Fetal Research Articles

Nucleated red blood cells: unexpected orchestrators of fetal immunity

Abstract Red blood cells (RBCs) are not typically considered active immune mediators. This dogma stems from the fact that RBC precursors discard organelles as they mature, thus losing the ability to alter gene expression in response to stimuli. Intriguingly, nucleated RBCs (nRBCs) circulate in human fetuses and neonates. Due to evolutionary pressure for successful reproduction, circulation of nRBCs during pregnancy is likely important. However, the role of nRBCs in uteroremains unknown. To define the role of human nRBCs, we queried single cell RNA-seq data and found that transcriptomics support nRBCs as putative immune mediators. Unexpectedly, we found that nRBCs express antigen processing & presentation machinery. nRBCs constitutively express MHC II & co-stimulatory molecules, hallmarks of specialized antigen-presenting cells. We further demonstrated that nRBCs internalize and cleave antigens. Currently, we aim to determine if nRBCs present antigens to T cells and to characterize the elicited response. In addition, we found that nRBCs express pattern recognition receptors capable of detecting pathogens and initiating an antimicrobial response. We demonstrated that nRBCs respond to viral infection through upregulation of antiviral genes, interferons/interferon-stimulated genes, MHC I, and pro-inflammatory cytokines/chemokines. These data suggest a putative functionality for nRBCs in mediating antiviral immunity in utero. We are currently investigating antiviral functions of nRBCs. Together, our findings shed light on an unexpected orchestrator of fetal immunity. Knowledge of the fetal immune system has potential to help us understand health and disease during pregnancy, as a neonate, and likely every stage of life after. Supported by grants from NIH/NIDDK 5T32DK007780, NIH/NIGMS K12GM081259, Burroughs Wellcome Fund 2022 Next Gen Pregnancy Initiative Award

Report of an Experiment With a Fetal Ex-Utero Support System in Piglets.

Extreme prematurity remains one of the leading causes of neonatal death. An ex-utero treatment strategy that allows the fetus to develop beyond this period until capable of tolerating the transition to post-natal physiology would significantly impact the quality of care offered for this pre-viable patient population. In this study, we report our experience with an ex-utero support system for fetal pigswith the goal of support and survival for eight hours. Our experiment included two pigs at a gestational age equivalent to a 32-week human fetus. Following ultrasound assessment and delivery via hysterotomy, the fetuses were transferred to a 40 L glass aquarium filled with warmed lactated Ringer's solution and connected to an arteriovenous (AV) circuit that included a centrifugal pump and a pediatric oxygenator.Fetus 1 was successfully cannulated and survived for seven hours (expected maximum duration of eight hours). Fetus 2 died shortly after hysterotomy, secondary to failure at the cannulation stage. Our results suggest that ex-utero support of the premature fetal pig is feasible, contributing to a scarce body of evidence. However, further studies are needed before effectively translating an artificial placenta system into the clinical arena.

A CRISPR/Cas9-generated mutation in the zebrafish orthologue of PPP2R3B causes idiopathic scoliosis

Idiopathic scoliosis (IS) is the deformation and/or abnormal curvature of the spine that develops progressively after birth. It is a very common condition, affecting approximately 4% of the general population, yet the genetic and mechanistic causes of IS are poorly understood. Here, we focus on PPP2R3B, which encodes a protein phosphatase 2A regulatory subunit. We found that PPP2R3B is expressed at sites of chondrogenesis within human foetuses, including the vertebrae. We also demonstrated prominent expression in myotome and muscle fibres in human foetuses, and zebrafish embryos and adolescents. As there is no rodent orthologue of PPP2R3B, we used CRIPSR/Cas9-mediated gene-editing to generate a series of frameshift mutations in zebrafish ppp2r3b. Adolescent zebrafish that were homozygous for this mutation exhibited a fully penetrant kyphoscoliosis phenotype which became progressively worse over time, mirroring IS in humans. These defects were associated with reduced mineralisation of vertebrae, resembling osteoporosis. Electron microscopy demonstrated abnormal mitochondria adjacent to muscle fibres. In summary, we report a novel zebrafish model of IS and reduced bone mineral density. In future, it will be necessary to delineate the aetiology of these defects in relation to bone, muscle, neuronal and ependymal cilia function.

Anti-Müllerian hormone - clinical use and future possibilities.

Anti-Müllerian hormone (AMH) is a protein produced already in human fetus. It has an essential role in the differentiation of the reproductive tract, regulation of the ovaries and testes. The determination of serum AMH levels is used in clinical practice. Today, especially in reproductive medicine in the assessment of ovarian reserve and in the prediction of the response to ovarian stimulation. However, in young cancer patients, it can also predict the risk of ovarian failure after anticancer treatment. It finds further use in pediatric endocrinology in the diagnosis of sexual differentiation disorders. In oncology, it is used as a tumor marker for monitoring patients with granulosa tumors. In the future, however, it is also promising to use the knowledge of AMH function for the treatment of gynecological as well as other solid malignancies expressing a tissue-specific receptor for AMH.

Nuclear Receptor Gene Variants Underlying Disorders/Differences of Sex Development through Abnormal Testicular Development.

Gonadal development is the first step in human reproduction. Aberrant gonadal development during the fetal period is a major cause of disorders/differences of sex development (DSD). To date, pathogenic variants of three nuclear receptor genes (NR5A1, NR0B1, and NR2F2) have been reported to cause DSD via atypical testicular development. In this review article, we describe the clinical significance of the NR5A1 variants as the cause of DSD and introduce novel findings from recent studies. NR5A1 variants are associated with 46,XY DSD and 46,XX testicular/ovotesticular DSD. Notably, both 46,XX DSD and 46,XY DSD caused by the NR5A1 variants show remarkable phenotypic variability, to which digenic/oligogenic inheritances potentially contribute. Additionally, we discuss the roles of NR0B1 and NR2F2 in the etiology of DSD. NR0B1 acts as an anti-testicular gene. Duplications containing NR0B1 result in 46,XY DSD, whereas deletions encompassing NR0B1 can underlie 46,XX testicular/ovotesticular DSD. NR2F2 has recently been reported as a causative gene for 46,XX testicular/ovotesticular DSD and possibly for 46,XY DSD, although the role of NR2F2 in gonadal development is unclear. The knowledge about these three nuclear receptors provides novel insights into the molecular networks involved in the gonadal development in human fetuses.

Forever chemicals could expose the human fetus to xenobiotics by binding to placental enzymes: Prescience from molecular docking, DFT, and machine learning

The accumulation of toxic perfluoroalkyl and polyfluoroalkyl substances (PFAS), also known as forever chemicals, in umbilical cord blood calls for an urgent need to explore PFAS kinetics at the maternal-fetal interface placenta. Therefore, this study modeled the possible effects of ten PFAS on two enzymes (glutathione S-transferase (GST) and N-acetyltransferase (NAT2) that are active in the placenta and can protect the fetus from xenobiotics. Molecular docking was used to determine the binding affinities of some common PFAS at two placental enzyme targets. Density functional theory (DFT) analysis and artificial neural networks (ANN) on the PFAS were performed to identify their chemical reactivity descriptors and the most important one responsible for binding, respectively. The molecular docking studies showed that perfluorooctanesulphonamide (PFOSA) and perfluorodecanoic acid (PFDA) consistently had higher binding affinities on the two placental enzymes than the controls, glutathione, and coenzyme A. DFT revealed that out of the ten PFAS analyzed, PFDA had the lowest binding affinity and chemical softness, making it the most reactive and as such toxic PFAS in the group. At normalized importance of >80 %, the ANN analysis predicted that the molecular weight and total energy were the primary reactivity descriptors of the PFAS responsible for their binding on the GST. In contrast, their binding energy was responsible for binding at the NAT2. The results from these simulations indicate that PFAS, especially PFDA, have the potential to inhibit placental enzyme activity in humans. This may have far-reaching consequences for placental functions and fetal development, which needs to be clarified in future studies.

Sexual dimorphism based on the sternum bone morphometry in human fetuses: a pilot study

The recognition and determination of sex from fragments and remnants of human skeletons has been, until now, a complex task for forensic experts and anthropologists. For the former, it becomes crucial in cases of mass disasters, catastrophes, such as terrorist acts and wars. The study with bones of the pelvis, skull, femur and other long bones has significantly contributed to analyze the determination of sex in these situations. The study of sternum dimorphism can become one more element that may collaborate with this type of knowledge. The present study sought to investigate, in human fetuses, the sexual dimorphism of the sternum, based on its perimeter measurements, which were treated using statistical methods. For this purpose, three different observers used a digital pachymeter with a precision of 0.01mm and the average of the measurements obtained was calculated. Differences in average were evaluated using the t-test and Mann-Whitney test, as well as discriminant analysis. Findings from measurements of the sternum in human fetuses did not seem to us to be a reliable indicator of sex determination. We hope that further studies with a larger number of samples and the use of other possible techniques will also collaborate with the subject.

Astrocytes express aberrant immunoglobulins as putative gatekeeper of astrocytes to neuronal progenitor conversion

Using multi-omics analyses including RNAseq, RT-PCR, RACE-PCR, and shotgun proteomic with enrichment strategies, we demonstrated that newborn rat astrocytes produce neural immunoglobulin constant and variable heavy chains as well as light chains. However, their edification is different from the ones found in B cells and they resemble aberrant immunoglobulins observed in several cancers. Moreover, the complete enzymatic V(D)J recombination complex has also been identified in astrocytes. In addition, the constant heavy chain is also present in adult rat astrocytes, whereas in primary astrocytes from human fetus we identified constant and variable kappa chains as well as the substitution lambda chains known to be involved in pre-B cells. To gather insights into the function of these neural IgGs, CRISPR-Cas9 of IgG2B constant heavy chain encoding gene (Igh6), IgG2B overexpression, proximal labeling of rat astrocytes IgG2B and targets identification through 2D gels were performed. In Igh6 KO astrocytes, overrepresentation of factors involved in hematopoietic cells, neural stem cells, and the regulation of neuritogenesis have been identified. Moreover, overexpression of IgG2B in astrocytes induces the CRTC1-CREB-BDNF signaling pathway known to be involved in gliogenesis, whereas Igh6 KO triggers the BMP/YAP1/TEAD3 pathway activated in astrocytes dedifferentiation into neural progenitors. Proximal labeling experiments revealed that IgG2B is N-glycosylated by the OST complex, addressed to vesicle membranes containing the ATPase complex, and behaves partially like CD98hc through its association with LAT1. These experiments also suggest that proximal IgG2B-LAT1 interaction occurs concomitantly with MACO-1 and C2CD2L, at the heart of a potentially novel cell signaling platform. Finally, we demonstrated that these chains are synthesized individually and associated to recognize specific targets. Indeed, intermediate filaments Eif4a2 and Pdia6 involved in astrocyte fate constitute targets for these neural IgGs. Taken together, we hypothese that neural aberrant IgG chains may act as gatekeepers of astrocytes' fate.

Smooth muscle contributes to the development and function of a layered intestinal stem cell niche.

Wnt and Rspondin (RSPO) signaling drives proliferation, and bone morphogenetic protein inhibitors (BMPi) impede differentiation, of intestinal stem cells (ISCs). Here, we identify the mouse ISC niche as a complex, multi-layered structure that encompasses distinct mesenchymal and smooth muscle populations. In young and adult mice, diverse sub-cryptal cells provide redundant ISC-supportive factors; few of these are restricted to single cell types. Niche functions refine during postnatal crypt morphogenesis, in part to oppose the dense aggregation of differentiation-promoting BMP+ sub-epithelial myofibroblasts at crypt-villus junctions. Muscularis mucosae, a specialized muscle layer, first appears during this period and supplements neighboring RSPO and BMPi sources. Components of this developing niche are conserved in human fetuses. The invivo ablation of mouse postnatal smooth muscle increases BMP signaling activity, potently limiting a pre-weaning burst of crypt fission. Thus, distinct and progressively specialized mesenchymal cells together create the milieu that is required to propagate crypts during rapid organ growth and to sustain adult ISCs.

Histogenesis of Parotid Gland in Human Fetuses

Background: The present study attempted to find out the histological changes of parotid gland in the developing human fetuses. Materials and Methods: Parotid glands from 60 fresh fetuses of gestational weeks ranging from 12weeks to term were studied after staining with Hematoxylene & Eosin, Masson’s Trichome stain, Van Gieson’s stain and Verhoeff’s stains. Results: The gland of the fetus at 12 weeks composed of solid epithelial cords with occasional canalization, surrounded by loose mesenchyme. Canalization of cords was completed at 25 weeks and adult picture attained at 36 weeks. Division of the glandular parenchyma into lobes and lobules by connective tissue septa started at 17 weeks. A well formed capsule was seen around the gland at 20 weeks. A gradual decrease in intra-glandular connective tissue occurred in late gestational age. Variety of cells such as fibroblasts, mesenchymal cells, fibrocytes and lymphocytes were seen. Numerous adipocytes were found within the glandular parenchyma and around the gland. Ductal tree showed gradual differentiation, presence of cilia-like surface projections from epithelia of larger ducts were seen in 14-32 week fetuses. Conclusion: When compared with various authors, some findings of the present study followed the foot-steps of previous workers whereas some were in contrary, the most important difference being the age of full maturation of the glandular architecture. One of the unique finding being the presence of cilia-like surface projections seen in the larger ducts in 14-32 week aged fetuses.

Fetal Supraventricular Tachycardia: Histologic Evidence of Accessory Pathways Due to Incomplete Annulus Fibrosus Formation.

Atrioventricular (AV) reentrant tachycardia is a common type of supraventricular tachycardia (SVT) that occurs in the fetus and neonate. Although many tachycardias resolve within several weeks of birth or respond to medical management, disruptions in the cardiac annulus fibrosus and development of additional accessory pathways may lead to refractory dysrhythmia resulting in fetal hydrops and ultimately, fetal death. While accessory pathways have been well documented anatomically in adult and childhood tachyarrhythmias, there are no reports of the histology of these pathways in human fetuses with SVT. This is a small case series of 2 fetuses with a history of SVT that resulted in fetal hydrops. In both cases, examination of the cardiac conduction system was unremarkable and examination of the atrioventricular junction revealed a focally thinned and/or discontinuous annulus fibrosus with documented direct continuity between the atrial and ventricular myocardium in 1 case. This case series demonstrates that thinning or absence of the annulus fibrosus is a feature seen in fetal SVT, and the development of subsequent aberrant AV connections due to defective formation of the annulus fibrosus suggests a possible cause for these arrhythmias.

Nasal capsule ossification: A histological study using human foetuses to find an association between the foetus and adult morphologies of the nasal wall.

Recent molecular biology studies have revealed the process of nasal capsule determination. We aimed to create a fate map showing the association between the adult and embryonic components of the nasal wall and nasal capsule derivatives. We examined paraffin-embedded histological sections between 15 mid-term (9-16 weeks) and 12 near-term (27-40 weeks) foetuses. Until 15 weeks, membranous ossification occurred 'along' the capsular cartilage, contributing to the formation of the vomer, maxilla and bony nasal septum as well as the nasal, frontal and lacrimal bones. After 15 weeks, a wide lateral part of the capsule became thin and fragmented, and degenerative cartilage was observed near the lacrimal bone, in the three conchae, and at the inferolateral end of the capsule sandwiched between the maxilla and palatine bone. The disappearing cartilages appeared to be replaced by nearby membranous bones. This type of membranous ossification did not appear to use the capsular cartilage as a 'mould', although the perichondrium may have a role in inducing ossification. Calcified cartilage indicated endochondral ossification in the inferior concha until 15 weeks and, later, at the bases of three conchae and around the future sphenoid sinus (i.e. the concha sphenoidalis). The capsular cartilage extended antero-superiorly over the frontal bone and inserted into the nasal bone. At 40 weeks, the capsular cartilage remained in the cribriform plate and at the inferolateral end along the palatine bone. Consequently, less guidance from the nasal capsule seemed to provide great individual variation in the shape of the wide anterolateral wall of the nasal cavity.

Quantity discrimination in newly hatched zebrafish suggests hardwired numerical abilities

An intriguing hypothesis to explain the ubiquity of numerical abilities is that all vertebrates are born with hardwired neuronal networks for processing numbers. To date, only studies on human foetuses have clearly supported this hypothesis. Zebrafish hatch 48–72 h after fertilisation with an embryonic nervous system, providing a unique opportunity for investigating this hypothesis. Here, we demonstrated that zebrafish larvae exposed to vertical bars at birth acquired an attraction for bar stimuli and we developed a numerical discrimination task based on this preference. When tested with a series of discriminations of increasing difficulty (1vs.4, 1vs.3, 1vs.2, and 2vs.4 bars), zebrafish larvae reliably selected the greater numerosity. The preference was significant when stimuli were matched for surface area, luminance, density, and convex hull, thereby suggesting a true capacity to process numerical information. Converging results from two phylogenetically distant species suggests that numerical abilities might be a hallmark feature of vertebrates’ brains.

Development and growth of median structures in the human tongue: A histological study using human fetuses and adult cadavers.

Glossectomy is a surgical procedure performed to remove all or part of the tongue in patients with cancer. The removal of a significant part of the tongue has a marked effect on speech and swallowing function, as patients may lose not only the tongue muscles but also the median lingual septum (MLS). Therefore, to achieve successful tongue regeneration, it is necessary to investigate the developmental processes of not only the tongue muscles but also the MLS. This study was conducted to clarify the mutual development of the tongue muscles and the MLS in human fetuses. Serial or semi-serial histological sections from 37 embryos and fetuses (aged 5-39 weeks) as well as nine adults were analyzed. The MLS appeared at Carnegie stage 15 (CS15), and until 12 weeks of gestation, abundant fibers of the intrinsic transverse muscle crossed the septum in the entire tongue. However, in near-term fetuses and adults, the contralaterally extending muscles were restricted to the deepest layer just above the genioglossus muscle. This finding indicates that the crossing transverse muscle showed the highest density at mid-term. A thorough understanding of both the MLS and the tongue muscles is necessary for successful tongue regeneration.

MTHFD1 is critical for the negative regulation of retinoic acid receptor signalling in anencephaly.

Neural tube defects are the most severe congenital malformations that result from failure of neural tube closure during early embryonic development, and the underlying molecular mechanisms remain elusive. Retinoic acid, an active derivative of vitamin A, is critical for neural system development, and retinoic acid receptor (RAR) signalling malfunctions have been observed in human neural tube defects. However, retinoic acid-retinoic acid receptor signalling regulation and mechanisms in neural tube defects are not fully understood. The mRNA expression of RARs and retinoid X receptors in the different human neural tube defect phenotypes, including 11 pairs of anencephaly foetuses, 10 pairs of hydrocephalus foetuses and nine pairs of encephalocele foetuses, was investigated by NanoString nCounter technology. Immunoprecipitation-mass spectrometry was performed to screen the potential interacting targets of retinoic acid receptor γ. The interactions between proteins were confirmed by co-immunoprecipitation and immunofluorescence laser confocal microscopy. Luciferase and chromatin immunoprecipitation with quantitative real-time polymerase chain reaction assays were used to clarify the underlying mechanism. Moreover, a neural tube defect animal model, constructed using excess retinoic acid, was used for further analysis with established molecular biology technologies. We report that level of retinoic acid receptor γ (RARγ) mRNA was significantly upregulated in the brain tissues of human foetuses with anencephaly. To further understand the actions of retinoic acid receptor γ in neural tube defects, methylenetetrahydrofolate dehydrogenase 1 was identified as a specific retinoic acid receptor γ target from IP-MS screening. Additionally, methylenetetrahydrofolate dehydrogenase 1 negatively regulated retinoic acid receptor γ transcription factor activity. Furthermore, low expression of methylenetetrahydrofolate dehydrogenase 1 and activation of retinoic acid receptor signalling were further determined in human anencephaly and a retinoic acid-induced neural tube defect mouse model. This study reveals that methylenetetrahydrofolate dehydrogenase 1, the rate-determining enzyme in the one-carbon cycle, might be a specific regulator of retinoic acid receptors; these findings provide new insights into the functional linkage between nuclear folate metabolism and retinoic acid receptor signalling in neural tube defect pathology.

Defective jagged-1 signaling affects GnRH development and contributes to congenital hypogonadotropic hypogonadism.

In vertebrate species, fertility is controlled by gonadotropin-releasing hormone (GnRH) neurons. GnRH cells arise outside the central nervous system, in the developing olfactory pit, and migrate along olfactory/vomeronasal/terminal nerve axons into the forebrain during embryonic development. Congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome are rare genetic disorders characterized by infertility, and they are associated with defects in GnRH neuron migration and/or altered GnRH secretion and signaling. Here, we documented the expression of the jagged-1/Notch signaling pathway in GnRH neurons and along the GnRH neuron migratory route both in zebrafish embryos and in human fetuses. Genetic knockdown of the zebrafish ortholog of JAG1 (jag1b) resulted in altered GnRH migration and olfactory axonal projections to the olfactory bulbs. Next-generation sequencing was performed in 467 CHH unrelated probands, leading to the identification of heterozygous rare variants in JAG1. Functional in vitro validation of JAG1 mutants revealed that 7 out of the 9 studied variants exhibited reduced protein levels and altered subcellular localization. Together our data provide compelling evidence that Jag1/Notch signaling plays a prominent role in the development of GnRH neurons, and we propose that JAG1 insufficiency may contribute to the pathogenesis of CHH in humans.

Role of Albumin and Alpha-Fetoprotein in Prenatal Ontogenesis of the Human Eye

The vitreous body of the eye of human fetuses contains serum albumin (SA) and alpha-fetoprotein (AFP), which is normally characteristic of human embryos and fetuses. In the second trimester, both proteins are found in the vitreous at a concentration comparable to that in blood serum, after which their content decreases sharply. In this analytical review, taking into account the biological properties of SA and AFP, the role of these proteins in the processes of growth and differentiation of the structures of the developing eye is discussed.

Early exposure to wildfire smoke can lead to birth defects.

The results of two previously published reports of the events and impacts of the Campfire wildfire smoke exposure that occurred in California in 2018 are amplified from the point of view of the potential toxic mechanism involved. The Campfire wildfire led to the exposure of a breeding colony of macaque monkeys (Macaca mulatta) during the peak of their breeding season in 2018-2019. Considering the timing, adverse effects, and endocrine implications reported, the cumulative evidence points to an early toxic sensitive period that can lead to birth defects in higher primates and human pregnancies. This deeper inspection of the published observations provides important caveats and useful guidance for future investigators. The unique higher primate placental-adrenal-brain axis may limit the use of many traditional toxicologic approaches. Retrospective neurological evaluations of human fetuses exposed to air pollutants during organogenesis and subsequent retrospective characterization of air samples using in vitro and animal models may be the best procedures to follow.

The so-called absorption process of the pulmonary vein into the left atrium of the heart: a histological study using human embryos and fetuses.

Embryonic pulmonary veins (PVs) are believed to be absorbed into the left atrium (LA) to provide an adult morphology in which "four" veins drain separately into the atrium. Serial histological sections were obtained from 27 human embryos and fetuses. Between 5 and 6weeks, the four PVs joined together to form a trunk-like structure (initial spatium pulmonalis) that was larger than the initial LA (two-ostia pattern). The cardiac nerves ran inferiorly along the posterior aspect of the four veins, as well as the spatium. At and until 7weeks, the cardiac nerves were concentrated to elongate the nerve fold, and the latter separated the left PV trunk from the expanding LA (left spatium). Similarly, the right PV opened to a thick and deep LA recess (right spatium). At 8-12weeks, depending on the growth of the LA, the opening of the left and right PVs became distant, and the spatium was elongated transversely. The left spatium was enlarged to open widely to the proper left atrium in contrast to the right spatium pushed anteriorly by the right atrium. The three-ostia pattern was transiently observed because of the lost delimitation between the left spatium and proper atrium. The myocardium was thin in the left spatium behind the left atrial nerve fold, whereas the right spatium was tube-like with a thick myocardium. The four-ostia pattern seemed to be established at birth due to a drastically increased venous return from the lung, resulting in a flat smooth left atrial posterior wall.

Topographic and anatomical relationships of the lower jaw and auricle in human prenatal ontogenesis

Aim to describe the topographic and anatomical relationships of the fetal lower jaw and auricle in the mid-gestation period.
 Material and methods. The 110 mandibles of human fetuses of the second trimester were selected for the study and divided into groups by sex and age. The morphological techniques and the method of ultrasound scanning were used to determine the topographic relationships of the lower jaw and the fetal ear, the location of the central part of the auricle relative to the lower jaw (the line connecting the gnathion point and the external occipital protuberance) at different age periods.
 Results. During the mid-gestation period, with the growth of the fetus, the auricle normally shifts upward relative to the mandible. At the beginning of the study period, the auricle is located just below the angle of the lower jaw. Its central part (C) is below the line (AB) connecting the gnathion point and the external occipital protuberance. The perpendicular from the conditional center of the auricle to the line AB is half the diameter of the auricle 3.7 1.1 mm. In the second age group, the auricle is located at the level of the branch and angle of the lower jaw Its conditional center (C) is below the line AB and is of the diameter of the auricle 3.1 0.8 mm. By the end of the mid-gestation period, the auricle is displaced to the level of the processes of the lower jaw above the notch. Its central part is above line AB, the perpendicular from point C to line AB is 6.1 1.4 mm.
 Conclusion. The deviations in the formation of the topographic and anatomical relationships of the lower jaw and auricle of the fetus from 14 to 27 weeks of gestation can be additional criteria for the development of congenital fetal pathology and require the fetoabnormal alertness.