Unit Two - Key Area 4 Flashcards
What is antenatal and postnatal screening?
When a variety of techniques are used to monitor the health of the mother, developing foetus and baby. Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered.
What are the two ultrasound scans women are given?
dating scan and an anomaly scan
When does the dating scan take place/what is it used for?
Takes place between 8 and 14 weeks. It determines the stage of pregnancy and due date. This is used with tests for marker chemicals which vary normally during pregnancy.
When does the anomaly scan take place/what is it used for?
Takes place between 18-20 weeks and may detect serious physical abnormalities in the foetus.
Why are routine blood and urine tests carried out?
to monitor the concentrations of marker chemicals
What is amniocentesis?
Amniocentesis is a procedure is usually carried out between the 15th and 20th week of pregnancy which involves the collection of foetal cells contained within amniotic fluid. A needle is inserted through the abdomen/uterus wall into the amniotic sac and a sample of the amniotic fluid is collected.
What are advantages and disadvantages of amniocentesis?
Advantage – it is used to detect genetic or chromosomal abnormalities of the foetus.
Disadvantage - the procedure carries a risk of miscarriage.
What is chorionic villus sampling (CVS)?
Chorionic villus sampling is procedure usually carried out between the 11th and 14th week of pregnancy. This procedure removes a small sample of cells from the placenta. These can be obtained through the abdomen or through the cervix.
What are advantages and disadvantages of CVS?
Advantage – it is used to detect genetic or chromosomal abnormalities of the foetus and can be performed earlier than an amniocentesis.
Disadvantage - the procedure carries a higher risk of miscarriage than an amniocentesis.
What is a karyotype?
A karyotype shows an individual’s chromosomes arranged as homologous pairs
What is PKU (phenylketonuria)?
Phenylketonuria is caused by a substitution mutation meaning that an enzyme which converts phenylalanine to tyrosine is non-functional. Individuals with high levels of phenylalanine are placed on a restricted diet.
