Elizabeth Kagan Arleo MD, Presenter: Nothing to Disclose

Robert Nicholas Troiano MD, Abstract Co-Author: Nothing to Disclose

To prospectively observe the pregnancy outcome of patients with the sonographic finding of a chorionic "bump," an irregular, convex bulge from the choriodecidual surface into the first-trimester gestational sac.

Study design: prospective observational study. Number of patients: N = 53. Time period: 3 years (2004-2007). Primary endpoint: Live birth rate. Secondary endpoints included: chorionic bump size. Statistics: Fisher exact test of proportions.

13% (7/53) of the pregnancies with chorionic bump on first-trimester ultrasound were anembryonic. Of the remaining 46 embryonic pregnancies with first-trimester chorionic bumps, 74% (34/46) resulted in live births, all at term with the exception of one set of twins and one set of triplets, who were electively delivered early at 35 weeks and 32 weeks, respectively. There was only one associated anatomic anomaly, a left forearm limb reduction defect diagnosed antenatally in one case. Bump size was not correlated with pregnancy outcome. In most patients, the bump was avascular, but in two cases slow intraluminal flow was noted.

The presence of a chorionic bump on first trimester ultrasound is not necessarily a poor prognostic indicator. The likelihood of subsequent first-trimester survival is significantly higher if an embryo is seen at the time of chorionic bump diagnosis. In such a scenario, in this series, the largest to date of such a cohort, the live birth rate (74%) was significantly higher than previously reported in smaller series (live birth rate <50%).

This largest series on chorionic bumps demonstrates that this US finding is not necessarily a poor prognostic indicator & therefore, interpreting radiologists should recommend close interval followup.

Arleo, E, Troiano, R, Presence of a Chorionic Bump May Not Be Associated with a Guarded Prognosis.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13012971.html