Chorionic Bump in First-trimester Sonography

The present research was motivated by providing new insight into early pregnancies with a chorionic bump diagnosis in first-trimester sonography and its impact on live birth rate.

To determine the rate of CB, first trimester sonograms of pregnant women referring to Akbarabadi Hospital, which is a treatment and training center affiliated to Iran University of Medical Sciences as well as those referring to a private center were analyzed. The total number of transvaginal sonographies performed was 1900 cases from whom 8 cases of CB were detected. The chorionic bump size and number and history of infertility or coagulation disorders were considered as our independent variables and multiple gestation with pregnancy outcome as dependent ones.

Overall, the prevalence rate of CB was 0.4% (4 per 1000), with 8 patients diagnosed with CB from 1900 the first trimester pregnant women. Of 8 pregnant women, 5 showed live birth (62.5%) and 3 experienced fetal demise (37.5%). The chorionic bumps ranged in size from 0.1 cc to 1.8 cc (average, 0.73 cc). No significant relationship was found between history of smoking, coagulopathy, infertility, multiple gestation and the size of CB.

The main finding was that the frequency of live birth in our sample was 62.5% (5 from 8). The clinical inference is that a chorionic bump on first-trimester sonography does not definitely guarantee a secure prediction. The correlation between bump size and pregnancy outcome is not clear, which warrants further research.