Objective:To test the hypothesis that increased echogenicity of the fetal bowel at second‐trimester scans results from intra‐amniotic bleeding.Methods:We studied 726 patients undergoing secondtrimester amniocentesis for advanced maternal age. Three groups were identified according to the color of the amniotic fluid (AF) obtained: clear fluid, blood‐stained fluid, and dark brown fluid. Two to 4 weeks after the amniocentesis, all patients had a targeted ultrasound examination for the detection of fetal structural anomalies and markers of chromosomal abnormalities, which included a survey of the fetal bowel. The incidence of hyperechogenic bowel in each group was compared by Fisher exact test.P< .05 was considered significant.Results:In 694 cases, the AF was clear (95%), in 20 blood‐stained (3%), and in 12 dark brown (2%). Hyperechogenic bowel was detected in 14 fetuses with clear fluid (2%), in two with blood‐stained fluid (10%), and in three with dark brown fluid (25%). Fetuses with proven intra‐amniotic bleeding (ie, dark brown or blood‐stained AF at amniocentesis) had a significantly higher incidence of hyperechogenic bowel compared to those with clear AF (five of 32 [15.6%] and 14 of 694 [2.0%], respectively;P< .001, 95% confidence interval for the difference in proportions 6.3‐17.6%).Conclusions:Our study demonstrates that intra‐amniotic bleeding is associated with an increased incidence of fetal hyperechogenic bowel at second‐trimester ultrasound scans. This sonographic phenomenon may be due to the presence of blood in the fetal bowel caused by fetal swallowing of bloody AF.(Obstet Gynecol 1994;83:947‐50)