Echogenic bowel on second-trimester ultrasonography: evaluating the risk of adverse pregnancy outcome.

OBJECTIVE

To estimate if echogenic bowel diagnosed on second-trimester ultrasonography has an independent risk association with intrauterine growth restriction (IUGR) and intrauterine fetal demise.

METHODS

This is a retrospective cohort study of all patients with singleton gestations who presented to our institution for second-trimester ultrasonography between 1990 and 2008. Study groups were defined by the presence or absence of echogenic bowel. Primary outcomes were IUGR, defined as birth weight less than the 10th percentile for gestational age and intrauterine fetal demise at 20 weeks or more of gestation. Univariable and multivariable logistic regression analyses were used to estimate the risk of intrauterine fetal demise and IUGR in fetuses with echogenic bowel. Analyses were repeated after excluding cases of aneuploidy, cytomegalovirus (CMV) infection, other major congenital anomalies, and abnormal second-trimester serum screening results.

RESULTS

Of 64,048 patients, the incidence of echogenic bowel was 0.4%. Of these, echogenic bowel was an isolated finding in 188 (72.3%) cases. There were 579 (0.9%) cases of intrauterine fetal demise and 8,173 (12.8%) cases of IUGR in the entire cohort. After excluding cases of aneuploidy and CMV infection, the incidence of intrauterine fetal demise was 7.3% in the echogenic bowel group compared with 0.9% in the nonechogenic bowel group, translating to an absolute risk increase of 6.4%. The incidence of IUGR in the echogenic bowel group was 19.5% compared with 12.9% in the nonechogenic bowel group (absolute risk increase, 6.6%). After controlling for potential confounders, echogenic bowel was significantly associated with both intrauterine fetal demise (adjusted odds ratio [OR] 9.6, 95% confidence interval [CI] 5.8-15.9) and IUGR (adjusted OR 2.1, 95% CI 1.5-2.9). This risk association remained significant even when evaluating echogenic bowel as an isolated sonographic finding.

CONCLUSION

The presence of echogenic bowel on ultrasonography is independently associated with an increased risk for both IUGR and intrauterine fetal demise. Serial growth assessment and antenatal testing may be warranted in these patients.