Antenatal screening Flashcards Preview

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Flashcards in Antenatal screening Deck (33)
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1
Q

What are the principles of screening

A
Sensitivity = true positive rate
Specificity = true negative rate 
Positive predictive value 
Easily used in large populations 
Safe and cheap
2
Q

when is the booking appointment

A

8-12 weeks

3
Q

What is done in the booking appointment

A
History 
Examination - BP, BMI, CVS and abdo exams 
FBC - Hb 
G&S - Ab, ABO, Rh 
STI check 
Urinalysis 
USS 
Estimated date of delivery
4
Q

How can you estimate the due date in the booking appointment

A

Naegele’s rule = LMP + 9 months and 7 days

Crown Rump Length (CRL) = length from head to bottom (more accurate)

5
Q

What does USS assess on the booking visit

A
viability of pregnancy - foetal heart 
singleton vs multiple 
in utero 
gestational age 
major structural anomalies 
Downs syndrome screening offered
6
Q

What is done on follow up visits

A
BP, urinalysis
physical and mental health assessment 
symphyseal fundal height 
lie and presentation 
foetal head engagement 
foetal heart auscultation
7
Q

When is the foetal anomaly scan done

A

20 weeks

8
Q

What can the foetal anomaly scan screening programme pick up

A
NTD 
cleft lip 
heart defects 
Abdominal wall defects - gastroschisis
diaphragmatic hernia 
bilateral renal agenesis 
skeletal dysplasia 
Trisomies - Edwards (18), Pataus (13), Downs (21)
9
Q

If you do not find any anomalies on scan this completely rules them out, true or false

A

False, need to know limitations of scans

10
Q

What is placental previa

A

Low lying placenta obstructing the cervix

11
Q

What is the bigest RF for having a baby with Down’s syndrome

A

Advanced maternal age

12
Q

When can you have Downs screening and when is it more accurate

A

1st and 2nd trimester

More accurate in 1st trimester

13
Q

What is measured in the 1st trimester for Downs screening

A

Nuchal thickness/translucency (NT) = measure of skin thickness behind foetal neck
PAPP-A levels = low
hCG levels = high

14
Q

What is involved in 2nd trimester screening for Downs

A

Blood test at 15-20+6 weeks
hCG levels = high
AFP levels = low

15
Q

What is measured in 2nd trimester screening for aneuploidy

A
Maternal age 
hCG 
AFP 
UE3 - unconjugated oestrodiol 
inhibin A
16
Q

what is non-invasive pre natal testing (NIPT)

A

detects cell free foetal DNA (cffDNA)
identifies women at higher risk of trisomies
more accurate
not yet available but will be soon

17
Q

what are specific diagnostic tests for Downs syndrome

A

amniocentesis

chorionic villus sampling CVS

18
Q

When can amniocentesis be done and what is a risk

A

> 15 weeks

miscarriage

19
Q

When can CVS be done and what is a risk

A

> 12 weeks

miscarriage

20
Q

What are the main haemoglobulinopathies and what is their inheritance pattern

A

Sickle cell disease and thalamssemias

Autosomal recessive

21
Q

Why is it important to check rhesus status

A

Rh+ father and Rh- mother could result in Rh+ baby in Rh- mother –> production of Rh antibodies in mother that circulate in her blood and can attack baby in future pregnancy causing Rh disease

22
Q

What is given to RhD- mothers with Rh+ baby

A

Anti-D to mop up foetal blood that has gotten into maternal circulation through sensitising events

23
Q

RhD+ mothers need anti-D, true or false

A

FALSE

24
Q

What does urinalysis look for in antenatal checks

A

Proteinuria
glucosuria
leukocytes
ketonuria

25
Q

How should you manage asymptomatic bacteriuria in pregnancy

A

Treat it!

26
Q

What are risk factors for GDM (gestational diabetes)

A
BMI>30 
previous GDM 
previous macrosomic baby >4.5kg
FH of DM 
minority ethnicity
27
Q

How do you diagnose GDM

A

OGTT
Fasting glucose >=5.1
2 hour plasma glucose >=8.5
SIGN guidelines ^^, differ from NICE

28
Q

Who should a pregnant mother see if they are are on the green or red pathway

A

Green - midwife

Red - obstetrician and midwife support

29
Q

When is symphyseal fundal height measured antenatally

A

from 24 weeks onwards

30
Q

What are high risk factors for PET (Pre eclampsic toxaemia)

A
hypertensive disease during previous pregnancy 
autoimmune conditions 
CKD 
Type 1 or 2 DM 
chronic HTN
31
Q

What are moderate RF for PET

A
1st pregnancy 
pregnancy interval >10 years 
BMI>35 
FH of PET 
multiple pregnancy
32
Q

How do you manage women at high risk of PET

A

150mg / low dose aspirin daily from 12wk –> birth

33
Q

When is aspirin contraindicated

A

asthamatics

PUD