Small for dates pregnancy and pre-term birth Flashcards
What is intrauterine growth restriction?
Condition where fetus is unable to achieve its genetically determined potential size
(usually below 10th percentile)
Definition of pre-term birth
Delivery between 24 and 36+6 weeks
Difference between survival rates of babies born at 24 and 27 weeks?
24 weeks - approx 20-30%
27 weeks - 80%
32 weeks - >95%
Risk factors/associations for pre-term birth
- previous PTL (20% risk x1; 40% x2)
- multiple
- uterine abnormalities
- age (teenagers)
- parity (=0 or >5)
- ethnicity
- poor socio-economic status
- smoking
- drugs (esp. cocaine)
- low BMI (
Why might you deliberately have a baby pre-term by cesarean?
e. g.
- severe pre-eclampsia
- kidney disease
- poor fetal development (e.g. i think BPS
Fetal exposure to pre-eclampsia is linked to what?
- autism
- developmental delay
How is pre-eclampsia clinically defined?
Hypertension and proteinuria, with or without pathologic edema
Infections that could cause poor fetal growth
Rubella
CMV
Toxoplasma
Example of congenital anomaly that could cause poor fetal growth
Absent kidneys
Example of chromosomal abnormality that could cause poor fetal growth
Down’s syndrome
What commonly causes placental problems (and therefore poor growth etc)
Often secondary to hypertension!!
e.g. infarcts, abruption
How does placental abruption present?
PAINFUL
Bleeding
Uterine contractions
Fetal distress
Is symmetric or asymmetric IUGR more common?
Asymmetric
List a couple of causes of asymmetric IUGR
- chronic high BP
- severe malnutrition
- genetic mutations (ehler’s danlos)
Post-natal consequences of being growth restricted?
- hypoglycemia
- effects of asphyxia
- hypothermia
- polycythemia
- hyperbilirubinemia
- abnormal neurodevelopment
Antenatal/in labour consequences of being growth restricted?
Hypoxia and/or death
Clinical features of poor growth
- pre-disposing factors
- reduced liquor
- reduced movements
- fundal height less than expected
What is cardiotocography?
CTG
-way to record fetal heartbeat and uterine contractions
How could you assess fetal wellbeing?
- assessment of growth
- cardiotocography
- biophysical assessment
- doppler ultrasound
What does an increase in fetal heart rate at the start of a uterine contraction (and then returning to normal before/after contraction) indicate?
This indicates good reflex reactivity of the fetal circulation
What might cause a loss of baseline variability in a fetal heart rate?
Sedative/analgesic drugs (used in labour)
LOSS OF BASELINE VARIABILITY IS BAD
- greater possibility of asphyxia
- persistantly minimal or absent FHR variability appears to be the most significant intrapartum sign of fetal compromise
What is loss of baseline variability of fetal heart rate?
Baseline variability of LESS THAN 5 BEATS PER MINUTE
What does the biophysical profile assess?
- movement
- tone
- breathing
- liquor volume
Biophysical score 8-10
Good
Biophysical score 4-6
Repeat
Biophysical score 0-2
Deliver
What does the umbilical arterial doppler measure?
Measures placental resistance to flow
What usually presents first: symmetrical or asymmetrical IUGR?
Symmetric usually presents earlier
Asymmetrical usually presents later in the 3rd trimester
Causes of symmetric growth restriction?
Triploidy 13, triploidy 18, infections e.g. torch
Causes of asymmetric IUGR?
Placental insufficiency, pre-eclampsia
The less baseline variability present, the greater risk of what ?
Asphyxia
