Although results from randomized controlled trials indicate that a single ultrasound examination in the second trimester can lead to increased birth weight and can reduce the perinatal death rate (largely through early detection of major anomalies resulting in induced abortion) the effectiveness of a single examination in increasing fetal survival through early detection of treatable prenatal problems has yet to be clearly demonstrated, and the positive and negative psychologic effects of screening on parents have not been adequately assessed. Therefore, there is fair evidence to support the inclusion of a routine single ultrasound examination in the management of women with no clinical indication for prenatal ultrasonography.
There is no evidence from randomized controlled trials indicating that serial prenatal ultrasonography leads to improved perinatal outcomes. However, the trials performed were not large enough to detect clinically significant outcomes of this intervention. Therefore, there is poor evidence to support the inclusion of routine serial ultrasound screening in or its exclusion from the management of women with no clinical indication for prenatal ultrasonography.