Increased echogenicity in the fetal abdomen: use of DNA analysis to establish a diagnosis of cystic fibrosis.

The sonographic finding of increased echogenicity within the fetal abdomen presents a diagnostic dilemma, with a differential diagnosis ranging from normal variation to CF. We report the diagnostic evaluation of four cases, two of which were found to be the result of CF. On the basis of this experience, we believe that persistence of an echogenic bowel pattern, especially with bowel dilation, after 20 weeks' gestation should prompt an evaluation for CF. Using DNA analysis, approximately 75% of the cases involving CF can be detected with noninvasive studies of the parents, and confirmation by amniocentesis is performed only in those cases in which both parents are carriers of known mutations.