L17 Part 2 Intra-Uterine Growth Restriction, Abnormal Fetal Development

Question 1

Development vs Growth

Answer 1

First 12 weeks fetal development occurs – organs formed

Then the baby needs to get bigger – fetal growth

Question 2

2 types of growth problems

Answer 2

Small for gestational age (SGA)

• <5th centile
• normal variant or growth restricted

Intra-uterine growth restriction (IUGR)

• <5th centile
• growth restricted (i.e. failure to achieve growth potential)

Question 3

Foetal growth restriction can be the result of

Answer 3

Deficient placental invasion
Reduced placental reserve
Foetal need exceeds supply
IUGR
Hypoxia
Foetal vascular redistribution
Oliguria
Abnormal CTG
Foetal death

Question 4

Diagnosis

Answer 4

Clinical suspicion - abdomen ‘looks smaller’

Clinical measurement of uterine size: symphysis - fundal height (SFH)

SFH = weeks +/- cms

Ultrasound scan

Question 5

How is fundal height measured?

Answer 5

From the pubic symphysis to the topmost portion of the uterus

Question 6

Symmetrical foetal growth restriction

Answer 6

In symmetrical growth restriction the Head circumference, the BPD (biparietal diameter of the head) and the abdominal circumference growth are ALL reduced/affected

Question 7

Causes of early (symmetrical) foetal growth restriction

Answer 7

Chromosomal anomaly (T21)

Viral infection (Rubella, CMV)

Severe placental insufficiency

OR normal small baby (look at parents)

Question 8

Asymmetrical growth restriction

Answer 8

Only the abdominal growth is reduced

Question 9

What does abdominal circumference reflect?

Answer 9

the size of the foetal liver

Question 10

Causes of asymmetrical growth restriction

Answer 10

Placental insufficiency - no excess glycogen being deposited within the liver

Question 11

Consequences of hypoxia in the foetus

Answer 11

Blood flow redirected to areas of greater importance - brain

Blood flow redirected away from areas of lesser importance - gut, kidneys (placenta clears waste), lungs (placenta brings o2)

Question 12

Ultrasound findings in IUGR

Answer 12

Small AC (small liver)

Decreased amniotic fluid (this is produced by the kidneys)

Increased blood flow to the brain (look at middle cerebral arteries in the brain - using the doppler effect scan)

Question 13

Clinical features of IUGR

Answer 13

SFH smaller than expected

Baby’s movements lessen to conserve energy

Foetal heart rate changed as hypoxia develops (as seen on CTG)

Foetal death

Question 14

Wait or deliver in IUGR?

Answer 14

Wait

• low chances of survival
• to give steroids
• reduce need for C/S

Deliver

• > /= 32 weeks
• doppler abnormality
• decreased movements
• CTG abnormality

Question 15

Betamethasone/dexamethasone

Answer 15

Crosses placenta and stimulates alveoli cells to produce surfactant gene

Surfactant stops the collapse of alveoli cells by coating cells and reducing surface tension

Helps prevent Resp distress syndrome which leads to death in premature babies

Produced from 24-34 weeks and usually the baby will have enough by 34 weeks in prep for term delivery

In premature babies it is lacking

Question 16

Foetal growth restriction - middle cerebral artery

Answer 16

Blood flow is maintained during both systole and diastole - increasing blood flow