Antenatal screening Flashcards
(25 cards)
Routine pre-pregnancy counselling topics
optimise maternal weight
make sure up to date with cervical smears
stop smoking
address any mental health issues
400mcg folic acid 3 months prior to conception and continue until 12 weeks gestation
address any maternal medical conditions prior to pregnancy
What should be considered in maternal medical conditions prior to conception?
effect of pregnancy on disease
effect of disease on pregnancy
medications
Who needs high dose folic acid pre-conception?
Diabetics
BMI>30
personal or FH of neural tube defects
on anti-epileptics or folate antagonists
on anti-retrovirals for HIV
Why does diabetic control worsen in pregnancy?
placenta produces increasing amounts of anti-insulin hormones
loss of hypo awareness
worsening retinopathy/nephropathy
Risks of diabetes to pregnancy
increased miscarriage rates and teratogenicity
macrosomic baby –> shoulder dystocia
high caesarean section rate
neonatal jaundice
When is a booking appointment with a midwife?
8-10 weeks
What foods should pregnant women avoid?
listeriosis - avoid unpasteurised cheese and milk, ripened soft cheese, pate, undercooked meals
salmonella - avoid raw or partially cooked meat especially poultry
What is done in a booking appointment?
risk assessment
extensive personal and family history and assessment of risk factors for this pregnancy:
- VTE assessment
- aspirin prophylaxis for pre-eclampsia
- smoking/obesity pathways
- GDM risk assessment
What are the booking bloods for pregnancy?
anaemia - test at booking and 28/40
blood group and red cell antibodies
if mother Rh -ve –> NIPT to check baby Rh (if +ve will need anti-D at 28 weeks)
haemoglobinopathies (sickle cell and thalassaemia)
blood-borne viruses:
- HIV
- hepatitis B
- syphilis
When is the dating scan done?
11-14 weeks
What is measured in a dating scan?
crown-rump length
nuchal translucency
Describe nuchal translucency screening
prenatal screening test done at dating scan
uses US to measure the fluid-filled space at back of baby’s neck to assess risk of chromosomal abnormalities
Screening test vs diagnostic test
screening test:
- identifies individuals at high or low risk
- high risk does not mean it will happen but prompts further testing
- low risk does not mean no risk
diagnostic test:
- gives definite yes or no
Describe the combined test
screening for common trisomies (13, 18, 21)
done between 10 and 13+6 weeks gestation
components:
- nuchal translucency
- serum free b-hCG and pregnancy associated plasma protein A (PAPP-A)
- foetal age (CRL)
- maternal age
high risk = offered NIPT or diagnostic amniocentesis or chorionic villus sampling
+ve = offered termination
Describe the quadruple test
if dating scan late, offered quadruple test between 16-20 weeks
blood test:
- AFP
- unconjugated oestriol
- hCG
- inhibin A
offer amniocentesis if high risk result (too late for chorionic villus sampling)
Describe NIPT
non-invasive prenatal testing
cell-free foetal DNA in maternal plasma measured
can detect trisomies 13, 18 and 21
What are the possible results following NIPT for trisomy 21?
positive = foetus likely to be affected by Down syndrome –> offer invasive test to confirm result
negative = foetus highly unlikely to be affected by Down syndrome
inconclusive = not enough foetal DNA in sample, NIPT may be repeated
Down syndrome features
low set eyes that slope upwards
epicanthic folds
small mouth - tongue appears big and may stick out
flattened back of head
flattened nose bridge
broad hands, single crease
floppiness - loose muscle tone
low set ears
low birth weight
Describe chorionic villus sampling
11-14 weeks
small miscarriage risk
sample taken from placenta
results:
- PCR in 3-4 days
- micro-array in 3 weeks
Describe amniocentesis
15 weeks+ (enough amniotic fluid present at this point)
small miscarriage risk
results:
- PCR 3-4 days
- micro-array 3 weeks
When is the foetal anatomy scan?
18+6 weeks - 20+6 weeks
What is done in the foetal anatomy scan?
all organs and structures are checked that they are present and in the correct place
What is gastroschisis?
a birth defect where a baby’s intestines protrude through a hole in the abdominal wall, usually to the right of the belly button, without a membrane covering them
What is an examphalos/omphalocele?
a birth defect where a baby’s abdominal wall doesn’t fully close, causing the intestines (and sometimes other organs) to protrude outside the body within a sac at the base of the umbilical cord.
