Unit 2 - Antenatal and Postnatal Screening Key Area 4

Question 1

A variety of techniques can be used to
monitor the health of the mother, developing
fetus and baby. Name them.

Answer 1

• Antenatal screening
• Ultrasound imaging
  
  • Anomaly scans
  • Dating Scans
• Blood and urine tests
• Diagnostic testing
• Cells from samples can be cultured to obtain
  sufficient cells to produce a karyotype to
  diagnose a range of conditions

Question 2

What is Antenatal Screening?

Answer 2

Antenatal screening identifies the risk of a
disorder so that further tests and a prenatal
diagnosis can be offered

Question 3

What are the two types of Ultrasound imaging and describe them

Answer 3

Ultrasound imaging
Pregnant women are given two ultrasound
scans.
Dating scans which determine pregnancy
stage and due date are used with tests for
marker chemicals which vary normally during
pregnancy.
Anomaly scans may detect serious physical
abnormalities in the fetus.
A dating scan takes place between 8 and 14
weeks and an anomaly scan between 18 and
20 weeks

Question 4

Why are blood and urine tests carried out?

Answer 4

Blood and urine tests
Routine blood and urine tests are carried out
throughout pregnancy to monitor the
concentrations of marker chemicals

Question 5

What can lead to a false positive result?

Answer 5

Measuring a chemical at the wrong time
could lead to a false positive result. An
atypical chemical concentration can lead to diagnostic testing to determine if the fetus
has a medical condition.

Question 6

What are the two types of diagnostic testing?

Answer 6

Diagnostic testing
Amniocentesis and chorionic villus sampling
(CVS)

Question 7

Advantage and Disadvantages of CVS and Amniocentesis.

Answer 7

CVS can be carried out earlier in pregnancy
than amniocentesis, although it has a higher
risk of miscarriage.

Question 8

What is a karyotype?

Answer 8

A karyotype shows an individual’s
chromosomes arranged as homologous
pairs

Question 9

What happens before and after the tests?

Answer 9

In deciding to proceed with these tests, the
element of risk will be assessed, as will the
decisions the individuals concerned are likely
to make if a test is positive.

Question 10

What is PKU and what causes it?

Answer 10

In PKU a substitution mutation means that
the enzyme which converts phenylalanine to
tyrosine is non-functional.

Question 11

What happens if you have PKU?

Answer 11

Individuals with high levels of phenylalanine

are placed on a restricted diet.

Question 12

What is a postnatal screening?

Answer 12

Postnatal screening is a diagnostic test for phenylketonuria (PKU).