U.2 K.A-4 Ante- And Postnatal Screening Flashcards
Name the technique by which high-frequency sounds are bounced off the fetid and converted to an image on a computer screen
Ultrasound imaging
Name two scans that are produced through ultrasound imaging
Dating scan and anomaly scan
When is a dating scan produced
8-14 weeks
What does a dating scan show
Stage of pregnancy and due date
When is an anomaly scan carried out
18-20 weeks
What does an anomaly scan show
Serious physical abnormalities in the fetus
Name a maker chemical that doctors check for the level of in a mothers urine/blood
HCG hormone or AFP
If the levels of these marker chemical are checked at an inappropriate point in the timeline and found to be high/low, this could lead to what two types of false alarm
False positives and false negatives
If a fetus is wrongly diagnosed as having a condition when it doesn’t then this is what type of mistake
False positive
If a fetus is wrongly diagnosed as not having a condition when is actual fact it does, then this is what type of mistake
False negative
What name is given to the type of tests where they look at marker chemical levels and other indicators that look for signs and symptoms of a disorder
Screening test
What name is given to a definitive test that established without doubt that the fetus has a disorder. It is usually carried out following concerns after a screening test
Diagnostic test
Name two diagnostic tests
Amniocentesis and Chorionic Villus sampling
Both diagnostic tests allow the collection of some of the baby’s cells and a photograph of the chromosomes all laid out. What name is given to the visual display of chromosomes
Karyotype
When is amniocentesis carried out
14-16 weeks
When are the cells taken from during amniocentesis
Amniotic sac
What is the negative aspect of amniocentesis
Risk of miscarriage
When is CVS carried out
As early as 8 weeks
Where are the cells for CVS taken from
The chorionic villus of the day placenta
What are the advantages of CVS over amniocentesis
CVS carried out earlier in a pregnancy and if there is any problem, then a termination can be considered much earlier when it is less traumatic. If parents wait until 14-16 weeks as with amniocentesis, then it is much more traumatic
What name is given to the charts used by genetic counsellors to assess the degree of risk in passing on a genetic disorder to children
Pedigree charts/family tree
What does a line through a symbol on a pedigree chart show
That the person has died
Which symbol is used to represent a female
A circle
Which symbol is used to represent a male
A square
What pattern of inheritance is shown when a condition carried on the autosomes has it relatively rarely expressed, skips generations and occurs more between members joined by a consanguineous marriage (too close in relation to each other)
Autosomal recessive inheritance
What pattern of inheritance is shown when a condition carried on the auto dome appears every generation? Each person affected has a parent who suffered the condition and once the condition is lost form a branch to f the tree it is lost altogether from the branch
Autosomal dominant inheritance
What pattern of inheritance is shown when both alleles are expressed together and this is the most common phenotype, the number of males and females affected in equal numbers
Autosomal incomplete dominance
What pattern on the inheritance is shown by a condition carried on the sex chromosomes, where many more males than females are affected and non of the affected males have sons with the trait
Sex-linked recessive inheritance
Name a condition whereby a baby is unable to change the amino acid Phenylalanine into tryrosine
Phenylketonuria
When is the test for phenylketonuria carried out in babies
A few days after birth
What name is given to the type of testing that occurs in babies after they are born
Postnatal screening
