Routine ultrasound screening in low-risk pregnancies: imperatives for further study

The benefits of screening ultrasonography in low-risk pregnancies are uncertain and require further investigation. As researchers organize future trials, however, they will need to define clearly the structure and content of the screening ultrasound examination and explicitly detail those outcomes considered important. Such studies must examine the effectiveness of screening sonography in comparison with and in the context of other available prenatal tests and screens. Until studies showing efficacy are available, screening ultrasound in low-risk pregnancies should be considered only when patients, guided by clinicians, consider the potential benefits to be of value.