Screening for abnormalities by ultra sound- chromosomal

Question 1

First visit scan- what are you looking out for? (50

Answer 1

Ensure pregnancy viable
Multiple pregnancy
Identify abnormalities incompatible with life
Offer and carry out Down’s syndrome screening
Ideally performed between 11 and 14 weeks gestation

Question 2

Screening for Chromosomal Abnormalities - what must women and partners be aware of?

Answer 2

tests for fetal abnormality only provide a risk of their baby being affected.

Question 3

Screening for down syndrome - what is it characterised by?
what is the overall risk?
- cut off for high risk?

Answer 3

3 copies of chromosome 21

• 1 in 700
• 1 in 150

Question 4

down syndrome risk is increased with

Answer 4

older age

Question 5

When is first trimester screening carried out?

Answer 5

10-14 weeks gestation

Question 6

What does the first trimester screening use? (5)

Answer 6

maternal risk factors, serum -human chorionic gonadotrophin (-hCG) and pregnancy associated plasma protein A (PAPP-A) and fetal nuchal translucency (NT) measurement

Question 7

What is the detection rate for Tris 21 in first trimester? what is the false positive rate?

Answer 7

90%,

Question 8

Nuchal Translucency measurements are taken between what length ?

Answer 8

Crown Rump Length’s of 45-84mm

Question 9

Where may NT measurement not be possible?

what may be an alternative option?

Answer 9

fetal position or maternal BMI

biochemical screening in second trimester

Question 10

Biochemical tests in second trimester may look for?

Answer 10

hCG, unconjugated oestrodiol, alpha-fetoprotein, inhibin-A

14+2 – 20+0 weeks gestation

Question 11

If Alpha-fetoprotein >2.0 MoM - what conditions may be there that could raise concern?

Answer 11

spinabifida or exomphalos

Question 12

What happens with a high risk result? (3)

Answer 12

Further testing is offered if risk is >1 in 150

Options:
CVS
Amniocentesis
Non-invasive Prenatal testing

Question 13

When may cvs be carried out?

- carries a ?

Answer 13

(chrorionic villus sampling) - 10-14 wks

- 1-2% miscarriage

Question 14

When may Amniocentesis be carried out?

- carries a?

Answer 14

15 weeks onwards

- 1% risk of miscarriage

Question 15

Non-invasive prenatal testing - what is the process?

- what can it detect

Answer 15

• Maternal blood taken
  Can detect fetal cell free DNA
  Can look for chromosomal trisomies
  Not currently offered on NHS but parents can have test privately
  If high risk, still recommended to have invasive testing to confirm

Question 16

As of 28th september what will 1st semester screening include?
what will be available for high risk results?

Answer 16

testing for Trisomy 13 and Trisomy 18

• NIPT

Question 17

Second Trimester Ultrasound is performed?

Answer 17

with the purpose of detecting fetal abnormality

Question 18

50% of fetuses with T21 will have?

Answer 18

a normal detailed USS

Question 19

T18 - what % will show normal on an ultrasound?

Answer 19

17%

Question 20

T13- what % will show normal on an ultrasound?

Answer 20

9%

Question 21

NICE recommends all pregnant women get a USS at?

- what 2 things can be detected in this?

Answer 21

20 weeks

• soft markers for chromosomal abnormalities and major structural abnormalities

Question 22

What is exomphalos?

Answer 22

weakness of the baby’s abdo wall where the umbilical chord joins it.

Question 23

What is hypoplastic left heart syndrome?

Answer 23

HLHS - affects BF through heart- left side doesn’t develop properly

Question 24

high quality antenatal care reduces?

Answer 24

reduces maternal and fetal morbidity and mortality