Figure S1
sFGR definition by expert consensus: A Delphi procedure_
| Definition establish in Delphi procedure | |
|---|---|
| DC twins | MC twins |
| EFW <3rd centile or | |
| EFW of one foetus <10th centile | EFW of one foetus <10th centile |
| AC is not taken into account | AC of one foetus <10th centile |
| The disproportion between foetal weight ≥25% | The disproportion between foetal weight ≥25% |
| UAPI of smaller foetus >95th centile | UAPI of smaller foetus >95th centile |
| 2/3 have to be present to recognise sFGR | 2/4 have to be present to recognise sFGR |
Assessment of hypertrophic twin pregnancies depending on chorionicity_
| sFGR twins | Color Doppler | Foetal growth assessment |
|---|---|---|
| DC | Biweekly or more frequent | Biweekly |
| MC | Once a week or more frequent |
sFGR definition in twins among societies_
| Society | Date of publication | Definition of sFGR | Growth charts | Other twins recommendation |
|---|---|---|---|---|
| NICE | 2019 | ≥25% EFW discordance and EFW of one foetus <10th centile for GA | Undefined | |
| ACOG | 2019 | One foetus has EFW <10th centile and disproportion between EFW >20% | Undefined | |
| ISOUG | 2016 | One foetus has EFW <10th centile and the intertwin weight discordance >25% | Singleton | |
| RAN-ZOG | 2017 | Undefined | Undefined | Recommendation about MC twins but without definitions of FGR |
| SOGC | 2017 | AC and/or EFW of one or both twins are <10th centile or when growth discordance is identified | Singleton | |
| ACR | 2017 | One foetus EFW <10th centile and the intertwin EFW discordance >25% | Singleton | |
| FIGO | 2019 | One foetus EFW <10th centile and the intertwin EFW discordance >25% | Twin | |
| Delphi consensus | 2019 | Separates MC and DC twins, EFW <3rd centile or contributory factors | Singleton |
Recommended GA at delivery in stable twins pregnancies complicated by sFGR according to Doppler assessment compared with FGR singleton pregnancies_
| sFGR Type | ||||
|---|---|---|---|---|
| Chorionicity | I | II | III | IV |
| DC | UAPI >95th centile | AEDF | REDF, DV PI >95th centile | DV a wave reversed |
| MC | I | II | III | |
| UAPI >95th | AREDF | iAREDF | DV a wave reversed (it is not stage IV in MC) | |
| Recommended GA at delivery (weeks) | ||||
| DC | 34–36 | 30–32 | 30–32 | >26 This is the UK-recommended treatment. In Poland, it is not legally possible to terminate a pregnancy or perform selective termination after the end of 22 weeks. |
| MC | 34–36 | 30–32 | 30–32 | >26 |
| Singletons | 37 | 34 | 30 | 26 |
The perinatal outcome of the second twin in the case of IUD of sFGR foetus depends on chorionicity_
| Perinatal outcome | DC | MC |
|---|---|---|
| Second twin IUD | 3% | 15% |
| Preterm labour before 32 weeks | 54% | 68% |
| Abnormalities in CNS imaging of survivor | 16% | 34% |
| Neurodevelopment retardation of survivor | 2% | 26% |