Ultrasound is a valuable diagnostic tool, which can be used to stratify pregnant women with adnexal masses into a conservative management protocol versus those that require further diagnostic and management decisions. Familiarity with the natural history and sonographic features of common adnexal lesions, such as simple cysts, hemorrhagic cysts, endometriomas, mature cystic teratomas, and ovarian conditions specific to pregnancy, may permit stratification of patients into management protocols. The goal of ultrasound evaluation in the pregnant patient with an adnexal mass is to identify those patients in whom conservative management is appropriate versus those who require more immediate interventions such as surgery. The risk of surgical interventions needs to be balanced against the potential risks of nonintervention, which may include torsion, rupture, hemorrhage, or the rare spread of a malignant cancer. Atypical features or persistent large lesions should initiate a multidisciplinary team approach to optimize diagnostic and management strategy. Acute symptoms may precipitate emergency intervention at any point in the pregnancy. We will present a diagnostic and management algorithm based on clinical symptoms, timing of detection, natural history, and sonographic features of adnexal masses in pregnancy.