Red Flags
- Reversed end-diastolic flow in umbilical artery — admit; antenatal corticosteroids if 24–34 weeks; deliver per gestation and ductus venosus a-wave; involve maternal-fetal medicine[1]
- Absent end-diastolic flow with abnormal CTG or biophysical profile — deliver at any gestation ≥26 weeks if fetal viability anticipated[1]
- Severe FGR (estimated fetal weight <3rd centile) with reduced fetal movements at any gestation — same-day obstetric review including CTG and Doppler[1]
- Suspected FGR with maternal pre-eclampsia, placental abruption, or PPROM — admit; deliver per maternal and fetal status[1]
First-line treatment
Interventions
- Distinguish small-for-gestational-age from FGR[1]FGR = pathological failure to reach growth potential; SGA = constitutionally small with normal Dopplers and growth velocity. Delphi-consensus criteria combine size centiles with Doppler indices
- Identify modifiable maternal causes[1]Smoking cessation; treat anaemia, thyroid disease, hypertension, infection; substance use counselling; address malnutrition
- Stratified surveillance pathway[1]Late-onset (≥32 weeks): UA + MCA Doppler, growth every 2 weeks, CTG. Early-onset (<32 weeks): add ductus venosus, biophysical profile; tertiary maternal-fetal medicine input
- Timing of delivery[1]EFW ≥3rd centile + normal Doppler: deliver at 37 weeks. EFW <3rd centile or abnormal UA: 36–37 weeks. AEDF: 34 weeks. REDF: 30–32 weeks. Abnormal DV or non-reassuring CTG: deliver after corticosteroid course completion if gestation permits
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Antenatal corticosteroids — betamethasone or dexamethasone[1] | Glucocorticoid for fetal lung maturation | Betamethasone 12 mg IM × 2 doses 24 h apart; dexamethasone 6 mg IM × 4 doses 12 h apart | — | All anticipated preterm delivery 24+0 to 34+6 weeks; consider single rescue course if delivery still anticipated >7 days after first course |
| Magnesium sulfate (fetal neuroprotection)[1] | Tocolytic / neuroprotective | 4 g IV over 20 min, then 1 g/h IV until delivery or 24 h | — | Anticipated delivery <32 weeks; reduces cerebral palsy risk by ~30% in survivors; monitor reflexes, respiration, urine output |
| Aspirin (FGR prevention in subsequent pregnancy)[1] | Antiplatelet (low-dose) | 150 mg PO at night from 12 weeks until 36 weeks (or term) | — | Prior pregnancy with FGR or pre-eclampsia, or other high-risk features; reduces recurrence; may be combined with calcium 1 g/day where dietary intake low |
Antenatal corticosteroids — betamethasone or dexamethasone[1]
Glucocorticoid for fetal lung maturation
- Adult
- Betamethasone 12 mg IM × 2 doses 24 h apart; dexamethasone 6 mg IM × 4 doses 12 h apart
- Paediatric
- —
All anticipated preterm delivery 24+0 to 34+6 weeks; consider single rescue course if delivery still anticipated >7 days after first course
Magnesium sulfate (fetal neuroprotection)[1]
Tocolytic / neuroprotective
- Adult
- 4 g IV over 20 min, then 1 g/h IV until delivery or 24 h
- Paediatric
- —
Anticipated delivery <32 weeks; reduces cerebral palsy risk by ~30% in survivors; monitor reflexes, respiration, urine output
Aspirin (FGR prevention in subsequent pregnancy)[1]
Antiplatelet (low-dose)
- Adult
- 150 mg PO at night from 12 weeks until 36 weeks (or term)
- Paediatric
- —
Prior pregnancy with FGR or pre-eclampsia, or other high-risk features; reduces recurrence; may be combined with calcium 1 g/day where dietary intake low
Safety-net
- Reduced or absent fetal movements at any gestation — same-day maternity assessment unit; do not wait until next antenatal visit[1]
- Attend every growth scan and Doppler appointment — most FGR deterioration is silent[1]
- Stop smoking and limit caffeine; addressing modifiable factors meaningfully changes neonatal outcomes[1]
Referral criteria
- Early-onset FGR (<32 weeks)Tertiary maternal-fetal medicine and neonatal team[1]
- Abnormal umbilical artery Doppler (PI >95th, absent or reversed end-diastolic flow)Maternal-fetal medicine for delivery planning and serial DV/CTG surveillance[1]
- Suspected co-existent pre-eclampsia or placental abruptionObstetric admission[1]
- Recurrent FGR or unexplained stillbirthPre-conception MFM and consideration of thrombophilia, autoimmune workup[1]
Clinical summary
Identification, surveillance, and timing of delivery for early- and late-onset fetal growth restriction in singleton pregnancies.