2024年8月22日 · transvaginal ultrasound scan is more accurate to assess placenta previa, the transabdominal scan may overdiagnose it in up to one-quarter of cases. when spotted in the second trimester, a third-trimester ultrasound scan (~32-34 weeks) should be performed to reassess the placenta position

2023年6月5日 · It is recommended to begin with a transabdominal ultrasound to locate the placenta first, followed by the transvaginal ultrasound if clinically indicated and necessary. However, due to the cervix and the vaginal canal angle, performing transvaginal ultrasound during the third trimester can be potentially safe.

2022年5月11日 · Most cases of placenta previa are diagnosed during a second-trimester ultrasound exam. The initial diagnosis may be done with an ultrasound device on your abdomen. For more accurate images, you may also need a transvaginal ultrasound, which uses a wandlike device placed inside your vagina.

Transvaginal ultrasound allows accurate visualization of the internal os in all cases. The exact distance from the internal os to the placental edge in cases of low-lying or marginal placenta previa (1).

Assessment by transvaginal ultrasound is recommended in all cases where placenta previa or a low-lying placenta is present or suspected by transabdominal sonography, with attempt to clearly define placental location (including laterality), characteristics of placental edge (including thickness, presence of a marginal sinus), and associated ...

The evolution of the sonographic diagnosis of placenta previa is reviewed with special emphasis on transvaginal sonography (TVS), which has been proved accurate at diagnosing different degrees of placenta previa, such as complete, partial, marginal and low-lying.

This protocol will address diagnosis and ultrasound management of low lying placenta, placenta previa, placenta accreta and vasa previa. Placenta previa refers to the presence of placental tissue that extends over or lies proximate to the internal cervical os.

Transvaginal sonography, if available, may be used to investigate placental location at any time in pregnancy when the placenta is thought to be low-lying. It is significantly more accurate than transabdominal sonography, and its safety is well established. (11–2A)

1992年7月1日 · Transvaginal ultrasound was most beneficial for those patients with posterior placenta previas because of increased clarity of diagnosis, decreased time of scanning, and no increased incidence of hemorrhage.

2020年9月28日 · Transvaginal ultrasonography is considered the gold standard for the diagnosis of placenta previa. Some clinicians advocate insertion of the probe no more than 3 cm for visualization of the...