Ultrasonographic differentiation of the gestational sac of early intrauterine pregnancy from the pseudogestational sac of ectopic pregnancy.

A retrospective review of 128 consecutively scanned pregnant patients who had either early intrauterine pregnancies (IUPs) or ectopic pregnancies was performed to determine the accuracy of the finding of an intrauterine double decidual sac (DDS) in distinguishing between these two groups of patients. The presence of a DDS correlated with an IUP in 59 of 60 patients (98.3%).