Pseudogestational sac

You all know to be wary of the pseudogestational sac in the setting of a potential ectopic pregnancy. An article by Benson this past March in the Journal of Ultrasound in Medicine gives us a little more data regarding this entity. The pub med link:

http://www.ncbi.nlm.nih.gov/pubmed/23443178

The quick and dirty summary…
This article was from the radiology department at Brigham and Women’s in Boston. It was a retrospective study covering 3 years from 2008 to 2011. They looked at the ultrasounds of women who had a proven ectopic pregnancy. Of the 229 cases in the study, 38 patients (16.6%) had some fluid within their uterus. In 31 cases (81.6%), the fluid collection was pointy or complex (with mixed echoes or debris). In 7 of the cases (18.4%), the fluid collection was smooth walled and similar in appearance to a true gestational sac. In 2 of these 7 cases, no adnexal mass was seen on ultrasound.

The bottom line is that, although the uterus will be empty in most cases of ectopic pregnancy, 1 out of 6 ectopic pregnancies will have what turns out to be a pseudo-gestational sac. Approximately 1 out of 6 of these pseudo-gestational sacs will be indistinguishable from a true gestational sac.

Go to Dr. Russ Claybo’s great podcast at EM Cases: Vaginal Bleeding in the First Trimester

Steve