Antenatal and neonatal screening

Question 1

Define screening

Answer 1

The process of identifying apparently healthy people who may have an increased chance of a disease or condition

Information, further tests and treatment are then provided to reduce associated problems or complications

Question 2

What are the wilson and jugner criteria for a screening programme?

Answer 2

1. it is an important health problem
2. the natural history of the condition is well understood
3. there is a detectable early stage
4. treatment at an early stage should be of more benefit than at a later stage
5. there is a suitable test to identify the early stage
6. the test is acceptable
7. intervals for repeating the test should be determined
8. there should be adequate service provision for the extra screening workload
9. the risks - both physical and psychological - should be less than the benefits
10. the costs should be balanced against the benefits

Question 3

What are the antenatal screening programmes?

Answer 3

Mother 
- Sickle cell and Thalassemia 
- Infectious diseases 
screening
- Diabetic eye screening

Fetus

• Down’s Edwards’ and Patau’s syndrome
• Fetal anomaly scan

Question 4

What are the neonatal screening programmes?

Answer 4

• Newborn infant physical examination
• hearing screen
• blood spot

Question 5

Who are screened for sickle cell and thalassaemia?

Answer 5

Both parents - to see if they are carriers

Question 6

How are sickle cell and thalassaemia inherited?

Answer 6

recessive

Question 7

If both parents are carriers of sickle cell or thalassaemia genes, what is the chance their baby will have it?

Answer 7

1 in 4

Question 8

What are the complications of sickle cell disease?

Answer 8

stroke
acute chest syndrome
blindness
bone damage
priapism 
chronic organ damage

Question 9

What is the cure for sickle cell disease?

Answer 9

Bone marrow transplant

Question 10

From which part of the world are people at highest risk of sickle cell disease?

Answer 10

West Africans
Afro-Caribbeans 
Mediterranean
Asia 
Middle East

Question 11

What are the main symptoms of sickle cell disease?

Answer 11

Symptoms of anaemia

Sickle cell crises - severe pain

Question 12

What are the two main forms of thalassaemia?

Answer 12

Alpha and beta

Question 13

What are alpha and beta thalassaemia?

Answer 13

hereditary disorders of reduced or absent synthesis of alpha or β globin chains respectively

Question 14

How is thalassaemia major treated?

Answer 14

regular blood transfusions

iron chelation to prevent iron overload

Question 15

What is the prognosis of alpha thalassaemia major?

Answer 15

usually fatal in utero due to hydrops fetalis
and haemolytic anaemia

• hydrops fetalis is abnormal accumulation of fluid in two or more fetal compartments, including ascites, pleural effusion, pericardial effusion, and skin edema

Question 16

Are both parents tested for thalassaemia trait?

Answer 16

If the mother does have the trait, the father is then offered a test to see if he carries it, too

Question 17

Which types of thalassaemia are screened for in pregnancy?

Answer 17

only beta, bot alpha as there are no good biological markers for detecting alpha thalassaemia CARRIERS

if the fetus develops hydrops fetalis, then can take a blood sample from the fetus to confirm whether the fetus has alpha thalassaemia

Question 18

Who is offered sickle cell and thalassaemia screening and when?

Answer 18

All women in high risk trusts
Certain women after using family origin questionnaire
by 8-10 weeks
Biological father of the baby is tested if female partner is a carrier

Question 19

What is used alongside the sickle cell and thalassaemia screening?

Answer 19

Family Origin Questionnaire assists laboratory to interpret results and request appropriate testing

Question 20

What is offered to mother and father if they are screened and found to be carriers of sickle cell and thalas.

Answer 20

offered counselling and prenatal diagnosis by chorionic villous sampling (taking a sample from the placenta) by 12+0 weeks

Can have TOP for an affected fetus

if born affected - will have referral to a paediatric haematologist

Question 21

What is the alternative to antenatal sickle cell and thalassaemia screening?

Answer 21

can wait as all babies tested for sickle and thalassaemia on blood spot testing

Question 22

What are the types of beta thalassaemia?

Answer 22

• Normal: genotype β2/β2.
  Slightly anaemic, clinically asymptomatic.
• β thalassaemia intermedia (genotype -/βo or β+/β+): Anaemic (symptoms usually develop when the haemoglobin level remains below 7.0 g/dL), very low MCV and MCH; splenomegaly, variable bone changes, variable transfusion dependency.
• β thalassaemia major (genotype -o/-o): Severe haemolytic anaemia, chronic transfusion dependency.

Question 23

What diseases are screened for in infectious diseases screening?

Answer 23

HIV
Hep B
Syphillis

Question 24

When are infectious diseases screened for in pregnancy?

Answer 24

women in early pregnancy

unbooked women in labour

Question 25

How are women who test positive for infectious disease treated?

Answer 25

- treatment - MDT plan of care and neonatal alert process - a form that is filled to alert the MDT of the plan for the baby when born eg bloods or tests eg an USS of kidneys

Question 26

How are babies born to hep B mothers treated?

Answer 26

Vaccination at these times: - within 24 hours of birth - 4, 8, 12 and 16 weeks - 12 months

Question 27

What happens to women who decline infectious diseases screening in early pregnancy?

Answer 27

Reofferred at 20 weeks | All unbooked women in labour must be offered

Question 28

How is syphilis transmitted in pregnancy?

Answer 28

transplacentally at any stage

Question 29

What can syphilis cause to the fetus?

Answer 29

miscarriage - eg hydrops fetalis pre-term labour stillbirth congenital syphilis

Question 30

What is congenital syphilis?

Answer 30

``` Early (first two years): rash including condylomata lata, vesiculobullous lesions snuffles - nasal discharge haemorrhagic rhinitis osteochondritis periostitis perioral fissures hepatosplenomegaly generalised lymphadenopathy glomerulonephritis neurological or ocular involvement, haemolysis thrombocytopenia ``` ``` Late: arthritis of the knees Hutchinson's incisors mulberry molars high palatal arch deafness facial deformity - frontal bossing, short maxilla, protuberance of mandible, saddle nose deformity, sternoclavicular thickening neurological or gummatous involvement. ```

Question 31

What is vertical trasmisssion?

Answer 31

Transmission of an infection from mother to fetus during pregnancy or childbirth

Question 32

Which infections are transmitted vertically?

Answer 32

``` TORCH infections T – toxoplasmosis from Toxoplasma gondii O – other infections (see below) R – rubella C – cytomegalovirus H – herpes simplex virus-2 ``` ``` Other infections include: Parvovirus B19 Coxsackievirus Chickenpox (caused by varicella zoster virus) Chlamydia HIV Syphilis ```

Question 33

What are the two types of vertical transmission?

Answer 33

Transplacental | During childbirth

Question 34

What types of infection can be transmitted during childbirth?

Answer 34

- Blood borne infections eg Hep B and HIV , as the placental barrier is broken - STIs

Question 35

What factor is predictive of greater chance of getting hepatitis B as a fetus?

Answer 35

- higher viral load of mother: will known this from the maternal blood sample given at screening

Question 36

Which genetic fetal anomalies are screened for

Answer 36

Down's Edwards Patau

Question 37

What genetic abnormality is Down's?

Answer 37

T21

Question 38

What genetic abnormality is Edwards?

Answer 38

T18

Question 39

What genetic abnormality is Patau?

Answer 39

T13

Question 40

Who is offered Downs, Edwards and Patau screening?

Answer 40

All women

Question 41

When do we screen for Downs, Edwards and Patau ?

Answer 41

between 11+2 to 14+1 weeks (same as the booking scan times - as done in the booking scan)

Question 42

How is Downs tested between 11+2 to 14+1 weeks ie at booking scan?

Answer 42

the Nuchal Combined test which is: 1. Nuchal translucency 2. Blood test - Serum levels of PAPP-A & Free Beta HCG (levels help to identify downs, edwards and patau) Maternal age also inputted and crown-rump length is used to identify the gestational age to understand whether the scan is being done at the right time between 11+2 to 14+1 weeks and the concentration of the biochemistry markers depends on the gestational age of the fetus.

Question 43

What happens in terms of downs testing when a pt misses their booking scan or not possible to measure nuchal translucency ?

Answer 43

Quadruple testing

Question 44

When is quadruple testing for down's done?

Answer 44

14+2 – 20+0 | so if one day late for booking

Question 45

Why might it not be possible to measure nuchal translucency?

Answer 45

- foetal position | - maternal obesity

Question 46

Apart from the booking scan and the quadruple testing (for Down's only), how can we test for Downs, Edwards and Patau?

Answer 46

Anatomy scan at 18+0 – 20+6 weeks for anatomical abnormalities of these syndromes

Question 47

What anatomical abnormalities would you find on the anatomy scan for Down's?

Answer 47

AVSD Ventriculomegaly (brain) Duodenal atresia Neural tube defects

Question 48

What is the main exception for doing booking scan testing for Down AND quadruple testing rather than one or the other?

Answer 48

Twin pregnancies

Question 49

What conditions is Down's syndrome associated with?

Answer 49

``` Epilepsy Childhood leukaemia Autism Thyroid disorders Heart conditions Problems with hearing and vision ```

Question 50

What are the different types of genetic abnormalities that lead to Down's?

Answer 50

Most are a trisomy (95%) Some are a translocation - extra copy of the chromosome 21 is attached to another chromosome Very few are mosaic - some cells have normal DNA and other's don't

Question 51

How would you denote a male with trisomy 21?

Answer 51

47 XY

Question 52

What defects will a fetus/baby with edwards have?

Answer 52

Severe learning disability heart defects problems with respiratory system, kidneys and digestive system Most do not survive past their 1st birthday, very rarely they may survive to adulthood

Question 53

What defects will a fetus with Patau have and what is the prognosis?

Answer 53

``` 80% have congenital heart defects Holoprosencephaly - forebrain fails to develop into two hemispheres Midline facial defects Abdominal wall defects Urogenital malformations Abnormalities of hands and feet ``` Most will die before they are born, be stillbirth or die shortly after birth

Question 54

What is the cut off risk for classifying a fetus as high risk for Downs, edwards and patau?

Answer 54

1 in 150 Less than this is low risk Higher than this is high risk

Question 55

What is the cut off risk for diagnostic testing for Down's edwards and pataus

Answer 55

Only for high risk women 1 in1 50

Question 56

What are the DIAGNOSTIC tests for Down's

Answer 56

Chorionic villous sampling | Amnioscentesis

Question 57

What is the difference between Chorionic villous sampling and Amnioscentesis and what are their adv and disadv

Answer 57

Chorionic villous sampling - Sample from the placenta - can be mosaic - some cells represent cells of the baby and others do not represent the cells of the baby - risk of miscarriage 2% - done from 11-14 weeks, so provides early diagnosis and early termination Amnioscentesis - sample of amniotic fluid which contains cells shed from the skin of the baby - NOT done before 15 weeks, so 15+ weeks only - risk of miscarriage 1%, can lead to pre-term delivery if done after 24 weeks

Question 58

What does the quadruple test test for?

Answer 58

``` Down's syndrome only Is a blood test - Alpha Feto Protein - total Beta HCG - Oestriol - Inhibin A ```

Question 59

What are the options for women with a high risk for downs?

Answer 59

1. No further testing – await anomaly scan (not diagnostic) 2. Non Invasive Prenatal Testing in private sector (screening) 3. Invasive diagnostic test – CVS or Amniocentesis (carries 0.5 – 1% risk of miscarriage)

Question 60

What is Non Invasive Prenatal Testing for down's?

Answer 60

analyses fragments of fetal DNA in maternal blood only available privately and not on nHS Can give risk of T21, T13, T18 and fetal gender Up to 99% detection rate 0.1% false positive rate - and because of this, it is not considered diagnostic and no one would terminate on the basis of this test, more provides reassurance if negative. Reason is that some of the placenta may have genetically abnormal cells but this does not represent the cells of the fetus (placental mosaicism)

Question 61

What is the purpose of the booking scan in general?

Answer 61

Confirm viability Ascertain if it is a singleton or multiple pregnancy Estimate gestational age Detect major structural anomalies that may be identified in early pregnancy, e.g. anencephaly Screening for down's edwards and patau

Question 62

What is the purpose of the anatomy scan in general?

Answer 62

to identify major abnormalities which indicate the baby may die shortly after birth to identify conditions that may benefit from treatment before birth to optimise treatment after the baby is born to plan delivery in an appropriate hospital/centre to provide choices for the woman and her family about continuance or termination of the pregnancy

Question 63

To revise again: when are the dating and anatomy scans done?

Answer 63

Dating: 11+2 - 14+1 weeks Anatomy: 18+0 – 20+6

Question 64

How often are diabetic women screened for diabetic retinopathy?

Answer 64

at least twice during the pregnancy - all diabetic women are offered this

Question 65

What scan do diabetic women get before the booking scan?

Answer 65

viability scan

Question 66

WHo is offered diabetic eye screening?

Answer 66

existing diabetics who become pregnant

Question 67

When is newborn examination done and where?

Answer 67

- within 72 hours of birth - At hospital or in community by midwife - at 6-8 weeks - done by GPs

Question 68

What is examined during the newborn exmainations?

Answer 68

eyes - cataract heart - murmurs hips - developmental dysplasia of the hip testes - undescended testes

Question 69

What are the neonatal screening tests?

Answer 69

- eyes, heart, hips, testes - hearing loss - blood spot

Question 70

What conditions does the blood spot screen for?

Answer 70

- sickle cell disease - CF - congenital hypothyroidism - inherited metabolic diseases o Phenylketonuria (PKU) o Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) o Maple syrup urine disease (MSUD) o Isovaleric acidaemia (IVA) o Glutaric aciduria type 1 (GA1) o Homocystinuria (HCU)