Preconception and antenatal care

Question 1

What general advice can you give someone pre-conception if they are planning to have a baby?

Answer 1

Smoking - cease
Alcohol and substance use - no safe amount
Nutrition - 5 food groups with folic acid and iodine supplements
Physical activity - continue
Weight - healthy BMI
Optimise disease management - diabetes, HTN, hypothyroidism, epilepsy (change meds)
CST screening an continue in pregnancy
Vaccinations - rubella, varicella, flu, HBV

Question 2

How do you calculate estimated due date?

Answer 2

1. LMP
   1st day of LMP + 7 days + 9 months
2. Early USS
   At 8-13wks
   If EDD from LMP and USS differ by >5days, use the date from the USS.
   If they differ by <5days use LMP.

Question 3

When do you give anti-D?

Answer 3

28wks
34wks
After delivery

Question 4

Booking in antenatal appt - what investigations do you order and why

Answer 4

FBC - anaemia and thrombocytopenia
Group and hold - rhesus status and isoimmunisation
Rubella IgG - congenital rubella syndrome
Syphilis serology
Hepatitis B serology
Hepatitis C Abs
HIV
MSU and dipstick
Chlamydia (endocervical swab PCR)
Early OGTT if high risk

Book the dating scan for 8-12wks

Question 5

What labs do you need to order for the 28wk antenatal appt

Answer 5

OGTT
FBC
Syphilis serology if high risk

Question 6

What’s the antenatal visit schedule?

Answer 6

Every 4 weeks until 28 wks
Every 2 wks until 36 wks
Every week until delivery

Question 7

What do you look for in genetic pre-conception testing

Answer 7

1. Cystic fibrosis
2. SMA (spinal muscular atrophy)
3. Fragile X syndrome

Option to look for more genetic diseases with Expanded genetic testing ($900)

NB: “pre-conception testing” can also be done in the 1st trimester.

Question 8

What problems can the nuchal translucency screening detect?

Answer 8

Probability of T21/18/13
Problematic placentation
Foetal anatomy (anencephaly, hydrops fetalis)
CHD

Question 9

Compare the sensitivity of nuchal translucency screening VS NIPT test

Answer 9

NTS = 90% sensitivity (but $0)
NIPT = 98% sensitivity (but $400)

Question 10

What genetic screening tests are available antenatally? And what do they involve for the mum e.g. how are they conducted, what is looked at.

Answer 10

Preconception testing

Nuchal translucency screening

• US and bloods
• maternal risk factors (height and weight, smoking status, diabetes status, ethnicity, parity, IVF, prev hx trisomy)
• PAPPA
• hcg
• nasal bone
• foetal HR

Non-Invasive prenatal test (NIPT)
- tests for foetal DNA in maternal blood

Question 11

What happens if NIPT comes back as high risk?

Answer 11

Still not diagnostic - offer amniocentesis

Question 12

What is the main risk assoc with amniocentesis

Answer 12

1 in 200 risk of miscarriage