Table 4 Second trimester TAS for VCI screening studies. Summary characteristics
| Â | Di Salvo 1998 [63] | Hasegawa 2006 [69] | Nomiyama 1998 [66] | Pretorius 1996 [16] | Sepulveda 2006 [67] | Sepulveda 2003 [68] |
|---|---|---|---|---|---|---|
Participant Selection | Unclear [RoB: unclear] | Retrospective enrollment of pregnancies [RoB: high] | Prospectively enrolled consecutive samples of pregnancies [RoB: low] | Prospectively enrolled consecutive samples of pregnancies [RoB: low] | Prospectively enrolled consecutive samples of pregnancies [RoB: low] | Excluded pregnancies with inadequate amniotic fluid volume [RoB: high] |
Index Test/Technique | Grey-scale TAS, with colour. Doppler imaging at the discretion of the sonologist [RoB: high] | Grey-scale TAS, with colour. Doppler imaging at the discretion of the sonologist [RoB: high] | Colour Doppler TAS. If inconclusive, 3rd trimester repeat testing, using Doppler TVS if needed. The same screening methods used for all patients [RoB: low] | TAS. Use of colour Doppler unclear [RoB: high] | Grey-scale TAS. Colour Doppler imaging at the discretion of the sonologist; supplemented with use of TVS if TAS was inconclusive [RoB: high] | Colour Doppler TAS, with colour Doppler TVS used if insufficient image quality was obtained from TAS [RoB: high] |
Reference Standard | VCI confirmed by postnatal examination [RoB: high] | VCI confirmed by postnatal examination for all participants [RoB: unclear] | VCI confirmed by postnatal examination for all participants Placental cord insertion was obtained from medical records [RoB: high] | VCI confirmed by postnatal examination, performed by a pathologist blinded to the screening result [RoB: low] | VCI confirmed by postnatal examination for all participants [RoB: unclear] | VCI confirmed by postnatal examination for all participants [RoB: unclear] |
Participant Flow | Postnatal exam for participants with perinatal complications or in multiple gestation pregnancies Long interval between the index test and the reference standard [RoB: high] | Long interval between the index test and the reference standard [RoB: high] | Long interval between the index test and the reference standard [RoB: high] | Many specimens were not sent for pathologic study by the obstetricians Long interval between the index test and the reference standard [RoB: high] | Long interval between the index test and the reference standard [RoB: high] | Long interval between the index test and the reference standard [RoB: high] |
Ultrasound Timing (GA, weeks) | 13 to 39 | 18 to 20 | 18 to 20 | ≥15 | 11 to 14 | 16 to 40 |