Week 3- small for dates. Large for dates Flashcards
What are the reasons for having a small baby?
Pre-term delivery
Intra-uterine growth restriction
Constitutionally small- (healthy and small, nothing abnormal about it)
What weeks mean a baby is “pre-term” delivery?
24- 36+6 weeks
What is a term delivery?
37 onwards.
What things can cause pre-term births?
Commonest cause is idiopathic
Infection- typically one that causes systemic upset
Intercurrent illness e.g. pneumonia, appendicitis, pyelonephritis
Over-distension- anything that overextends the uterus can cause issues in pregnancy e.g. twin pregnancies, polyhydramnios (too much fluid).
Cervical insufficiency- the cervix didn’t hold together during pregnancy
Vascular- placental abruption.
What risk factors are there for pre-term birth?
Previous pre term birth Multiple pregnancy (twins) Uterine anomalies Extremes of age Poor socio-economic status Smoking Drugs Low BMI
When might you plan a C section in pre-term birth?
Severe pre-eclampsia, kidney disease or poor foetal development.
If premature rupture of membranes occurs, what would you do?
Speculum examination to make sure the membrane has actually ruptured and its not just incontinence/discharge.
Give steroids to mature the babies lungs. Give them erythromycin (supposedly lengthens the time from membrane rupture to delivery).
What is meant by the term ‘small for gestational age’?
Infant with a birthweight that is less than 10th centile for gestation corrected for maternal height, weight, fetal sex and birth order.
What is intra-uterine growth restriction?
Poor growth- can be due to maternal factors, fetal factors or placental factors.
What maternal factors can result in poor growth?
Lifestyle- smoking, alcohol, drugs
Height and weight
Age
Maternal disease e.g. hypertension
What fetal factors can result in poor growth?
Infection e.g. rubella, CMV, toxoplasma.
Congenital abnormalities e.g. absent kidneys
Chromosomal abnormalities e.g. downs syndrome
What placental factors can result in poor growth?
Infarcts
Abruption
Often secondary to hypertension
How can intrauterine growth restriction be classified?
As symmetrical or non-symmetrical.
Symmetrical- everything is proportionally small.
Asymmetrical- one part of the foetus is small inproportionaitely to another.
What are the antenatal/during labour risks of being growth restricted?
Risk of hypoxia or death.
What are the post natal risks of being growth restricted?
Hypoglycaemia
Effects of asphyxia (body deprived of oxygen)
Hypothermia
Polycythaemia (too many RBC’s)
Hyperbilirubinaemia (too much bilirubin- baby will be jaundiced).
Abnormal neurodevelopment
What clinical features indicate a poor growth of the foetus?
Fundal height less than expected- should be roughly same as gestation +/- 2cm.
Reduced fetal movements
Predisposing factors
How do you assess fetal wellbeing?
Assess growth- head circumference, femur length and waist circumference.
Cardiocotography
Biophysical assessment
Doppler ultrasound- specifically looking at umbilical artery , middle cerebral artery and ductus venosus.
What is a cardiocotography?
Two belts on the tummy- one picks up foetal heart on ultrasound on doppler. The other picks up contractions.
Produces two traces- top one tells you what the babies heart is doing while the bottom one tells you about contractions.
What is acceleration on cardiocotography?
What is it a sign of?
An increase in the babies heart beat above the base line rate lasting 10-15 seconds.
A healthy baby.
What is loss of baseline variability on cardiocotography?
What is it a sign of?
When there isn’t much up and down deflection on the babies heart rate (variability of less than 5 beats/minute)
Worrying sign if prolonged. However can be a result of sedative drugs.
What are late decelerations on cardiocotography?
Decelerations of the babies heart rate often after contractions. Worrying if 10-15 beats over 10-15mins.
What is meant by biophysical profile? How is it scored?
Assessing on ultrasound the following: -Movement -Tone -Fetal breathing movements -Liquor volume Scored out of 10. 8-10 is satisfactory, 4-6 repeat, 0-4 deliver.
How does loss of amniotic fluid reflect the babies health?
If good blood perfusion to the baby, the foetus will have good kidney perfusion meaning it pees a lot- increasing amniotic fluid volume. If bad perfusion, amniotic fluid will be lost.
What circulation is needed for the baby to be well perfused?
What happens if the placenta is bad?
A high flow, low resistance network.
If the placenta is bad you get narrowed vessels with high resistance, which aren’t good for allowing transfer of oxygen and nutrients.
What should a doppler ultrasound of the umbilical artery supposed to look like?
A toblerone- with peaks of chocolate but also chocolate in-between peaks.
What does absent end diastolic flow look like on doppler ultrasound of the babies umbilical artery?
Why is this?
Just triangles not connected.
This is because the resistance is too high which means no blood can get into the placenta. Sign of a poor placenta.
What does reverse diastolic flow look like? What does this mean the blood is doing?
What is the significance of this?
The peak goes on the other side of the line.
Means blood is flowing backwards.
Pre-death marker so need to get the baby out.
Why do you doppler the middle cerebral artery?
If the baby isn’t getting enough oxygen, it directs blood from the gut to the brain. Called cerebral redistribution..
Look at peak systolic flow. However does increase as pregnancy goes on.