Prenatal Screening

Question 1

During screening when a woman becomes pregnant, they may have the combined test, what is the combined test?

1 - ultrasound scan of foetus and blood test
2 - ultrasound scan and X-ray
3 - blood test and X-ray
4 - blood test and transvaginal ultrasound

Answer 1

1 - ultrasound scan of foetus and blood test

Question 2

During screening when a woman becomes pregnant, they may have the combined test, which is an ultrasound scan of foetus and blood test. What 2 maternal blood markers are measured here, but are optional?

1 - trisomy and BhCG
2 - BhCG and PAPP-A
3 - trisomy and PAPP-A
4 - BhCG and HbA1c

BhCG = Beta human chorionic gonadotropin
PAPP-A (Pregnancy associated plasma protein)

Answer 2

2 - BhCG and PAPP-A

Question 3

During screening when a woman becomes pregnant, they may have the combined test, which is an ultrasound scan of foetus and blood test. When is this normally performed?

1 - 0-6 weeks
2 - 6-10 weeks
3 - 10-12 weeks
4 - >12 weeks

Answer 3

3 - 10-12 weeks

Question 4

A dating scan which estimates the due date based on the babies dimensions is performed at week 12 weeks. This scan also assess for congenital defects. What 3 defects are tested for here?

1 - Down, metabolic and Patau Syndrome
2 - Down, Edward and Patau Syndrome
3 - Anti-phospholipid, Edward and Patau Syndrome
4 - Metabolic, Edward and Patau Syndrome

Answer 4

2 - Down, Edward and Patau Syndrome

Question 5

At dating scan which estimates the due date based on the babies dimensions is performed at which week?

1 - 0-6 weeks
2 - 6-10 weeks
3 - 10-12 weeks
4 - >12 weeks

Answer 5

3 - 10-12 weeks

Question 6

At booking what is the mother tested for?

1 - antibody screening, ultrasound, haemoglobinopathies, OGTT
2 - antibody screening, trisomy, haemoglobinopathies, OGTT
3 - trisomy, infectious disease, haemoglobinopathies, OGTT
4 - antibody screening, infectious disease, haemoglobinopathies, OGTT

Answer 6

4 - antibody screening, infectious disease, haemoglobinopathies, OGTT

Question 7

A blood test to assess for trisomy (3 chromosomes) is conducted on which week normally?

Answer 7

• weeks 12-13

Question 8

A blood test to assess for trisomy (3 chromosomes) is conducted on weeks 12-13. What are the 3 most common chromosomes that are normally found in this blood test?

1 - 6, 18 and 21
2 - 13, 6 and 21
3 - 13, 18 and 21
4 - 12, 18 and 21

Answer 8

3 - 13, 18 and 21

Question 9

What is a sensitising event in relation to blood?

Answer 9

• baby is rhesus + and mum is rhesus -
• a small amount of the baby’s blood enters the mother’s bloodstream during pregnancy or birth
• mother produces antibodies against the rhesus positive cells (known as ‘anti-D antibodies’)
• in a 2nd baby the antibodies can cross the placenta and attack the foetus RBCs

Question 10

When screening a woman who is pregnant, we need to screen her for blood type, why?

Answer 10

• prevent a type II hypersensitivity
• determine classification according to ABO (A, B, AB or O blood type)
• also determine if woman has D antigen which determine rhesus + or -
• 1st pregnancy is fine, but in 2nd pregnancy, maternal antibodies may attack babies RBCs
• screening identifies if this is an issue, and if so Anti-D immunoglobulin are provided
• performed around 20 weeks

Question 11

During screening when a woman becomes pregnant, they may have the combined test:

• ultrasound scan of foetus
• blood test
• normally performed at 6 weeks

What 2 major things are they looking for on the ultrasound?

Answer 11

• growth patterns (foetal growth restriction or small gestational age)
• detection of trisomy (13, 18 and 21)

Question 12

During screening when a woman becomes pregnant, they may have the combined test:

• ultrasound scan of foetus
• blood test
• normally performed at 6 weeks

On the ultrasound we are generally looking at growth patterns (foetal growth restriction or small gestational age) and for the detection of trisomy (13, 18 and 21). What syndromes is each of the 3 most common chromosomes affected linked with? (think of the mnemonic PED)

Answer 12

• 13 = patau syndrome
• 18 = edward syndrome
• 21 = down syndrome
• remember PED from low to high in number

Question 13

When performing a blood test we are trying to detect if the mother or baby have haemoglobinopathies, pathology of the blood. What are the 2 most common haemoglobinopathies that we are trying to detect?

1 - sickle cell disease and thalassaemia
2 - sickle cell disease and type II hypersensitivity
3 - thalassaemia and haemolytic anaemia
4 - sickle cell disease and anaemia

Answer 13

1 - sickle cell disease and thalassaemia

Question 14

What is thalassaemia?

1 - genetic mutation affecting RBCs ability to bind haemoglobin
2 - genetic mutation affecting WBCs ability to fight pathogens
3 - genetic mutation increasing RBCs ability to bind haemoglobin
4 - genetic mutation affecting lymphocytes

Answer 14

1 - genetic mutation affecting RBCs ability to bind haemoglobin

• alpha and beta globin chains are affected
• patients may be anaemic causing them to be pale and tired

Question 15

What is sickle cell disease?

1 - genetic mutation affecting shape of RBCs
2 - genetic mutation affecting WBCs ability to fight pathogens
3 - genetic mutation affecting RBCs ability to bind haemoglobin
4 - genetic mutation affecting lymphocytes

Answer 15

1 - genetic mutation affecting shape of RBCs

• RBCs look like moons instead of donuts
• the odd shape and stickiness of the cells mean they get stuck in blood vessels
• blood vessels can become blocked or restricted limiting O2 to the body

Question 16

Sickle cell disease causes RBCs to become moon shaped instead of like round donuts. The odd shape and stickyness of the cells mean they get stuck in blood vessels, causing blood vessels to become blocked or restricted limiting O2 to the body. Which populations are most likely to have sickle cell disease?

1 - Caucasian
2 - African, Caribbean, Mediterranean, Indian or Asian backgrounds

Answer 16

2 - African, Caribbean, Mediterranean, Indian or Asian backgrounds

Question 17

What are the 3 main infectious diseases that mothers will be screening for when pregnant?

1 - HIV, T1DM, syphylis
2 - HIV, T2DM, syphylis
3 - HIV, hepatitis B, syphylis
4 - HIV, hepatitis B, gonorrhoea

Answer 17

3 - HIV, hepatitis B, syphylis

- if infected mother will need to be treated, reducing risk of transmission

Question 18

Generally, when can babies contract infectious diseases off their mothers?

Answer 18

• during birth

Question 19

What is the nuchal translucency scan?

1 - measure of nuschal thickness
2 - measure of nuschal length
3 - measure from nuschal to the caudal end of the body

Answer 19

1 - measure of nuschal thickness

- marker for down syndrome if thicker than normal levels

Question 20

What is the nuchal translucency scan?

Answer 20

• part of ultrasound scan

- generally performed at week 12

Question 21

During the nuchal translucency scan the sonographer will attempt to measure the crown rump length. In addition, 3 other measurements will try to be taken, what are they?

1 - femur length, femur and cranial circumference
2 - femur length, abdominal and cranial circumference
3 - femur length, humeral and cranial circumference
4 - humeral length, abdominal and cranial circumference

Answer 21

2 - femur length, abdominal and cranial circumference

Question 22

During the nuchal translucency scan the sonographer will attempt to measure fluid behind the babies neck. An increased volume of fluid here increases the risk of what?

1 - Down Syndrome
2 - Edward Syndrome
3 - Patau Syndrome
4 - Metabolic Syndrome

Answer 22

1 - down syndrome

- has been linked with blockages in lymphatics

Question 23

What % of woman have a miscarriage that is detected at the 12 week scan?

1 - 10-15%
2 - 25-30%
3 - 5-10%
4 - 2-3%

Answer 23

4- 2-3%

Question 24

The ultrasound scan can be useful for detecting the number of placenta and amniotic sacs. What are these 2 terms called?

Answer 24

• chorionicity = number of placentas (twins triplets etc..)

- amnionicity = number of amniotic sacs (twins triplets etc..)

Question 25

During an ultrasound scan, what is used to predict gestation length, and therefore date of delivery, which can be useful when identifying if a women needs to be induced?

Answer 25

• last menstrual period

Question 26

What are the 4 most common structural anomalies that can be detected at the 12 week scan?

Answer 26

1 - spina bifida​ (poor neural tube closing)
2 - anencephaly (absence of brain and/or skull)
3 - exomphalos and gastroschisis​ (internal organs on outside of the body)
4 - bladder outflow obstruction​ (reduced amniotic fluid around the foetus causing under development)

Question 27

What screening scan is performed at weeks 18-20?

1 - foetal anomaly scan
2 - gestation
3 - estimate due date
4 - abdominal circumference

Answer 27

1 - foetal anomaly scan

- baby is big enough to detect abnormalities (brain, bladder, heart)

Question 28

What happens to the risk of trisomy as a woman ages?

Answer 28

• risk of trisomy increases

Question 29

What are 2 of the key markers that are measured in the blood during the combined screening tests of a pregnancy?

1 - trisomy and BhCG
2 - BhCG and PAPP-A
3 - trisomy and PAPP-A
4 - BhCG and HbA1c

BhCG = Beta human chorionic gonadotropin
PAPP-A (Pregnancy associated plasma protein)

Answer 29

2 - BhCG and PAPP-A

Question 30

What are some risk factors trisomy?

Answer 30

• maternal age​
• gestational age​
• ethnicity​
• smoking​
• IVF​
• multiple pregnancy​
• BMI​
• diabetes​
• past historyof chromosome abnormality​
• foetalsex (males are more likely)​
• analytical imprecision​

Question 31

What are the detection rates of congenital anomalies?

1 - 10-15%
2 - 25-30%
3 - 5-10%
4 - 2-3%

Answer 31

4 - 2-3%

Question 32

What are the detection rates of down syndrome (chromosome 21), patau syndrome (chromosome 13) and edwards syndrome (chromosome 18)?

Answer 32

• patau syndrome (chromosome 13) = 80%
• edwards syndrome (chromosome 18) = 80%
• down syndrome (chromosome 21)= 85%

Remember PED to remember which is which

Question 33

Down syndrome is a genetic defect where an additional chromosome of the 21st chromosome is present. What are some of the most common characteristics of down syndrome?

Answer 33

• learning difficulties
• flat face with an upward slant to the eyes.
• short neck.
• abnormally shaped ears.
• protruding tongue.
• small head.
• deep crease in the palm of the hand with relatively short fingers.
• white spots in the iris of the eye.
• poor muscle tone, loose ligaments, excessive flexibility

Question 34

Down syndrome is a genetic defect where an additional chromosome of the 21st chromosome is present. Patients with down syndrome often have what disease that they can often die from?

1 - cardiovascular disease
2 - renal disease
3 - T1DM
4 - autoimmune disease

Answer 34

1 - cardiovascular disease

Question 35

Edwards syndrome is a genetic defect where an additional chromosome of the 18th chromosome is present. What are some of the most common characteristics of Edwards syndrome, who generally die before or just after birth?

Answer 35

• low birth weight
• small head (microcephaly)
• severe learning disability
• small jaw (micrognathia)
• malformations of the heart
• malformations of kidneys
• clenched fists and malformed feet
• feeding and breathing problems
• cleft lip and/or cleft palate

Question 36

Patau syndrome is a genetic defect where an additional chromosome of the 13th chromosome is present. What are some of the most common characteristics of Patau syndrome, who generally die before or just after birth?

Answer 36

• cleft lip and palate
• abnormally small eye or eyes (microphthalmia)
• absence of 1 or both eyes (anophthalmia)
• reduced distance between the eyes (hypertelorism)
• problems with the development of the nasal passages
• Other abnormalities of the face and head include:
• smaller than normal head size (microcephaly)
• skin missing from the scalp (cutis aplasia)
• ear malformations and deafness
• raised, red birthmarks (capillary haemangiomas)

Question 37

Patau, Edward and Down syndrome are all congenital abnormalities that are trisomy, meaning they have an extra chromosome on the 13, 18 and 21st chromosomes, respectively. Of the 3 which generally survive the longest and die early do to the phenotype of the patient?

Answer 37

• down syndrome live the longest

- patau and edwards die early on

Question 38

The foetal screening programme is an ultrasound scan performed between 18-20 weeks. How many conditions is this screening used to detect?

Answer 38

• 11

Question 39

The foetal screening programme is an ultrasound scan performed between 18-20 weeks to detect 11 conditions. if a woman is diagnosed with any condition, what are these women advised regarding giving birth?

Answer 39

• advised to give birth in a hospital

- more likely to have problems following birth, being in hospital provides safest enviroment

Question 40

If any condition is detected, the couples options need to be discussed with them. What are the 3 main options commonly offered?

Answer 40

• continue with pregnancy
• continue with pregnancy and look at adoption
• termination (medical/surgical)

Question 41

If any condition is detected in a pregnant women, one option offered to the couple is termination under ground E. What is ground E?

Answer 41

• if there is a substantial risk that if the child were born itwould suffer from such physical or mental abnormalities asto be seriously handicapped​
• termination would therefore be better for the baby

Question 42

What is cell free foetal DNA non invasive prenatal testing?

Answer 42

• mother and babies DNA is extracted from blood sample
• both are screened for trisomy (13, 18 and 21)
• marketed as Harmony of SAFE

Question 43

If a patient wants an abortion, which act of the abortion act can the abortion be justified based on there being a substantial risk to the baby and/or mother?

1 - ground A
2 - ground C
3 - ground E
4 - ground G

Answer 43

3 - ground E