Early sonographic detection of fetal intestinal obstruction and possible diagnostic pitfalls

Intrauterine volvulus: systemic review of the literature with pooled analysis

Our objective is to analyse the observations related to intrauterine volvulus and assess how clinical manifestations and treatment strategies impact prognosis. We conducted a comprehensive search on Pubmed and ClinicalTrials.gov from inception to July 2022, using search terms like "intrauterine volvulus" or "foetal volvulus," supplemented by manual scrutiny of reference lists in relevant texts and articles. Our review encompassed 57 case reports/case series, involving 88 cases. The presence of foetal bradycardia during prenatal visits (p = 0.002) and the existence of meconium cyst or pseudocyst (p = 0.038) significantly influence survival rates. Preterm labour occurred more frequently among cases resulting in mortality (54% vs 21%; p = 0.055). Our study's limitations include the inability to access all reported cases and reliance solely on available data. We advocate for vigilant monitoring of foetuses exhibiting signs of intestinal obstruction, and consideration of an emergent caesarean section as a pre-emptive measure before foetal biophysical profile deterioration worsens.

Prenatal detection of gastrointestinal bubbles since early pregnancy: Clues to correct diagnosis

OBJECTIVE

To characterize gastrointestinal bubbles detected since early pregnancy and to describe corresponding diagnoses.

METHOD

A retrospective cohort review of all cases in which gastrointestinal bubbles were detected starting in early prenatal transvaginal scans at 14-17 weeks of gestation between the years 2007 and 2021. Sonographic features and data regarding associated anomalies, genetic abnormalities, and pregnancy outcome were evaluated.

RESULTS

Bubbles were detected in 23 of 27 073 early scans and a total of 31 394 scans. Diagnosis was available in 22 cases. Transient bubbles were detected in 10 cases and represented normal peristalsis. Fixed double bubble was detected in nine cases. Double-walled double bubbles represented duodenal duplications (three cases) and esophageal duplications (two cases). Simple cysts represented duodenal atresia (three cases) and a pancreatic cyst (one case). A triple bubble represented duodenal obstruction from Ladd bands in one case. Quadribubble was detected in two cases and represented jejunal atresia.

CONCLUSION

Prenatal detection of gastrointestinal bubbles can accurately diagnose physiological versus pathological upper gastrointestinal conditions. Transient bubbles are physiological. Fixed double bubbles might represent either duodenal atresia or esophageal/duodenal duplications when a double wall is demonstrated. Three or four bubbles might represent more distal intrinsic or extrinsic obstruction.

Prenatal imaging features and perinatal outcomes of foetal volvulus-A literature review

OBJECTIVE

To conduct a review of the literature on foetal volvulus with emphasis on prenatal imaging, pregnancy characteristics and clinical outcomes.

METHODS

A review of all published cases of foetal volvulus diagnosed prenatally and indexed in Medline, EBSCOhost, CINAHL, SOCIndex and Healthy Policy Reference Centre. Studies without antenatal sonographic signs of foetal volvulus and without a postpartum surgical diagnosis were excluded. Data were analysed for frequencies and distributions and tested for statistical significance.

RESULTS

Eighty-eight cases of foetal volvulus were identified from 58 published case reports/series. The most common ultrasound findings were dilated bowel/stomach (77.3%), polyhydramnios (30.7%) and whirlpool/snail sign (28.4%). Median gestation at diagnosis was 31.9 weeks (IQR 27-34) and mean gestation at delivery was 34.5 weeks (SD 2.8). Underlying aetiology included intestinal malrotation (15.9%), cystic fibrosis (14.8% of all cases, 32.5% of tested cases) and abnormal mesenteric fixation (12.5%). Complications included intestinal atresia (36.4%) and foetal anaemia (9.1%). The overall perinatal mortality rate was 14.5%.

CONCLUSION

Foetal volvulus is a rare condition with high rates of preterm birth and perinatal mortality. Intestinal malrotation and cystic fibrosis are common predisposing causes, although the majority are idiopathic. Bowel and/or gastric dilatation is by far the most common sonographic finding.

The diagnosis of an imperforate anus in female fetuses

Imperforate anus is an anomaly caused by a defect in the development of the hindgut during early pregnancy. It is a relatively common congenital malformation and is more common in males. Although there are cases of a solitary imperforate anus, the condition is more commonly found as a part of a wider spectrum of other congenital anomalies. Although urgent reconstructive anorectal surgery is not necessary, immediate evaluation is important and urgent decompressive surgery may be required. Moreover, as there are often other anomalies that can affect management, prenatal diagnosis can help in optimizing perinatal care and prepare parents through prenatal counseling. In the past, imperforate anus was diagnosed by prenatal ultrasonography based on indirect signs such as bowel dilatation or intraluminal calcified meconium. Currently, it is diagnosed by directly checking the perineum with prenatal ultrasonography. Despite advances in ultrasound technology, accurate prenatal diagnosis is impossible in most cases and imperforate anus is detected after birth. Here, we present two cases of imperforate anus in female fetuses that were not diagnosed prenatally.

Evaluation of the development of the fetal anal sphincter with tomography ultrasonography imaging

The aim of the study described here was to examine the potential of tomography ultrasonography imaging (TUI) in evaluation of the fetal anal sphincter. In this prospective cross-sectional study of the fetal anal sphincter with TUI, 326 singleton pregnancies (mean age = 28 y, range: 22-38 y) were scanned at 19-40 wk of gestation. The fetal anal region and ischium were revealed in 320 of 326 patients (98.2%). The normal fetal anal sphincter diameter and ischial space reached maximums of 15 and 39 mm, respectively. The normal fetal anal sphincter diameter and the ischial space were plotted as a function of gestational age (GA) on a linear curve, and the regression equations for normal fetal anal sphincter diameter and ischial space as a function of GA in weeks were obtained. A scatterplot was also created that revealed a significant positive relationship between normal fetal anal sphincter diameter and ischial space. On the basis of these criteria, imperforate anus was diagnosed in one fetus. Ultrasonographic assessment of the fetal anal sphincter and the ischium with TUI is feasible. The reference values reported in this article may be useful in prenatal diagnosis of fetal anal sphincter abnormalities.

Role of magnetic resonance imaging in the prenatal diagnosis of gastrointestinal fetal anomalies

PURPOSE

This study was done to evaluate the role of fetal magnetic resonance imaging (MRI) in the study of gastrointestinal malformations in comparison to prenatal ultrasound (US).

MATERIALS AND METHODS

A prospective (2010-2012) study of 38 fetal MRI scans was performed on 38 fetuses between 24 and 38 weeks of gestation. All the fetuses had a US diagnosis of gastrointestinal anomalies. T2-weighted HASTE, T1-weighted fast gradient echo, TrueFISP and diffusion-weighted images of the fetal abdomen were obtained on a 1.5-Tesla magnet. All fetal MRI diagnoses were compared with postnatal US findings, autopsy or surgical reports.

RESULTS

Fetal MRI was able to confirm the sonographic findings in nine of 38 fetuses (23.7%), to provide additional information in 23 of 38 fetuses (60.6%), to exclude the US diagnosis in five cases (5.2%) and to change it in two cases (5.2%). It was not able to characterize a case of gastric duplication and a case of abdominal cystic lymphangioma (5.2%).

CONCLUSIONS

Fetal MRI can be used as a complementary imaging modality to US in prenatal evaluation of gastrointestinal anomalies and can be considered a valuable tool not only for confirming or excluding but also for providing additional information to fetal ultrasonographic findings.

Sonographic evaluation of the development of the fetal rectum and anal canal

PURPOSE

To describe the sonographic (US) appearance of fetal anal canal and rectum and establish nomograms of their normal measurements.

METHODS

This was a prospective, cross-sectional study of 524 healthy women (mean age, 27 years; range, 21-37 years) with normal singleton pregnancy between 18 and 40 weeks of gestational age (GA). High-resolution transabdominal US was used to visualize and measure the normal fetal anal canal and rectum.

RESULTS

Satisfactory images and measurements of the fetal anal canal and rectum were obtained in 496 normal fetuses. The diameters of the normal anal canal and rectum were plotted as a function of GA in a sigmoid curve. The curve estimations were expressed by the following cubic regression equations with R(2) of 0.87 and 0.88, respectively (p < 0.001): anal canal diameter (mm) = 18.272 - 2.151 × GA + 0.0095 × GA(2) - 0.0011 × GA(3) , and rectal diameter (mm) = 18.545 - 2.543 × GA + 0.1237 × GA(2) - 0.0016 × GA(3) .

CONCLUSIONS

The fetal anal canal and rectum are visible sonographically between 18 and 40 weeks of GA. The knowledge of their normal US appearance and size from the second trimester of pregnancy onwards may help identify developmental anomalies.

Sonographic features of anorectal atresia at 12 weeks

We present the sonographic features of a fetus with anal atresia at 12 weeks of gestation. Follow-up ultrasound examination at 17 week revealed apparently normal bowel. Spontaneous miscarriage occurred at 18 weeks and postmortem examination showed anorectal atresia and arthrogryposis multiplex. It seems that dilatation of the bowel in the early pregnancy is a possible marker for anorectal atresia, and the abnormality may be overlooked if a mid-trimester scan alone is performed.

Midgut volvulus causing fetal demise in utero

Intestinal malrotation has an incidence of 1 per 6000 live births. The most serious consequence of malrotation is volvulus. Midgut volvulus is a rare condition in which the small bowel and proximal colon twist around the superior mesenteric artery, leading to a high-grade proximal bowel obstruction and vascular compromise of the intestine, thereby leading to infarction of the involved intestine. Midgut volvulus rarely occurs antenatally and is usually not lethal in utero. There are only 7 cases of intrauterine fetal demise caused by midgut volvulus reported in the literature. We report a case of intrauterine fetal demise at 38 weeks of gestation, due to cardiovascular failure and shock from midgut volvulus. Non-specific abnormalities, including ascites and dilated bowel, had been seen on the antenatal ultrasound from the 15th week of gestation. In addition to the volvulus, the fetus had intestinal atresia and arthrogryposis.

Imperforate anus: A relatively common anomaly rarely diagnosed prenatally

OBJECTIVE

Despite the relatively common occurrence of imperforate anus, prenatal diagnosis is rarely reported. In this study, we investigated the presence and diagnosis of imperforate anus along with strategies for improving prenatal diagnosis of the condition.

PATIENTS AND METHODS

Fetuses and infants with imperforate anus who had been examined prenatally by ultrasound at the National Center for Fetal Medicine (NCFM) from 1987 to 2004, were evaluated.

RESULTS

Of 69 cases with imperforate anus, only 11 (15.9%) were diagnosed prenatally, at a median gestation of 18 + 4 (range, 15 + 6 to 35 + 6) weeks. In all 11, dilatations of the rectum or lower part of the bowel were seen. Additional anomalies, most of them diagnosed prenatally, were present in 59/69 (85.5%) of the cases. The most frequent additional anomalies were urogenital (53.6%). The karyotype was abnormal in nine cases (13.0%). A retrospective evaluation of available videotapes of 22 cases of imperforate anus that were not diagnosed prenatally revealed that it was possible to suspect the diagnosis in 11/22 (50%) cases. Sixteen infants were born with imperforate anus without prenatal diagnosis of any abnormality. In total, 31/69 (44.9%) cases were terminated, two (2.9%) died in utero and 12 (17.4%) died postnatally. Twenty-four (34.8%) infants survived, including all 10 with isolated imperforate anus and seven of eight cases with only one additional anomaly.

CONCLUSIONS

The prenatal detection rate of imperforate anus was only 15.9%. Imperforate anus is often associated with other anomalies; in this study, 85.5% had additional anomalies. Prenatal diagnosis makes prenatal counseling possible and facilitates optimized postnatal care. We believe that the prenatal detection rate of imperforate anus could be improved. Examiners should intensify their search for typical findings of imperforate anus especially when other anomalies that frequently accompany this condition are present.

Fetal Anal Atresia Presenting as Transient Bowel Dilatation at 16 Weeks of Gestation

Congenital anal atresia is a rare abnormality which in two thirds of the cases is associated with other congenital abnormalities or syndromes. Prenatal diagnosis is usually achieved in cases with coexisting abnormalities. The diagnosis of isolated anal atresia is extremely difficult and can be suspected in the presence of colon dilatation. We present the case of a fetus in which marked dilatation of the colon was diagnosed at 16 weeks of gestation. Four weeks later the sonographic appearance of the bowel was normal and remained normal for the rest of the pregnancy. Anal atresia was diagnosed immediately after birth and corrected surgically. No other abnormalities were present. This case report illustrates that in anal atresia, bowel dilatation may be only transient.

Sonographic prenatal diagnosis of malpositioned stomach as a feature of uncomplicated intestinal malrotation

Intestinal malrotation is a developmental anomaly affecting the position and peritoneal attachments of the small and large intestines during fetal life. Most often the diagnosis is established in the first year of life on the basis of abdominal pain and bile-stained vomiting secondary to bowel obstruction. The antenatal diagnosis can be suggested by identification of the complications such as bowel dilatation, ascites or meconium peritonitis. We describe two cases of isolated antenatal gastric malposition without any other associated anomaly that were confirmed after birth to be due to intestinal malrotation. We suggest that such an antenatal finding should alert the paediatrician to close clinical follow-up and prompt the diagnosis and surgical treatment in case of abdominal pain and/or bilious vomiting.

First-trimester diagnosis of imperforate anus

Imperforate anus or anorectal atresia is often associated with major fetal structural defects but it may also be an isolated abnormality. Prenatal diagnosis is difficult but may be assisted by ultrasound detection of a dilated distal bowel or rectum. We report on a fetus at 12 weeks of gestation in which a dilated colon was detected at ultrasound examination. Dilatation of the colon was clearly seen in the first and third trimesters of pregnancy, but was difficult to detect in the second trimester. At birth, the newborn was diagnosed with a low type of imperforate anus.

Nonobstructive dilatation of the fetal bowel in twin gestations. A possible sonographic marker for fetal compromise

OBJECTIVE

To assess the possible association of in-utero bowel dilatation and circulatory changes with fetal compromise.

METHODS

A retrospective survey of all ultrasound examinations was performed at the Chaim Sheba Medical Center (n approximately 10,000) between 1995 and 1999. Cases with ultrasonographic evidence of bowel dilatation, but without evidence of obstruction, were recruited. In utero Doppler studies of umbilical, splenic, superior mesenteric arteries, and middle cerebral artery (MCA) were performed: systolic/diastolic ratio (S/D), pulsatility index (PI) and resistance index (RI) were calculated in the above arteries and compared with those of normal fetuses. Nonstress test and cord blood pH were also assessed. Neonatal medical records were procured.

RESULTS

Four fetuses, all of who were products of twin gestations, showed bowel dilatation without evidence for obstruction. Three of the four fetuses were small-for-gestation-age (SGA) and of bichorionic gestation, while one was of monochorionic twin gestation, with twin transfusion syndrome. In all three SGA fetuses, Doppler studies revealed increased peripheral resistance in the umbilical artery and adaptive peripheral vasodilatation in the fetal midcerebral, splenic and superior mesenteric arteries. In all cases, an abnormal nonstress test led to prompt delivery.

CONCLUSIONS

Acute fetal bowel dilatation in a twin gestation is associated with abnormal splanchnic and gut perfusion that may lead to fetal compromise.

Sonographic features of anal atresia at 12 weeks

Anorectal atresia results from abnormal development of the anorectal septum. Prenatal diagnosis is difficult but the condition may be suspected by the sonographic demonstration of a dilated colon. We present the sonographic features of a fetus with anal atresia and a ventricular septal defect at 12 weeks of gestation. This case illustrates that a dilated colon may be present in association with fetal anal atresia as early as 12 weeks.