Applications of Pediatric Body CT Angiography: What Radiologists Need to Know.

OBJECTIVE. Pediatric CT angiography (CTA) can be useful for assessing numerous congenital and acquired disorders. This article discusses common pediatric applications of thoracoabdominal CTA, including for congenital pulmonary airway malformation, sequestration, vascular rings, aortic coarctation, pulmonary embolism, nontraumatic hemorrhage, abdominal transplant evaluation, and several vascular disorders, and highlights key clinical and imaging features. CONCLUSION. With appropriate use, CTA can play a fundamental role in diagnostic and preprocedural assessment in a variety of pediatric conditions.

Congenital Epidermoid Cyst of the Liver: A Rare Entity Characterized by Antenatal Onset, Slow Postnatal Growth, and Consistent Histologic and Immunohistologic Features.

BACKGROUND: There are only 15 reported hepatic epidermoid cysts; they include patients presenting congenitally through adulthood, with varied speculations about pathogenesis. Aside from recently reported pancytokeratin staining, no other descriptions have included immunohistochemistry. Splenic epidermoid cysts were recently characterized as positive for HBME-1, p63, CEA, CK7 (luminal), and CK19. We interrogate 2 hepatic epidermoid cysts with a broad panel of immunohistochemistry, with the aim of elucidating histogenesis. METHODS: Archives were searched for "liver," "hepatic," and "cyst." Hepatic cysts lined by squamous epithelium were included. Clinical records, macroscopic findings, and hematoxylin and eosin and immunohistochemically stained slides were reviewed. RESULTS: We identified 2 patients with epidermoid cysts of the liver, first detected on antenatal ultrasound. Both were females and asymptomatic; neither had other congenital abnormalities. Cysts enlarged slowly after birth. Resection was at ages 2 and 6 months, done to avoid potentially more difficult surgery in the future. Cysts were unilocular (4.8 cm) and multilocular (7.0 cm). Both were lined by stratified nonkeratinizing squamous to focally transitional-like epithelium and surrounded by paucicellular fibrous stroma. In the multilocular cyst, hepatocytes and fibrous stroma populated septa. Epithelium was positive for HBME-1, p63, CK19, CEA, Cam5.2, and CK7, negative for EMA, D2-40, WT-1, calretinin, and Ca19-9. Cytogenetic analysis of one showed a normal female karyotype. During the study period, 22 other pediatric liver cysts were diagnosed. CONCLUSION: Hepatic epidermoid cyst is a distinct entity, rare but nevertheless constituting 8% of pediatric hepatic cysts at our institution. It is characterized by intrauterine onset and growth roughly commensurate with that of the fetus/infant; it is apparently unsyndromic. It may be unilocular or multilocular. It stains for an array of epithelial markers as well as HBME-1. Strong immunohistochemical overlap with splenic epidermoid cyst points to a shared pathogenesis and detracts from hypotheses that hepatic epidermoid cysts derive from hepatic elements.

Biallelic IARS Mutations Cause Growth Retardation with Prenatal Onset, Intellectual Disability, Muscular Hypotonia, and Infantile Hepatopathy.

tRNA synthetase deficiencies are a growing group of genetic diseases associated with tissue-specific, mostly neurological, phenotypes. In cattle, cytosolic isoleucyl-tRNA synthetase (IARS) missense mutations cause hereditary weak calf syndrome. Exome sequencing in three unrelated individuals with severe prenatal-onset growth retardation, intellectual disability, and muscular hypotonia revealed biallelic mutations in IARS. Studies in yeast confirmed the pathogenicity of identified mutations. Two of the individuals had infantile hepatopathy with fibrosis and steatosis, leading in one to liver failure in the course of infections. Zinc deficiency was present in all affected individuals and supplementation with zinc showed a beneficial effect on growth in one.

A multicentre study to predict neonatal survival according to lung-to-head ratio and liver herniation in fetuses with left congenital diaphragmatic hernia (CDH): Hidden mortality from the Latin American CDH Study Group Registry.

OBJECTIVE: To evaluate natural history of fetuses congenital diaphragmatic hernia (CDH) prenatally diagnosed in countries where termination of pregnancy is not legally allowed and to predict neonatal survival according to lung area and liver herniation. METHODS: Prospective study including antenatally diagnosed CDH cases managed expectantly during pregnancy in six tertiary Latin American centres. The contribution of the observed/expected lung-to-head ratio (O/E-LHR) and liver herniation in predicting neonatal survival was assessed. RESULTS: From the total population of 380 CDH cases, 144 isolated fetuses were selected showing an overall survival rate of 31.9% (46/144). Survivors showed significantly higher O/E-LHR (56.5% vs 34.9%; P < .001), lower proportion of liver herniation (34.8% vs 80.6%, P < .001), and higher gestational age at birth (37.8 vs 36.2 weeks, P < 0.01) than nonsurvivors. Fetuses with an O/E-LHR less than 35% showed a 3.4% of survival; those with an O/E-LHR between 35% and 45% showed 28% of survival with liver up and 50% with liver down; those with an O/E-LHR greater than 45% showed 50% of survival rate with liver up and 76.9% with liver down. CONCLUSIONS: Neonatal mortality in CDH is higher in Latin American countries. The category of lung hypoplasia should be classified according to the survival rates in our Latin American CDH registry.

Retrohepatic Gallbladder Masquerading as Hydatid Cyst in a Patient with Right Liver Agenesis.

Agenesis of the right liver is a rare congenital anomaly which can be associated with an ectopic gallbladder. Hereby, it is presented the case of a 39-year-old man investigated for right upper quadrant abdominal pain and diagnosed at computed tomography with a cystic liver mass initially considered as hydatid cyst. At laparotomy, it was discovered agenesis of the right liver and the presumed hydatid cyst was a retrohepatic gallbladder with lithiasis. Cholecystectomy was performed with an uneventful outcome. Reassessment of the computed tomography images by an experienced radiologist confirmed the intraoperative diagnosis. Although agenesis of the right liver with retrohepatic gallbladder is an exceptional appearance, surgeons should be aware of this anomaly because it can raise challenging issues of diagnosis and surgical planning during cholecystectomy.

Access to care in rare liver diseases: New challenges and new opportunities.

Patients with rare diseases are often disadvantaged, particularly those with rare liver diseases. Reasons for disadvantage include delayed or overlooked diagnosis, lack of local expertise and high-quality care, poor scientific understanding of the disease process and limited therapeutic options. In adult liver disease this can be compounded by prejudices towards patients with liver disease in general, because of a perception (incorrect for all rare liver diseases) that liver disease is lifestyle related and thus "self-inflicted". In paediatric rare liver diseases, such as biliary atresia, optimising outcomes requires a particularly timely diagnosis. Irrespective of patient age, the scientific and medical community must rise to the challenge of advancing our understanding of rare liver disease, searching for more effective and specific therapies, and providing the infrastructure to provide the best care for all patients, infants, children, young and older adults. The European Reference Network for Rare Liver Diseases is an important step in this direction.

Five-year histological and serological follow-up of operationally tolerant pediatric liver transplant recipients enrolled in WISP-R.

Pediatric liver transplant recipients arguably have the most to gain and the most to lose from discontinuing immunosuppression (IS). Whereas IS undoubtedly exerts a cumulative toll, there is concern that insufficient or no IS may contribute to allograft deterioration. Twelve pediatric recipients of parental living donor liver grafts, identified as operationally tolerant through complete IS withdrawal (WISP-R; NCT00320606), were followed for a total of 5 years (1 year of IS withdrawal and 4 years off IS) with serial liver tests and autoantibody and alloantibody assessments. Liver biopsies were performed 2 and 4 years off IS, and, at these time points, immunoglobulin G (IgG) subclass and C1q binding activity for donor-specific antibodies (DSAs) were determined. There were no cases of chronic rejection, graft loss, or death. Allografts did not exhibit progressive increase in inflammation or fibrosis. Smooth-muscle actin expression by stellate cells and CD34 expression by liver sinusoidal endothelial cells remained stable, consistent with the absence of progressive graft injury. Three subjects never exhibited DSA. However, 3 subjects showed intermittent de novo class I DSA, 4 subjects showed persistent de novo class II DSA, and 5 subjects showed persistent preexisting class II DSA. Class II DSA was predominantly against donor DQ antigens, often of high mean fluorescence intensity, rarely of the IgG3 subclass, and often capable of binding C1q. CONCLUSION: Operationally tolerant pediatric liver transplant recipients maintain generally stable allograft histology in spite of apparently active humoral allo-immune responses. The absence of increased inflammation or progressive fibrosis suggests that a subset of liver allografts seem resistant to the chronic injury that is characteristic of antibody-mediated damage. (Hepatology 2017;65:647-660).

Characteristics of Liver Disease in 100 Individuals With Joubert Syndrome Prospectively Evaluated at a Single Center.

BACKGROUND AND AIMS: Joubert Syndrome (JS) is a rare, inherited, ciliopathy defined by cerebellar and brainstem malformations and is variably associated with liver, kidney, and ocular dysfunction. This study characterizes the hepatic findings in JS and identifies factors associated with probable portal hypertension. METHODS: Hundred individuals with JS were prospectively evaluated at the National Institutes of Health Clinical Center. Laboratory tests, imaging, and DNA sequencing were performed. Patients were stratified based on the spleen length/patient height ratio as a marker of splenomegaly, used as a surrogate for probable portal hypertension. RESULTS: Forty-three patients (43%) had liver involvement based on elevated liver enzymes and/or liver hyperechogenicity and/or splenomegaly. None of the patients had macroscopic liver cysts or bile duct dilatation. Based on the spleen length/patient height ratio, 13 patients were stratified into a probable portal hypertension group. We observed significant elevations in alkaline phosphatase (269 vs 169 U/L, P ≤ 0.001), alanine aminotransferase (92 vs 42 U/L, P = 0.004), aspartate aminotransferase (77 vs 40 U/L, P = 0.002), and gamma-glutamyl transferase (226 vs 51 U/L, P ≤ 0.001) in the probable portal hypertension group. Platelets were lower in the probable portal hypertension cohort (229 vs 299 × 10 cells/µL, P = 0.008), whereas synthetic function was intact in both groups. Probable portal hypertension was also more prevalent in patients with kidney disease (P = 0.001) and colobomas (P = 0.02), as well as mutations in the TMEM67 gene (P = 0.001). CONCLUSIONS: In JS, probable portal hypertension is associated with abnormal hepatic enzymes, as well as presence of kidney disease, coloboma, and/or mutation in TMEM67. These findings may allow early identification of JS patients who have or are more likely to develop liver disease.

Lung size and liver herniation predict need for extracorporeal membrane oxygenation but not pulmonary hypertension in isolated congenital diaphragmatic hernia: systematic review and meta-analysis.

OBJECTIVES: To identify antenatal predictors of persistent pulmonary hypertension (PPH) and the need for extracorporeal membrane oxygenation (ECMO) in fetuses with congenital diaphragmatic hernia (CDH). METHODS: We performed a systematic literature review on antenatal diagnostic tests in fetuses with isolated CDH. The primary outcomes assessed were PPH within 28 days of age and the need for ECMO. Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed when at least three studies reported on the same test. Sensitivity analysis was performed according to prenatal management of CDH (tracheal occlusion vs expectant management). RESULTS: Thirty-eight studies met the inclusion criteria. Fifteen reported on the incidence of PPH only, 19 on the need for ECMO only and four reported on both outcomes. The general quality of the studies was moderate; most studies were retrospective (61%) and single-center series (92%). One study included only fetuses undergoing tracheal occlusion, 22 included only fetuses managed expectantly in utero and 15 included both populations. We could not identify antenatal predictors of PPH. The need for ECMO was predicted by parameters indicative of lung size: lung-to-head ratio (LHR) (relative risk (RR) for LHR < 1, 1.65 (95% CI, 1.27-2.14)) and observed/expected LHR (standardized mean difference (SMD), -0.70 (95% CI, -0.98 to -0.42)) measured by ultrasound and observed/expected total lung volume (SMD, -1.00 (95% CI, -1.52 to -0.48)) measured by magnetic resonance imaging. Liver herniation was also associated with an increased risk of need for ECMO (RR, 3.04 (95% CI, 2.23-4.14)). These results were confirmed by a sensitivity analysis of studies that included only expectantly managed cases. Data on vascular assessment for the prediction of PPH could not be pooled as most of the parameters were evaluated in a single series or in different series by the same principal investigator. CONCLUSIONS: In fetuses with CDH, lung size and liver herniation predict the need for ECMO, however a predictor for PPH is still lacking. Further studies aimed at diagnosing impaired vascular development in utero should therefore be undertaken. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasound of congenital and inherited disorders of the pediatric hepatobiliary system, pancreas and spleen.

Ultrasound is often the initial imaging examination performed of the solid organs of the pediatric abdomen. The sonographic appearance of the hepatobiliary system, pancreas and spleen changes with growth and development. This article reviews the normal US appearance of these organs in children and illustrates, through case examples, congenital and inherited conditions that affect them.

Compound heterozygous mutations in NEK8 in siblings with end-stage renal disease with hepatic and cardiac anomalies.

We studied two brothers who presented in the newborn period with cardiac, renal, and hepatic anomalies that were initially suggestive of ALGS, although no mutations in JAG1 or NOTCH2 were identified. Exome sequencing demonstrated compound heterozygous mutations in the NEK8 gene (Never in mitosis A-related Kinase 8), a ciliary kinase indispensable for cardiac and renal development based on murine studies. The mutations included a c.2069_2070insC variant (p.Ter693LeufsTer86), and a c.1043C>T variant (p.Thr348Met) in the highly conserved RCC1 (Regulation of Chromosome Condensation 1) domain. The RCC1 domain is crucial for localization of the NEK8 protein to the centrosomes and cilia. Mutations in NEK8 have been previously reported in three fetuses (from a single family) with renal-hepatic-pancreatic dysplasia 2 (RHPD2), similar to Ivemark syndrome, and in three individuals with nephronophthisis (NPHP9). This is the third report of disease-causing mutations in the NEK8 gene in humans and only the second describing multi-organ involvement. The clinical features we describe differ from those in the previously published report in that (1) a pancreatic phenotype was not observed in the individuals reported here, (2) there were more prominent cardiac findings, (consistent with observations in murine models), and (3) we observed bile duct hypoplasia rather than ductal plate malformation. The patients reported here expand our understanding of the NEK8-associated phenotype. Our findings highlight the variable phenotypic expressivity and the spectrum of clinical manifestations due to mutations in the NEK8 gene.

Transdiaphragmatic Approach to Attenuate Porto-Azygos Shunts Inserting in the Thorax.

OBJECTIVE: To describe the surgical technique and document the application of a transdiaphragmatic approach to attenuate porto-azygos shunts inserting in the thoracic section of the azygos vein. STUDY DESIGN: Cadaveric study and prospective case series. ANIMALS: Canine cadavers (n=6) and client-owned dogs with porto-azygos shunts inserting in the thoracic section of the azygos vein (n=9). METHODS: In the cadavers, the azygos vein was filled with aqueous latex. Landmarks were established for creating a safe transdiaphragmatic approach to the caudal intrathoracic portion of the azygos vein. In the clinical cases, porto-azygos communication was diagnosed by trans-splenic portal scintigraphy. All shunts were attenuated close to their insertion site via ventral midline celiotomy and a transdiaphragmatic approach to the shunt. Perioperative complications were recorded. RESULTS: A 3-5 cm incision, 0.5-1 cm ventral and lateral to the level of the aortic hiatus, was made in the pars lumbalis part of the diaphragm. Stay sutures at both sides of the diaphragmatic incision were placed to open up the incision and a retractor was used to push the esophagus away from the aorta. Intrathoracic insertion of the shunt was confirmed intraoperative. Exposure of the shunt insertion site at the azygos vein was excellent in all clinical cases. No intraoperative or postoperative complications were encountered. CONCLUSION: If thoracic attenuation of a porto-azygos shunt is considered, a transdiaphragmatic approach exposes the insertion site for shunt attenuation. This approach is straightforward, without unnecessary abdominal organ manipulation, and since attenuates at the insertion, avoids missing additional contributing branches.

Determination of Porto-Azygos Shunt Anatomy in Dogs by Computed Tomography Angiography.

OBJECTIVE: To describe the morphology of porto-azygos shunts in a large series of dogs using computed tomography (CT) angiography. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=36) with porto-azygos shunts. METHODS: CT angiography was performed in dogs subsequently proven to have a porto-azygos shunt. The origin and insertion of the shunts were assessed on native images. The diameter of the porto-azygos shunt and the portal vein, cranial and caudal to the shunt origin, were measured. The porto-azygos shunt anatomy was studied on three-dimensional images. RESULTS: All porto-azygos shunts originated either in the left gastric vein (33 left gastro-azygos shunts) or the right gastric vein (3 right gastro-azygos shunts). Two left gastro-azygos shunts had concurrent caval-azygos continuation and 2 right gastro-azygos shunts had a caudal splenic loop. All shunts crossed the diaphragm through the esophageal hiatus. The majority of porto-azygos shunts (32) followed a straight pathway after traversing the diaphragm, although 4 shunts followed a tortuous route. All shunts terminated in the thoracic part of the azygos vein, perpendicular to the aorta. The shunt diameter at insertion was only 3 mm on average. The insertion site was consistently the narrowest part of the shunt. CONCLUSION: CT angiography was well suited to provide anatomic details of porto-azygos shunts and comprehensively documented that all porto-azygos shunts had a thoracic terminus, after crossing the diaphragm through the esophageal hiatus. Different shunt types existed with minor variations.

Correlation of observed-to-expected total fetal lung volume with intrathoracic organ herniation on magnetic resonance imaging in fetuses with isolated left-sided congenital diaphragmatic hernia.

OBJECTIVES: To assess using fetal magnetic resonance imaging (MRI) the relationship between the position of the stomach as well as the volume of herniation of organs into the thorax, and the observed-to-expected total fetal lung volume (o/e-TFLV), as a measure of pulmonary hypoplasia, in fetuses with isolated left-sided congenital diaphragmatic hernia (LCDH). METHODS: This was a single-center retrospective study using archived MR images from fetuses > 20 weeks' gestation evaluated for isolated LCDH over an 11-year period between July 2002 and September 2013. We retrieved data on the gestational age at MRI, o/e-TFLV and liver position. Images were also reviewed by a single operator to determine retrospectively the position of the stomach as well as the proportion of the total thorax volume occupied by the herniated fetal liver, stomach and other viscera. Following confirmation of reproducibility, we assessed the correlation of intrathoracic organ volumes and stomach position with o/e-TFLV. RESULTS: The study included 205 fetuses which underwent a total of 259 MR examinations. The reproducibility of organ volume measurements was excellent (intraclass correlation coefficient range, 0.928-0.997). The average time spent to obtain intrathoracic organ volumes ranged from 2.28 to 5.13 min. Of all herniated organ-to-thoracic volume ratios, the liver-to-thoracic volume ratio had the strongest correlation with o/e-TFLV (ρ = -0.429, P<0.0001). Stomach volume did not correlate, although, when categorized by the position and extent of stomach herniation, there was an inverse relationship to o/e-TFLV. No intrathoracic organ-to-thoracic volume ratio was related to gestational age. CONCLUSIONS: We observed in fetuses with isolated LCDH an inverse relationship between lung volume and the amount of liver herniated as well as the position of the stomach in the chest.

A case series of congenital hepatic hilar cyst: recommendations for diagnosis and management.

BACKGROUND: Congenital hepatic hilar cysts are rare. Some are simple and do not require intervention, but some biliary cystic malformations impose the risk of morbidity and mortality. OBJECTIVES: To assess a series of five patients presenting with congenital hepatic hilar cysts. METHODS: We retrospectively reviewed all cases presenting to our pediatric surgical service between January 2010 and December 2012 and found to have a congenital hepatic hilar cyst. Data regarding clinical, radiological, operative and pathological features were analyzed. RESULTS: Five children with congenital cyst of the hepatic hilum were identified; four of them were diagnosed prenatally. Four children had undergone surgical intervention: one with intrahepatic choledochal cyst, one with epidermoid cyst, and two with biliary atresia and an associated cyst of the common bile duct. In another case of choledochal cyst the treatment was conservative. All children except one had a good prognosis; one child with biliary atresia required liver transplantation. CONCLUSIONS: The differential diagnosis of congenital hepatic hilar cyst includes a broad spectrum of pathologies. It is essential to diagnose biliary atresia as early as possible. Signs such as smaller cysts in association with a hypoplastic gallbladder and direct hyperbilirubinemia may be suggestive of biliary atresia.

Diagnostic challenge of large congenital liver cyst in the newborn.

Liver cysts in the newborn often pose significant diagnostic challenges. Described herein is a case of large congenital liver cyst that was difficult to diagnose both antenatally and postnatally and which was later diagnosed as Caroli disease.

Current diagnosis and management of simple hepatic cysts detected prenatally and postnatally.

PURPOSE: The optimal management of simple hepatic cysts (SHCs) remains controversial. A retrospective review was carried out to evaluate the clinical presentation and surgical consideration of children with SHCs and outcome of management at our institution. METHODS: We performed a retrospective review of all patients diagnosed with SHCs between January 1993 and May 2013. Patient variables included prenatal findings, age, gender, presenting symptoms, signs and diagnostic modality. Operative management and nonoperative follow-up were abstracted. RESULTS: The 67 patients comprised 42 females and 25 males: 16 had prenatally detected, and 51 had postnatally detected hepatic cysts with a mean follow-up of 3.2 years (10 months-12 years). The average age was 5.9 years (0-17 years). Ten patients (six females and four males) were treated surgically. Fifty-seven asymptomatic patients were observed. Of those 57 patients, 9 (17%) had enlarged cysts, and 1 (2%) had clinical signs. The average enlargement time was 36 months (6-67 months). The cysts occurred in the right lobe in 47 patients, in the left lobe in 17 patients and in both lobes in 3 patients. The median cyst size for the asymptomatic cases was 2.1 cm (1.5-6 cm) and 13.7 cm (8-25 cm) for the surgery group. A statistically significant difference in cyst size was found between these two groups (p < 0.05). Prenatally detected cysts (n = 5) were subjected to surgery postnatally at an average age of 1.5 months (1 week-6 months). The main indication was the compressive effect of the cyst on the surrounding area. There was one case of hepatomegaly found to be causing pressure symptoms, two cases of respiratory distress, one case of hydroureteronephrosis, and one case of jaundice due to compression of the biliary system. Five patients underwent surgery in the postnatally detected group, and the main indication was a complication of the cyst or progressive enlargement. Symptoms included abdominal discomfort and pain in all five patients: one case exhibited a hemorrhage within the cyst, one case displayed a rupture with possible peritonitis, one case had a 25-cm cyst leading to secondary infection, and two cases were admitted with progressive enlargement with clinical symptoms. CONCLUSION: Conservative management of SHCs is practical. Surgical excision is recommended in patients with larger cysts, causing pressure symptoms, or if the cyst size does not seem to involute with intractable abdominal pain or becomes complicated in the follow-up period.

Congenital hepatic cyst with antenatal diagnosis: a case report and literature review.

Congenital hepatic cysts are rare lesions of infancy. While operative management and outcomes have been extensively studied in adult patients with hepatic cysts, data in pediatric patients are limited. We discuss our experience in an infant and review relevant literature regarding operative technique and surgical outcomes.

Multiple congenital PSS in a dog: case report and literature review.

A 4 yr old spayed female mixed-breed dog presented with a 2 yr history of recurring increases in liver enzymes. Two congenital portosystemic shunts (PSSs) were identified using computed tomography (CT) angiography, which included a portoazygous and portorenal extrahepatic shunt. Double right renal veins were also identified. The shunts were successfully identified and attenuated with cellophane banding. Multiple congenital PSS is a rare phenomenon, but should be considered during exploratory laparotomy for PSS and in dogs with poor response to surgical attenuation of a single PSS. CT proved to be a crucial part of accurate diagnosis and surgical planning for this dog with multiple congenital PSS.

Placental mesenchymal dysplasia with hepatic mesenchymal hamartoma: a case report and literature review.

Placental mesenchymal dysplasia (PMD) is characterized by placentomegaly and grapelike vesicles resembling a partial molar pregnancy and in most cases, a phenotypically normal fetus. Hepatic mesenchymal hamartoma (HMH) is a benign hamartomatous proliferation of mesenchymal liver tissue. PMD has been associated with HMH. Although rare, in combination, it is known to carry a poorer prognosis than in fetuses without structural abnormalities. There are only a few reported cases of PMD and associated HMH with varying management strategies and outcomes, precluding ascertainment of the most appropriate treatment plan. We present a case of PMD with associated cystic HMH resulting in fetal death. We also reviewed the published literature on this issue and explored possible management strategies to prevent adverse fetal and neonatal outcomes.