Topic 12

Question 1

What is antenatal screening?

Answer 1

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

Question 2

Name 4 Techniques used in antenatal screening

Answer 2

Ultrasound imaging
Biochemical tests
Diagnostic tests
Rhesus antibody testing

Question 3

What are the 2 types of ultrasound scanning you will receive, and what are they used for?

Answer 3

Anomaly scans may detect serious physical problems. Dating scans, for pregnancy stage and due date, are used with tests for marker chemicals which vary normally during pregnancy.

Question 4

What could happen if the tests are measured at inappropriate points in a pregnancy timescale?

Answer 4

A false positive or a false negative result.

Question 5

What are biochemical tests used to detect?

Answer 5

the normal physiological changes during pregnancy.

Question 6

What other routine tests will be carried out during pregnancy?

Answer 6

Blood pressure, blood type and general
health checks (including routine blood and urine tests).

Question 7

Name 3 reasons a diagnostic test would be offered.

Answer 7

Any problems emerged from routine screening tests, there is a history of genetic disorder(s) in the family, the women is already in a high risk category e.g. over 35

Question 8

Out of amniocentesis and CVS what carries the greatest risk of miscarriage?

Answer 8

CVS

Question 9

What is CVS?

Answer 9

.chorionic villus sampling. A sample of placental cells are taken, Cells from samples can be cultured to obtain sufficient cells to produce a karyotype to diagnose a range of conditions.

Question 10

When is amniocentesis carried out?

Answer 10

16-18 weeks

Question 11

What is one benefit of CVS?

Answer 11

Can be carried out as early as 8 weeks

Question 12

Why is rhesus antibody testing needed?

Answer 12

if a Rhesus negative mother is pregnant with a rhesus positive baby, the rhesus antigens on the surface of the babies red blood cells are regarded as foreign by the mothers immune system if she comes into contact with them in a ‘sensitizing’ event e.g. birth.

Question 13

What will rhesus negative mothers be given after birth?

Answer 13

Anti-rhesus antibodies are given to rhesus negative

mothers after a sensitizing event or after birth

Question 14

What will newborn babies be routinely screened for?

Answer 14

phenylketonuria (PKU), an inborn error of metabolism.

Question 15

How is PKU controlled?

Answer 15

Individuals with high levels of phenylalanine are placed on a restricted diet.