T2 L13 Prenatal Screening Flashcards
(52 cards)
What does screening do?
Identifies apparently healthy people who may be at increased risk of a disease or condition, enabling earlier treatment or informed decisions
How do healthcare professionals (HCPs) see screening in comparison to parents?
HCPs: scan is a medical test – need to concentrate to take precise measurements
Parents: Scan is often seen as a social event - - chance to see baby and have photos – bring their family along
What are the various public organisations involved in screening? What is their role?
UK National Screening Committee: makes independent, evidence based recommendations to ministers
Public Health England: exists to protect and improve the nations health and wellbeing and reduce health inequalities.
Develops standards, implements and supports screening policy in collaboration with NHSE.
Quality assures screening [Screening Quality Assurance Service]
NHS England: implements and runs screening services across England
When is screening carried out?
Early pregnancy scan
- First trimester combined test
- Second trimester quad test
18+0 – 20+6 weeks fetal anomaly scan
Give examples of chromosomal abnormalities?
Down’s syndrome - Trisomy 21
Edward’s syndrome - Trisomy 18
Patau’s syndrome - Trisomy 13
Why is the scan carried out between 10-14 weeks?
Viability Accurate dating Detect multiple pregnancy (determine chorionicity) Diagnosis of structural abnormality Screening for chromosomal conditions
What % of women attending a scan would have miscarried?
2-3 %
What are NICE guidelines for scans?
use scan dates in:
- lieu of LMP (last menstrual period) dates
- crucial for screening tests
- reduces need for post dates induction
of labour
Give examples of structural abnormalities?
- spina bifida
- anencephaly
- exomphalos & gastroschisis (hole in the abdominal wall)
- bladder outflow obstruction
Give two example of prenatal diagnostic invasive tests?
1) Chorionic Villus Sampling (CVS)
2) Amniocentesis
When does CVS occur?
11+ weeks
When does amniocentesis occur?
16+ weeks
What is the risk of miscarriage in prenatal diagnostic invasive tests?
1%
NOTE: The risk is higher in twins
What does a low chance result in a screening test not exclude?
It does not exclude the baby having the condition (e.g. trisomy 21: Down’s syndrome)
What does a high chance result in a screening test not indicate?
That the baby will have the condition (e.g Trisomy 13 : Patau’s syndrome
TRUE OR FALSE
There is a risk of miscarriage in screening test
FALSE
There is no risk of miscarriage in a screening test
TRUE OR FALSE
There is a risk of miscarriage in a diagnostic test
TRUE
What is the aim of a diagnostic test?
Give definitive information on the foetal chromosomes by confirming the presence of an extra chromosome or absence of a chromosome.
What week of gestation is the combined screening test carried out?
11 (+2) - 14 (+1) weeks
First trimester
What screening methods are used in the combined screening test?
- maternal age
- amniotic sample
- maternal blood pressure
What is PAPPA and Beta-hCG? What does it indicate?
Pregnancy-associated plasma protein A (PAPPA)
-Women with low blood levels of PAPPA at 8 to 14
weeks of gestation have an increased chance of
their baby having Trisomy 21 and/or Trisomy 13/18
Beta Human chorionic gonadotropin (beta-hCG)
-Used to diagnose pregnancy. Beta-hCG is higher
than average in Down’s syndrome
What is a Nuchal Translucency Scan (NTS)?
Measurement of the fluid at the back of the baby’s neck (nuchal translucency) with an ultrasound scan
What happens to the nuchal translucency in babies with Down’s syndrome?
It is increased
80% of Down’s syndrome (T21) foetuses have increased nuchal translucency
What % of T18 (Edward’s Syndrome) and Turner Syndrome have increased nuchal translucency?
75% of T18
87% Turners
