The sonography of pregnancy loss.

Sonography is critical to the current management of pregnancy loss. It is used to predict and/or confirm viability. Knowledge of the early embryology as well as the timing of these events is important to appropriate management. Sonographic parameters can be divided into hard and soft signs. Hard signs include the absence of visible heart motion or embryonic poles at certain cutoffs. The soft signs are generally related to findings more likely to be associated with poor outcomes. Ultrasound is now also used to help determine which patients may not require surgical intervention.