Chorionic bump at 11 to 13 weeks' gestation: Prevalence and clinical significance

Abstract

Objective To gather additional data on pregnancy outcome when a chorionic bump is detected at the time of the 11‐ to 13‐week scan. Methods The presence of a chorionic bump was prospectively recorded in a database of women presenting for their first‐trimester sonographic screening. Clinically relevant information was obtained by reviewing ultrasound reports and medical records or contacting the referring obstetrician or the parents themselves. Results During a 4.5‐year study period from June 2014 to December 2018, a chorionic bump was identified in 23 out of 3375 pregnancies, for a prevalence of 1/147 or 0.7%. All women were asymptomatic at the time of evaluation. The chorionic bump was single in 21 (91%) cases, located in the central part of the placenta in 17 (74%) cases, and the median largest diameter was 20 mm (range, 10‐43). Although the placenta was low‐lying in 14 (61%) cases, all but one patient had a normally located placenta at the midtrimester anatomy scan. With the exception of one pregnancy complicated with trisomy 21, the outcome was universally good. Conclusion Our experience suggests that a chorionic bump detected during the 11‐ to 13‐week scan is usually a transient, is incidental finding, and probably has no clinical significance.

Chorionic Bump: Radiologic Features and Pregnancy Outcomes

“…The former is the choriodecidual membrane bulging into the gestational sac, whereas the latter is blood collection between chorion and deciduas [ 4 ]. It is a rare sonographic finding observed in the first-trimester obstetric ultrasound with a low incidence, from 1.5/1000 to 7/1000 pregnancies [ 5 ]. The average gestational age of diagnosis is approximately 11 weeks after the umbilical cord's appearance at the thicker end of the chorion frondosum [ 4 , 6 ].…”

“…A prospective study of patients screened at 11-13-week gestation concluded that chorionic bump is an incidental and transient first trimester finding with no bearing on pregnancy outcome. However, this study was limited because it missed the patients presenting earlier than 11 weeks, leading to a somewhat better prognosis [ 5 ]. On the contrary, Harris et al reported a significantly higher prevalence of first and second-trimester pregnancy loss in their study group than matched controls [ 3 ].…”

Chorionic bump in early pregnancy associated with first-trimester miscarriage

“…2 In another study of 3375 pregnancies, CB was diagnosed in 23 cases. 3 All pregnancies resulted in a live birth, except for one pregnancy affected by trisomy 21. In contrast, a case-control study comparing the outcomes of 52 CB cases with 151 controls reported double the risk of miscarriage in the CB group.…”

A single‐center retrospective study of the clinical significance of chorionic bump at early stage of gestation

“…Recent literature indicates that chorionic bump detected later in the first trimester does not affect the pregnancy outcomes. 6 Therefore, we checked if the time when chorionic bump was detected was important in determining pregnancy outcomes. There were 67 cases who had their chorionic bump detected early in the first trimester (<56 days of pregnancy), out of which 34 cases Out of the 83 diagnosed cases, there were 74 cases (89.2%) had single lesion, 6 cases had 2 lesions (7.2%), and 3 cases had 3 lesions (3.6%).…”

“…Recent studies indicate that chorionic bump detected later in the first trimester did not affect the pregnancy outcomes. 6 Thus, we checked if the time when chorionic bump was detected the cases with ≥2 lesions, 7 cases (77.8%) had poor pregnancy outcomes. Thus, the subjects with more than one lesion tended to have a higher incidence rate of poor pregnancy outcomes, although it did not achieve statistically significant (P = .0749).…”