ACR Appropriateness Criteria® Multiple gestations.

Multiple gestations are high-risk compared with singleton pregnancies. Prematurity and intrauterine growth restrictions are the major sources of morbidity and mortality common to all twin gestations. Monochorionic twins are at a higher risk for twin-twin transfusion, fetal growth restriction, congenital anomalies, vasa previa, velamentous insertion of the umbilical cord and fetal death. Therefore, determination of multiple gestation, amnionicity and chorionicity in the first trimester is important. Follow up examinations to evaluate fetal well-being include assessment of fetal growth and amniotic fluid volume, umbilical artery Doppler, nonstress test and biophysical profile. To date, there is a paucity of literature regarding imaging schedules for follow-up. At the very least, antepartum testing in multiple gestations is recommended in all situations in which surveillance would ordinarily be performed in a singleton pregnancy.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed biennially by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging.