Small & Large Births Flashcards
What are the 2 main causes for a small baby?
Pre-term delivery
Small for gestational age due to intrauterine growth restriction (IUGR) or simply constitutionally small!
How is a birth defined as preterm?
Delivery between 24-36 weeks gestation
List some causes of preterm birth
Infection
Overdistention (multiple pregnancy, polyhydraminos)
Placental abruption
Cervical incompetence
Intercurrent illness (UTI, appendicitis, pneumonia)
Idiopathic
How is a baby defined as being small for gestational age? What is IUGR? What is LBW?
Estimated fetal weight or abdominal circumference below 10th centile
Failure to achieve growth potential
Birth weight below 2.5kg regardless of gestation
What maternal factors cause poor growth of a foetus?
Lifestyle: smoking, drugs, alcohol
BMI 19 or less
Extremes of age
Disease: hypertension (placental infarcts)
What foetal factors cause poor growth of a foetus?
Infection: rubella, CMV
Congenital anomalies
Chromosomal abnormality
What are the consequences to the foetus if there is growth restriction?
Hypoxia Hypoglycaemia Asphyxia Hypothermia Polycythaemia Abnormal neurodevelopment
What are some clinical indicators of poor growth?
Syphysial-fundal height less than expected (from 24w)
Reduced liquor or amniotic fluid index
Reduced foetal movements
List some antenatal methods for assessing fetal wellbeing with poor growth
Serial growth scans
Biophysical assessment
Cardiotocography (measure foetal heartbeat)
Doppler US (umbilical artery, MCA, ductus venosous)
How is poor growth of the fetus monitored during pregnancy?
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
What are the main aetiology behind large babies?
Wrong date Multiple pregnancy Diabetes Polyhydramnios Fetal macrosomia
What is the difference between zygosity and chorionicity?
Zygosity: number of eggs fertilied to produce twins
Chorionicity: membrane pattern of the twins
Which is the outer layer - chorion or amnion?
Chorion outside
Amnion inside
Describe a dichorionic diamniotic pregnancy
Each foetus has its own amniotic sac and its own placenta
All dizygotic twins
Describe a monochorionic diamniotic pregnancy
Each foetus has its own amniotic sac but shared placenta
Describe a monochorionic monoamniotic pregnancy
Both foetuses share amniotic sac and placenta
Multiple pregnancies carry higher perinatal mortality due to what?
Congenital anomalies Preterm labour Growth restriction Pre-eclampsia Twin-twin transfusion Cerebral palsy PPH
Outline management options for multiple pregnancy
Consultant-led care
Pregnancy clinic and US (MZ every 2w, DZ every 4w)
Maternal education and support
How are triplets and twins delivered?
C-section if triplets
Aim for vaginal if twins
How is multiple pregnancy diagnosed?
USS confirmation at 12 weeks
High AFP
What are the clinical signs and symptoms of multiple pregnancy?
Exaggerated pregnancy e.g. hyperemesis gravidarum
Greater maternal age
Use of ACT
Family history
How is fetal macrosomia diagnosed?
‘Big baby’
USS EFW > 90th centile
What are the risks associated with macrosomia?
Clinician and maternal anxiety
Labour dystocia
Shoulder dystocia
Post partum haemorrhage
How is fetal macrosomia managed?
Exclude diabetes (OGTT)
Reassurance
Conservative vs induction of labour vs c-section
What is polyhydramnios?
Excess amniotic fluid
What causes polyhydramnios?
Maternal diabetes Monochorionic twin pregnancy Foetal anomaly Diabetes Hydrops fetalis (accumulating fluid in fetus) Idiopathic
List clinical features of polyhydramnios
Abdominal discomfort
Tense shiny abdomen
Malpresentation
Inability to feel fetal parts
List diagnostic techniques for polyhydramnios
USS
OGTT
Serology (toxoplasmosis, CMV, parovirus)
Antibody screen
Outline management options for polyhydramnios
Patient information on complications
Serial USS
Induction of labour by 40 weeks
Neonatal exam
List complications of polyhydramnios
Cord prolapse
Preterm labour
Post-partum haemorrhage
List the forms of diabetes in pregnancy
Pregestational (type 1, type 2, MODY)
Gestational DM
List management options for pregestational diabetes during pregnancy
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
Describe the pathophysiology of gestational diabetes mellitus
Placental hormones cause insulin resistance in the mother, causing hyperglycaemia
How does gestational diabetes lead to macrosomia?
Overgrowth of insulin sensitive tissues due to hyperinsulinaemia
How is gestational diabetes diagnosed?
OGTT in 1st trimester and 24-28 weeks
Fasting: 5.1 mmol/l or more
2-hour: 8.5 mmol/l or more
List risk factors for gestational diabetes
Previous GDM BMI >30 FHx Previous big baby or big baby on USS Polyhydramnios Glycosuria
Outline antenatal management options for gestational diabetes
Care plan Education on diet, weight control, exercise Targets for glycaemic control Growth scans Monitor for PET Hypoglycaemic agents (oral or insulin)
What is the indications for hypoglycaemic agents in gestational diabetes?
Diet and exercise fail to maintain target
Macrosomia on US
What are the targets for glycaemic control in gestational diabetes?
Measure minimum 4 x a day and before bed
Fasting: 3.5-5.9 mmol/l
1 hr <7.8 mmol/l
Outline postnatal management options for gestational diabetes
Fasting blood sugar 6-8 weeks post-natal
If T2DM suspected - OGTT 6 weeks post-natal
Annual FBS and lifestyle changes
Maternal diabetes can cause foetal hyperinsulinaemia and increased foetal growth. What are the consequences of this?
Macrosomia
Polyuria, polyhydramnios
Increased O2 demands
Neonatal hypoglycaemia
