Large for Dates

Question 1

What is the Definition of Large for Dates?

Answer 1

Weight at birth above 4.5kg, During pregnancy EFW > the 90th centile is considered Large for gestational Age.

Question 2

What are the possible Aetiologies for LFD?

Answer 2

Wrong dates.
Multiple Pregnancy.
Foetal Macrosomia.
Polyhydramnios.

Question 3

How is Foetal Macrosomia Diagnosed? (Antenatal)

Answer 3

USS EFW > 90th centile, AC > 97th centile.

Question 4

What is the general management for Macrosomia ?

Answer 4

• Exclude Diabetes.
• Reassure.
• Conservative vs IOL vs C-section delivery.

NICE recommendation: In the absence of any other indications, induction of labour should not be carried out simply because LFD is suspected.

Question 5

What measurements define Polyhydramnios?

Answer 5

Deepest Pool >8cm.
Amniotic Fluid Index (AFI >25cm).
Subjective.

All Describe Excess Amniotic Fluid.

Question 6

What are the riskfactors for Large for gestational Age?

Answer 6

Constitutional (Genetics, Tall Parents).
Maternal diabetes.
Previous macrosomia.
Maternal obesity or rapid weight gain.
Being Overdue for dates.
Male baby.

Question 7

What are the risks to the mother of Large for gestational Weight?

Answer 7

Shoulder dystocia. (Babies shoulder stuck)
Failure to progress.
Perineal tears.
Instrumental delivery or caesarean.
Postpartum haemorrhage.
Uterine rupture (rare).

Question 8

What are the risks to the baby for Large for Gestational Weight?

Answer 8

Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia).
Neonatal hypoglycaemia (Blood Glucose dropping after birth).
Obesity in childhood and later life.
Type 2 diabetes in adulthood.

Question 9

What are the investigations for LGA?

Answer 9

USS to Exclude Polyhydramnios and estimate the Foetal weight.

Oral-GTT for Gestational Diabetes.

Question 10

What is the main risk for a baby with Macrosomia?

Answer 10

Shoulder Dystocia.

Others:
- Tears in labour.
- PPH.
- Labour Dystocia.
- Maternal Anxiety

Question 11

What is the most likely cause of Foetal Macrosomia?

Answer 11

Gestational Diabetes

Question 12

What is Polyhydramnios and how is it caused?

Answer 12

Too much Amniotic Fluid surrounding the Foetus.

Caused by:
- A twin or Multiple pregnancy.
- Gestational Diabetes.
- Viral Infection (Erythrovirus B19, CMV, Toxo)
- Rhesus disease. (Hydrops Fetalis)
- Foetal Gut Atresia.

Question 13

What are things you might see clinically in Polyhydramnios?

Answer 13

Tense, shiny abdomen.
Inability to feel Foetus.
Pre-labour rupture of membranes.

Symptoms:
- Abdo discomfort.
- Pre-term labour.
- Cord prolapse.

Question 14

How is Polyhydramnios diagnosed?

Answer 14

USS confirmation.
Deepest Vertical Pool > 8cm.
Amniotic Fluid Index > 25mm.

The diagnosis is subjective to the clinician who determines it.

Question 15

What Investigations should be done in Polyhydramnios?

Answer 15

OGTT.
Viral Serology (Toxo, CMV, Parvovirus).
Antibody screen.
USS - Foetal Survery - Lips, stomach bubble.

Question 16

How is Polyhydramnios managed?

Answer 16

Inform patient of potential complications.
Serial USS (growth, LV, Presentation)
IOL by 40 wks.

Question 17

What is the incidence of Spontaneous twins and triplets?

Answer 17

Spontaneous Twins: 1 in 80.
Spontaneous Triplets: 1 in 10,000.

Increased with Assisted Conception.

Question 18

What are risks for Multiple pregnancy?

Answer 18

Assisted conception.

Race - African.
Geography - Africa.
Family Hx.
Increased Maternal Age.
Increased Parity. (Increased number of times a female has been pregnant)

Question 19

What does Zygosity mean?

Answer 19

It refers to the degree to which two chromosomes have the same genetic sequence.

Question 20

How are Monozygotic and Dizygotic twins formed?

Answer 20

Monozygotic (Identical): Splitting of a single fertilised egg - 30%.

Dizygotic (non-identical): Two seperate ova fertilised by two seperate spermatozoa - 70%.

Question 21

What does Chorionicity refer to?

Answer 21

Refers to whether multiple foetuses share a placenta or whether they have separate.

Question 22

Do Dizygous twins have 1 placenta or 2 placentas?

Answer 22

2

They are always Dichorionic Diamniotic (DCDA) meaning they have individual chorionic and amniotic sacs.

Question 23

Do Monozygous twins have 1 or 2 placentas?

Answer 23

Can differ depending on the time of the splitting of the Fetilised Ovum.

MCMA - Monochorionic Monoamniotic.

MCDA - Monochronic Diamnionic.

DCDA - Dichorionic Diamniotic.

Conjoined.

Question 24

When would Monozygous twins be Dichorionic Diamniotic (DCDA)?

Answer 24

Fertilised ovum splitting Day 3 after fertilisation.

Question 25

When would Monozygous twins be Monochorionic Diamniotic (MCDA)?

Answer 25

Fertilised Ovum splitting day 4-7 post fertilisation.

Question 26

When would Monozygous twins be Monochorionic Monoamniotic (MCMA)?

Answer 26

Fertilised Ovum splitting day 8-14 after fertilisation.

Question 27

When would Monozygous twins be Conjoined?

Answer 27

Fertilised Ovum splitting Day 15 onwards after fertilisation.

Question 28

Which set of twins carry a greater risk of Pregnancy complications?

Answer 28

Monochorionic / Monozygous.

Question 29

What is Medications are given in Multiple pregnancy?

Answer 29

Fe Supplementation.
Low dose Aspirin.
Folic Acid.

Question 30

How often are pregnancies scanned up in Multiple pregnancy?

Answer 30

MC 2 weekly from 16/40.
Anomaly USS 18-20 wks.
Deep Vertical pool, Bladder and Umbilical Artery Doppler (UAPI), EFW.

DC 4 weekly.

Question 31

What are some Complications that can occur with Monochorionic twins?

Answer 31

• Single Foetal death.
• Selective Growth Restriction (sGR).
• Twin to Twin Transfusion Syndrome (TTTS).
• Twin Anaemia - Polycythemia Sequence (TAPS).
• Absent End Diastolic Volume (AEDV) or reversed (REDV).