Prenatal Evaluation for Detection of Anorectal Atresia: Value of Ultrasound

A practical method for prenatal diagnosis of anal atresia by second trimester ultrasound screening - A retrospective study

OBJECTIVES

The study aimed to demonstrate the performance of anal atresia ultrasound screening in the second trimester and to describe associated experiences in a primary care fetal medicine clinic.

MATERIALS AND METHODS

We retrospectively analyzed the medical records of fetuses who underwent a second-trimester screening at the Taiji clinic between November 2019 and May 2022. Fisher's exact test was conducted to investigate potential risk factors.

RESULTS

There were 28 459 fetuses screened in our clinic during the study period; eventually, 6 cases were diagnosed with anal atresia after birth. The incidence of anal atresia in our sample was 2.11 in 10 000. Based on our findings, potential risk factors significantly associated with anal atresia included: multiple pregnancies (p-value = 0.0185) and in-vitro fertilization (p-value = 0.038). Half of the anal atresia cases were associated with abnormalities affecting other organ systems, most frequently the genitourinary system (66.7%) and cardiovascular system (66.7%), especially persistent left superior vena cava (2 cases).

CONCLUSION

Anal atresia is a malformation that requires extensive care; the clinical management after the prenatal discovery of its signs should include testing for chromosomal abnormalities and close monitoring of the amniotic fluid volume. Therefore, prenatal ultrasound screening for anal atresia in the second trimester is critical, particularly in the cases of multiple and IVF pregnancies, and multiple abnormalities. The fetuses with ultrasound signs of anal atresia should be followed at a later gestational period and referred to a specialized institution for postnatal management planning and parental counseling.

Prevalence and mortality among children with anorectal malformation: A multi-country analysis

PURPOSE

We examined the total prevalence, trends in prevalence, and age-specific mortality among individuals with anorectal malformation (ARM) METHODS: We conducted a retrospective cohort study using data from 24 population- and hospital-based birth defects surveillance programs affiliated with the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) from 18 countries and for births from 1974 to 2014. We estimated pooled and program-specific total prevalence per 10,000 total births. Poisson regression was used to assess time trends in prevalence from 2001 to 2012 when most programs contributed data. We calculated selected age-specific proportions of deaths, stratified by case status RESULTS: The pooled total prevalence of ARM was 3.26 per 10,000 total births (95% Confidence Interval = 3.19, 3.32) for birth years 1974-2014. About 60% of cases were multiple or syndromic. Prevalence of multiple, syndromic, and stillborn cases decreased from 2001 to 2012. The first week mortality proportion was 12.5%, 3.2%, 28.3%, and 18.2% among all, isolated, multiple, and syndromic cases, respectively CONCLUSIONS: ARM is relatively rare, with multiple and syndromic cases showing decreasing prevalence during the study period. Mortality is a concern during the first week of life, and especially among multiple and syndromic cases. Our descriptive epidemiological findings increase our understanding of geographic variation in the prevalence of ARM and can be used to plan needed clinical services. Exploring factors influencing prevalence and mortality among individuals with ARM could inform future studies.

Sonographic detection and localization of fistulas in fetuses with imperforate anus: Case reports

Imperforate anus (IA) requires urgent treatment after birth, which is dependent on the type of IA, and is also frequently associated with other congenital abnormalities. Most patients with IA have an accompanying fistula, whose location is strongly associated with the type of IA. The fistula location can be a key factor in defining appropriate treatment, especially in neonates presenting with severe associated abnormalities. Herein, we report three cases of IA in which fistulas were detected and localized prenatally. Examination of the fetal pelvis through the sagittal or coronal view, using high-frequency transducers, revealed the location of the fistulas. In particular, the sagittal view obtained using the fetal infracoccygeal or perineal approach allowed us to determine the precise anatomy of the fistulas. Neonatal assessment confirmed the fistula locations. We recommend using the sagittal view obtained using the fetal infracoccygeal or perineal approach with high-frequency transducers to assess fistulas in fetuses with IA.

Can Anorectal Atresia Be Diagnosed in the First Trimester of Pregnancy? A Systematic Literature Review

Anorectal atresia (ARA) is a common congenital anomaly, but prenatal diagnosis is difficult, late, and unspecific. Utilizing a case of a 46 year old primipara with an egg donation In Vitro Fertilization (IVF) pregnancy, diagnosed at the first trimester scan with an anechoic isolated structure, which indicates anal atresia, we performed a systematic literature review in order to evaluate early prenatal ARA diagnosis. A total of 16 cases were reported as first trimester ARA suspicion, and only three had no associated anomalies. The most frequent ultrasound (US) sign was the presence of a cystic, anechoic pelvic structure of mainly tubular shape, or a plain abdominal cyst. In the majority of cases, structures were thin-walled and delimitated from the bladder. The presence of hyperechoic spots signifying enterolithiasis and peristaltic movements were helpful in order to establish the bowel origin of the lesion. Considering the high eventuality that the lesion is transitory, meaning later in pregnancy the fetus looks normal, early detection of such a sign should prompt further structural detailed evaluation, karyotyping, and appropriate pregnancy and postnatal counselling.

Prenatal imaging of anorectal malformations - 10-year experience at a tertiary center in Switzerland

BACKGROUND

Anorectal malformation is a spectrum of congenital defects of the distal bowel, mostly diagnosed at birth.

OBJECTIVE

To describe the prenatal imaging findings of anorectal malformations, explore the causes of the low rates of prenatal diagnosis, compare the accuracy of prenatal ultrasound (US) and magnetic resonnance imaging [MRI] and evaluate the relevance of information obtained at MRI.

MATERIALS AND METHODS

Children treated for anorectal malformation at our hospital and with available prenatal studies were retrospectively identified and included in the study. We reviewed prenatal imaging exams, listed findings suggestive of the diagnosis, and compared results with the final classification.

RESULTS

Fourteen fetuses and neonates - eight with intermediate-high type anorectal malformation and six with cloacae - fulfilled the inclusion criteria. All had associated congenital anomalies. Prenatal exams included 13 US and 8 MRI exams, with 7 children having both exams. Suggestive findings for anorectal malformation were detected in 50% of the cases prenatally and in 85% upon review. They were prospectively detected in 31% and 50% of the cases at US and MRI and retrospectively in 62% and 100% at US and MRI, respectively. MRI was superior to US because it improved the diagnosis, especially in cloacae, and provided relevant additional information that changed management in two cases.

CONCLUSION

The most important signs suggesting anorectal malformation are an absent target sign and anomalous distal bowel wall and rectal fluid. Complementary prenatal MRI improves the diagnosis of anorectal malformation.

Prenatal Dilated Rectum: Do We Need to Worry?

BACKGROUND

Advances in prenatal imaging is increasing detection of abnormally dilated bowel. There is no literature to date defining the criteria for a dilated rectum or its association with postnatal pathology. The aim of this study is to investigate the clinical significance of a prenatally identified dilated rectum.

METHODS

A retrospective review was performed of all cases of "dilated bowel" on prenatal ultrasound between January 2000 and December 2017 at a single institution. We excluded ventral wall defects from review and sought to include only cases of a prominent or dilated rectum. Collected data included prenatal bowel measurements, postnatal diagnoses, need for surgical intervention, and outcomes. Descriptive statistics were applied.

RESULTS

One hundred and ninety-three cases of prenatal "dilated bowel" were identified in which 12 (6.2%) had specifically visualized a prominent or dilated rectum. Nine of these (75.0%) had no rectal or intestinal abnormality on postnatal evaluation and were discharged feeding and defecating normally. The remaining three cases exhibited clinical pathology necessitating additional management: (1) meconium plug, (2) jejunal atresia with cecal perforation, and (3) rectal perforation with retroperitoneal abscess. All three had rectal biopsies with identification of ganglionated submucosa.

CONCLUSIONS

Although a prenatal dilated rectum is a normal variant in the vast majority of cases, it may be associated with a gastrointestinal abnormality requiring surgical intervention. Interestingly, there were no cases of Hirschsprung's disease or anorectal malformations in this cohort. These results, in conjunction with continued efforts to identify and define rectal dilation, are useful for prenatal counseling and postnatal evaluation.