Baby Large/Small Gestational Age (L/SGA) Flashcards
What weight and what gestational age make a baby ‘low birth weight (LBW)’?
LBW = >2.5kg regardless of gestation
What are risk factors for a small gestational age baby?
History of pre-term birth Multiple pregnancy Drug use Poverty High parity
What is intrauterine growth restriction (IUGR)?
A failure for a baby to reach its growth potential
What is symmetrical IUGR and asymmetrical IUGR?
Symmetrical: small head and small body
Asymmetrical: small head and normal body
What complications can occur with IUGR?
Fetal hypoxia/death
Maldevelopment
Infection
Hypothernia
Polycythaemia
What are some maternal causes of IUGR?
Drug use
Chronic disease
Poor nutrition
What are some foetal causes of IUGR?
Infection (CMV, rubella, toxoplasma)
Chromosomal abnormality
What are some placental causes of IUGR?
Abruption (placenta seperates from uterine wall)
When should you aim to deliver a SGA baby?
37 weeks
What indicates a c-section for a SGA baby?
Static growth
Abnormal doppler testing
What should you give a baby which is going to born prematurely and why?
Steroids (matures lungs)
Magnesium sulphate (protects brain)
What makes a baby large for dates?
Fundal height > 2cm bigger than estimated for gestational age
What is macrosomia and why is it important to pick up?
Estimated foetal weight (EFW) > 90th centile
Risks gestational diabetes (do OGTT)
Risks dystocia (organise delivery plan)
Can cause post partum haemorrhage
What is polyhydramnios and why is it important to pick up?
Excess amniotic fluid
Can cause
- cord prolapse
- preterm labour
- malpresentation
What are the maternal causes of polyhydramnios?
Diabetes
maternal hyperglycaemia causes foetal hyperglycaemia and poluria - polyuria produces excess fluid
What are the foetal causes of polyhydramnios?
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)
How does polyhydramnios present?
Abdominal discomfort
Tense shiny abdomen
Can’t feel foetal parts
How do you diagnose polyhydramnios?
Amniotic fluid index > 25cm
(US measurement of amniotic fluid)
Deepest pool > 8cm
(US measurement of deepest visible pocket of fluid)
How do you manage polyhydramnios?
OGTT, viral serology
Serial scans for monitoring
Deliver by 40 weeks
What are the risk factors for multiple pregnancy?
Assisted conception
Family history
Increased age/parity
Define
- zygosity
- chorionicity
- amniocity
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
Describe the following types of twin
- Monochorionic monoamniotic (MCMA)
- Monochorionic diamniotic (MCDA)
- Dichorionic monoamniotic (DCMA)
- Dichorionic diamniotic (DCDA)
MCMA: One placenta, one amniotic sacs
MCDA: One placenta, two amniotic sacs
DCMA: Two placentas, one amniotic sac
DCDA: Two placentas, two amniotic sacs
What determines the form of monozygotic (identical) twins?
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
What determines the form of dizygotic twins?
Always DCDA
two seperate fertilisations so they develop their own placenta and amniotic sacs
What form of twin is associated with poor outcomes, requiring more frequent observation?
Monochorionic
One placenta has to provide nutrients for two babies
How does multiple pregnancy present?
Larger uterus
Hyperemesis gravidarum
High alpha fetoprotein
(exaggerated symptoms of normal pregnancy)
Why is multiple pregnancy important to recognise?
Big risk to both foetuses
How should you manage single foetal death in multiple pregnancy?
MRI other foetal brain 4 weeks after death of twin
risk of death/neurological abnormality in survivor
What is twin-twin transfusion syndrome (TTTS) and how do you manage it?
One baby takes most of amniotic fluid (becomes polyhydramniotic) while the other gets less (becomes oligohydramniotic)
Fetoscopic laser ablation
What form of twin is most likely to get cord entanglement?
MCMA
share everything, more likely to get tangled up
How do you assess chorionicity?
USS
Lamba sign = DCDA
T sign = MCDA
What medications should you give a mother with multiple pregnancy?
Iron/folic acid
Low dose aspirin
How often should you US multiple pregnancy?
Monochorionic - fortnightly
Dichorionic - monthly
When should you deliver multiple pregnancy?
Monochorionic - 36 weeks with steroids
Dichorionic - 37 weeks
How do you manage preexisting DM in pregnancy?
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)
What is gestational diabetes?
Onset of glucose intolerance causing hyperglycaemia in pregnancy
What causes gestational diabetes?
Human placental lactogen
(normally causes insulin resistance in pregnancy to ensure good glucose supply to baby - in at risk patient can cause diabetes)
What are the complications of gestational diabetes?
Macrosomia
Maternal/baby diabetes later
How do you diagnose gestational diabetes?
Oral glucose tolerance test (OGTT)
When do you deliver in gestational diabetes?
Depends on hypoglycaemic agent
Diet controlled - 40 weeks
Metformin - 39 weeks
Insulin - 38 weeks
(method maternal preference but warn of shoulder dystocia risk)
Women travelling from abroad presents with baby large gestational age.
Cause?
Late booker
risk factors: concealed pregnancy, vulnerable women, transfer of care
Describe the basics of foetal growth assessment.
12 week dating scan (all women given growth chart)
Serial growth assessment from week 26
Concerning growth patterns may indicate growth scan/doppler assessment
How do you measure growth at the growth assessments?
Fundal height - 1cm=1 week gestation
USS biometry if
- this won’t work (e.g. fibroids, high BMI, multiple pregnancy)
- high risk (diabetes)
What are the indications for a growth scan?
(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
What do growth scans measure?
Estimated foetal weight (EFW)
What do you do if the growth scan shows the baby is
- small gestational age (SGA)
- large gestational age (LGA)
SGA (EFW <10th centile)
- umbilical/middle cerebral artery doppler
LGA
- OGTT
What do umbilical artery doppler and middle cerebral artery doppler assess?
Umbilical
- growth
- abnormal suggests grwoth restrition
Middle cerebral
- cardiovascular
- abnormal suggests foetal cardiovascular distress
When should you deliver multiple pregnancy?
Dichorionic: week 37
Monochoiornic: week 36 (steroids)
Triplets: week 35 (steroids and c-section)
