Cystic fibrosis and chromosome abnormalities associated with echogenic fetal bowel

Obstet Gynecol. 1999 Jul;94(1):135-8. doi: 10.1016/s0029-7844(99)00286-0.


Objective: To determine the prevalence of cystic fibrosis mutations and chromosome abnormalities in the fetuses of a heterogeneous population of pregnant women referred for prenatal testing for echogenic fetal bowel.

Methods: Fetal or parental samples obtained after a second-trimester sonographic finding of echogenic fetal bowel were submitted to a referral diagnostic laboratory during a 2-year period. Results of DNA testing and karyotyping on these samples were analyzed to determine the prevalence of cystic fibrosis transmembrane reductase gene mutations and chromosome abnormalities.

Results: Of 244 cases tested, two fetuses were positive for two cystic fibrosis mutations. This rate (0.8% or two of 244) is 20 times higher than the general white population rate of one per 2500. In a third case, both parents were carriers but the fetus was not tested. Nine (8%) of 113 fetuses tested had one cystic fibrosis mutation. Of 106 fetuses for whom chromosome results were available, three (2.8%) fetuses had a chromosomal abnormality: two had trisomy 21 and one had Klinefelter syndrome. A fourth fetus carried a de novo, apparently balanced, 5;12 translocation.

Conclusion: These laboratory results are representative of a broad spectrum of clinical settings and indicate a generalized increased risk associated with this sonographic finding. Therefore, when a second-trimester sonographic diagnosis of fetal echogenic bowel is made, fetal testing for both cystic fibrosis and chromosome abnormalities is warranted.

MeSH terms

  • Adult
  • Chromosome Aberrations / epidemiology
  • Chromosome Aberrations / genetics*
  • Chromosome Disorders
  • Cystic Fibrosis / diagnostic imaging*
  • Cystic Fibrosis / epidemiology
  • Cystic Fibrosis / genetics*
  • Female
  • Humans
  • Intestines / diagnostic imaging*
  • Intestines / embryology*
  • Mutation
  • Pregnancy
  • Prevalence
  • Ultrasonography, Prenatal*