Small for Dates Flashcards
Define
SGA = derived from birth weight à describes a baby with AC or EFW ≤10th centile for GA
- 5% of pregnancies
- EFW = Estimated Foetal Weight; AC = Abdominal Circumference; GA = Gestational Age
· IUGR = derived from growth rate à describes a baby with a reduced growth rate à baby becomes SGA
o All IUGR babies are SGA but not all SGA babies are IUGR
Risk factors
o Biggest RFs (maternal): previous stillbirth > APLS > renal disease
o Foetal – chromosomal abnormalities (à symmetrical IUGR), infection (CMV, rubella), multiple pregnancy
o Other – placental insufficiency (à asymmetrical IUGR)
Investigations
(assess risk factors at booking):
1st -> if ≥1 major risk factor or ≥3 minor risk factors, reassess at 20 weeks
2nd -> at 20 weeks, if still at risk, consider…
- Minor risk (≥3 RFs) -> uterine artery doppler (20-24w) à if abnormal, serial USS from 26-28w
- Major risk (≥1 RF) à foetal size and umbilical artery doppler (serial USS from 26-28w)
- If SGA or IUGR, ultrasound biometry (biparietal diameter, head circumference, abdominal circumference and femur length) and umbilical artery doppler serial measurements (every 2 weeks) should be taken
- Screen for congenital infections
Management
(n.b. no widely accepted treatments for IUGR due to uteroplacental insufficiency):
- Smoking, alcohol and drugs should be stopped
- Low-dose aspirin may have some role in preventing (not reversing) IUGR in high-risk pregnancies
Monitoring:
- 1st -> SFH or risk status determined (at booking or any antenatal appointment)
- 2nd -> confirm SGA with foetal biometry (20w)
- 3rd -> uterine artery doppler (20-24w)
- Normal -> repeat scans every 2 weeks (from 20-24w onwards)
Abnormal:
- Serial growth scans every week (from 26-28w onwards)
- Doppler ultrasound scans can be performed twice a week (umbilical artery flow)
Delivery:
- Indications for IMMEDIATE DELIVERY:
- Abnormal CTG (and reduced foetal movements)
Reversal of end-diastolic flow
- Delivery by 37 weeks is usually necessary à dependent on severity and gestation
- Steroids should be given <36 weeks
- Consultant-led clinics and decision-making
Conclusions
Stillbirth PTL Intrapartum foetal distress
- Birth asphyxia
- Meconium aspiration
- Postnatal hypoglycaemia
- Neurodevelopmental delay
- Risk T2DM and HTN in adult life
Prognosis -> increased perinatal morbidity and mortality, increased neurodevelopmental delay if onset <26/40