Fetal Abnormality Screening Flashcards
What are the possible causes of an increased nuchal translucency?
Down syndrome, Edwards syndrome, Turners syndrome, Patau’s syndrome
Congenital heart defects
Abdominal wall defects
What is a SIGNIFICANT nuchal translucency finding?
NT greater than or equal to 3.5mm
When is a nuchal scan usually performed?
11- 13 weeks 6 days
What bio markers are measured in the quadruple test?
Alpha-fetoprotein (AFP)
Oestriol (uE3)
hCG
Inhibin A
When is the quadruple test not recommended?
for multiple pregnancies
At what time is the quadruple test carried out?
15-18 weeks
When is the combined test carried out?
11-14 weeks
If too late, refer for a quadruple test
What does an elevated AFP indicate?
Neural tube defect:
Spina bifida
Anencephaly
What is the significance of a decreased oestriol level?
Marker for Down syndrome and trisomy 18 (Edward’s)
What are the screening tests used for Down syndrome?
Combined and Quadruple test
These give a risk, not a definite diagnosis
What diagnostic test can be used to confirm a foetus has Down Syndrome?
Amniocentesis
When is amniocentesis offered to those women with an increased risk of birth defects?
15-18 weeks
What increased risk factors allow you to have the option of an amniocentesis?
- 35 years or older at time of birth
- screening that showed a defect
- previous children with birth defects
- family history of genetic disorders
What does the combined test measure?
Biochemical markers:
PAPP-A
beta - hCG
Ultrasound measurement of crown rump length and nuchal translucency
During what time period of the pregnancy is a detailed foetal anomaly scan carried out?
18 - 20 weeks 6 days
What is the purpose of the early pregnancy scan?
Detect gestational age
Detect multiple pregnancies
Take measurements required for the Down Syndrome screening programme
What diseases are tested for at the booking blood test?
Sickle cell disease Thalassaemia Congenital infections: Syphillis Hepatitis B HIV
What are the lab findings of biochemical markers when a women is pregnant with a child who has Down Syndrome?
Elevated hCG and INH-A
Lower than average levels of uE3 and AFP
Combined - low PAPP-A
When can chorionic villus sampling be performed from?
From 9 weeks into the pregnancy (earlier than an amniocentesis which is performed at 15-18weeks)
What is the risk of spontaneous miscarriage in chorionic villus sampling?
0.5 - 2%
What is the risk of infection and spontaneous miscarriage in an amniocentesis?
1%
What is the next generation of diagnostic testing?
NIFTY
Examines peripheral blood from the mother to estimate the risk of foetal chromosomal aneuploidies carried in the newborn
When does the early pregnancy scan occur?
10-12 weeks
