedure, it is normal to have cramps similar to period pain and
vaginal bleeding can occur.
• It is a high risk procedure as it is performed at an early stage of pregnancy
and may cause foetal problems later on in the pregnancy.
• The reliability of the results is less than with amniocentesis, especially in
predicting neural tube defects.
• The risk of miscarriage is at least 1-3%, or 2-6 times higher with CVS than
with amniocentesis.
• CVS can cause a decrease in amniotic fluid production in some cases.

9. ETHICAL ISSUES
• Informed consent- there should be provision of accurate, understandable information to ensure a
fully informed choice.
• There should be no coercion- a mother and father should understand that ultimately it is their
choice to agree to the procedure despite what the health care provider may suggest.
• Privacy- results of the test should not be revealed to any unapproved individual’s; and the parents
can decide to receive the results in person, or over the phone or through the mail.
• Psychosocial impact- parents should undergo genetic counselling before and after the test to
ensure that their emotional wellbeing is protected
• Test utility- it has to be considered whether the test is absolutely necessary due to the side effects
that may come about as a result of the procedure.
• Test validity and reliability- the healthcare provider has to be sure that the test is actually
measuring what is intended to be measured and that the results will be accurate and usable
• Beneficence and non-maleficence- there is need to ensure that the test benefits both the parents
and the developing foetus; as well as to ensure that no harm comes to the mother and the foetus
during or after the test

10. QUESTIONS:
• Chorionic villus sampling can be done around the------------ week of pregnancy.
o Fifth
o Tenth
o Fifteenth
o Twentieth
• Where does chorionic villi emerge from?
o Placenta
o Chorion
o Uterus
o Foetus
• The chorion develops into a large portion of the------------
o Foetus
o Uterus
o Placenta
o Umbilical cord

11. QUESTIONS contd….
• Choose the statement which is true
o CVS is more reliable than any other test for detecting chromosomal abnormalities because it is
performed earlier in the pregnancy
o There are minimal risks associated with performing CVS
o CVS is used to test for chromosomal defects and neural tube defects because of its reliability and
accuracy in predicting these abnormalities.
o CVS is performed earlier during pregnancy which increases the chances of miscarriage in women;
and can lead to less reliable results as the foetus will not be at a fully developed stage which is
always best for determining any abnormalities.
• What are the two methods of testing used during CVS?
o Transcervical and biopsy
o Transabdominal and transuterine
o Transcervical and transabdominal
o Vaginal and cervical

12. PARTICIPANTS:
• TESLYNE J ASHLEY R216464D(HDP)
• KEISHA D KUDITA
R216423Q(HDP)
• NOMTHANDAZO P MOYO R216441P(HDP)
• IVY ANTONIO R216459D(HDP)
• TENDAI T WATSIKA
R216424L(HDP)
• ESTHER C MADONDO
R216435U(HDP)
• NOMALANGA M SIBANDA
R216449U(HDP)
• BENHILDA T VIRIRI
R216444G(HDP)
• NICOLE M MUSHORE
R215417Q(HCDP)
• MILLICENT MUTSATSA
R215423R(HCDP)
• YOLANDA VERE
R215458R(HCDP)
• PROVIDENCE CHITURI
R215438B(HCDP)
• RUTENDO M MACHIVENYIKA
R215431C(HCDP)
• MEMORY MACHEKA
R215455D(HCDP)
• EVERJOY MTOMBENI
R215419F(HCDP)
• TARISO MAVESERE
R215461L(HCDP)
• NYASHA MUTONGOREYA R216438P(HDP)

13. REFERENCES:
• https://www2.palomar.edu/anthro/abnormal/abnormal_2.htm
• https://Www.marchofdimes.org/Chorionicvillisampling
• https://my.clevelandclinic.org/health/diagnostics/4028-chorionic-
villus-sampling-for-prenatal-diagnosis