Increased echogenicity in the lower fetal abdomen: a common normal variant in the second trimester.

Ten cases displaying a focal area of increased echogenicity in the lower fetal abdomen on prenatal sonography are reported. This was an isolated finding in each case. Nine cases were noted early in the second trimester. The last case corresponded to a postmature gestation. In all cases, a normal lower abdomen was documented on follow-up prenatal sonography, at birth, or at autopsy. The authors believe that increased echogenicity in the lower fetal abdomen represents a normal variant that is more common than suggested by the literature. A possible explanation of this pattern is offered.