2D Ante- And Postnatal Screening Flashcards Preview

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Flashcards in 2D Ante- And Postnatal Screening Deck (19):

Why is antenatal screening used?

It can identify the risk of a disorder so that further tests and prenatal diagnosis can be offered.


What is an anomaly scan used for?

To detect serious physical abnormalities.


Why is a dating scan used?

For pregnancy date and due date and are used with tests for marker chemicals which vary normally during pregnancy.


Why are biochemical tests used?

Detect the normal physiological changes of pregnancy.


What is a diagnostic test used for?

To detect that the medical conditions can be detected by a range of marker chemicals that indicate a condition but not necessarily be part of the conditions.


What are high risk individuals offered?

Routine screening or for individuals in high risk categories, further tests may be offered. In deciding to proceed with these tests, the element of risk will be assessed as will the decisions the individuals concerned are likely to make if a test is positive.


What is Chorionic Villus sampling (CVS)?

Removing cells from the foetal tissue (placenta).


What is done with the cells of the foetal tissue?

Cultured and a karyotype performed (chromosomes lined up in pairs) and counted.


What is the advantage of CVS?

It can be carried out early in pregnancy (8-14 weeks).


What is a disadvantage of CVS?

It has a higher risk of miscarriage.


What is amniocentesis?

Removing cells from the amniotic fluid.


What is done with the dells found in the amniotic fluid?

Cultured and then a karyotype is performed (chromosomes lines up in pairs) and counted.


What is an advantage of amniocentesis?

It has a lower chance of miscarriage than CVS.


What is a disadvantage of amniocentesis?

It is carried out between 14-16 weeks which may be more traumatic if the woman decides to go for an abortion.


What is a rhesus antigen?

An antigen found on the surface of red blood cells.


Under what conditions is the rhesus antigen a problem?

A rhesus negative mother and a rhesus positive baby.


Which pregnancy is usually riskier?

The second pregnancy.


Why is there a problem at all?

The bloods from the first rhesus positive child may have mixed with the blood of the mother. The mother's immune system will produce antibodies against the Rhesus positive antigen.


Can antibodies pass through the placenta?

Yes. The antibodies can travel through and cause haemolytic disease of the new-born.