Conclusion
In summary, vasa previa results in poor pregnancy outcomes if not diagnosed prenatally. Ultrasonography, specifically transvaginal scan with color Doppler is commonly utilized as diagnostic method. We have presented a series of cases with suspected but inconclusive ultrasonography diagnosis of vasa previa. MRI was applied to further detect the existence of vasa previa and achieved satisfied results that confirmed by pathology examination. Therefore, when inconclusive ultrasonography results come in such cases, MRI may offer some assistance in diagnosis.