Unit 6 (K4) - Antenatal and Postnatal screening Flashcards
What is a dating scan used for?
To determine pregnancy stage and due date.
When does a dating scan take place?
Between 8 and 14 weeks of pregnancy.
What is an anomaly scan used for?
To detect any serious physical abnormalities.
When does an anomaly scan take place?
Between 18 to 20 weeks of pregnancy.
What is a biochemical test?
This is a routine test on the blood and urine throughout pregnancy to monitor the concentration of marker chemicals.
What happens if there is an a-typical concentration during a biochemical test?
This leads to diagnostic testing to determine if the foetus has a medical condition.
What is a diagnostic test used for?
To establish whether a person is suffering a specific condition or disorder.
Offer 3 reasons why a diagnostic test may be offered?
- If any problems emerge from routine screening tests.
- There is history of genetic disorder(s) in the family.
- The women is already in a “high risk” category, over 35 years of age.
When is an amniocentesis carried out?
Between 14 to 16 weeks of pregnancy.
What happens during an amniocentesis?
A small volume of amniotic fluid containing foetal cells is withdrawn. These cells are cultured and chromosomes used to produce a karyotype.
When does Chorionic Villus Sampling (CVS) take place?
As early as 8 weeks of pregnancy.
What occurs during Chorionic Villus Sampling (CVS)?
Placental cells are withdrawn and these cells are cultured and chromosomes used to produce a karyotype.
What are the disadvantages of Amniocentesis and CVS?
- Amniocentesis carries a slight risk of miscarriage.
- CVS carries a much higher risk to miscarriage.
What is the advantage of Chorionic Villus Sampling (CVS)?
It can be carried out at an earlier stage in pregnancy.
What are the indicators that a trait is autosomal recessive?
- Males and females are affected equally.
- Trait is rarely expressed.
- Trait may skip generations.
- All sufferers are homozygous recessive (cc)
- Non-sufferers are homozygous dominant (CC) or heterozygous