Small & Large Births

Question 1

What are the 2 main causes for a small baby?

Answer 1

Pre-term delivery

Small for gestational age due to intrauterine growth restriction (IUGR) or simply constitutionally small!

Question 2

How is a birth defined as preterm?

Answer 2

Delivery between 24-36 weeks gestation

Question 3

List some causes of preterm birth

Answer 3

Infection
Overdistention (multiple pregnancy, polyhydraminos)
Placental abruption
Cervical incompetence
Intercurrent illness (UTI, appendicitis, pneumonia)
Idiopathic

Question 4

How is a baby defined as being small for gestational age? What is IUGR? What is LBW?

Answer 4

Estimated fetal weight or abdominal circumference below 10th centile
Failure to achieve growth potential
Birth weight below 2.5kg regardless of gestation

Question 5

What maternal factors cause poor growth of a foetus?

Answer 5

Lifestyle: smoking, drugs, alcohol
BMI 19 or less
Extremes of age
Disease: hypertension (placental infarcts)

Question 6

What foetal factors cause poor growth of a foetus?

Answer 6

Infection: rubella, CMV
Congenital anomalies
Chromosomal abnormality

Question 7

What are the consequences to the foetus if there is growth restriction?

Answer 7

Hypoxia
Hypoglycaemia
Asphyxia
Hypothermia
Polycythaemia
Abnormal neurodevelopment

Question 8

What are some clinical indicators of poor growth?

Answer 8

Syphysial-fundal height less than expected (from 24w)
Reduced liquor or amniotic fluid index
Reduced foetal movements

Question 9

List some antenatal methods for assessing fetal wellbeing with poor growth

Answer 9

Serial growth scans
Biophysical assessment
Cardiotocography (measure foetal heartbeat)
Doppler US (umbilical artery, MCA, ductus venosous)

Question 10

How is poor growth of the fetus monitored during pregnancy?

Answer 10

Syphysial-fundal height from 24 weeks
Growth scan if measurement below 10th centile
Estimated fetal weight (abdo, head circ, femur length)
Liquor volume or amniotic fluid index

Question 11

What are the main aetiology behind large babies?

Answer 11

Wrong date
Multiple pregnancy
Diabetes
Polyhydramnios
Fetal macrosomia

Question 12

What is the difference between zygosity and chorionicity?

Answer 12

Zygosity: number of eggs fertilied to produce twins
Chorionicity: membrane pattern of the twins

Question 13

Which is the outer layer - chorion or amnion?

Answer 13

Chorion outside

Amnion inside

Question 14

Describe a dichorionic diamniotic pregnancy

Answer 14

Each foetus has its own amniotic sac and its own placenta

All dizygotic twins

Question 15

Describe a monochorionic diamniotic pregnancy

Answer 15

Each foetus has its own amniotic sac but shared placenta

Question 16

Describe a monochorionic monoamniotic pregnancy

Answer 16

Both foetuses share amniotic sac and placenta

Question 17

Multiple pregnancies carry higher perinatal mortality due to what?

Answer 17

Congenital anomalies
Preterm labour
Growth restriction
Pre-eclampsia
Twin-twin transfusion
Cerebral palsy
PPH

Question 18

Outline management options for multiple pregnancy

Answer 18

Consultant-led care
Pregnancy clinic and US (MZ every 2w, DZ every 4w)
Maternal education and support

Question 19

How are triplets and twins delivered?

Answer 19

C-section if triplets

Aim for vaginal if twins

Question 20

How is multiple pregnancy diagnosed?

Answer 20

USS confirmation at 12 weeks

High AFP

Question 21

What are the clinical signs and symptoms of multiple pregnancy?

Answer 21

Exaggerated pregnancy e.g. hyperemesis gravidarum
Greater maternal age
Use of ACT
Family history

Question 22

How is fetal macrosomia diagnosed?

Answer 22

‘Big baby’

USS EFW > 90th centile

Question 23

What are the risks associated with macrosomia?

Answer 23

Clinician and maternal anxiety
Labour dystocia
Shoulder dystocia
Post partum haemorrhage

Question 24

How is fetal macrosomia managed?

Answer 24

Exclude diabetes (OGTT)
Reassurance
Conservative vs induction of labour vs c-section

Question 25

What is polyhydramnios?

Answer 25

Excess amniotic fluid

Question 26

What causes polyhydramnios?

Answer 26

Maternal diabetes 
Monochorionic twin pregnancy
Foetal anomaly
Diabetes
Hydrops fetalis (accumulating fluid in fetus)
Idiopathic

Question 27

List clinical features of polyhydramnios

Answer 27

Abdominal discomfort
Tense shiny abdomen
Malpresentation
Inability to feel fetal parts

Question 28

List diagnostic techniques for polyhydramnios

Answer 28

USS
OGTT
Serology (toxoplasmosis, CMV, parovirus)
Antibody screen

Question 29

Outline management options for polyhydramnios

Answer 29

Patient information on complications
Serial USS
Induction of labour by 40 weeks
Neonatal exam

Question 30

List complications of polyhydramnios

Answer 30

Cord prolapse
Preterm labour
Post-partum haemorrhage

Question 31

List the forms of diabetes in pregnancy

Answer 31

Pregestational (type 1, type 2, MODY)

Gestational DM

Question 32

List management options for pregestational diabetes during pregnancy

Answer 32

Pre-pregnancy counselling (HBA1c monitoring, advice)
Diabetic antenatal clinic
Consider continuous glucose monitoring
Folic acid 5mg
Low dose aspirin
Regular screening for microvascular complications
Growth scans

Question 33

Describe the pathophysiology of gestational diabetes mellitus

Answer 33

Placental hormones cause insulin resistance in the mother, causing hyperglycaemia

Question 34

How does gestational diabetes lead to macrosomia?

Answer 34

Overgrowth of insulin sensitive tissues due to hyperinsulinaemia

Question 35

How is gestational diabetes diagnosed?

Answer 35

OGTT in 1st trimester and 24-28 weeks
Fasting: 5.1 mmol/l or more
2-hour: 8.5 mmol/l or more

Question 36

List risk factors for gestational diabetes

Answer 36

Previous GDM
BMI >30
FHx
Previous big baby or big baby on USS
Polyhydramnios 
Glycosuria

Question 37

Outline antenatal management options for gestational diabetes

Answer 37

Care plan
Education on diet, weight control, exercise
Targets for glycaemic control
Growth scans 
Monitor for PET
Hypoglycaemic agents (oral or insulin)

Question 38

What is the indications for hypoglycaemic agents in gestational diabetes?

Answer 38

Diet and exercise fail to maintain target

Macrosomia on US

Question 39

What are the targets for glycaemic control in gestational diabetes?

Answer 39

Measure minimum 4 x a day and before bed
Fasting: 3.5-5.9 mmol/l
1 hr <7.8 mmol/l

Question 40

Outline postnatal management options for gestational diabetes

Answer 40

Fasting blood sugar 6-8 weeks post-natal
If T2DM suspected - OGTT 6 weeks post-natal
Annual FBS and lifestyle changes

Question 41

Maternal diabetes can cause foetal hyperinsulinaemia and increased foetal growth. What are the consequences of this?

Answer 41

Macrosomia
Polyuria, polyhydramnios
Increased O2 demands
Neonatal hypoglycaemia