Imaging of Acute Pelvic Pain: Pregnant (Ectopic and First-trimester Viability Updated).

Pelvic pain in the first trimester is nonspecific, with causes including pregnancy complications, pregnancy loss, and abnormal implantation, and symptom severity ranges from mild to catastrophic. Ultrasonography is the imaging modality of choice and essential to evaluate for the location of pregnancy, either intrauterine or not. If there is an intrauterine pregnancy, ultrasonography helps assess viability. If there is not an intrauterine pregnancy, ultrasonography helps assess for abnormal implantation, which accounts for a high percentage of maternal morbidity and mortality.