Antenatal And Postnatal Screening Flashcards
What is the purpose of antenatal screening?
Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered
What are the two forms of screening?
Ultrasound imagining
Blood and urine tests
What are the two types of scans used during antenatal screening?
Dating scans and anomaly scans
What are dating scans for?
Dating scans determine pregnancy and due date and are used with tests for marker chemicals. This occurs during 8-14 weeks (write 10 weeks for exam)
What are anomaly scans?
Anomaly scans detect serious physical abnormalities in the foetus and take place between 18-20 weeks (use 20 weeks for exam)
What are blood and urine tests for?
Routine blood and urine tests are carried out throughout pregnancy to monitor the concentrations of marker chemicals.
What could measuring a chemical at the wrong time cause?
A false positive result for a medical condition
What can an atypical chemical concentration lead to?
Diagnostic testing to determine if the foetus has a medical condition
What can be carried out first, CVS ( chorionic villus sampling ) or Amniocentesis?
CVS, although it has a higher risk of miscarriage.
What is the use of amniocentesis or CVS?
the use of amniocentesis or CVS is to sample and culture cells in order to obtain a karyotype to diagnose a range of conditions.
What is a karyotype?
A karyotype shows an individuals chromosomes arranged as homologous pairs.
What is Postnatal screening used for?
To test for phenylketonuria ( PKU )
What is PKU or phenylketonuria?
PKU is a substitution mutation meaning that an enzyme which converts phenylalanine to tyrosine is non-functional.
What is recommended for individuals with high levels of phenylalanine with PKU?
to be placed on a restricted diet, as PKU causes phenylalanine to not convert to tyrosine but rather toxic metabolites that cause brain damage.
