Evaluation of fetal echogenic bowel in the second trimester

Previous studies cite different possible etiologies for fetal echogenic bowel (FEB). The purpose of this study was to evaluate the possible etiologies for second-trimester FEB, and to provide clinical guidelines for evaluation of this finding. The study included 79 patients diagnosed with FEB in the second trimester. Fifteen cases (19%) were associated with maternal vaginal bleeding. Of these, 12 patients underwent amniocentesis, 9 of which had visible blood products in the amniotic fluid. Seven cases (8.9%) had associated severe malformation. Seven other cases (8.9%) were noted in multifetal pregnancies. Five fetuses (6.3%) had evidence of bowel obstruction or perforation not associated with cystic fibrosis (CF). Chromosomal aberrations were found in 5 fetuses (6.3%). Intrauterine infection with cytomegalovirus, herpes simplex virus, varicella-zoster virus, or parvovirus B-19 was documented in 5 patients (6.3%). Three cases (3.8%) were associated with subsequent unexplained stillbirth. Two fetuses (2.5%) were found to be affected by CF. Finally, in 30 cases (38%), no obvious reason for FEB was found. We conclude that the evaluation of second-trimester FEB should include targeted ultrasound for associated malformations, infectious studies, DNA analysis for CF mutations, amniocentesis for chromosomal analysis and evaluation of the amniotic fluid for degraded blood products, and an autopsy in cases of stillbirth. Even when no apparent reason is found, pregnancies should be considered at high risk for poor outcome.