Baby Large/Small Gestational Age (L/SGA)

Question 1

What weight and what gestational age make a baby ‘low birth weight (LBW)’?

Answer 1

LBW = >2.5kg regardless of gestation

Question 2

What are risk factors for a small gestational age baby?

Answer 2

History of pre-term birth
Multiple pregnancy
Drug use
Poverty
High parity

Question 3

What is intrauterine growth restriction (IUGR)?

Answer 3

A failure for a baby to reach its growth potential

Question 4

What is symmetrical IUGR and asymmetrical IUGR?

Answer 4

Symmetrical: small head and small body

Asymmetrical: small head and normal body

Question 5

What complications can occur with IUGR?

Answer 5

Fetal hypoxia/death

Maldevelopment

Infection

Hypothernia

Polycythaemia

Question 6

What are some maternal causes of IUGR?

Answer 6

Drug use
Chronic disease
Poor nutrition

Question 7

What are some foetal causes of IUGR?

Answer 7

Infection (CMV, rubella, toxoplasma)

Chromosomal abnormality

Question 8

What are some placental causes of IUGR?

Answer 8

Abruption (placenta seperates from uterine wall)

Question 9

When should you aim to deliver a SGA baby?

Answer 9

37 weeks

Question 10

What indicates a c-section for a SGA baby?

Answer 10

Static growth

Abnormal doppler testing

Question 11

What should you give a baby which is going to born prematurely and why?

Answer 11

Steroids (matures lungs)

Magnesium sulphate (protects brain)

Question 12

What makes a baby large for dates?

Answer 12

Fundal height > 2cm bigger than estimated for gestational age

Question 13

What is macrosomia and why is it important to pick up?

Answer 13

Estimated foetal weight (EFW) > 90th centile

Risks gestational diabetes (do OGTT)

Risks dystocia (organise delivery plan)

Can cause post partum haemorrhage

Question 14

What is polyhydramnios and why is it important to pick up?

Answer 14

Excess amniotic fluid

Can cause

• cord prolapse
• preterm labour
• malpresentation

Question 15

What are the maternal causes of polyhydramnios?

Answer 15

Diabetes

maternal hyperglycaemia causes foetal hyperglycaemia and poluria - polyuria produces excess fluid

Question 16

What are the foetal causes of polyhydramnios?

Answer 16

Malformation

Monochorionic twins
(one amniotic sac for two foetuses requires more fluid)

Hydrops fetalis (foetal anaemia produces excess fluid for sufficient oxygen delivery)

Viral infection (CMV, toxoplasma, erythrovirus B19)

Question 17

How does polyhydramnios present?

Answer 17

Abdominal discomfort
Tense shiny abdomen
Can’t feel foetal parts

Question 18

How do you diagnose polyhydramnios?

Answer 18

Amniotic fluid index > 25cm
(US measurement of amniotic fluid)

Deepest pool > 8cm
(US measurement of deepest visible pocket of fluid)

Question 19

How do you manage polyhydramnios?

Answer 19

OGTT, viral serology

Serial scans for monitoring

Deliver by 40 weeks

Question 20

What are the risk factors for multiple pregnancy?

Answer 20

Assisted conception
Family history
Increased age/parity

Question 21

Define

• zygosity
• chorionicity
• amniocity

Answer 21

Zygosity: how many eggs

• monozygotic = one fertilised egg splits (identical twins)
• dizygotic = two eggs fertilised by two sperm (non-identical)

Chorionicity: how many placentas

• monochorionic = one placenta for both twins
• dichorionic = two placentas, one for each twin

Amniocity: how many amniotic sacs

• monoamniotic = one amniotic sac for both twins
• diamniotic = two amniotic sacs, one for each twin

Question 22

Describe the following types of twin

• Monochorionic monoamniotic (MCMA)
• Monochorionic diamniotic (MCDA)
• Dichorionic monoamniotic (DCMA)
• Dichorionic diamniotic (DCDA)

Answer 22

MCMA: One placenta, one amniotic sacs

MCDA: One placenta, two amniotic sacs

DCMA: Two placentas, one amniotic sac

DCDA: Two placentas, two amniotic sacs

Question 23

What determines the form of monozygotic (identical) twins?

Answer 23

At what stage the fertilised egg splits

Day 0-3 (first half of week one)- DCDA

Day 4-7 (second half of week one) - MCDA

Day 8-14 (second week) - MCMA

Day >15 (after second week) - conjoined

Question 24

What determines the form of dizygotic twins?

Answer 24

Always DCDA

two seperate fertilisations so they develop their own placenta and amniotic sacs

Question 25

What form of twin is associated with poor outcomes, requiring more frequent observation?

Answer 25

Monochorionic One placenta has to provide nutrients for two babies

Question 26

How does multiple pregnancy present?

Answer 26

Larger uterus Hyperemesis gravidarum High alpha fetoprotein (exaggerated symptoms of normal pregnancy)

Question 27

Why is multiple pregnancy important to recognise?

Answer 27

Big risk to both foetuses

Question 28

How should you manage single foetal death in multiple pregnancy?

Answer 28

MRI other foetal brain 4 weeks after death of twin | risk of death/neurological abnormality in survivor

Question 29

What is twin-twin transfusion syndrome (TTTS) and how do you manage it?

Answer 29

One baby takes most of amniotic fluid (becomes polyhydramniotic) while the other gets less (becomes oligohydramniotic) Fetoscopic laser ablation

Question 30

What form of twin is most likely to get cord entanglement?

Answer 30

MCMA | share everything, more likely to get tangled up

Question 31

How do you assess chorionicity?

Answer 31

USS Lamba sign = DCDA T sign = MCDA

Question 32

What medications should you give a mother with multiple pregnancy?

Answer 32

Iron/folic acid Low dose aspirin

Question 33

How often should you US multiple pregnancy?

Answer 33

Monochorionic - fortnightly Dichorionic - monthly

Question 34

When should you deliver multiple pregnancy?

Answer 34

Monochorionic - 36 weeks with steroids Dichorionic - 37 weeks

Question 35

How do you manage preexisting DM in pregnancy?

Answer 35

Pre-pregnancy - HbA1c = 48 - high dose (5mg ) folic acid During pregnany - low dose aspirin - control BG - more regular retinopathy screening Delivery - aim for 38 weeks (earlier if complications)

Question 36

What is gestational diabetes?

Answer 36

Onset of glucose intolerance causing hyperglycaemia in pregnancy

Question 37

What causes gestational diabetes?

Answer 37

Human placental lactogen (normally causes insulin resistance in pregnancy to ensure good glucose supply to baby - in at risk patient can cause diabetes)

Question 38

What are the complications of gestational diabetes?

Answer 38

Macrosomia Maternal/baby diabetes later

Question 39

How do you diagnose gestational diabetes?

Answer 39

Oral glucose tolerance test (OGTT)

Question 40

When do you deliver in gestational diabetes?

Answer 40

Depends on hypoglycaemic agent Diet controlled - 40 weeks Metformin - 39 weeks Insulin - 38 weeks (method maternal preference but warn of shoulder dystocia risk)

Question 41

Women travelling from abroad presents with baby large gestational age. Cause?

Answer 41

Late booker | risk factors: concealed pregnancy, vulnerable women, transfer of care

Question 42

Describe the basics of foetal growth assessment.

Answer 42

12 week dating scan (all women given growth chart) Serial growth assessment from week 26 Concerning growth patterns may indicate growth scan/doppler assessment

Question 43

How do you measure growth at the growth assessments?

Answer 43

Fundal height - 1cm=1 week gestation USS biometry if - this won't work (e.g. fibroids, high BMI, multiple pregnancy) - high risk (diabetes)

Question 44

What are the indications for a growth scan?

Answer 44

(concerning growth patterns on serial growth assessment) - first fundal height measurement below 10th centile (above 90th not an indication) - dropping centiles - climbing centiles (above 90th) - static growth

Question 45

What do growth scans measure?

Answer 45

Estimated foetal weight (EFW)

Question 46

What do you do if the growth scan shows the baby is - small gestational age (SGA) - large gestational age (LGA)

Answer 46

SGA (EFW <10th centile) - umbilical/middle cerebral artery doppler LGA - OGTT

Question 47

What do umbilical artery doppler and middle cerebral artery doppler assess?

Answer 47

Umbilical - growth - abnormal suggests grwoth restrition Middle cerebral - cardiovascular - abnormal suggests foetal cardiovascular distress

Question 48

When should you deliver multiple pregnancy?

Answer 48

Dichorionic: week 37 Monochoiornic: week 36 (steroids) Triplets: week 35 (steroids and c-section)