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Echogenic bowel

Question
Since the 24th week of pregnancy, our unborn first child has had an echogenic bowel. After infections were ruled out, and chromosomal aberrations, bleedings and placentar insufficiency were regarded as very unlikely, we had our blood tested for any CF mutations. My husband was found to have dF508, and I R1162X.
It is now week 33, the bowel is still echogenic but not dilated. How high would you presume the chances of the child not having CF to be? We are aware of the 25% chance of CF just because of our mutations, but how high is the probability of CF knowing the child has an echogenic bowel?
Thank you very much!
Answer
Dear Parents
Thank you for your question regarding your genetics and echogenic bowel on your antenatal ultrasound scan.
As both of you are carriers for CF causing genes then the risk of your baby having CF is 25% and that probability remains the same for any subsequent pregnancies. The association between echogenic bowel on antenatal ultrasound scan is well established, however the incidence reported varies widely from 3.1%-62% in different studies. The combination of both parents being identified as carriers along with echogenic bowel increases the probability of the baby having CF but an exact figure cannot be placed on it. There have been some reports of carriers having echogenic bowel noted on antenatal scan. If only one or neither of you had been identified as a carrier for common CF genes then the Bayesian formula could have been used to calculate the risk.
The only way to be sure is to test the baby’s DNA either by amniocentesis or by taking cord blood after the baby is born. As you are now 33 weeks pregnant we assume that you have opted not to have an amniocentesis. When the baby is born they should also be monitored for any signs of abdominal obstruction. It is important to check they pass meconium (the first bowel movement) within the first 48hrs after birth.
You should discuss these options with your obstetrician. We wish you all the best in your pregnancy and with your baby.
Dr Laura Jenkins CF Paediatric Associate Specialist, Hazel Mills Paediatric CF Nurse Specialist

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3.Calculating posterior cystic fibrosis risk with echogenic bowel and one characterized cystic fibrosis mutation: avoiding pitfalls in the risk calculations.
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4. Predicting the risk of cystic fibrosis with echogenic fetal bowel and one cystic fibrosis mutation. Bosco AF, Norton ME, Lieberman E. Obstet Gynecol 1999 Dec;94(6):1020-3

11.07.2013
The answer is edited by: Laura Jenkins