Incidence of Chromosomopathies and Cystic Fibrosis Mutations in Second Trimester Fetuses with Isolated Hyperechoic Bowel

Objective: Fetal echoic bowel can be a normal second trimester ultrasonographic finding which usually disappears by 20 weeks on serial sonograms. Recent studies have suggested a possible association of hyperechoic fetal bowel with chromosomopathies and cystic fibrosis. The aim of our study is to determine the incidence of chromosomopathies and cystic fibrosis mutations among the fetuses with isolated hyperechoic bowel.

Methods: Sixteen fetuses with isolated echoic bowel were detected: 13 fetuses S20 weeks gestation (group I) and 3 fetuses at 20-26 weeks gestation (group II). Cytogenetic studies were performed in all 16 cases and 11 families had deoxyribonucleic acid-based risk assessment for cystic fibrosis. The echogenity of bowel was that of surrounding bone.

Results: Two cases of trisomy 21 and 1 case of trisomy 13 were detected (18.7%). The other ultrasonographic markers begin to appear after 21 weeks gestation in fetuses with trisomy 13. Two of 3 pregnant women with pathological karyotype were younger than 35 years. One of 11 cases (9%) was found to be a heterozygote carrier for ΔF508 mutation.

Conclusions: Isolated hyperechoic bowel in the second trimester was found to be associated with a significantly higher risk of fetal aneuploidy.