The clinical significance of fetal echogenic bowel

The purpose of this study was to determine the incidence of cystic fibrosis, aneuploidy, and intrauterine infection with toxoplasmosis and cytomegalovirus in second-trimester fetuses with the sonographic finding of echogenic bowel.

All cases of echogenic bowel that were diagnosed in our ultrasound unit from 1993 to 2000 were identified. Only cases in which bowel echogenicity was as bright as bone with no associated major fetal anomalies were included. Patients who were referred from other hospitals were excluded. Echogenicity was classified as focal or multifocal. Fetal karyotypes, cystic fibrosis carrier testing, and maternal serologic test results were determined.

One hundred seventy-five fetuses in 171 pregnancies met inclusion criteria. Cystic fibrosis mutations were identified in 7 of 138 mothers (5%) and 9 of 86 fathers (10.5%) who were tested. Five fetuses were affected with cystic fibrosis. Fetal karyotype was obtained in 139 cases, and autosomal trisomy was diagnosed in 5 cases (3.6%). One hundred sixty-six patients were tested for toxoplasmosis, and 111 patients were tested for cytomegalovirus. There were no cases of congenital toxoplasmosis. There was maternal serologic and fetal pathologic evidence of cytomegalovirus infection in 1 case. In all cases of cystic fibrosis and aneuploidy, echogenicity was multifocal; in the case of cytomegalovirus, echogenicity was focal.

In our population, mid-trimester fetal echogenic bowel was associated with a high prevalence of cystic fibrosis, aneuploidy, and cytomegalovirus (11/175 fetuses [6.3%]). This information should be considered when counseling patients after mid-trimester echogenic bowel is diagnosed.