Normal and Abnormal US Findings in Early First-Trimester Pregnancy: Review of the Society of Radiologists in Ultrasound 2012 Consensus Panel Recommendations.

Since being introduced more than 30 years ago, endovaginal ultrasonography (US) and quantitative testing of serum levels of the beta subunit of human chorionic gonadotropin have become the standard means of establishing the presence of normal intrauterine pregnancy (IUP), failed IUP, and ectopic pregnancy. Appropriate use of these powerful tools requires clear, standardized interpretations based on conservative criteria to protect both the pregnancy and the mother. Since diagnoses are assigned earlier and available medical treatments for ectopic pregnancy and failed IUP are expanding, emphasis must carefully shift toward watchful waiting when the mother is clinically stable and a definitive location for the pregnancy cannot be established with US. To this end and to prevent inadvertent harm to early normal pregnancies, the Society of Radiologists in Ultrasound convened a consensus panel of radiologists, obstetricians, and emergency medicine physicians in 2012 with the goal of reviewing current literature and clinical practices and formulating modern criteria and terminology for the various first-trimester outcomes.