Large for Dates Flashcards by Hannah Farquhar

Define large for dates

Symphyseal-fundal height >2cm for gestational age

Estimated foetal weight >90th centile

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State five causes for large for dates

wrong dates
foetal macrosomia
polydramnios
diabetes
multiple pregnancy

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What does an USS of foetal macrosomia show?

Estimated foetal weight >90th centile

Abdominal circumference >97th centile

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How is foetal macrosomia managed?

Exclude diabetes
Reassure
Conservative/induction/C-section

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What are the NICE guidelines for delivery of macrosomic babies?

Absence of other indications do not induce labour purely because of macrosomia

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What are the risks of macrosomia?

Dr/maternal anxiety 
Labour dystocia 
Shoulder dystocia 
Diabetes 
Post-partum haemorrhage

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What is the name for excess amniotic fluid?

Polyhydramios

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How is excess amniotic fluid quantified?

Amniotic fluid index >25cm

Deepest pool >8cm

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What can cause polyhydramios?

Maternal - diabetes
Foetal
- anomaly - GI atresia, cardiac, tumours
- monochorionic twin pregnancy
- hydros fetalis
- viral infection (toxoplasmosis, CMV, erythrovirus B19)

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What are the symptoms of polyhydramios?

Abdominal discomfort
Pre-labour rupture of membranes
Preterm labour
Cord prolapse

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What are the signs of polyhydramios?

Large for dates
Malpresentation
Shiny, tense abdomen
Inability to feel foetal parts

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How is polyhydramios diagnosed?

Ultrasound - AFI >25cm, DVP >8cm

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What are the investigations for polyhydramios?

Oral glucose tolerance test
Serology (toxoplasmosis, CMV, parvovirus)
Antibody screen
USS - foetal survey

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How is polyhydramios managed?

Induce labour by 40 weeks

Serial USS to assess growth, presentation

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What are the labour risks of polyhydramios?

Risk of malpresentation
Cord prolapse
Preterm labour
PPH

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Define multiple pregnancy

Presence of more than one foetus

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What are the risk factors for multiple pregnancy?

Assisted conception 
African 
Geography 
Family History 
Increased maternal age 
Increased parity 
Tall women

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Define zygosity

Whether the foetus’ have developed from a single ovum or different ova

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What is the difference between monozygosity and dizygosity?

Mono - splitting of a single fertilised egg

Di - fertilisations of two ova by two spermatozoa

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Define chrionicity

Number of placenta

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Name the four variations of monozygosity

Dichorionic diamnitoic
Monochorionic diamniotic
Monochorionic monoamnitoic
Conjoined twins

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What chorionicity is dizygous always?

Dichorionic diamniotic

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When can chorionicity and zygosity be determined?

Shape and thickness of membrane at booking scan

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What two signs can be seen on ultrasound to determine the chorionicity?

Lamdba - di

T sign - mono

What type of twins are at higher risk?

Monochorionic/monozygous

What are the signs/symptoms of multiple pregnancy?

Exaggerated pregnancy symptoms | Signs - high AFP, large for dates uterus, multiple fetal poles

State the fetal complications of multiple pregnancy

Congenital anomalies, intrauterine death, preterm birth, growth restriction, cerebral palsy, twin to twin trasfusion

State the maternal complications of multiple pregnancy

``` Hyperemesis gravidarum Anaemia Pre-eclampsia C-section Antepartum haemorrhage Diabetes ```

What medications should be given to patients with multiple pregnancy?

Iron supplements, low dose aspirin, folic acid

How many ultrasounds will a multiple pregnancy patient have?

MC - 2 weekly from 16 weeks | DC 4 weekly

If the pregnancy is monochorionic monoamniotic what is the management?

Deliver by c-section at 32-34 weeks

State the complications of monochorionic twins

- single fetal death - selective growth restriction - twin anaemia polycythaemia - absent/reversed end diastolic flow - twin to twin transfusion

How is single fetal death managed?

MRI 4 weeks post IUD and MCA US to check for fetal anaemia. Risk of death and neurological abnormality to the survivor are high.

If abnormal doppler is found on selective growth restriction what may be required?

Selective reduction

What is twin anaemia polycythaemia sequence?

Imbalance in blood levels between the two babies

What can cause twin anaemia polycythaemia sequence?

Spontaneously | Following laser ablation for TTTS

How is twin anaemia polycythaemia sequence diagnosed?

US of middle cerebral artery peak systolic velocity

Define twin to twin transfusion syndrome

Syndrome with artery-vein anastomoses, donor twin perfuses the recipient twin

How is twin to twin transfusion diagnosed?

Oligohydramios - donor | Polyhydramios - recipient

What are the complications of twin to twin transfusion?

Mortality >90% with no treatment | Neurological morbidity

How is twin to twin transfusion treated?

<26/40 weeks fetoscopic last ablation | >26/40 weeks amnioreduction/septostomy

When should babies with twin to twin transfusion be delivered?

34-36 weeks

What is the risk of C-section in multiple pregnancy?

50% greater risk of c-section

What are the indications for c-section in multiple pregnancy?

MCMA | Triplets or more

Describe labour in multiple pregnancy

``` Epidural Fetal monitoring (USS,FSE) Synthetic oxytocin after twin 1 USS for presentation <30 mins between deliveries ```

Define gestational diabetes

Carbohydrate intolerance resulting in hyperglycaemia of variable severity with onset/first recognition during pregnancy

What are the fetal complications of maternal diabetes?

Congenital anomalies, miscarriage, IUD, worsening diabetic complications, pre-eclampsia, polyhydramios, macrosomia, shoulder dystocia, neonatal hypoglycaemia

How is T1/T2 DM managed in pregnancy?

Low dose aspirin from 12 weeks Fetal anomaly scan 18-20weeks Growth scan 4 weekly Deliver at 38 weeks

What are the risk factors for gestational diabetes?

``` Previous GDM (50% recurrence) BMI >30 Family history - mum or sister Ethnic variation Previous big baby Big baby Glycosuria ```

Describe the pathogenesis of gestational diabetes

HPL and cortisol cause placental hormones to induce insulin resistance/deficiency causing overgrowth of sensitive tissues

How is gestational diabetes investigated?

BG monitoring, OGTT 24-28 weeks

What is the diagnostic fasting and 2 hour glucose for gestational diabetes?

Fasting >5.1/5.6 | 2 hour >8.5/7.8

What are the target values for fasting glucose and 1 hour?

Fasting 3.5-5.5 | 1 hour <7.8

What does delivery date depend on in diabetics?

Management

Describe the different delivery dates for diabetics

Insulin 38-39 weeks Metformin 39-40 weeks Diet 40-41 weeks Macrosomia/PET/IUGR - earlier delivery

When is a c-section indicated in diabetes?

EFW >4.5kg

What is the risk of post natal T2DM after gestational diabetes?

Up to 70%

What are the risk factors for post natal T2DM?

Obesity, use of insulin in pregnancy, ethnic group, OGTT fasting levels, IGT post partum

When are bloods checked post natally?

6-8 weeks fasting/OGTT