The fetal venous system, Part II: ultrasound evaluation of the fetus with congenital venous system malformation or developing circulatory compromise

The human fetal venous system is well-recognized as a target for investigation in cases of circulatory compromise, and a broad spectrum of malformations affecting this system has been described. In Part I of this review, we described the normal embryology, anatomy and physiology of this system, essential to the understanding of structural anomalies and the sequential changes encountered in intrauterine growth restriction and other developmental disorders. In Part II we review the etiology and sonographic appearance of malformations of the human fetal venous system, discuss the pathophysiology of the system and describe venous Doppler investigation in the fetus with circulatory compromise.

Development of the human fetal pons: in utero ultrasonographic study

OBJECTIVES

To examine the ultrasonographic feasibility of imaging the fetal pons and to construct a reference chart for its normal development during gestation.

METHODS

A cross-sectional, prospective study on 293 healthy fetuses of low-risk pregnancies between 19 and 34 weeks was performed. The transfontanel approach, via the abdominal or vaginal routes, was used to evaluate the fetal metencephalon (pons and cerebellum). The anteroposterior diameter of the fetal pons was measured in a mid-sagittal plane. The longitudinal diameter of the cerebellar vermis was measured at the same plane and the vermis-pons ratio (VPR) was established.

RESULTS

One hundred and forty-four fetuses were in vertex position. In 140 (97.2%) satisfactory visualization and measurements of the pons and cerebellar vermis were obtained. One hundred and forty-nine fetuses were breech presentations and measurements were successfully performed in 147 (98.6%). The pons anteroposterior and vermis longitudinal diameters showed a linear correlation with gestational age (GA) (r = 0.95 for both measurements; P < 0.001). The mean VPR was 1.5 (+/-0.1 SD) and did not change in the gestational interval that was considered.

CONCLUSION

By using the transfontanel approach, evaluation of the fetal pons is feasible via the mid-sagittal plane. The nomograms developed and the ratio to fetal vermis provides reference data that may be helpful when evaluating anomalies of the brainstem.

Fetal aberrant right subclavian artery in normal and Down syndrome fetuses

OBJECTIVES

To evaluate the prevalence of fetal aberrant right subclavian artery (ARSA) in a low-risk population and compare it with that among Down syndrome fetuses, in order to estimate its potential as a marker in Down syndrome screening.

METHODS

Women undergoing routine fetal sonographic examination between 13 and 26 weeks of gestation were evaluated once for the presence of ARSA using either a transvaginal multifrequency 5-9-MHz probe or a transabdominal 4-8-MHz probe as appropriate. Early pregnancy outcome was obtained in all cases.

RESULTS

Nine hundred and twenty-four fetuses were recruited. An ARSA was detected in 13 fetuses (1.4%) with normal karyotype. During the study period, eight fetuses with Down syndrome referred either with known karyotype or with signs suspicious for Down syndrome were evaluated by the same protocol. Three of eight fetuses (37.5%) were found to have an ARSA. In none of these cases was ARSA an isolated finding. The odds ratio for ARSA in Down syndrome compared with normal fetuses was 42.04 (95% CI, 9.08-194.6).

CONCLUSIONS

An ARSA was found in 1.4% of the normal population. In the small group of Down syndrome fetuses we observed a trend towards a higher rate of ARSA than in normal fetuses. In none of the Down syndrome fetuses was ARSA an isolated finding. Larger prospective studies are needed to examine the significance of ARSA as an isolated finding and the potential of ARSA as a marker in Down syndrome screening.

Fetal umbilical-portal-systemic venous shunt: in-utero classification and clinical significance

OBJECTIVES

To review our experience with fetal umbilical-portal-systemic venous shunts (UPSVS), to devise an in-utero classification system, and to analyze their clinical and prognostic characteristics.

METHODS

This was a retrospective review of cases of UPSVS examined at an academic tertiary referral center over the 14-year period from 2001 to 2014 inclusive. The anatomical origin and drainage of the fetal umbilical, portal, ductus venosus and hepatic venous systems, and the integrity of the intrahepatic portal venous system (IHPVS), were assessed using two- and three-dimensional color Doppler sonography. Fetomaternal clinical characteristics and long-term outcome were investigated by means of medical files, imaging documentation and telephone interviews with the mothers.

RESULTS

Forty-four cases with UPSVS were reviewed. Prenatal classification was based on the anatomical origin of the shunt (umbilical, portal or ductal), with cases classified into four types: Type I, umbilical-systemic shunt (n = 9 (20.4%)); Type II, ductus venosus-systemic shunt (n = 19 (43.2%)); and Type III, portal-systemic shunt, divided into two subtypes: Type IIIa, intrahepatic portal-systemic shunt (n = 12 (27.2%)) and Type IIIb, extrahepatic portal-systemic shunt (n = 4 (9.1%)). Each type presented particular clinical and prognostic characteristics. The most important favorable prognostic factors were absence of associated major malformation and presence of the IHPVS. Thus, Type IIIa (intrahepatic portal-systemic shunt) had the best outcome.

CONCLUSIONS

Fetal UPSVS are anomalies with a broad spectrum of manifestations and prognoses. Accurate mapping of the IHPVS is paramount for optimizing prenatal counseling and postnatal care. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

The human fetal venous system: normal embryologic, anatomic, and physiologic characteristics and developmental abnormalities

OBJECTIVE

The introduction of high-resolution ultrasonography combined with color-coded Doppler imaging offered a breakthrough in the evaluation of the human fetal venous system, considerably enhancing our understanding of fetal venous circulation in normal physiologic conditions, as well as providing us the ability to study circulatory changes in abnormal circumstances. The purpose of this study was to describe the normal anatomic development and complex of anomalies of the human fetal venous system and to review recently published series of these anomalies.

METHODS

Normal embryologic and anatomic development is described. An English language literature search of recent MEDLINE listings was performed to glean data from recently published series reporting prenatal diagnosis of the various anomalies and their associated malformations.

RESULTS

Anomalies of the human fetal venous system occur sporadically, often associated with cardiac or other malformations. The pathophysiologic mechanisms leading to abnormal in utero development of the human venous system remain largely undetermined. On the basis of the type of vein involved, embryologic precursor, and etiologic correlation (primary or secondary), classification into 4 major groups is described.

CONCLUSIONS

Prenatal evaluation of fetuses found to have anomalies of the venous system should include a careful search for cardiac anomalies, including pulmonary venous drainage, and a detailed anatomic survey of the umbilical, portal, hepatic, and ductal systems to determine aberrant communication and, if possible, to discover clues to systemic diseases or thromboembolic phenomena.

Prenatal diagnosis of congenital agenesis of the fetal portal venous system

OBJECTIVE

To describe the prenatal diagnosis and review our experience of fetal congenital agenesis of the portal venous system (CAPVS) and to review the current literature on this poorly documented vascular malformation.

METHODS

This was a retrospective survey covering the 12-year period between 1996 and 2008. The database of a single, large, ultrasonographic tertiary academic referral center in Israel was analyzed and cases with a prenatal diagnosis of CAPVS were identified. All fetuses underwent detailed biometric and structural ultrasound examinations and a precise anatomical description of the fetal umbilical, portal and hepatic venous system was noted, as well as the presence of aberrant vessels, shunt location and the presence or absence of the DV. Results of fetal echocardiography, karyotyping and toxoplasma, rubella, cytomegalovirus and herpes evaluations were determined. Medical records were evaluated. Diagnosis was confirmed by pathology, postmortem venography or neonatal ultrasound or venography. Liveborns were examined by a certified neonatologist and long-term follow-up from pediatric gastroenterology units was determined.

RESULTS

Nine cases with CAPVS were studied. In all cases an aberrant umbilical-portal vein was the primary indication for detailed portal system evaluation. Five fetuses demonstrated total CAPVS (Type I) and four showed partial agenesis of the portal vein (Type II). Among the five Type I fetuses, there was a shunt from the umbilical vein to the inferior vena cava in three (60%), to the right atrium in one and to the coronary sinus in one. In this group, in only one case could we delineate a common confluence between the splenic vein and the superior mesenteric vein shunting to the inferior vena cava. In four cases termination of pregnancy was performed due to additional findings: one case with hydrothorax, ascites and mitral atresia, one with cleft lip/palate and one with trisomy 21. One case had no additional anomalies, but the parents elected to terminate the pregnancy. All four of the Type II fetuses had a portosystemic shunt: in two cases to the right atrium, in one to the iliac vein and in one to the right hepatic vein. In three, the shunt resolved spontaneously. In only one case was abnormal liver function present over a follow-up period of 2-10 years.

CONCLUSION

CAPVS can be detected prenatally. An abnormal course of the umbilical vein necessitates prompt sonographic evaluation of the umbilical-portal venous system and meticulous investigation for additional anomalies. Complete CAPVS may be associated with remote clinical consequences of which the parents should be informed. Partial CAPVS has a favorable prognosis.

The fetal venous system, part I: normal embryology, anatomy, hemodynamics, ultrasound evaluation and Doppler investigation

Since its introduction in the mid-1980s sonographic evaluation of the human fetal venous system has advanced dramatically. The venous system is well-recognized as a target for investigation in cases of circulatory compromise, and a broad spectrum of malformations affecting this system has been described. Appreciation of the normal embryology, anatomy and physiology of this system is essential to an understanding of structural anomalies and the sequential changes encountered in intrauterine growth restriction or other developmental disorders. We review the normal embryology, anatomy, and hemodynamics of the human fetal venous system, and provide an overview of Doppler investigation, as well as three- and four-dimensional ultrasound modalities and their application to this system.

In-utero evaluation of the fetal umbilical-portal venous system: two- and three-dimensional ultrasonic study

OBJECTIVES

To describe the normal anatomy of the fetal umbilical-portal venous system (UPVS) and to assess possible anatomical variants of the main portal vein (MPV) insertion into the portal sinus (PS).

METHODS

This was a prospective cross-sectional study of low-risk patients between 14 and 36 weeks of gestation. Two- (2D) and three-dimensional (3D) ultrasound techniques combined with color and high-definition flow Doppler were used to evaluate the fetal UPVS. The standard transverse plane of the fetal upper abdomen, used for measuring the abdominal circumference, was taken in all cases as the point of reference. A longitudinal section was taken to identify the normal course of the umbilical vein and ductus venosus (DV). We performed offline analysis of all gray-scale and color Doppler 2D and 3D volume datasets.

RESULTS

Two hundred and eight fetuses were included in the study. The umbilical vein was observed to course in a cephalad direction from its entry point into the fetal abdomen, joining the L-shaped PS, a confluence of vessels that is the main segment of the left portal vein (LPV). Three branches emerge from the LPV: two to the left, the inferior and superior branches, and one to the right, the medial branch. The main LPV then courses abruptly to the right. Following the emergence of the DV, the communication of the MPV with the LPV marks the point at which the vessel becomes the right portal vein (RPV), giving rise to its anterior and posterior branches. We were able to define three main variants of connection between the MPV and the PS. In 140 (67.3%) fetuses the MPV was connected to the LPV in an end-to-side T-shaped anastomosis, in 26 (12.5%) fetuses the MPV connected with a side-to-side X-shaped anastomosis and in 30 (14.4%) fetuses the two vessels ran in parallel with a short communicating segment, in an H-shaped anastomosis. In the remaining 12 (5.7%) cases classification into one of these three groups was not possible due to intermediate morphology.

CONCLUSIONS

Knowing the normal anatomy of the UPVS and being aware of the possible variants of the connection between the MPV and the PS is a fundamental requirement for accurate prenatal diagnosis of the anomalies of the fetal UPVS.

Pubic arch angle in prolonged second stage of labor: clinical significance

OBJECTIVE

To evaluate the clinical significance of the pubic arch angle (PAA) measured by transperineal ultrasound during prolonged second stage of labor.

METHODS

We evaluated prospectively 62 women ≥ 37 weeks of gestation with failure to progress in the second stage of labor. Transperineal ultrasound (transverse plane) was used to measure the pubic arch angle. Correlations with fetomaternal characteristics, mode of delivery and perinatal outcome were evaluated.

RESULTS

The mean PAA was 101.1° (± 13.1°; range, 80°-135°). We found a negative correlation with maternal age. Patients with an occipitotransverse fetal position had a significantly smaller angle compared with those with occipitoanterior positions (94.3° ± 5.5° vs. 103.2° ± 14.8°, P < 0.05), as did those with operative deliveries compared with those with spontaneous vaginal delivery (97.1° ± 11.5° vs. 110.1° ± 14.0°, P < 0.05). The prediction of operative delivery in prolonged second stage of labor by receiver-operating characteristics curve using PAA alone yielded an area under the curve of 0.75. The predicted probability for operative delivery increased as PAA decreased, with an odds ratio of 0.933 for each decrease in angle of 1°.

CONCLUSION

Our study suggests a correlation between the PAA and mode of delivery in prolonged second stage of labor. This may be used as an adjunctive parameter when considering delivery mode.

Fetal brain asymmetry: in utero sonographic study of normal fetuses

OBJECTIVE

The objective of the study was to evaluate the magnitude of normal fetal brain asymmetry.

STUDY DESIGN

This was a prospective study. Normal fetuses between 19-28 weeks of gestation were studied. The cerebral atria, occipital cortex, and hemispheres in both sides were measured. The difference between each side was evaluated and was correlated with sex, head biometry, and estimated weight.

RESULTS

Four hundred six fetuses were studied. Mean atrial width was larger in the males and on the left side (5.2% and 6.5%, respectively). Mean cortical width was 2.6% larger in males but 5.5% thinner on the left side. Mean hemisphere width was larger in males and on the left side (2.3% and 1.5%, respectively). The atria and the cortex presented an inverse relationship regarding fetal growth parameters.

CONCLUSION

Brain asymmetry represents normal fetal brain developmental phenomena. It is sex dependent and lateralized in most cases to the left. Lateralization was more accentuated in males.

Head progression distance in prolonged second stage of labor: relationship with mode of delivery and fetal head station

OBJECTIVE

To evaluate the clinical significance of fetal head progression distance (HPD), measured by transperineal ultrasound, during prolonged second stage of labor.

METHODS

In this prospective study, a single operator, who was blinded to the results of the digital examination, assessed using transperineal ultrasound women at ≥ 37 weeks of gestation with failure to progress in the second stage of labor. Patients had an empty urinary bladder and the examination was performed during maternal pushing. HPD was defined as the length of the line perpendicular to the infrapubic line that would connect it to the lowest part of the fetal bony skull. We analyzed associations between HPD and digital examination of fetal head station, fetomaternal characteristics, mode of delivery and perinatal outcome.

RESULTS

Sixty-five patients in prolonged second stage of labor participated in the study. The overall mean HPD was 6.50 (± 1.35; 95% CI, 6.16-6.83) cm. No correlation was found between HPD and head position or mode of delivery, but HPD was positively correlated with fetal head station and neonatal head circumference measured after delivery. Logistic regression and receiver-operating characteristics curve analysis demonstrated no significant predictive value of HPD with respect to mode of delivery.

CONCLUSION

Although HPD in prolonged second stage of labor could not predict mode of delivery, it may have a role as an ancillary tool for fetal head station assessment.

Prenatal Anogenital Distance Is Shorter in Fetuses With Hypospadias

OBJECTIVES

Recent research provides evidence that anogenital distance may serve as a novel metric to assess reproductive potential in men. In children, a shorter anogenital distance was linked with cryptorchidism, hypospadias, and micropenis. Scarce data exist in the literature regarding anogenital distance measurement in the fetus. The aim of our study was to assess whether intrauterine measurement of fetal anogenital distance could assist in the differential diagnosis of male genital anomalies.

METHODS

Anogenital distance was prospectively measured in all cases referred for suspected isolated abnormal male genitalia. Final diagnoses, confirmed by a pediatric urologist, were compared with anogenital distance prenatal measurements.

RESULTS

Fifty-two cases were referred for evaluation because of suspected male external genital malformation during a 12-month period. Cases with normal-appearing genitalia, associated major malformations, and early severe fetal growth restriction were excluded from the study. Postnatal examination revealed 14 cases of hypospadias in varying severity and 8 cases of a buried penis. All fetuses with hypospadias had an anogenital distance measurement below the fifth percentile. Statistical analysis revealed a significant difference between the normal mean anogenital distance for gestational age versus those with hypospadias (mean ± SD, 16.90 ± 4.08 and 11.68 ± 3.31 mm, respectively; P = .001). No significant difference was found between the normal mean anogenital distance for gestational age versus those with a buried penis (18.85 ± 2.76 and 19.46 ± 3.41 mm; P = .700).

CONCLUSIONS

Fetuses with hypospadias have a statistically significant shorter anogenital distance compared with the general population. Therefore, anogenital distance may serve as a complementary objective sonographic parameter in the prenatal assessment and counseling of male external genital anomalies.

The Normal Fetal Pancreas

OBJECTIVES

The aim of the study was to assess the sonographic feasibility of measuring the fetal pancreas and its normal development throughout pregnancy.

METHODS

We conducted a cross-sectional prospective study between 19 and 36 weeks' gestation. The study included singleton pregnancies with normal pregnancy follow-up. The pancreas circumference was measured. The first 90 cases were tested to assess feasibility.

RESULTS

Two hundred ninety-seven fetuses of nondiabetic mothers were recruited during a 3-year period. The overall satisfactory visualization rate was 61.6%. The intraobserver and interobserver variability had high interclass correlation coefficients of of 0.964 and 0.967, respectively. A cubic polynomial regression described best the correlation of pancreas circumference with gestational age (r = 0.744; P < .001) and significant correlations also with abdominal circumference and estimated fetal weight (Pearson r = 0.829 and 0.812, respectively; P < .001). Modeled pancreas circumference percentiles for each week of gestation were calculated. During the study period, we detected 2 cases with overgrowth syndrome and 1 case with an annular pancreas.

CONCLUSIONS

In this study, we assessed the feasibility of sonography for measuring the fetal pancreas and established a normal reference range for the fetal pancreas circumference throughout pregnancy. This database can be helpful when investigating fetomaternal disorders that can involve its normal development.

Monozygotic twins following blastocyst transfer: a report of two cases

Several studies have shown an increased risk for monozygotic twinning after fertilization treatments. We present the clinical and sonographic characteristics of two monozygotic twin cases following blastocyst transfer. It is suggested that delayed transfer of the embryo in the blastocyst stage is a contributing factor to monozygotic twinning.

Fetal interlens distance: normal values during pregnancy

OBJECTIVES

The aims of this study were to establish normal ranges of values for interlens distance (ILD) during gestation, and to assess the correlation between ILD and growth of the orbits and other fetal biometric parameters.

METHODS

A cross-sectional study of morphologically normal, singleton fetuses was carried out in low-risk pregnant women. We measured the distance between the centers of the fetal lenses from 12 to 37 completed weeks of gestation. An oblique anterior coronal section was used to measure the ILD. The biorbital diameter (BOD) was measured in the same plane. We analyzed the correlation between the ILD and gestational age (GA), BOD, biparietal diameter (BPD), head circumference (HC), femur length (FL) and abdominal circumference (AC). Fetal gender was assessed to evaluate possible significant differences.

RESULTS

Four hundred and fifty normal fetuses were recruited for the study. In 427 fetuses appropriate ILD measurements were obtained, and complete evaluation of all parameters was accomplished in 377 of these. ILD demonstrated a high positive correlation with GA (r(2) = 0.969), BPD (r(2) = 0.959), HC (r(2) = 0.962), AC (r(2) = 0.949) and FL (r(2) = 0.956) as pregnancy advanced. The mean BOD : ILD ratio was 1.50 +/- 0.08, remaining constant throughout pregnancy (linear regression r(2) = 0.006). No statistically significant differences were found between genders for mean ILD and GA of the study population (P = 0.604 and 0.595, respectively).

CONCLUSIONS

The results of this study confirm previous hypotheses regarding the close relationship between eyeball growth and growth of the surrounding bony structures. Measurement of fetal ILD, which can be used interchangeably with BOD measurement in either the axial or coronal plane, can be taken to reflect the expected development of the fetal orbits whilst simultaneously providing valuable information on eyeball development. It is likely that ILD could be used as a complementary tool in the elaboration of various severe abnormalities, mainly related to craniofacial and nervous system malformations.

Early Diagnosis of Bladder Exstrophy: Quantitative Assessment of a Low-Inserted Umbilical Cord

OBJECTIVES

Bladder exstrophy is a rare severe congenital malformation. Early prenatal diagnosis is scarcely described in the literature. Low insertion of the umbilical cord is a constant anatomic feature of bladder exstrophy. The aim of our study was to assess whether early measurements of the umbilical cord insertion-to-genital tubercle length may serve as quantitative measurements for a low-inserted umbilical cord in cases of bladder exstrophy.

METHODS

The umbilical cord insertion-to-genital tubercle length was prospectively measured in all cases referred for a nonvisualized urinary bladder before 18 weeks' gestation. Final diagnoses were compared with prenatal measurements.

RESULTS

Fifteen fetuses were evaluated for a nonvisualized bladder at a mean gestational age of 15.7 weeks (range, 14-17 weeks). Of them, 6 cases were diagnosed with bladder exstrophy, and 9 cases had a normal urinary bladder. All cases with bladder exstrophy had an umbilical cord insertion-to-genital tubercle length below the fifth percentile for gestational age, whereas cases with a normal bladder had a normal measurement.

CONCLUSIONS

Fetuses with bladder exstrophy have an umbilical cord insertion-to-genital tubercle length below the fifth percentile of the general population. This measurement may serve as a complementary objective sonographic parameter in the prenatal assessment and counseling of cases suspected of having bladder exstrophy during early pregnancy.

The diagnostic potential of targeted imaging of the fetal pancreas

OBJECTIVE

To report our experience with targeted scans of the fetal pancreas.

METHODS

Targeted scans were performed in 16 cases referred for anatomical or genetic conditions associated with structural pancreatic malformations.

RESULTS

Four fetuses were evaluated for nephromegaly and macroglossia. In three of them, the pancreas circumference was >90th percentile. Genetic testing revealed Beckwith-Wiedemann syndrome. In the fourth case, the pancreas circumference was normal; exome sequencing revealed two heterozygous ETFDH gene mutations consistent with glutaric acidemia type II. In a case referred for non-visualization of the gallbladder, the fetal pancreas was not visualized and genetic analysis revealed a mutation in the ONECUT1 gene encoding for HNF6. Targeted scan for heterotaxia revealed three cases with variable degrees of agenesis of the pancreas, one case with a normally structured right sided pancreas and one case with a normal pancreas. Cases referred following a genetic diagnosis included a case of maternal nesidioblastosis with an extremely large fetal pancreas; and five fetuses diagnosed with a TCF2 deletion all with a normal pancreas.

CONCLUSIONS

Prenatal assessment of the fetal pancreas may be a significant factor in prenatal diagnosis and counselling in cases presenting with anatomical and genetic conditions reported post-natally to be associated with pancreatic structural and functional abnormalities.

Outcomes of fetuses with umbilical cord cysts diagnosed during nuchal translucency examination

OBJECTIVES

The purpose of this study was to report the outcomes of fetuses with the finding of an umbilical cord cyst during nuchal translucency examination in a low-risk population.

METHODS

A retrospective study was conducted in a large tertiary referral academic center over a 3-year period. All fetuses with umbilical cord cysts during the nuchal translucency scan were recruited, and their medical data concerning the pregnancy and neonatal course were analyzed.

RESULTS

Eight fetuses (0.7%) had a diagnosis of an umbilical cord cyst among the 1080 nuchal translucency examinations. The mean cyst diameter was 19 mm (range, 10-38 mm). The male to female ratio was 6:2. Isolated umbilical cord cysts were found in 5 cases (62.5%), and in all, the nuchal translucency measured less than 2 mm; the cysts resolved; and the outcomes were normal. Three fetuses (37.5%) had additional associated malformations. In all of them, the cysts persisted during pregnancy. Two of them had increased nuchal translucency (3.2 and 4.2 mm). In these 2 cases, 1 fetus had a hypoplastic left heart with a normal karyotype, and the other had multiple malformations and trisomy18. Both pregnancies were terminated. The third case, with normal nuchal translucency, had an ectopic kidney and a patent urachus, which closed spontaneously at 23 weeks and resulted in a normal pregnancy outcome.

CONCLUSIONS

A favorable outcome is expected when an umbilical cord cyst diagnosed during late first trimester presents as an isolated finding associated with normal nuchal translucency and resolves later on.

The intra-hepatic umbilical-Porto-systemic venous shunt and fetal growth

OBJECTIVE

The fetal liver circulation has an important role in fetal growth. The intra-hepatic Umbilical-Porto-Systemic Venous Shunt (IHUPSVS) causes a reduction of the umbilical blood flow to the liver and has been reported to have a restrictive effect on fetal growth. The aim of this study was to evaluate the effect of IHUPSVS on fetal growth.

METHODS

We conducted a retrospective cohort study of IHUPSVS diagnosed between 2001 and 2019. IHUPSVS was defined as any abnormal communication between any branch of the portal vein and hepatic vein. Pre- and postnatal characteristics were collected from medical files and compared between cases with fetal growth restriction (FGR) and those appropriate for gestational age (AGA).

RESULTS

Twenty-five fetuses were included in the study. Eighteen (72%) had last estimated fetal weight and birth weight below the 10th centile, four (16%) of them between the third and fifth centile, and 11 (44%) below the third centile. Median gestational age at delivery was lower for FGR than AGA fetuses (37 vs. 38 weeks, p = 0.034) and rate of preterm delivery was higher (38.9 vs. 14.3, P = 0.24). Four cases had associated structural anomalies (2 in each group), and two had minor genetic aberrations (1 in each group).

CONCLUSIONS

Growth restriction is prevalent in fetuses with IHUPSVS, suggesting that fetal growth should be monitored. In equal measure, in cases with growth restriction, especially without other apparent cause, an intrahepatic shunt should be looked for.