Physiology and Health: Antenatal and Postnatal Screening

Question 1

A variety of techniques can be used to do what?

Answer 1

Monitor the health of the mother, developing fetus and baby

Question 2

Antenatal and prenatal screening involves what?

Answer 2

Testing for diseases or conditions in a fetus or embryo before it is born

Question 3

What does antenatal screening do?

Answer 3

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

Question 4

Common antenatal testing procedures include what?

Answer 4

Ultrasound scanning, amniocentesis and chorionic villus sampling (CVS)

Question 5

What is an ultrasound scanner used for?

Answer 5

Producing an ultrasound image on a computer screen

Question 6

Pregnant women are given two scans, what are they?

Answer 6

A dating scan and an anomaly scan

Question 7

Dating scans do what and are used for what?

Answer 7

Determine pregnancy stage and due date.

Are used with tests for marker chemicals which vary normally during pregnancy.

Question 8

When does a dating scan take place?

Answer 8

Between 8 and 14 weeks

Question 9

Anomaly scans can detect what?

Answer 9

Physical abnormalities in the fetus

Question 10

When does an anomaly scan take place?

Answer 10

Between 18 and 20 weeks

Question 11

Routine blood and urine tests are carried out throughout pregnancy to monitor what?

Answer 11

The concentrations of marker chemicals

Question 12

When are marker chemicals produced?

Answer 12

During normal physiological changes that take place during pregnancy

Question 13

Measuring a chemical at the wrong time could lead to what?

Answer 13

A false positive result

Question 14

An atypical chemical concentration can lead to what?

Answer 14

Diagnostic testing to determine if the fetus actually has s medical condition

Question 15

What do diagnostic tests include?

Answer 15

Amniocentesis and chorionic villus sampling (CVS) from the placenta

Question 16

Amniocentesis and CVS allow what?

Answer 16

A prenatal diagnosis to be made and can confirm the presence of conditions such as Down syndrome

Question 17

Amniocentesis has a small risk of what?

Answer 17

Miscarriage

Question 18

CVS can be carried out earlier in pregnancy than amniocentesis although it has what?

Answer 18

A higher risk of miscarriage

Question 19

Cells from an amniocentesis sample or CVS can be cultured to obtain sufficient cells to produce what?

Answer 19

A karyotype to diagnose a range of conditions

Question 20

A karyotype shows what?

Answer 20

An individual’s chromosomes arranged as homologous pairs

Question 21

In deciding to proceed with these tests the element of risk will be assessed, as well as what?

Answer 21

The decisions the individuals concerned are likely to make if a test is positive

Question 22

Family trees or pedigree charts are what and used to do what?

Answer 22

Are compiled.

Used to analyse patterns of inheritance in genetic screening and counselling.

Question 23

Family trees are constructed to do what?

Answer 23

Provide information and advice in situations where there is the possibility of passing on a genetic disorder to potential offspring

Question 24

Family trees can be used to analyse patterns of inheritance involving what?

Answer 24

Autosomal recessive, autosomal dominant, incomplete dominance and sex-linked recessive single gene disorders

Question 25

Alleles are forms of the same gene what are the two types and describe them?

Answer 25

Homozygous - Individuals have two copies of the same allele.

Heterozygous - Individuals have copies of two different alleles.

Question 26

Describe the autosomal recessive disorder, such as cystic fibrosis?

Answer 26

It is expressed rarely in the offspring, affects males and females equally and may skip generations

Question 27

Describe the autosomal dominant disorder such as Huntington’s disease (HD)?

Answer 27

Shows up in every generation and affects males and females equally

Question 28

Describe autosomal incomplete dominance?

Answer 28

The fully expressed form of the condition is rare, the partly expressed form is more common and males and females are affected equally

Question 29

Describe sex-linked recessive disorders?

Answer 29

Males are affected more than females. Male offspring receive the condition from their mother; fathers cannot pass the condition on to their sons and female offspring can only be affected if the father has the condition and the mother is a carrier.

Question 30

What does postnatal screening involve and why is it used?

Answer 30

Health checks that are carried out after the birth of the baby.
They are used for detecting certain conditions or abnormalities.

Question 31

Postnatal diagnostic testing is used to do what?

Answer 31

Detect metabolic disorders such as phenylketonuria (PKU)

Question 32

What is PKU?

Answer 32

An inborn error of metabolism caused by an autosomal recessive genetic disorder

Question 33

In PKU a substitution mutation means what?

Answer 33

That the enzyme which converts phenylalanine to tyrosine is non-functional

Question 34

If PKU is not detected soon after birth what happens?

Answer 34

The baby’s mental development can be affected

Question 35

Individuals with a high level of phenylalanine are placed on what?

Answer 35

A restricted diet that lacks the amino acid phenylalanine