THE CLINICAL SIGNIFICANCE OF ISOLATED FETAL ECHOGENIC BOWEL

Abstract

OBJECTIVE: To determine the incidence of aneuploidy, cystic fibrosis (CF), and intrauterine infection with toxoplasmosis and cytomegalovirus (CMV) in second-trimester fetuses with the sonographic finding of isolated echogenic bowel.

STUDY DESIGN: All cases of echogenic bowel diagnosed in our ultrasound unit from 1993-1999 were reviewed. Only cases in which echogenicity was as bright as bone were included. Cases with associated fetal anomalies diagnosed with ultrasound were excluded. Echogenicity was classified as focal or multifocal.

RESULTS: Echogenic bowel was diagnosed in 250 patients during the study period. The study is limited to the 180 patients who were receiving prenatal care at our hospital. To date, follow-up has been obtained on 104 patients with isolated fetal echogenic bowel. The mean gestational age at diagnosis was 18.6 ± 2.1 weeks (range 14-24 weeks) and the mean maternal age was 32.1 ± 5.9 years (range 15-47 years). CF mutations were identified in 6 of 79 (7.6%) mothers and 5 of 58 (8.6%) fathers who were tested. Follow-up is available for 5 of 8 pregnancies in which at least one parent was found to carry a CF mutation. Three fetuses were affected with CF and one was found to be a carrier. Parents of affected fetuses were not known carriers prior to the diagnosis of echogenic bowel. Fetal karyotype was obtained in 87 cases and autosomal trisomy was diagnosed in 3 (3.4%). One fetus was infected with CMV demonstrated by maternal serology and inclusion bodies characteristic of CMV infection in the autopsy specimen. In all cases of CF and aneuploidy, echogenicity was multifocal; in the case of CMV, echogenicity was focal.

CONCLUSION: Serious conditions were diagnosed in 7 out of 104 patients with isolated echogenic bowel: cystic fibrosis 3, autosomal trisomy 3, and CMV infection 1. There was a multifocal pattern of echogenicity in CF affected and trisomic fetuses.