Ante- And Postnatal Screening Flashcards
What does antenatal screening involve?
Testing for diseases or conditions in a fetus or embryo before it is born.
What does Antenatal Screening do?
Identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered.
Give examples of common Antenatal testing procedures.
Ultrasound scanning, amniocentesis, chronic villus sampling and rhesus antibody testing.
What is an Ultrasound scan?
Where an ultrasound scanner is used to produce an ultrasound image on a computer screen. They can be used to produce a pregnancy or gestational dating scan which is used to determine the stage of pregnancy and the date that the baby is due.
What is another use for an ultrasound scan?
It can be used to produce an anomaly scan which is used to detect the presence of serious physical problems in the fetus.
Why might Biochemical tests be carried out?
To detect marker chemicals that are produced during normal physiological changes that take place during pregnancy.
What might diagnostic tests such as amniocentesis and Chronic Villus Sampling (CVS) confirm?
The presence of conditions such as Down Syndrome.
What is the use of cells from an amniocentesis sample or CVS?
They can be cultured to obtain sufficient cells to produce a karyotype.
What is a karyotype?
An image of an individual’s chromosomes, arranged in homologous pairs.
A karyotype is used to identify anomalies in the numbers or structure of chromosomes.
What may be the implications of diagnostic tests such as amniocentesis and CVS?
CVS and amniocentesis are invasive procedures and so they carry a small risk of inducing miscarriage.
What are the differences between CVS and amniocentesis?
CVS can be carried out earlier in the pregnancy than amniocentesis but has a higher risk of miscarriage.
What is Rhesus Antibody Testing?
Rhesus Antibody Testing is carried out early in a pregnancy to determine the Rhesus status of the mother to ensure she shows no immune response to her fetus. In the event of a second pregnancy, complications can arise if a mother is Rhesus negative and the fetus is Rhesus positive.
What is done to prevent complications during the second pregnancy of a mother who is Rhesus negative, if she is pregnant with a Rhesus positive fetus?
Anti-Rhesus antibodies are given to Rhesus negative mothers after a sensitising event such as the birth of the baby.
What does Postnatal Screening involve?
Health checks that are carried out after the birth of the baby. These are aimed at detecting certain conditions
Or abnormalities.
What is postnatal diagnostic testing used for?
Detecting metabolic disorders such as Phenylketonuria (PKU).
