Which of the following is the IOC to detect abnormally located placenta?

Transvaginal sonography (TVS) is the investigation of choice and is superior to Transabdominal sonography(TAS) for detecting placental abnormalities. Approach to placenta pre after confirmation by TVS at anomaly scan. Bleeding present: Individual management. No Bleeding/Minor Pre: Repeat USG at 36 weeks No bleeding/Major Pre or accreta: USG at 32 weeks followed by elective CS at 37 to 38 weeks. Note: Transabdominal sonographic assessment (TAS) of placental location is one of the standard components of the basic obstetrical ultrasound examination, and thus can be considered a screening test for placenta pre, however according to recent studies TVS generally provides a clearer image of the relationship between the edge of the placenta and the internal cervical os than transabdominal ultrasound. Randomized trials and prospective comparative studies have established the superior performance of TVS over transabdominal sonography for diagnosis of placenta pre. Ref: Williams Obstetrics 24th edition Pgno: 802