Prenatal ultrasound findings in Koolen-de Vries foetuses: Central nervous system anomalies are frequent markers of this syndrome.

OBJECTIVE: Prenatal diagnoses of microdeletion syndromes without ultrasound findings in the first and second trimester are always difficult. The objective of this study is to report the prenatal ultrasound findings in four foetuses diagnosed with 17q21.31 microdeletions (Koolen-de Vries syndrome) using chromosomal microarrays (CMA). PATIENTS AND METHODS: We present four foetuses with 17q21.31 microdeletion. All showed CNS anomalies in the third trimester, three had ventriculomegaly, and one hypogenesis of corpus callosum at 31 weeks of pregnancy. RESULTS: Array-SNPs and CGH-array were performed on uncultured amniocytes and peripheral blood revealing a 17q21.31 microdeletion. CONCLUSIONS: Prenatal CNS anomalies (mainly ventriculomegaly) at third trimester, in spite of isolate, should be considered a prenatal ultrasound marker of this syndrome. This kind of malformations raise the possibility of an underlying genetic conditions including 17q21.31 microdeletion; thus, CMA should be taken into consideration when offering prenatal genetic counselling.

Normal cavum veli interpositi at 14-17 gestational weeks: three-dimensional and Doppler transvaginal neurosonographic study.

OBJECTIVES: To provide evidence to support the hypothesis that the midline cyst-like fluid collection that is frequently observed on fetal brain ultrasound (US) imaging during the early second trimester represents a normal transient cavum veli interpositi (CVI). METHODS: This was a retrospective analysis of 89 three-dimensional normal fetal brain volumes, acquired by transvaginal US imaging in 87 pregnant women between 14 and 17 gestational weeks. The midsagittal view was studied using multiplanar imaging, and the maximum length of the fluid collection located over (dorsal to) the tela choroidea of the third ventricle was measured. We calculated the correlation of the transverse cerebellar diameter (TCD) and of the maximum length of the fluid collection with gestational age according to last menstrual period. Color Doppler images were analyzed to determine the location of the internal cerebral veins with respect to the location of the fluid collection. Reports of the second-trimester anatomy scan at 22-24 weeks were also reviewed. RESULTS: Interhemispheric fluid collections of various sizes were found in 55% (49/89) of the volumes (mean length, 5 (range, 3.0-7.8) mm). There was a strong correlation between TCD and gestational age (Pearson's correlation, 0.862; P < 0.001). There was no correlation between maximum fluid length and gestational age (Pearson's correlation, -0.442; P = 0.773). Color Doppler images were retrieved in 32 of the 49 fetuses; in 100% of these, the internal cerebral veins coursed within the echogenic roof of the third ventricle. The midline structures were normal at the 22-24-week scan in all cases. CONCLUSIONS: In approximately half of normal fetuses, during the evolution of the midline structures of the brain, various degrees of fluid accumulate transiently in the velum interpositum, giving rise to a physiologic CVI. Patients should be reassured that this is a normal phenomenon in the early second trimester that, if an isolated finding, has no influence on fetal brain development. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Camel regulates development of the brain ventricular system.

Development of the brain ventricular system of vertebrates and the molecular mechanisms involved are not fully understood. The developmental genes expressed in the elements of the brain ventricular system such as the ependyma and circumventricular organs act as molecular determinants of cell adhesion critical for the formation of brain ventricular system. They control brain development and function, including the flow of cerebrospinal fluid. Here, we describe the novel distantly related member of the zebrafish L1-CAM family of genes-camel. Whereas its maternal transcripts distributed uniformly, the zygotic transcripts demonstrate clearly defined expression patterns, in particular in the axial structures: floor plate, hypochord, and roof plate. camel expresses in several other cell lineages with access to the brain ventricular system, including the midbrain roof plate, subcommissural organ, organum vasculosum lamina terminalis, median eminence, paraventricular organ, flexural organ, and inter-rhombomeric boundaries. This expression pattern suggests a role of Camel in neural development. Several isoforms of Camel generated by differential splicing of exons encoding the sixth fibronectin type III domain enhance cell adhesion differentially. The antisense oligomer morpholino-mediated loss-of-function of Camel affects cell adhesion and causes hydrocephalus and scoliosis manifested via the tail curled down phenotype. The subcommissural organ's derivative-the Reissner fiber-participates in the flow of cerebrospinal fluid. The Reissner fiber fails to form upon morpholino-mediated Camel loss-of-function. The Camel mRNA-mediated gain-of-function causes the Reissner fiber misdirection. This study revealed a link between Chl1a/Camel and Reissner fiber formation, and this supports the idea that CHL1 is one of the scoliosis factors.

Development of the Neuro-Immune-Vascular Plexus in the Ventricular Zone of the Prenatal Rat Neocortex.

Microglial cells make extensive contacts with neural precursor cells (NPCs) and affiliate with vasculature in the developing cerebral cortex. But how vasculature contributes to cortical histogenesis is not yet fully understood. To better understand functional roles of developing vasculature in the embryonic rat cerebral cortex, we investigated the temporal and spatial relationships between vessels, microglia, and NPCs in the ventricular zone. Our results show that endothelial cells in developing cortical vessels extend numerous fine processes that directly contact mitotic NPCs and microglia; that these processes protrude from vessel walls and are distinct from tip cell processes; and that microglia, NPCs, and vessels are highly interconnected near the ventricle. These findings demonstrate the complex environment in which NPCs are embedded in cortical proliferative zones and suggest that developing vasculature represents a source of signaling with the potential to broadly influence cortical development. In summary, cortical histogenesis arises from the interplay among NPCs, microglia, and developing vasculature. Thus, factors that impinge on any single component have the potential to change the trajectory of cortical development and increase susceptibility for altered neurodevelopmental outcomes.

Normal appearances and dimensions of the foetal cavum septi pellucidi and vergae on in utero MR imaging.

PURPOSE: The aim of this study is to provide normative data about the appearances and dimensions of the cavum septi pellucidi and vergae (CSPV) on in utero MR (iuMR) imaging in second and third trimester foetuses. METHODS: Two hundred normal foetuses (from a low-risk pregnancy, with normal ante-natal USS findings and no intracranial abnormality of iuMR) had iuMR imaging between 18 and 37 gestational weeks (gw). The anatomical features on those studies were compared with published atlases of post-mortem foetal brains. The length, width and volume of the CSPV were measured in all foetuses. RESULTS: The anatomy of the CSPV and its relationship with the corpus callosum and the fornices on iuMR imaging was comparable with post-mortem data at all gestational ages studied. The length of the CSPV increased throughout pregnancy, whereas the width and volume of CSPV reached a maximum between 29 and 31 gw and then showed a reduction later in pregnancy. CONCLUSION: The iuMR imaging features of the CSPV and its close anatomical relations closely correspond to post-mortem data. The CSPV was patent in all cases but we have shown that closure commences in the midpart of the third trimester and advances in a posterior to anterior direction.

Radial Glial Cell-Derived VCAM1 Regulates Cortical Angiogenesis Through Distinct Enrichments in the Proximal and Distal Radial Processes.

Angiogenesis in the developing cerebral cortex accompanies cortical neurogenesis. However, the precise mechanisms underlying cortical angiogenesis at the embryonic stage remain largely unknown. Here, we show that radial glia-derived vascular cell adhesion molecule 1 (VCAM1) coordinates cortical vascularization through different enrichments in the proximal and distal radial glial processes. We found that VCAM1 was highly enriched around the blood vessels in the inner ventricular zone (VZ), preventing the ingrowth of blood vessels into the mitotic cell layer along the ventricular surface. Disrupting the enrichment of VCAM1 surrounding the blood vessels by a tetraspanin-blocking peptide or conditional deletion of Vcam1 gene in neural progenitor cells increased angiogenesis in the inner VZ. Conversely, VCAM1 expressed in the basal endfeet of radial glial processes promoted angiogenic sprouting from the perineural vascular plexus (PNVP). In utero, overexpression of VCAM1 increased the vessel density in the cortical plate, while knockdown of Vcam1 accomplished the opposite. In vitro, we observed that VCAM1 bidirectionally affected endothelial cell proliferation in a concentration-dependent manner. Taken together, our findings identify that distinct concentrations of VCAM1 around VZ blood vessels and the PNVP differently organize cortical angiogenesis during late embryogenesis.

New Insights into the Anterior Complex.

OBJECTIVE: To introduce visualization of the germinal matrix (GM), external angle of the frontal horn, and periventricular white matter while evaluating the anterior complex (AC) during basic ultrasound assessment of the fetal brain. CASE PRESENTATIONS: This is a retrospective observational study of healthy women with singleton pregnancies, with no increased risk of fetal central nervous system anomalies, attending routine ultrasound screening at 20-32 weeks' gestation. Seventeen cases are presented in which an abnormal aspect of the GM or external angle of the frontal horn or periventricular white matter on AC evaluation has allowed a prenatal diagnosis of peri-intraventricular hemorrhage, subependymal cysts, connatal cysts, periventricular venous hemorrhagic infarction, and white matter injury. CONCLUSION: An extended AC evaluation could significantly improve the -diagnosis of hemorrhagic/cystic/hypoxic-ischemic lesions during the performance of a basic ultrasound study of the fetal brain.

Trend in ventricle size during pregnancy and its use for prediction of ventriculoperitoneal shunt in fetal open neural tube defect.

OBJECTIVES: Fetal surgery for repair of open neural tube defect (ONTD) typically results in decreased need for a ventriculoperitoneal shunt (VPS). Our objectives were to determine the trend in ventricle size (VS) during pregnancy and whether VS and change in VS, as assessed by ultrasound, were predictive of the need for VPS in pregnancy with ONTD. METHODS: This was a retrospective analysis of prospectively collected data of consecutive pregnancies with ONTD, evaluated in a single center from January 2012 to May 2018. Two groups were identified: the first consisted of pregnancies that underwent in-utero repair (IUR) and the second those that had postnatal repair (PNR). Penalized B splines were used to determine the trend in VS, across 2-week gestational-age (GA) epochs, between 24 and 36 weeks of gestation. VS at each GA epoch and the change in VS between each GA epoch were compared between the IUR and PNR groups. To determine whether VS at any GA was predictive of VPS, receiver-operating-characteristics (ROC) curves were used and the optimal cut-off at each GA epoch was identified. Univariate analysis and multiple logistic regression were used for further analysis. RESULTS: ONTD was diagnosed in 110 fetuses, of whom 69 underwent IUR and 41 had PNR. Fetuses in the IUR group were more likely to have Chiari II malformation (100.0% vs 82.9%; P < 0.01), lower GA at delivery (34.9 ± 3.2 vs 37.1 ± 2.1 weeks; P < 0.01) and lower rates of VPS within the first year postpartum (36.2% vs 61.0%; P = 0.02) compared with the PNR group. In both groups, VS increased steadily with GA from the initial evaluation to delivery. In the IUR group, there was a significant change in VS between the 24 + 0 to 25 + 6-week and the 26 + 0 to 27 + 6-week epochs (2.3 (95% CI, 0.4-4.1) mm; P = 0.02). There was a positive trend in the change in VS at later GAs, but this was not significant. Although there was no significant change in VS in the PNR group before 30 weeks, there was a positive trend after that time. On multivariate analysis, each week of advancing GA was associated with a mean increase of 0.74 mm in VS (P < 0.0001) in both groups. VS was not associated with the level or type of lesion, but presence of Chiari II malformation was associated with a mean increase of 5.88 mm (P < 0.0001) in VS in both the IUR and PNR groups. VS was modestly predictive of need for VPS in both groups, with area under ROC curves between 0.68 and 0.76 at the different GA epochs. Change in VS between the first and last measurements was also modestly predictive of the need for VPS, with better performance in the PNR group. CONCLUSIONS: VS increased with advancing GA in all fetuses with ONTD, although in the IUR group this increase occurred immediately after fetal surgery and in the PNR group it occurred after 30 weeks of gestation. In-utero surgery was associated with a decreased rate of VPS and was more predictive of need for VPS than was VS. Postnatal factors resulting in increased need for VPS in the PNR group need to be assessed further. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Cavum velum interpositum cysts in normal and anomalous fetuses in second trimester of pregnancy: Comparison of its size and prevalence.

OBJECTIVE: Cavum veli interpositi (CVI) is a potential space below the splenium of corpus callosum and sometimes presents as a cyst. MATERIALS AND METHODS: In this prospective cross-sectional study, 360 fetuses with normal second trimester scan and 152 s trimester fetuses with structural abnormalities were included. RESULTS: The CVI cysts were more common in fetuses with brain anomaly compared to normal fetuses and fetuses with extra-central nervous system (CNS) anomalies (23% vs 18.3% and 18% respectively; p value < 0.01). The mean size of cysts in normal fetuses, fetuses with extra-CNS anomalies and fetuses with brain abnormalities was 4.6 mm, 5.8 mm and 9.2 mm respectively. There was a significant difference between cysts size in normal fetuses and fetuses with brain anomalies (p value < 0.01) and the cut-point was 7.1 mm. CONCLUSION: The prevalence of CVI cysts is more in fetuses with brain anomaly. Fetuses with a cyst size >7.1 mm need a more detailed brain examination.

Synergistic Activity of Floor-Plate- and Ventricular-Zone-Derived Netrin-1 in Spinal Cord Commissural Axon Guidance.

In vertebrates, commissural axons extend ventrally toward the floor plate in the spinal cord and hindbrain. Netrin-1, secreted by floor plate cells, was proposed to attract commissural axons at a distance. However, recent genetic studies in mice have shown that netrin-1 is also produced by ventricular zone (VZ) progenitors and that in the hindbrain, it represents the main source of netrin-1 for commissural axons. Here, we show that genetically deleting netrin-1 either from the VZ or the floor plate does not prevent midline crossing in the spinal cord, although axon pathfinding and fasciculation are perturbed. Strikingly, the VZ and floor plate act synergistically, as the simultaneous ablation of netrin-1 from these two sources severely impedes crossing. These results suggest that floor-plate-derived netrin-1 has a distinct impact on commissural axons in the spinal cord and hindbrain.

Long-Range Guidance of Spinal Commissural Axons by Netrin1 and Sonic Hedgehog from Midline Floor Plate Cells.

An important model for axon pathfinding is provided by guidance of embryonic commissural axons from dorsal spinal cord to ventral midline floor plate (FP). FP cells produce a chemoattractive activity, comprised largely of netrin1 (FP-netrin1) and Sonic hedgehog (Shh), that can attract the axons at a distance in vitro. netrin1 is also produced by ventricular zone (VZ) progenitors along the axons' route (VZ-netrin1). Recent studies using region-specific netrin1 deletion suggested that FP-netrin1 is dispensable and VZ-netrin1 sufficient for netrin guidance activity in vivo. We show that removing FP-netrin1 actually causes guidance defects in spinal cord consistent with long-range action (i.e., over hundreds of micrometers), and double mutant analysis supports that FP-netrin1 and Shh collaborate to attract at long range. We further provide evidence that netrin1 may guide via chemotaxis or haptotaxis. These results support the model that netrin1 signals at both short and long range to guide commissural axons in spinal cord.

Nuclear factor-kappaB regulates multiple steps of gliogenesis in the developing murine cerebral cortex.

Nuclear factor-kappaB (NF-κB) is activated in neural progenitor cells in the developing murine cerebral cortex during the neurogenic phase, when it acts to prevent premature neuronal differentiation. Here we show that NF-κB activation continues in mouse neocortical neural progenitor cells during the neurogenic-to-gliogenic switch. Blockade of endogenous NF-κB activity during neocortical gliogenesis leads to the formation of supernumerary committed gliogenic progenitors and premature glial cell differentiation. Conversely, forced NF-κB activation during the neocortical neurogenic-to-gliogenic transition causes delayed gliogenic commitment and decreased astroglial gene expression. NF-κB activation continues in neocortical gliogenic progenitors following commitment and is important to inhibit the differentiation of oligodendrocyte precursor cells and to maintain persistent expression of glial fibrillary acidic protein in maturing astrocytes. These results reveal a number of previously uncharacterized roles for NF-κB during different phases of neocortical gliogenesis and identify NF-κB as an inhibitor of early oligodendrocyte development in the cerebral cortex.

Evaluation of choroid plexus with fetal magnetic resonance imaging: What happens in ventriculomegaly?

OBJECTIVES: Diagnosis of ventriculomegaly (VM) and identification of choroid plexus (CP) can be challenging with fetal magnetic resonance imaging (MRI). Our aim is to create an adjunct method for supporting the diagnosis of VM by investigating the CP-ventricular wall separation distance in fetuses with and without VM (nV) with fetal MRI. METHODS: T2-weighted fetal MRIs of 154 fetuses were retrospectively evaluated. The CP separation was defined as the distance between the medial wall of the dependent ventricle and distal tip of the CP glomus. The measurement was performed at the same plane with the dependent ventricle measurement by two blinded readers. RESULTS: 41 fetuses with VM (mean gestational age 27 (19-35 weeks), and 44 nV fetuses (mean gestational age 28 (20-39 weeks) were included. Interobserver reliability was excellent for ventricle diameters (R = 0.99, confidence interval (CI) 95%) and the separation of CP (R = 0.98, CI 95%). Mean distance of CP separation was 10.7 mm ±â€¯4.2 mm and 3.0 ±â€¯1.6 mm in VM and nV fetuses, respectively (p < 0.001). The distance of CP separation to differentiate VM cases was 6.5 mm (sensitivity: 0.98, specificity: 0.98). Separation of CP was correlated to ventricle diameter in cases with (R = 0.674) and without VM (R = 0.805). For the cut-off value >0.65 cm for the distance between the medial wall of the dependent ventricle and the medial border of choroid plexus sensitivity is 97.56, specificity 95.45, positive predictive value (PPV) 95.20, negative predictive value (NPV) 97.70, and likelihood ratio (LR) (+) is 21.46. CONCLUSION: Fetal CP can be efficiently evaluated with MRI, and the increase of CP-ventricular wall separation distance in correlation with the ventricle diameter is a reliable sign in the diagnosis of fetal VM.

Outcome of fetuses with prenatal diagnosis of isolated severe bilateral ventriculomegaly: systematic review and meta-analysis.

OBJECTIVE: To quantify from the published literature survival and neurodevelopmental outcome of fetuses with prenatally detected isolated severe bilateral ventriculomegaly. METHODS: MEDLINE, EMBASE and the Cochrane Library were searched electronically. Only cases with a prenatal diagnosis of apparently isolated severe ventriculomegaly and postnatal neurodevelopmental assessment were selected and included. Severe ventriculomegaly was defined as enlargement of the ventricular atria, with a diameter of greater than 15 mm in the transventricular plane. All cases in which the investigators were unable to detect associated structural abnormality, chromosomal abnormality or fetal infection, and in which the ventriculomegaly was therefore regarded as apparently isolated, were included. Those for which the etiology was identified prenatally were excluded, whereas those with postnatal identification of the underlying cause were not excluded, since this information was not available prenatally. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS) for cohort studies. Pregnancy outcomes such as termination, stillbirth, neonatal survival and developmental outcome of the baby, were recorded. The degree of disability was classified as no, mild or severe disability. Statistical assessment was performed by meta-analysis of proportions to combine data, weighting the studies using the inverse variance method and a random-effects model. Proportions and CIs were reported. RESULTS: Eleven studies including 137 fetuses were found. Twenty-seven pregnancies underwent termination and were excluded. The remaining 110 fetuses with apparently isolated severe ventriculomegaly for which continuation of pregnancy was intended, form the study population. Overall quality assessed using NOS for cohort studies was good. Survival was reported in 95/110 (pooled proportion 87.9% (95% CI, 75.6-96.2%)) cases. In 15/110 (pooled proportion 12.1% (95% CI, 3.8-24.4%)), either stillbirth or neonatal demise was reported. No disability was reported in 41/95 survivors (pooled proportion 42.2% (95% CI, 27.5-57.6%)). However, 17/95 showed mild/moderate disability (pooled proportion 18.6% (95% CI, 7.2-33.8%)) and 37/95 were reported to have severe disability (pooled proportion 39.6% (95% CI, 30.0-50.0%)). CONCLUSIONS: Four-fifths of fetuses with severe ventriculomegaly survive and, of these, just over two-fifths show normal neurodevelopment. The overall survivors without disability account for more than one third of the total. Given that many cases undergo termination of pregnancy and require longer follow-up in order to detect subtle abnormalities, mortality and prevalence of developmental delay may be even higher than that reported in this paper. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Development of brain ventricular system.

The brain ventricular system (BVS) consists of brain ventricles and channels connecting ventricles filled with cerebrospinal fluid (CSF). The disturbance of CSF flow has been linked to neurodegenerative disease including hydrocephalus, which manifests itself as an abnormal expansion of BVS. This relatively common developmental disorder has been observed in human and domesticated animals and linked to functional deficiency of various cells lineages facing BVS, including the choroid plexus or ependymal cells that generate CSF or the ciliated cells that cilia beating generates CSF flow. To understand the underlying causes of hydrocephalus, several animal models were developed, including rodents (mice, rat, and hamster) and zebrafish. At another side of a spectrum of BVS anomalies there is the "slit-ventricle" syndrome, which develops due to insufficient inflation of BVS. Recent advances in functional genetics of zebrafish brought to light novel genetic elements involved in development of BVS and circulation of CSF. This review aims to reveal common elements of morphologically different BVS of zebrafish as a typical representative of teleosts and other vertebrates and illustrate useful features of the zebrafish model for studies of BVS. Along this line, recent analyses of the two novel zebrafish mutants affecting different subunits of the potassium voltage-gated channels allowed to emphasize an important functional convergence of the evolutionarily conserved elements of protein transport essential for BVS development, which were revealed by the zebrafish and mouse studies.

Single-Shot Version of FLAIR Sequence in the Detection of Intraventricular Anomalies: Preliminary Experience in Fetal MR Imaging.

OBJECTIVE: To evaluate single-shot (ss) FLAIR sequence in the detection of intraventricular anomalies in a series of fetuses showing mild-moderate ventriculomegaly at ultrasound. SUBJECTS AND METHODS: Fetuses with mild-moderate isolated ventriculomegaly, which underwent MR imaging between 2003 and 2014 were considered eligible. Fetuses were examined by standard MR protocol and ss-FLAIR sequence, tailored for snapshot imaging. Two paediatric neuroradiologists evaluated MR images. RESULTS: 542 cases were selected. MR imaging was performed at mean 26 weeks of gestation. ss-FLAIR sequence detected intraventricular findings, consistent with cysts in 10 cases. In 3/10 intraventricular cysts were also evident on ss-FSE T2 and FSE T1-weighted images. In no case diffusion weighted imaging was able to detect cyst. No cyst was highlighted on ss-FSE-T2 and FSE-T1-weighted images, without being visible also on ss-FLAIR. CONCLUSION: ss-FLAIR sequence may be useful to detect intraventricular anomalies especially when fetal position or maternal obesity prevents adequate visualization by ultrasound.

Formation of the calcarine sulcus: a potential marker to predict the progression in utero of isolated mild fetal ventriculomegaly.

Our previous study confirmed the negative association between the development of calcarine sulcus and the width of lateral ventricles. The purpose of current study was to evaluate the reliability of calcarine sulcus depth in the 2nd trimester to predict the prenatal enlargement of lateral ventricle in fetuses with isolated mild fetal ventriculomegaly (IMVM).This study used a retrospective cohort study design. A total of 97 pregnant women with IMVM diagnosed between 20 and 26 weeks' gestation returned for a 2nd examination at 30 to 32 weeks. Lateral ventricular size and calcarine sulcus depth were acquired from ultrasonography and magnetic resonance imaging (MRI) scans, respectively. Progression was defined as the process of developing from a lower group toward a higher (<10 mm, 10-12 mm, 13-15 mm, and ≥16 mm).Significant correlation was observed between calcarine sulcus depth and ventricular measurements at the 2nd scan (r = -0.71, P < .0001). Receiver-operating characteristic curves showed that calcarine sulcus depth (area under curve [AUC] = 0.83, 95% confidence interval [CI] = 0.74-0.92) had the best diagnostic performance in predicting the prenatal progression, as compared with lateral ventricle width (AUC = 0.69, 95%CI = 0.54-0.84) and gestational age (AUC = 0.70, 95%CI = 0.57-0.83) at the initial scan. The cutoff value for calcarine sulcus depth was 3.3 mm, with the corresponding sensitivity and specificity were 75.0% and 81.3%, respectively. Multivariate analyses showed that calcarine sulcus depth ≥3.3 mm (odds ratio = 0.09, 95%CI = 0.02-0.38, P = .001) was an independent predictor of the prenatal progression.For IMVM, calcarine sulcus depth might be a powerful marker to identify subjects at higher risk for worse prenatal progression.