KA4-Ante- and Postnatal screening Flashcards
What is antenatal screening used for?
It it used before pregnancy or during pregnancy. It identifies the risk of a disorder so that further testes and a prenatal diagnosis can be offered.
When and how many ultrasound scans are women given during pregnancy?
Women are given two ultrasound scans. A dating scan and a anomaly scan.
Explain what is a dating scan?
A dating scan takes place between 8 and 14 weeks to determine pregnancy stage and due date. Dating scans are used with tests for marker chemicals which vary during pregnancy.
Explain what is an anomaly scan?
An anomaly scan takes place between 18 and 20 weeks and may detect serious physical abnormalities in the foetus.
Explain why blood and urine tests are takes routinely during pregnancy?
Routine blood and urine tests are carried out throughout pregnancy to monitor the concentrations of marker chemicals.
What could happen if a marker chemical is measured at a wrong time?
It could lead to a false positive.
What happens if an atypical chemical concentration is recorded?
An atypical concentration can lead to diagnostic testing to determine if the foetus has a medical condition.
What may diagnostic testing be offered for?
It may be offered to confirm if the foetus has a medical condition.
What are the two main types of diagnostic testing?
Chorionic villus sampling
Amniocentesis
How is chronic villus sampling used?
A sample of placental cells are taken and they are cultured for karyotyping.
What is the advantage of chorionic villus sampling?
It is carried out earlier in pregnancy than amniocentesis.
What is the disadvantage of chorionic villus sampling?
It has a higher risk of miscarriage than amniocentesis.
How is amniocentesis used?
A sample of of amniotic fluid is taken and are cultured to produce a karyotype.
What is an advantage of amniocentesis?
It has a lower risk of miscarriage than chorionic sampling villus.
What is a disadvantage of amniocentesis?
It is carried out later in pregnancy than CVS.
