Antenatal screening Flashcards
When would you use the quadruple test?
If patient has missed ‘combined screening’ (eg. booking late)
When is the quadruple test done?
14+2 - 20+0 weeks
What does the quadruple test involve?
Blood test only
What is the test for down’s syndrome (and other disorders) that is currently only available in private sector?
NIPT (non-invasive pre-natal testing)
will be on NHS for high-risk women soon
Why is NIPT better than combined and quadruple test?
Detection rate of over 99%
How does NIPT work?
Placental DNA extracted from maternal blood sample
Different tests screening for different conditions
What does IONA screen for?
Down’s
Edwards
Pataus
When is an HIV test for pregnant women?
Booking bloods
Consent needed
Opt-out system
Why is an HIV test done for mothers?
Intervene quickly for the mother’s health and reduce risk of Mother to Child transmission
What would happen if a woman declines HIV test ONLY?
MDT meeting to discuss reasons behind it
What is important to remember when writing in notes re. someone’s HIV status?
DO NOT WRITE IN HAND-HELD NOTES
What guidelines must you follow for someone with HIV?
2014 BHIVA guidelines
When is Hepatitis B screening done?
Booking bloods
What has to be done if patient has Hep B? Why?
Screening team to contact HPA
Idenifty clearly in notes
Notifiable disease
Refer household contacts to GP for hepatitis screen and vaccination
Health protection advice
How is a mother with Hep B managed?
Referred to hepatology
Newborn vaccination programme. 5 dose vaccine (up to primary school)
Are people with Hep B antibody + and B antigen - at low or high risk?
lower risk
Are people with Hep B antibody - and B antigen + at low or high risk?
higher risk
Newborn will require dose of immunoglobulin at birth
How are women with Hep B managed?
High viral load: anti-retroviral therapy in pregnancy
AND
for short periods following delivery to reduce risk of transmission
Can a woman who screens positive for Hep B breastfeed?
YES
Can a woman who screens positive for HIV breastfeed?
Would not recommend
What should you do for someone who has screened positive for syphilis?
refer to GUM for ABX (if no evidence of previous treatment)
?partner tracing
When is the deadline for receiving the full syphilis treatment to prevent the baby needing IV therapy?
4 weeks prior to delivery
If a mother doesn’t receive the full syphilis treatment by 4 weeks prior to delivering the baby, what does the baby need to receive?
IV therapy (ABX)
What rhesus status indicates a need for anti-D immunoglobulin?
rhesus negative
If a woman is rhesus negative, what will she be offered?
Anti-D immunoglobulin IV at 28-30 weeks
When is Rhesus done?
booking
28 weeks
What is ROUTINELY screened for during the antenatal period?
Foetal anomalies
Infectious diseases: HIV
Hep B
Syphilis
Rhesus -ve
Haemoglobinopathies
What screening programmes are available for foetal anomaly?
Two programmes:
Early pregnancy scan: 11+2 - 14+1
Anomaly scan 18+0 - 20+6
Is the combined screening test opt-in or opt-out?
opt in
When is the combined screening test done?
Done in first trimester from 11+2 - 14+1
What does combined screening include?
Nuchal translucency scan
Maternal blood test:
hCG (human chorionic gonadotrophin)
PAPPA (pregnancy-associated plasma protein A)
How are the results of combined screening presented?
as a ‘risk factor’
Cut off is 1 in 150
What is the detection rate for the combined test?
85% (about 2% of women will get a high-risk result)
What tests can you offer a woman who’s had a high-risk combined test result?
CVS (chorionic villus sampling) from 11 weeks (1% risk miscarriage)
Amniocentesis from 15 weeks (with risk of miscarriage 0.8%)
- diagnostic tests
What is the combined test looking for?
Risk of down’s syndrome
What detection rate does the quadruple test have?
80%
What is the detection rate of NIPT?
over 99%
What sorts of things does a foetal anomaly scan look for?
anencephaly
gastroschisis
heart defects
trisomies 13 and 18
What happens if a foetal anomaly is detected during screening?
Woman is referred to obstetrician/foetal medicine
Are HIV and Hep B opt-in or opt-out tests?
opt out
How does anti-D immunoglobulin IV at 28-30 weeks help pregnant women with rhesus negative blood?
neutralises foetal RhD+ antigens which would have entered maternal blood
prevents creation of antibodies
How is the baby’s blood tested at birth?
Cord blood test
What is done for the female patient if she delivers a Rhesus positive baby?
IM injection of Anti-D
When are haemoglobinopathies screened for?
Booking bloods
Which haemoglobinopathies are being looked for in antenatal screening?
Sickle cell
Thalassemia
Is haemoglobinopathy screening an opt-in or opt-out test?
opt out
Other than a blood sample, what else is completed to determine patient/baby risk of haemoglobinopathy?
Family origin questionnaire
identify higher risk ethnic groups in low prevalence areas
If the mother is found to have haemoglobinopethy traits/carrying status, what must be done next?
FATHER must be checked (not necessarily partner)
How are newborns tested for haemoglobinopathies? When is this done?
Newborn blood spot
5 days post delivery
Which infections are NOT commonly screened for?
Hep C
Chlamydia
Group B strep
When might you screen for Hep C?
Hx of drug abuse or obstetric cholestasis
When might you screen for chlamydia?
Encourage in under 25s (opportunistic screening)
When might you screen for group B strep?
swab/urine tests are performed
