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Journal of Nippon Medical School =... Dec 2004The metabolic rate of the fetus per tissue weight is relatively high when compared to that of an adult. Moreover, heat is transferred to the fetus via the placenta and... (Review)
Review
The metabolic rate of the fetus per tissue weight is relatively high when compared to that of an adult. Moreover, heat is transferred to the fetus via the placenta and the uterus, resulting in a 0.3 degrees C to 0.5 degrees C higher temperature than that of the mother. Therefore, fetal temperature is maternally dependent until birth. At birth, the neonate rapidly cools in response to the relatively cold extrauterine environment. Thus, the neonatal temperature rapidly drops soon after birth. In order to survive, the neonate must accelerate heat production via nonshivering thermogenesis (NST), which is coupled to lypolysis in brown adipose tissue. Heat is produced by uncoupling ATP synthesis via the oxidation of fatty acids in the mitochondria, utilizing uncoupled protein. Thermogenesis must begin shortly after birth and continue for several hours. Since thermogenesis requires adequate oxygenation, a distressed neonate with hypoxemia cannot produce an adequate amount of heat to increase its temperature. In contrast to the neonate, the fetus cannot produce extra heat production. This is because the fetus is exposed to inhibitors to NST, which are produced in the placenta and then enter the fetal circulation. The important inhibitors include adenosine and prostaglandin E2, both of which have strong anti-lypolytic actions. The inhibitors play an important role in the metabolic adaptation of a physiological hypoxic fetus because NST requires adequate oxygenation. Furthermore, the presence of NST inhibitors allows the fetus to accumulate an adequate amount of brown adipose tissue before birth. The umbilical circulation transfers 85% of the heat produced by the fetus to the maternal circulation. The remaining 15% is dissipated through the fetal skin to the amnion, and is then transferred through the uterine wall to the maternal abdomen. As long as fetal heat production and loss are appropriately balanced, the temperature differential between the fetus and the mother remains constant (heat clump). However, when the umbilical circulation is occluded for any reason, the fetal temperature will rise in relation to the extent of the occlusion. The fetal temperature may elevate to the hyperthermic range in cases of acute cord occlusion; if this occurs, fetal growth, including brain development, may be impacted. Experimentally induced cord occlusion, which is recognized as a significant cause of brain damage, results in a rapid elevation of body temperature; however, the brain temperature tends to remain constant. This is considered to be a cerebral thermoregulatory adaptation to hypoxemia, which has the physiologic advantage of protecting the fetus from hyperthermia, a condition that predisposes the fetus to hypoxic injury (cerebral hypometabolism). A number of thermoregularatory mechanisms are in place to maintain normal fetal and neonatal growth. Data has primarily been collected from animal studies; aside from the strict thermal control provided in the newborn nursery, little information exists concerning these mechanisms in the human fetus and neonate. Probably further information on thermoregulation is necessary specially to improve perinatal management for hypoxic fetuses.
Topics: Body Temperature Regulation; Fetus; Humans; Infant, Newborn
PubMed: 15673956
DOI: 10.1272/jnms.71.360 -
Genes Aug 2022Congenital malformations diagnosed by ultrasound screening complicate 3-5% of pregnancies and many of these have an underlying genetic cause. Approximately 40% of... (Review)
Review
Congenital malformations diagnosed by ultrasound screening complicate 3-5% of pregnancies and many of these have an underlying genetic cause. Approximately 40% of prenatally diagnosed fetal malformations are associated with aneuploidy or copy number variants, detected by conventional karyotyping, QF-PCR and microarray techniques, however monogenic disorders are not diagnosed by these tests. Next generation sequencing as a secondary prenatal genetic test offers additional diagnostic yield for congenital abnormalities deemed to be potentially associated with an underlying genetic aetiology, as demonstrated by two large cohorts: the 'Prenatal assessment of genomes and exomes' (PAGE) study and 'Whole-exome sequencing in the evaluation of fetal structural anomalies: a prospective cohort study' performed at Columbia University in the US. These were large and prospective studies but relatively 'unselected' congenital malformations, with little Clinical Genetics input to the pre-test selection process. This review focuses on the incremental yield of next generation sequencing in single system congenital malformations, using evidence from the PAGE, Columbia and subsequent cohorts, with particularly high yields in those fetuses with cardiac and neurological anomalies, large nuchal translucency and non-immune fetal hydrops (of unknown aetiology). The total additional yield gained by exome sequencing in congenital heart disease was 12.7%, for neurological malformations 13.8%, 13.1% in increased nuchal translucency and 29% in non-immune fetal hydrops. This demonstrates significant incremental yield with exome sequencing in single-system anomalies and supports next generation sequencing as a secondary genetic test in routine clinical care of fetuses with congenital abnormalities.
Topics: Female; Fetus; High-Throughput Nucleotide Sequencing; Humans; Hydrops Fetalis; Infant, Newborn; Pregnancy; Pregnancy Trimester, First; Prospective Studies; Ultrasonography, Prenatal
PubMed: 36140685
DOI: 10.3390/genes13091517 -
BioMed Research International 2013Metabolomics in maternal-fetal medicine is still an "embryonic" science. However, there is already an increasing interest in metabolome of normal and complicated... (Review)
Review
Metabolomics in maternal-fetal medicine is still an "embryonic" science. However, there is already an increasing interest in metabolome of normal and complicated pregnancies, and neonatal outcomes. Tissues used for metabolomics interrogations of pregnant women, fetuses and newborns are amniotic fluid, blood, plasma, cord blood, placenta, urine, and vaginal secretions. All published papers highlight the strong correlation between biomarkers found in these tissues and fetal malformations, preterm delivery, premature rupture of membranes, gestational diabetes mellitus, preeclampsia, neonatal asphyxia, and hypoxic-ischemic encephalopathy. The aim of this review is to summarize and comment on original data available in relevant published works in order to emphasize the clinical potential of metabolomics in obstetrics in the immediate future.
Topics: Amniotic Fluid; Female; Fetal Blood; Fetus; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Maternal-Fetal Relations; Metabolomics; Obstetric Labor, Premature; Placenta; Pregnancy; Pregnancy Complications
PubMed: 23841090
DOI: 10.1155/2013/720514 -
Physiological Measurement Mar 2019Fetal magnetocardiography (fMCG) is the most direct and precise method of assessing fetal rhythm and conduction. Although the utility of fMCG for evaluation of fetuses...
BACKGROUND
Fetal magnetocardiography (fMCG) is the most direct and precise method of assessing fetal rhythm and conduction. Although the utility of fMCG for evaluation of fetuses with serious arrhythmia is generally acknowledged, many aspects of fetal rhythm and conduction are relatively unstudied.
OBJECTIVE
To record fMCG in a large group of normal fetuses in order to provide a more comprehensive evaluation of fMCG waveform characteristics, including waveform intervals, amplitudes, and morphology.
METHODS
The subjects were 132 healthy women with uncomplicated singleton pregnancies, studied at 15.7-39.9 (mean 28.9) weeks' gestation in 259 sessions. The P, PR, QRS, QT, QTc, and RR intervals and the P/QRS and T/QRS amplitude ratios were measured.
MAIN RESULTS
The P, PR, QRS, and RR intervals increased with gestational age, but QT and QTc did not. U-waves were seen in 11% of fetuses. The T-waves were often flat with low T/QRS amplitude ratios. Equiphasic QRS complexes were associated with tall P-waves. The PR, QRS, and QT intervals showed a power law dependence on RR interval with power law exponents 0.445, 0.363, and 0.381, respectively.
SIGNIFICANCE
The data establish prediction intervals for fMCG waveform intervals and amplitudes in normal fetuses. This is critical for identification of fetuses with abnormal rhythm. Our study is the first to document the incidence of U-waves and flat T-waves in the fetus, both of which are uncommon postnatally. The association of tall P-waves with equiphasic QRS complexes provides a useful means of improving the resolution of fetal P-waves.
Topics: Adult; Female; Fetus; Gestational Age; Healthy Volunteers; Humans; Magnetocardiography; Pregnancy; Signal Processing, Computer-Assisted
PubMed: 30802886
DOI: 10.1088/1361-6579/ab0a2c -
NeuroImage Jan 2019Spatial distribution and specific geometric and topological patterning of early sulcal folds have been hypothesized to be under stronger genetic control and are more... (Review)
Review
Spatial distribution and specific geometric and topological patterning of early sulcal folds have been hypothesized to be under stronger genetic control and are more associated with optimal organization of cortical functional areas and their white matter connections, compared to later developing sulci. Several previous studies of sulcal pit (putative first sulcal fold) distribution and sulcal pattern analyses using graph structures have provided evidence of the importance of sulcal pits and patterns as remarkable anatomical features closely related to human brain function, suggesting additional insights concerning the anatomical and functional development of the human brain. Recently, early sulcal folding patterns have been observed in healthy fetuses and fetuses with brain abnormalities such as polymicrogyria and agenesis of corpus callosum. Graph-based quantitative sulcal pattern analysis has shown high sensitivity in detecting emerging subtle abnormalities in cerebral cortical growth in early fetal stages that are difficult to detect via qualitative visual assessment or using traditional cortical measures such as gyrification index and curvature. It has proven effective for characterizing genetically influenced early cortical folding development. Future studies will be aimed at better understanding a comprehensive map of spatio-temporal dynamics of fetal cortical folding in a large longitudinal cohort in order to examine individual clinical fetal MRIs and predict postnatal neurodevelopmental outcomes from early fetal life.
Topics: Brain; Fetus; Humans
PubMed: 29601953
DOI: 10.1016/j.neuroimage.2018.03.057 -
PloS One 2019Many parameters treated as constants in traditional physiologically based pharmacokinetic models must be formulated as time-varying quantities when modeling pregnancy...
Many parameters treated as constants in traditional physiologically based pharmacokinetic models must be formulated as time-varying quantities when modeling pregnancy and gestation due to the dramatic physiological and anatomical changes that occur during this period. While several collections of empirical models for such parameters have been published, each has shortcomings. We sought to create a repository of empirical models for tissue volumes, blood flow rates, and other quantities that undergo substantial changes in a human mother and her fetus during the time between conception and birth, and to address deficiencies with similar, previously published repositories. We used maximum likelihood estimation to calibrate various models for the time-varying quantities of interest, and then used the Akaike information criterion to select an optimal model for each quantity. For quantities of interest for which time-course data were not available, we constructed composite models using percentages and/or models describing related quantities. In this way, we developed a comprehensive collection of formulae describing parameters essential for constructing a PBPK model of a human mother and her fetus throughout the approximately 40 weeks of pregnancy and gestation. We included models describing blood flow rates through various fetal blood routes that have no counterparts in adults. Our repository of mathematical models for anatomical and physiological quantities of interest provides a basis for PBPK models of human pregnancy and gestation, and as such, it can ultimately be used to support decision-making with respect to optimal pharmacological dosing and risk assessment for pregnant women and their developing fetuses. The views expressed in this article are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.
Topics: Blood Circulation; Female; Fetus; Hematocrit; Humans; Models, Anatomic; Models, Biological; Mothers; Pregnancy; Tissue Distribution
PubMed: 31048866
DOI: 10.1371/journal.pone.0215906 -
British Medical Journal Aug 1948
Topics: Abortion, Missed; Female; Fetus; Humans; Pregnancy
PubMed: 18934254
DOI: 10.1136/bmj.2.4573.443-a -
The Medical Journal of Malaysia Jun 2010Foetus-in-fetu is a rare condition in which a calcified mass is in the abdomen of its host, a newborn or an infant. We report a case of a newborn in whom abdominal...
Foetus-in-fetu is a rare condition in which a calcified mass is in the abdomen of its host, a newborn or an infant. We report a case of a newborn in whom abdominal radiograph and ultrasonography revealed a mass in which the contents favour a foetus-in-fetu. Diagnosis was confirmed by macroscopic examination that showed a soft tissue mass resembling a foetus, attached to the membranous sac. It was covered entirely with intact skin. There were two malformed lower limbs with a rudimentary digit and one malformed upper limb.
Topics: Abdomen; Fetus; Humans; Upper Extremity
PubMed: 23756803
DOI: No ID Found -
Folia Morphologica 2022The lateral compartment of the leg, due to its distal and concurrent superficial positioning, is a multiple trauma site. Detailed knowledge of compartimentum lateralis...
BACKGROUND
The lateral compartment of the leg, due to its distal and concurrent superficial positioning, is a multiple trauma site. Detailed knowledge of compartimentum lateralis cruris (CLC) structure is crucial for physicians. Musculus peroneus longus (MPL) is located within the structures of the CLC most superficially. There is a lot of data on the morphology of the MPL but there is no publication analysing in detail its anatomy in the foetal period. The aim of the study was to determine the variability of metric and morphological parameters of MPL in a studied period of prenatal ontogenesis.
MATERIALS AND METHODS
The analysis included 207 human foetuses (101 males and 106 females) at calendar age from 113 to 222 days. The analysed material comes from the local anatomy collection. Foetuses were stored in typical preservation solutions. Access to the muscle was obtained on the basis of standard preparation techniques. The authors evaluated the metric parameters of the muscle showing the presence of variable dynamics of metric increments of the examined muscle in particular age classes.
RESULTS
In the studied period of prenatal ontogenesis, MPLs of the foetuses increased by about 60% in the length and width dimension and by about 100% in the thickness dimension. The topography of the initial and final muscle attachment was also evaluated. Statistically significant dimorphic differences were found in some aspects of muscle attachment topography.
CONCLUSIONS
The analysis of the place of the origin and insertion of MPL showed a relatively large variety of these features.
Topics: Female; Fetus; Humans; Leg; Male; Muscle, Skeletal; Pregnancy
PubMed: 33124032
DOI: 10.5603/FM.a2020.0129 -
Considering the Effects and Maternofoetal Implications of Vascular Disorders and the Umbilical Cord.Medicina (Kaunas, Lithuania) Nov 2022The umbilical cord is a critical anatomical structure connecting the placenta with the foetus, fulfilling multiple functions during pregnancy and hence influencing... (Review)
Review
The umbilical cord is a critical anatomical structure connecting the placenta with the foetus, fulfilling multiple functions during pregnancy and hence influencing foetal development, programming and survival. Histologically, the umbilical cord is composed of three blood vessels: two arteries and one vein, integrated in a mucous connective tissue (Wharton's jelly) upholstered by a layer of amniotic coating. Vascular alterations in the umbilical cord or damage in this tissue because of other vascular disorders during pregnancy are worryingly related with detrimental maternofoetal consequences. In the present work, we will describe the main vascular alterations presented in the umbilical cord, both in the arteries (Single umbilical artery, hypoplastic umbilical artery or aneurysms in umbilical arteries) and the vein (Vascular thrombosis, aneurysms or varicose veins in the umbilical vein), together with other possible complications (Velamentous insertion, vasa praevia, hypercoiled or hypocoiled cord, angiomyxoma and haematomas). Likewise, the effect of the main obstetric vascular disorders like hypertensive disorders of pregnancy (specially pre-eclampsia) and chronic venous disease on the umbilical cord will also be summarized herein.
Topics: Pregnancy; Female; Humans; Umbilical Cord; Umbilical Arteries; Umbilical Veins; Placenta; Fetus; Obstetric Labor Complications
PubMed: 36556956
DOI: 10.3390/medicina58121754