Antenatal Care - High Risk Pregnancy

Question 1

What are the two main options for diagnostic testing for foetal abnormalities?

Answer 1

Chorionic villus sampling (CVS)

Amniocentesis

Question 2

When can CVS be done?

Answer 2

Between 11 and 13+6 weeks

Question 3

What can amniocentesis be done?

Answer 3

After 15 weeks

Question 4

What are the risks associated with diagnostic tests?

Answer 4

Miscarriage

• 2% for CVS
• 1% for amniocentesis

Also risk of amniotic fluid embolism with CVS

Question 5

When are diagnostic tests offered to women?

Answer 5

If she is considered to be at increased risk of foetus having a genetic syndrome e.g.

• high risk at Down’s screening
• abnormality at foetal anomaly scan
• known genetic condition in mother or father

Question 6

Which other screening test is available for genetic conditions, but not on the NHS?

Answer 6

Non-invasive prenatal testing (NIPT)

- analyses foetal DNA in mother’s blood

Question 7

What is the benefit of NIPT?

Answer 7

More sensitive than 1st trimester down’s screening

–> reduces number of false positives, therefore reduces number of women undergoing CVS or amniocentesis

Question 8

What are the risk factors for multiple pregnancy?

Answer 8

Assisted conception
Ethnicity (African)
Family history on maternal side
Increasing maternal age
Increasing parity
Tall women > short women

Question 9

How is zygosity described in multiple pregnancy?

Answer 9

Monozygotic - splitting of a single fertilised egg

Dizygotic - fertilisation of 2 ova by 2 sperm

Question 10

How is Chorionicity described in multiple pregnancy?

Answer 10

(1 placenta or 2 placentas)

Dichorionic 
- always dichorionic diamniotic
Monochorionic:
- monochorionic monoamniotic
- monochorionic diamniotic
conjoined twins

Question 11

Which type of twins are at the highest risk of complications?

Answer 11

Monochorionic/monozygous twins

–> twin-twin transfusion syndrome

Question 12

What are the signs and symptoms of multiple pregnancy?

Answer 12

Exaggerated pregnancy symptoms e.g. sickness/hyperemesis gravidarum
High AFP
Large for dates uterus
Multiple fetal poles

Question 13

How is antenatal care different for multiple pregnancy?

Answer 13

Consultant led care
Every 2 weeks for monochorionic pregnancy, every 4 weeks for dichorionic pregnancy
Iron + folic acid supplements
Low dose aspirin to prevent hypertensive disorders
From 16th week, USS every 2 weeks

Question 14

What is twin-twin transfusion syndrome (TTTS)?

Answer 14

Disproportionate blood supply to foetuses in monochorionic pregnancies

• donor twin has reduced blood supply
• recipient twin has increased blood supply

Question 15

What are the features of the donor twin in TTTS?

Answer 15

Reduced growth + development

Decreased urine output –> anaemia + oligohydramnios

Question 16

What are the features of the recipient twin in TTTS?

Answer 16

Increased urinary output –> polyhydramnios, polycythaemia + eventually heart failure

Question 17

How is TTTS treated?

Answer 17

Fetoscopic laser ablation recommended before 26 weeks

Question 18

When would a C-section be planned for multiple pregnancy?

Answer 18

Triplets or more
Monochorionic monoamniotic twins
Other twins - mother’s choice

Question 19

What are the options for delivery of a baby in breech position?

Answer 19

Vaginal/external cephalic version
or Elective C-section

(maternal choice)

Question 20

When would external cephalic version be offered for breech presentation?

Answer 20

At/after 36 weeks

breech is normal up to 36 weeks

Question 21

When is a pregnancy considered ‘prolonged’?

Answer 21

After 42 weeks

Question 22

What are the risks of prolonged pregnancy?

Answer 22

Increased risk of stillbirth

Meconium aspiration –> respiratory distress

Question 23

When is induction of labour offered to prevent prolonged pregnancy?

Answer 23

Between 41-42 weeks

Question 24

How is a pregnancy dated during the first trimester (usually booking visit)?

Answer 24

Crown-rump length on USS

Question 25

How is foetal growth assessed during the third trimester?

Answer 25

Abdominal circumference, head circumference + femur length

–> equation calculated an estimated foetal weight

Question 26

Which scans are safe during pregnancy?

Answer 26

USS

MRI

Question 27

How many scans does an uncomplicated pregnancy usually get?

Answer 27

2

• booking + anomaly
• foetal growth scans only done in high risk pregnancies

Question 28

How is foetal growth monitored in low risk pregnancies?

Answer 28

Symphyseal fundal height (SFH)

- if too large or small, referred for a growth scan

Question 29

What is the definition of stillbirth?

Answer 29

Baby born with no signs of life at or after 28 weeks gestation

Question 30

What are the definitions of neonatal mortality, early neonatal mortality + later neonatal mortality?

Answer 30

Noeonatal mortality:
- death of a live born baby within 28 days of life
Early:
- death within 7 days
Late:
- death after 7 days, before 28 days