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

Chorionic bump: Progression to a subamniotic hematoma

INTRODUCTION

A chorionic bump is an increasingly recognized ultrasound finding in first-trimester scans, which has been associated with early pregnancy loss. In ongoing second-trimester pregnancies, however, chorionic bumps usually resolve over time with no deleterious effect on the fetus. In this report, we describe the incidental ultrasound detection of a chorionic bump in early pregnancy and its progression to a subamniotic hematoma in the second trimester of pregnancy that persisted as such until delivery.

CASE REPORT

A round, echogenic mass protruding from the choriodecidual surface measuring 13 × 11 × 8 mm was first identified during a transvaginal scan at 6.3 weeks' gestation. Subsequent follow-up scan at 8.3 weeks revealed an increase in the size of the chorionic bump to 25 × 20 × 19 mm, which remained stable as determined by the routine late first-trimester scan. At the second-trimester scan, a subamniotic hematoma was identified in the surface of the placenta, close to the insertion of the umbilical cord. Subsequently, the pregnancy proceeded uneventfully.

DISCUSSION

The etiopathology and clinical significance of a chorionic bump remain unclear. The case herein reported demonstrates that a chorionic bump can grow considerably without having a deleterious effect on the early embryo and, occasionally, can persist throughout pregnancy as a subamniotic hematoma.

CONCLUSION

A chorionic bump can occasionally progress to a subamniotic hematoma from the second trimester onwards. This observation further supports the hypothesis that a chorionic bump is the result of choriodecidual bleeding. An alternative explanation for the development of subamniotic hematomas is proposed.

Pregnancy and perinatal outcomes in pregnancy with diagnosis of chorionic bump on first-trimester sonography: a systematic review and meta-analysis

OBJECTIVE

To assess the relationship between the presence of the sonographic finding of chorionic bump (CB) during first trimester and miscarriage rate or other perinatal outcomes.

METHODS

PubMed, Medline, Embase, Cinahl and Clinicaltrials.gov databases, from inception to April 8, 2021 were explored utilizing combinations of the relevant medical subject heading (MeSH) terms, key words, and word variants for "CB" and "pregnancy." Prospective and retrospective case-control studies were eligible for inclusion. Odds ratios (ORs) comparing obstetrical outcomes among pregnancies with CB and normal pregnancies were determined with 95% confidence intervals (CI) using random-effects models. Primary outcome of interest was miscarriage rate. Secondary outcomes were: alive newborns (ANB) rate, adverse pregnancy outcomes (APO) and vaginal bleeding. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale.

RESULTS

Five studies including 173 pregnant women with CB (study group) and 1,263 pregnant women without CB (control group) were included. Pregnancies affected by CB resulted to be associated with a significantly higher miscarriage rate (43.3% vs 20.7%; OR 2.95 95% CI 2.02-4.31, p < .00001), and conversely with a significantly lower rate of ANB (60.3% vs 82%; OR 0.35 95% CI 0.20-0.63, p = .0004). In addition, the risk of APO was around three-fold higher in the study group (52.2% vs 4.12%; OR 2.98 95% CI 1.04-8.51, p = .04), while the rate of vaginal bleeding was higher in the study group, without reaching a statistical significance (48% vs 16.4%; OR 2.21 95% CI 0.64-7.65 p = .21).

DISCUSSION

The presence of CB at first trimester ultrasound significantly increases the risk of miscarriage and APO, and intact the rate of ANB. This article is protected by copyright. All rights reserved. Key message: The presence of CB on early first trimester ultrasound increases three-fold the risk of miscarriage and adverse pregnancy outcomes and reduces the rate of alive newborns. It is important to consider CB as an ultrasound marker that requires a close surveillance throughout pregnancy to prevent long-term complications and provide adequate counseling to the patient.

Chorionic Bump: Radiologic Features and Pregnancy Outcomes

Background

Chorionic bump is a rare condition defined as a bulge or protrusion from the choriodecidual surface into the gestational sac. The limited literature on this infrequent entity suggests that the pregnancies with multiple chorionic bumps mostly result in fetal demise.

Aims

To review the available literature and the patients from our institute having sonographic findings of chorionic bump and making the sonographers and radiologists aware of this known cause of first-trimester pregnancy loss.

Study design

A retrospective review of the cases diagnosed at our institute during the last four years.

Methods and materials

Single-center institutional data for four years (January 2016-December 2019) was accessed using ICD codes. IRB approval was waived owing to the anonymized use of patient data.

Results

Six female patients diagnosed with chorionic bump were included, with a mean age of 29.83±12 years. The average gestational age at the time of diagnosis was 8.16±3 weeks. The most common sonographic findings were a protrusion from the chorionic wall into the gestational sac cavity, having a central hypoechoic region with peripheral hyperechoic rim (isoechoic to the chorion) and having no vascularity (n=5), and the less common finding was a hyperechoic protrusion with no vascularity (n=1). n=5 had a single lesion, and n=1 had two lesions. The average diameter of the lesion in the largest dimension was 18±11 mm. n=3 pregnancies resulted in a first-trimester miscarriage, and n=3 pregnancies delivered healthy babies at term. 

Conclusions

A chorionic bump significantly increases the risk of a first-trimester miscarriage.

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

PROBLEM

The chorionic bump is a distinct rare sonographic abnormality. Until now, there is contradictory evidence about if it associates with poor pregnancy outcomes. We performed this retrospective study to provide additional clinical data to investigate the clinical significance of chorionic bump at early stage of pregnancy.

METHOD OF STUDY

A single-center retrospective study was performed using the sonographic and clinical data of the pregnant women who had antenatal checkup and childbirth at Shanghai First Maternal and Child Health Care Center from December 2018 to December 2019. Sonographic examination was performed by experts at 5-10 weeks' gestation. Maternal age and gestational age matched controls from the same period were selected for analysis.

RESULTS

We observed 83 chorionic bump cases showing a prevalence of 0.33%. We found previous intrauterine operations and/or adverse maternal history posed a risk of having chorionic bump. In our cohort, chorionic bump associates with poor pregnancy outcomes. Poor pregnancy outcomes were more frequently found in the patients whose lesions were detected early (<56 days of pregnancy), or in the patients with the lesion relative sizes more than 40% of the sizes of the gestational sac, or in the patients with multiple lesions.

CONCLUSION

Intrauterine operations and/or adverse maternal history associate with an increased incidence of chorionic bump, which associates with poor pregnancy outcomes. Early detection, bigger relative size, and multiple lesions are factors likely leading to poor pregnancy outcomes.