High Risk Pregnancies

Question 0

When does Rhesus isoimmunisation occur?

Answer 0

If foetus is D Rhesus positive, and mother is D Rhesus negative

Question 1

What is Rhesus isoimmunisation?

Answer 1

Occurs when a maternal antibody response is mounted against foetal red cells.

These igG antibodies cross the placenta and cause foetal RBC destruction

Mild: neonatal jaundice, anaemia, haemolytic disease of the newborn

Severe: cardiac failure, ascites, oedema, foetal death

Question 2

What are sensitising events?

Answer 2

TOP and ERPC
Ectopic pregnancy
Vaginal bleeding
Miscarriage OVER 12 weeks
External cephalic version
Amniocentesis or CVS
Delivery

Question 3

When should Anti D be given to prevent Rhesus haemolytic disease?

Answer 3

28 and 34 weeks

After sensitising events (250 units before 20 weeks, 500 after)

In all Rhesus negative women

Postnatal anti d if baby is Rhesus positive (500 units)

Question 4

How can the foetal blood group be assessed?

Answer 4

Fathers blood group

PCR of foetal cells in maternal blood

Question 5

When and how can foetal anaemia be assessed?

Answer 5

If the maternal antibodies are >10 IU/ml

Doppler of foetal middle cerebral artery

If Doppler velocity is increased, perform foetal blood sampling to assess haematocrit

Question 6

When and how should foetal anaemia be treated?

Answer 6

If foetal haematocrit is <30

Packed red cells can be transfused into the umbilical vein - may need to be repeated

Anaemia can be corrected by transfusion after delivery

Question 7

Does blood pressure rise or fall in normal pregnancy?

Answer 7

Blood pressure falls until 24 weeks due to decrease in vascular resistance

Blood pressure rises after 24 weeks due to increase in cardiac output

Question 8

How many women with pre-existing hypertension go on to develop pre-eclampsia?

Answer 8

25%

Question 9

What is pregnancy induced hypertension?

Answer 9

Hypertension greater than 140/90 in the second half of pregnancy

This occurs in the absence of proteinuria and other markers of ore-eclampsia

Question 10

How common is pregnancy induced hypertension?

Answer 10

Affects 6-7% of pregnancies

Increased risk of going in to get pre-eclampsia (15-26%)

Question 11

When should a woman with pre-eclampsia/hypertension be admitted?

Answer 11

BP >140/90 and proteinuria

Symptoms of pre-eclampsia

Foetal distress on ctg, umbilical artery Doppler wave form, biophysical profile

Question 12

What are the maternal complications of pre-eclampsia?

Answer 12

Cerebrovascular haemorrhage
Eclampsia
Hepatic coagulopathy - hellp syndrome
Pulmonary
Renal

Question 13

What are the foetal complications of pre-eclampsia?

Answer 13

Prematurity - often results from necessary intervention

IUGR due to placental insufficiency

Placental abruption

Question 14

How is pre-eclampsia managed?

Answer 14

Consider oral treatments - BP>170 requires treatment
Labetalol
Nifedipine
Methyl dopa

Delivery may be an option

Question 15

How is eclampsia managed?

Answer 15

Control airway/O2

IV diazepam until fits stop

IV magnesium sulphate

Question 16

What is IUGR?

Answer 16

A foetus that is pathologically small

Question 17

What are the maternal causes of IUGR?

Answer 17

Chronic maternal disease - HTN, CKD
Alcohol and substance abuse
Smoking
Autoimmune disease
Genetic disorders - phenylketonuria
Poor nutrition
Low socio-economic status

Question 18

What are the placental causes of IUGR?

Answer 18

Abnormal trophoblast invasion - pre-eclampsia and placenta accreta
Infarction
Abruption
Placenta previa
Placental haemangioma
Abnormal umbilical cord - two vessels

Question 19

What are the foetal causes of IUGR?

Answer 19

Genetic abnormalities:
trisomy 13, 18, 21
Turners syndrome
Triploidy

Congenital abnormalities:
Tetralogy of fallot, transposition
Gastroschisis

Congenital infection:
CMV
Rubella
Toxoplasmosis
Multiple pregnancy

Question 20

What is symmetric growth restriction?

Answer 20

A foetus whose entire body is proportionately small

Tends to be seen with early onset IUGR, often due to chromosomal abnormalities

Question 21

What is asymmetric growth restriction?

Answer 21

Foetus which has a normal head size with small abdominal circumference and thin limbs

Seen in an undernourished foetus who is directing energy to maintain growth of vital organs such as brain and heart

Most often seen in placental insufficiency

Question 22

What investigations are used to foetal growth and well being in IUGR foetuses?

Answer 22

Weekly umbilical artery dopplers

Daily CTG if Doppler waveforms are consistently abnormal

The compromised foetus is normally delivered once maturity is attained (37 weeks)

Question 23

What is the long term outcome for IUGR babies?

Answer 23

Most congenitally normal IUGR babies go on to grow normally in childhood

However subtle differences may occur such as not reaching predicted height, or childhood attention and performance deficit