Hyperechogenic fetal bowel as a markerof fetal cystic fibrosis

Czech version

Authors: M. Sukupová ^1,2; I. Dhaifalah ^2,3; Z. Adamík ¹; J. Havalová ^1,2
Authors‘ workplace: Gynekologicko-porodnické oddělení, Krajská nemocnice T. Bati, a. s. Zlín, přednosta MUDr. Z. Adamík, Ph. D. ¹; Centrum fetální medicíny a lékařské genetiky, Krajská nemocnice T. Bati, a. s. Zlín vedoucí pracoviště doc. MUDr. I. Dhaifalah, Ph. D. ²; Ústav lékařské genetiky LF UP, Olomouc, přednostka doc. MUDr. I. Dhaifalah, Ph. D. ³
Published in: Ceska Gynekol 2015; 80(1): 20-24

Overview

Introduction:
Hyperechogenic bowel (HB) occurs in 0.1 to 1.8% of normal pregnancies. In most cases it has no consequence for the foetus, but can be associated with cystic fibrosis (CF), chromosomal defects, genetic syndromes, viral infections, gastrointestinal pathology, missed gravidity, IUGR and preterm labour.

Objectives:
Assessment the risk of the foetus having CF or other abnormalities when HB was detected during ultrasound screening in the second trimester of pregnancy in our centre.

Design:
Retrospective study.

Setting:
Department of Obstetrics and Gynecology, Centre of Fetal Medicine and Genetics, KNTB a.s. Zlín.

Methods:
Retrospective analysis of 149 cases of HB between 17 to 22 weeks of pregnancy detected from January 2008 to April 2012.

HB was evaluated according to its degree of echogenicity (Slotnik/Abuhamed classification), presence or absence of other ultrasound markers and the result of first trimester combined screening result. When stage II or III HB and/or borderline risk in first trimester screening, and presence of other ultrasound markers was detected, amniocentesis (AMC) was performed to investigate the karyotype, mutations in the CFTR gene and presence of viral infections (cytomegalovirus and parvovirus B19). If stage I or II HB and/or negative I. trimester screening and no other ultrasound markers, viral infections and mutations in the CFTR gene were investigated form maternal blood. If positive, paternal blood sampling testing for mutation in the CFTR gene was performed. If a mutation was detected in both parents, AMC was performed.

Mutations of the CFTR gene was investigated with a com-mercial panel of 33 to 50 most common mutations.

Postnatally the outcome of neonatal screening for CF(IRT) and any newborns with congenital malformations were ascertained.

Results:
HB was seen in 149 foetuses, AMC was performed in 94 (63%), and blood sampling in 55 (37%). Two mutations in the CFTR gene associated with a severe form of CF (deltaF508/3849 KBC +10 T) were found in one foetus from the AMC group with stage III HB. The parents decided to terminate the pregnancy.

The incidence of HB in our group was 0.7%. In 4 foetuses (2.7%) with stage II HB heterozygous deltaF508 mutation was found, in the rest no mutations were detected. Parents of heterozygous carriers underwent genetic consultation. Postnatal CF screening (IRT level from a heel prick sample) was negative; therefore no further molecular genetic analysis was performed.

Infection was detected in three foetuses; one case was managed with intrauterine transfusion and in the other two cases parents decided for termination. Four cases (2.7%) were terminated because of severe congenital anomalies. Minor congenital abnormalities were detected in seven (4.7%) cases. Intrauterine death was detected in three (2%) pregnancies.

Conclusion:
Based on our results, HB can be considered as a significant marker for the risk of CF, especially in HB stages II and III. It also demonstrates the importance of this marker for the risk of other foetal abnormalities.

Keywords:
hyperechogenic bowel, cystic fibrosis, mutation, amniocentesis, viral infection, chromosomal abnormalities

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