Nonobstructive Diffuse Dilated Bowel Loops: Prenatal Diagnosis, Fetal Characteristics and Neonatal Outcomes

Sonographic findings of transient marked proximal bowel dilatation in a growth-restricted fetus at 35 weeks' gestation

Etiologies underlying the relatively infrequent third-trimester sonographic depiction of dilated fetal bowel include (functional or mechanical) bowel obstruction, intestinal atresia, volvulus, annular pancreas, intestinal malrotation, intussusception, gastrointestinal duplications, cystic fibrosis-associated meconium ileus, congenital chloride diarrhea, microvillus inclusion disease, intestinal neuronal dysplasia, and meconium plug syndrome. Fetal bowel obstruction may be associated with aneuploidy (mostly Trisomy 21 in association with esophageal or duodenal atresia), and rarely select microduplications or deletions. We present unusual sonographic findings associated with transient marked proximal fetal bowel dilatation in association with concurrent development of oligohydramnios, in a growth-restricted fetus at 35 weeks' gestation. This case supports that upon observation of dilated loops of fetal bowel, while not negating the potential need for delivery secondary to potential bowel compromise, consideration should be given for observation in anticipation of potential spontaneous resolution of this condition, especially among growth-restricted fetuses with decreased amniotic fluid volume in prematurity.

Whole-exome sequencing applications in prenatal diagnosis of fetal bowel dilatation

This study introduced whole-exome sequencing (WES) in prenatal diagnosis of fetal bowel dilatation to improve the detection outcome when karyotype analysis and copy number variation sequencing (CNV-seq) were uninformative in detecting pathogenic variants. The work reviewed 28 cases diagnosed with fetal bowel dilatation and analyzed the results of karyotype analysis, CNV-seq, and WES. Among the 28 cases, the detection rate in cases with low risk of aneuploidy was 11.54% (3/26), which is lower than 100% (2/2) in cases with high risk of aneuploidy. Ten low-risk aneuploidy cases with isolated fetal bowel dilatation had normal genetic testing results, while the remaining 16 cases with other ultrasound abnormalities were detected for genetic variants at a rate of 18.75% (3/16). The detection rate of gene variation was 3.85% (1/26) by CNV-seq and 7.69% (2/26) by WES. This study suggested that WES could reveal more genetic risk in prenatal diagnosis of fetal bowel dilatation and has value in prenatal diagnosis to reduce birth defects.

Fetal intestinal loop dilatation: Follow-up and outcome of a series of 133 consecutive cases (the DILDIG study)

OBJECTIVES

To define the prognostic markers of fetal dilated bowel loops.

METHODS

National non-interventional study of 133 consecutive prenatal observations of dilated loops including ultrasound examinations, complementary laboratory tests, magnetic resonance imaging (MRI), outcomes, and postnatal diagnosis.

RESULTS

One hundred twenty seven cases were classified according to outcome: Group 1, very severe (n = 43), Group 2, children needing specific care (n = 39), and Group 3, healthy children (n = 45). Prenatal ultrasound scan suggested duodenal obstruction in 30 cases, small bowel obstruction in 81, colonic obstruction in 11, and diffuse dilatation in 5. Diameter of dilated loops did not significantly differ between the groups. A poor prognosis was significantly associated with duodenal obstruction, genetic anomalies (53% vs. 21.8%), including aneuploidies or CFTR gene mutations and abnormal amniotic fluid biochemistry (86.4% vs. 38.7%). A good prognosis was associated with regression of dilatation and normal MRI.

CONCLUSION

In this study, postnatal outcomes for fetuses with intestinal dilatation were best predicted by assessing the level of obstruction with prenatal ultrasound and MRI, determining the presence of associated malformations, amniotic fluid biochemical and genetic testing, and monitoring for regression of bowel dilatation. These results should help inform future guidelines on the prenatal and neonatal management of congenital intestinal obstruction.

Fetal sigmoid colon mesentery made visible by routine ultrasound in the first and second trimester of pregnancy

BACKGROUND

Ultrasound is a routine procedure performed during pregnancy to monitor the status of the human fetus, including the development of the digestive tract. The aim of this publication was to determine the shape of the fetal sigmoid colon mesentery during the first and second trimester of pregnancy by means of ultrasound.

METHODS

The study was performed in 45 pregnant women (age: 36.4 years on average, range 25-45) during a routine ultrasound examination. The fetuses were between 12 and 22 weeks of pregnancy. The shape of the fetal sigmoid colon mesentery was analyzed.

RESULTS

We visualized the triangular shape of the mesentery in all 45 cases. A prevalence of scalene or isosceles acute triangles was found in both trimesters. At the 12-13 weeks we observed 5 different forms of mesenteric triangles - the scalene or isosceles acute triangles appeared at 33.3% and 28.6%, respectively. The obtuse scalene was present in 23.8 %. In the 2nd trimester (20-22 weeks) 4 types were found, among them 37.5 % acute scalene and 33.3 % acute isosceles.

CONCLUSIONS

The fetal sigmoid colon mesentery can be visualized from the 12th week of pregnancy. The triangular shape of the sigmoid colon mesentery is easy to follow during routine ultrasound examinations.