Normal fetal motility: an overview

Made to move: A review of measurement strategies to characterize heterogeneity in normal fetal movement

Fetal movement is a crucial indicator of fetal well-being. Characteristics of fetal movement vary across gestation, posing challenges for researchers to determine the most suitable assessment of fetal movement for their study. We summarize the current measurement strategies used to assess fetal movement and conduct a comprehensive review of studies utilizing these methods. We critically evaluate various measurement approaches including subjective maternal perception, ultrasound, Doppler ultrasound, wearable technology, magnetocardiograms, and magnetic resonance imaging, highlighting their strengths and weaknesses. We discuss the challenges of accurately capturing fetal movement, which is influenced by factors such as differences in recording times, gestational ages, sample sizes, environmental conditions, subjective perceptions, and characterization across studies. We also highlight the clinical implications of heterogeneity in fetal movement assessment for monitoring fetal behavior, predicting adverse outcomes, and improving maternal attachment to the fetus. Lastly, we propose potential areas of future research to overcome the current gaps and challenges in measuring and characterizing abnormal fetal movement. Our review contributes to the growing body of literature on fetal movement assessment and provides insights into the methodological considerations and potential applications for research.

Systemic versus local patterns of limb joint articular morphology inferred from relative distances from morphological centroid

Joint morphogenesis is a complex process known to require the interaction of developmental cascades and mechanical loading, yet many details of this interaction are incompletely understood. While prior work has established populational patterns of joint morphological (co)variance, exploring how these patterns manifest within the individual provides information on the deployment of morphogenic processes as either systemic or local influences on joint shape. To better identify the patterns of variance-generating morphogenic processes, this study investigates the degree to which individual joint shapes deviate from population averages systematically across the body. Using three-dimensional landmark data from 200 adult skeletons, we ranked individuals based on their distances from morphological centroids for eight major joints. Spearman correlations assessed associations between ranks across various articular pairings, testing hypotheses regarding systemic versus localized variance. Results reveal low coordination between deviations observed in conarticular surfaces, functional analogs, and same-bone surfaces; however strong associations exist between antimeres, suggesting the left-right deployment of variance-generating morphogenic patterns is highly consistent. These results support a model of localized rather than systemic processes driving variation in joint shape. While more remains to be elucidated about the specifics of articular surface morphogenesis, these findings advance our understanding of the systems of variance generation at play during development and growth of our definitive joint morphology.

Prenatal diagnosis (or lack thereof) of arthrogryposis multiplex congenita and its impact on the perinatal experience of parents: A retrospective survey

OBJECTIVE

To examine parental experiences during pregnancies affected by Arthrogryposis Multiplex Congenita (AMC) by identifying commonalities, risk factors, and areas for improvement in detection rates, care protocols, and patient experience.

STUDY DESIGN

An online survey was distributed via AMC support groups on Facebook. Topics included demographics, risk factors, parental recall of sonographic findings, delivery characteristics and neonatal findings. Responses were divided into antenatally detected cases (ADCs) and postnatally detected cases (PDCs). Quantitative responses were analyzed with the Fisher exact test. Qualitative data were analyzed with thematic analysis.

RESULTS

The antenatal detection rate of arthrogryposis was 37%. Decreased fetal movement was reported by 53% and early bleeding by 21%. Sonographic findings in ADCs included clubfoot (83%), clenched hand (51%), decreased fetal movement (50%), elbow contracture (51%), and knee contracture (46%). Among ADCs, 29% delivered vaginally and 71% delivered by cesarean versus PDCs (44% vaginal, 56% cesarean). Neonatal intensive care unit admission rate was 63%. Bone fracture occurred in 9%. Detection led to a planned change in delivery mode in 33% and location in 50%. Among ADCs, 17% felt their concerns were not adequately addressed versus 43% of PDCs.

CONCLUSIONS

Antenatal detection of arthrogryposis was low. We propose enhanced screening criteria to aid prenatal diagnosis and promote utilization of more robust practice guidelines.

Decoding the spatiotemporal regulation of transcription factors during human spinal cord development

The spinal cord is a crucial component of the central nervous system that facilitates sensory processing and motor performance. Despite its importance, the spatiotemporal codes underlying human spinal cord development have remained elusive. In this study, we have introduced an image-based single-cell transcription factor (TF) expression decoding spatial transcriptome method (TF-seqFISH) to investigate the spatial expression and regulation of TFs during human spinal cord development. By combining spatial transcriptomic data from TF-seqFISH and single-cell RNA-sequencing data, we uncovered the spatial distribution of neural progenitor cells characterized by combinatorial TFs along the dorsoventral axis, as well as the molecular and spatial features governing neuronal generation, migration, and differentiation along the mediolateral axis. Notably, we observed a sandwich-like organization of excitatory and inhibitory interneurons transiently appearing in the dorsal horns of the developing human spinal cord. In addition, we integrated data from 10× Visium to identify early and late waves of neurogenesis in the dorsal horn, revealing the formation of laminas in the dorsal horns. Our study also illuminated the spatial differences and molecular cues underlying motor neuron (MN) diversification, and the enrichment of Amyotrophic Lateral Sclerosis (ALS) risk genes in MNs and microglia. Interestingly, we detected disease-associated microglia (DAM)-like microglia groups in the developing human spinal cord, which are predicted to be vulnerable to ALS and engaged in the TYROBP causal network and response to unfolded proteins. These findings provide spatiotemporal transcriptomic resources on the developing human spinal cord and potential strategies for spinal cord injury repair and ALS treatment.

Women's perception of fetal movements and perinatal outcomes: results of a prospective cohort study

BACKGROUND

Active fetal movements (AFMs) are a sign of the well-being of the baby during pregnancy and suggests the integrity of the cardiovascular, musculoskeletal, and nervous systems of the fetus. The abnormal perception of AFMs is associated with an increased risk of adverse perinatal outcomes such as stillbirth (SB) and brain damage. Several definitions of " decreased fetal movements" have been proposed, but none of them has been universally accepted. The aim of the study is to investigate the perinatal outcomes in relation to AFMs frequency and perception in term pregnancy with an ad hoc questionnaire administered to the women before delivery.

STUDY DESIGN

This was a prospective case-control study on pregnant women at term referring to the Obstetric Unit of the University Hospital of Modena, Italy, between January 2020 and March 2020. A validated questionnaire was administered to women who agreed to participate in the study. Therefore, women were subdivided into the case and control groups: cases included women who experienced adverse perinatal outcomes (APO) such as perinatal mortality (SB and early neonatal mortality), operative delivery (cesarean section or vacuum) due to fetal distress, Apgar 5' < 7, neonatal resuscitation at birth and NICU Admission, while controls were women who experienced delivery and birth without APO in the same period.

RESULTS

Seventy-seven cases and 178 controls that compiled the questionnaire were included in the analysis. Characteristics significantly associated with APO were low education (OR 1.57, CI 95% 1.11-2.22), nulliparity (OR 1.76, CI 95% 1.20-2.58), obesity (OR 1.55, CI 95% 1.10-2.17), neonatal male gender (OR 1.92 CI95% 1.33-2.78) and centile at birth (< 10° and >90°) (OR 2.77, 95%CI 2.17, 3.55). There was no association between any answer about strengths, frequency and vigor of perceived fetal movements and APO. Even any maternal perception of fetal hiccups or uterine contractions wasn't associated with APO. On the other hand, women who referred to frequent change positions during sleep (OR 1.55 CI95% 1.05-2.30) and women who snore (OR 1.43 CI95% 1.01-2.05) showed a statistically significant increase of APO.

CONCLUSIONS

Our data confirm the significant association between modifiable risk factors (such as obesity and low education) and APO. Thus, healthcare providers should be aware of the importance of intervention in reducing obesity, therefore snoring and related sleep apnea syndrome. Finally, changing position during sleep while not the perception of modified/reduced fetal movements significantly could induce the worst obstetric outcomes.

Safety of Magnetic Resonance Imaging in Pregnancy

Magnetic resonance imaging is being increasingly used to diagnose and follow up a variety of medical conditions in pregnancy, both for maternal and fetal indications. However, limited data regarding its safe use in pregnancy may be a source of anxiety and avoidance for both patients and their healthcare providers. In this review, we critically discuss the main safety concerns of Magnetic Resonance Imaging (MRI) in pregnancy including energy deposition, acoustic noise, and use of contrast agents, supported by data from animal and human studies. Use of maternal sedatives and concerns related to occupational exposure in pregnant personnel are also addressed. Exposure to gadolinium-based contrast agents and sedation for MRI during pregnancy should be avoided whenever feasible.

Congenital hypotonia: systematic approach for prenatal detection

OBJECTIVES

Congenital hypotonic conditions are rare and heterogeneous, and some are severely debilitating or lethal. Contrary to its prominent postnatal manifestation, the prenatal presentation of hypotonia is frequently subtle, inhibiting prenatal detection. We aimed to characterize the prenatal sonographic manifestation of congenital hypotonia throughout pregnancy, evaluate the yield of diagnostic tests and propose diagnostic models to increase its prenatal detection.

METHODS

This was a retrospective observational study of singleton pregnancies with congenital hypotonia, diagnosed either prenatally or immediately after birth, at a single tertiary center between the years 2012 and 2020. Prenatally, hypotonia was diagnosed if a fetus showed sonographic or clinical signs suggestive of hypotonia and had a confirmed underlying genetic condition, or in the absence of a known genetic abnormality if the fetus exhibited multiple prominent signs suggestive of hypotonia. Postnatally, it was diagnosed in neonates displaying reduced muscle tone leading to reduced spontaneous movement, reduced swallowing or feeding difficulty. We reviewed the medical records of pregnant patients carrying fetuses subsequently diagnosed with congenital hypotonia and assessed the yield of ultrasound scans, fetal magnetic resonance imaging, computed tomography and genetic tests. The detection rate of sonographic signs suggesting fetal hypotonia was calculated. The prevalence of non-specific signs, including polyhydramnios, persistent breech presentation, intrauterine growth restriction and maternal perception of reduced fetal movement, were compared between the study group and the local liveborn singleton population. Potential detection rates of different theoretical semiotic diagnostic models, differing in the threshold for referral for a targeted scan, were assessed based on the cohort's data.

RESULTS

The study group comprised 26 cases of congenital hypotonia, of which 10 (38.5%) were diagnosed prenatally, and the controls included 95 105 singleton live births, giving a prevalence of congenital hypotonia of 1:3658. Nuchal translucency thickness and the early anomaly scan at 13-17 weeks were normal in all 22 and 23 cases, respectively, in which this was performed. The mid-trimester scan performed at 19-25 weeks was abnormal in four of 24 (16.7%) cases. The overall prenatal detection rate of congenital hypotonic conditions in our cohort was 38.5%. Only cases which underwent a targeted scan were detected and, among the 16 cases which underwent this scan, the prenatal detection rate was 62.5% compared with 0% in pregnancies that did not undergo this scan (P = 0.003). An abnormal genetic diagnosis was obtained in 21 (80.8%) cases using the following modalities: chromosomal microarray analysis (CMA) in two (9.5%), whole-exome sequencing (WES) in 14 (66.7%) and methylation analysis in five (23.8%). CMA was abnormal in 8% (2/25) of the cases and WES detected a causative genetic mutation in 87.5% (14/16) of the cases in which these were performed. Comparison of non-specific signs in the study group with those in the local singleton population showed that hypotonic fetuses had significantly more polyhydramnios (64.0% vs 3.0%, P < 0.0001), persistent breech presentation (58.3% vs 4.2%, P < 0.0001), intrauterine growth restriction (30.8% vs 3.0%, P < 0.0001) and maternal perception of reduced fetal movement (32.0% vs 4.7%, P < 0.0001). Prenatally, the most commonly detected signs supporting a diagnosis of hypotonia were structural anomaly (62.5%, 10/16), reduced fetal movement (46.7%, 7/15), joint contractures (46.7%, 7/15) and undescended testes ≥ 30 weeks (42.9%, 3/7 males). Proposed diagnostic strategies that involved performing a targeted scan for a single non-specific ultrasound sign or two such signs, and then carrying out a comprehensive genetic evaluation for any additional sign, offered theoretical detection rates in our cohort of 88.5% and 57.7%, respectively.

CONCLUSIONS

Congenital hypotonic conditions are rare and infrequently detected prenatally. Sonographic signs are visible from the late second trimester. A targeted scan increases prenatal detection significantly. Comprehensive genetic testing, especially WES, is the cornerstone of diagnosis in congenital hypotonia. Theoretical diagnostic models which may increase prenatal detection are provided. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal arthrogryposis-what do we tell the prospective parents?

Arthrogryposis, also termed arthrogryposis multiplex congenita, is a descriptive term for conditions with multiple congenital contractures (MCC). The etiology is extremely heterogeneous. More than 400 specific disorders have been identified so far, which may lead to or are associated with MCC and/or fetal hypo- and akinesia as a clinical sign. With improved sensitivity of prenatal ultrasound and expanding prenatal diagnostic options, clinicians are tasked with providing early detection in order to counsel the prospective parents regarding further prenatal diagnostic as well as management options. We summarize the most important knowledge to raise awareness for early detection in pregnancy. We review essential points for counseling when MCC is detected in order to provide answers to common questions, which, however, cannot replace interdisciplinary expert opinion in the individual case.

Eye-tracking visual patterns of sonographers with and without fetal motor assessment expertise

OBJECTIVES

Fetal motor assessment (FMA) in addition to structural anomaly scan enhances prenatal detection of arthrogryposis multiplex congenita (AMC). In the Amsterdam UMC, sonographers are trained to perform FMA. We examined the effect of motor assessment training by comparing sonographers with (SMA) and without this training (S) on their qualitative motor assessment in fetuses with normal (FNM) and abnormal motility (FAM) and their visual processing by eye-tracking.

METHODS

The study was performed from 2019 to 2020. Five SMA and five S observed five FNM and five FAM videos. Qualitative FMA consisted of six aspects of the general movement and the overall conclusion normal or abnormal. The visual processing aspects examined through eye-tracking were fixation duration, number of revisits per region of interest (ROI) and scanpaths of saccades between fixation points.

RESULTS

Quality assessment by SMA revealed more correct aspects in FNM than in FAM but overall conclusions were equally correct (92-96 %). S scored aspects of FNM better than in FAM, but overall conclusion correct only in half of FNM and three quarters of FAM. Eye-tracking of SMA and S showed fixation duration and revisits with similar distributions per ROIs for FNM and FAM, but SMA perform more trunk revisits in FNM. Scanpaths had smaller circumference, less outliers and more consistency in SMA than S.

CONCLUSION

This modest population of qualified sonographers showed that additional FMA training improved qualitative motor assessment. Eye-tracking revealed differences in visual processing and stimulates continuous education for professionals active in the detection of these rare diseases.

Prenatal Diagnosis of Williams-Beuren Syndrome Based on Suspected Fetal Hypotonia in Early Pregnancy

In this report, we describe a rare case of prenatal diagnosis of Williams-Beuren syndrome (WBS). While the prenatal diagnosis of WBS is very rare, in the current case, WBS was diagnosed in early pregnancy. The key element was the detection of fetal hands hypotonia and generalized fetal hypotonia at 17 weeks of gestation. This led to the diagnosis of WBS by molecular karyotyping, specifically array comparative genomic hybridization (arrayCGH) of the fetal DNA. The genetic material was acquired by extraction from the fetal cells which are abundant in the amniotic fluid drawn by amniocentesis. Clinical hypotonia of the affected individuals is a clinical characteristic that is widely associated with WBS; however, fetal hypotonia has not been described as a diagnostic criterion for the prenatal diagnosis of WBS.

Building a Co-ordinated Musculoskeletal System: The Plasticity of the Developing Skeleton in Response to Muscle Contractions

The skeletal musculature and the cartilage, bone and other connective tissues of the skeleton are intimately co-ordinated. The shape, size and structure of each bone in the body is sculpted through dynamic physical stimuli generated by muscle contraction, from early development, with onset of the first embryo movements, and through repair and remodelling in later life. The importance of muscle movement during development is shown by congenital abnormalities where infants that experience reduced movement in the uterus present a sequence of skeletal issues including temporary brittle bones and joint dysplasia. A variety of animal models, utilising different immobilisation scenarios, have demonstrated the precise timing and events that are dependent on mechanical stimulation from movement. This chapter lays out the evidence for skeletal system dependence on muscle movement, gleaned largely from mouse and chick immobilised embryos, showing the many aspects of skeletal development affected. Effects are seen in joint development, ossification, the size and shape of skeletal rudiments and tendons, including compromised mechanical function. The enormous plasticity of the skeletal system in response to muscle contraction is a key factor in building a responsive, functional system. Insights from this work have implications for our understanding of morphological evolution, particularly the challenging concept of emergence of new structures. It is also providing insight for the potential of physical therapy for infants suffering the effects of reduced uterine movement and is enhancing our understanding of the cellular and molecular mechanisms involved in skeletal tissue differentiation, with potential for informing regenerative therapies.

Maternal perception of fetal movements: onset and associated factors

OBJECTIVES

The purpose of this study was to determine the onset of fetal movements' perception and to identify parameters that affect this timing.

METHODS

This was a prospective cohort study including singleton pregnancies that attended routine prenatal care, in a tertiary care center, in northern Greece, between January 2020 and July 2021. We collected data on medical and obstetric history, and invited women to record the time that they perceived the fetal movements for the first time, that being the primary outcome of the study. Furthermore, we studied the associations between this timing and several obstetric and sociodemographic parameters.

RESULTS

In total, 2,009 women participated in the study. The mean gestational age at first perception of fetal movements was 19 weeks (±1.5). This ranged from as early as 14⁺⁰-14⁺⁶ weeks (0.1%) to 24⁺⁰-24⁺⁶ weeks (0.1%). The majority of women (73.3%) reported initial perception of fetal movements between 18⁺⁰ and 20⁺⁶ weeks. Following multivariate logistic regression analysis, we found that nulliparity (OR: 2.607; 95% CI: 1.876-3.622; p<0.001), anterior placental position (OR: 1.918; 95% CI: 1.575-2.336; p<0.001), increasing body mass index (OR: 1.063; 95% CI: 1.040-1.088; p=0.001) and advancing maternal age (OR: 1.062; 95% CI: 1.040-1.084; p<0.001) were associated with a delayed perception of fetal movements. Multiparous women reported the onset of fetal movements almost one week earlier on average (18.6±1.4 weeks) compared to nulliparous (19.4±1.4 weeks; MD: 0.843; 95% CI: 0.718-0.968; p<0.001).

CONCLUSIONS

The onset of maternal perception of fetal movements is around 19 weeks and this timing may be delayed by higher maternal age, higher body mass index, nulliparity and anterior placental position.

Three-dimensional visualization and quantitative analysis of embryonic and fetal thigh muscles using magnetic resonance and phase-contrast X-ray imaging

The musculoskeletal system around the human hip joint has acquired a suitable structure for erect bipedal walking. However, little is known about the process of separation and maturation of individual muscles during the prenatal period, when muscle composition is acquired. Understanding the maturation process of the normal musculoskeletal system contributes to elucidating the acquisition of bipedal walking in humans and to predicting normal growth and detecting congenital muscle disorders and anomalies. In this study, we clarify the process of thigh muscle maturation from the embryonic stage to the mid-fetal stage using serial sections, phase-contrast X-ray computed tomography, and magnetic resonance imaging. We also provide a 4D atlas of human thigh muscles between 8 and 23 weeks of gestation. As a result, we first show that muscle separation in the lower thigh tends to progress from the superficial to the deep layers and that all musculoskeletal components are formed by Carnegie Stage 22. Next, we show that femur and muscle volume grow in correlation with crown-rump length. Finally, we show that the anterior, abductor, and posterior muscle groups in the thigh contain a high percentage of monoarticular muscle volume by the end of the embryonic period. This ratio approaches that of adult muscle composition during normal early fetal development and is typical of bipedal walking. This study of fetal muscle composition suggests that preparation for postnatal walking may begin in early fetal period.

Association of fetal eye movement density with sleeping and developmental problems in 1.5-year-old infants

Eye movement density (EMD) is an evaluation index of rapid eye movements observed during sleep. This study aimed to investigate the association of fetal EMD with sleeping and developmental problems in infancy. We observed 60 normal singleton pregnancies (gestational age 28-37 weeks) using ultrasonography for 1 h. Fetal eye movements were counted, and EMD was calculated. Participants answered questionnaires regarding their child's sleep and development 1.5 years after their delivery. The outcomes of an infant's sleep were night awakening (yes or no), bedtime (before or after 22:00), and nighttime sleep duration (< 9 or ≥ 9 h). An infant's development was evaluated using the Child Behavior Checklist (CBCL) T-score. We found that decreased fetal EMD was associated with increased night awakening at the age of 1.5 years (odds ratio 0.84, 95% confidence interval 0.69-1.00 per unit decrease in EMD). However, fetal EMD was not associated with bedtime or nighttime sleep duration. In addition, fetal EMD was independently associated with the total problems T-score of the CBCL at the age of 1.5 years in the multivariate model (p = 0.047). In conclusion, fetal EMD may be associated with sleep and developmental problems in infants.

Computation of Fetal Kicking in Various Fetal Health Examinations: A Systematic Review

Fetal movement has always been considered an essential indicator to evaluate the health of the unborn fetus. Many factors affect fetal movement. The frequency of fetal kicking is an important measurement of whether fetal development is progressing and healthy. Various instruments and methods of detecting fetal movement have been used and each method has its advantages and disadvantages. Although limited by the fetal environment in utero, the finite element method and musculoskeletal model can be used to calculate fetal lower limb movement. This review aims to summarize the current detection techniques for fetal movement, especially in the lower limbs. These will be outlined by describing the different measurements of fetal movement, and the related biomechanical analyses of fetal lower limb skeletogenesis and the associated muscular development to better evaluate and calculate the movements of the fetus in the womb.

Active head lifting from supine in infancy in the general population: Red flag or not?

BACKGROUND

Previously it had been had reported that active head lifting from supine (AHLS) in high-risk infants was associated with lower cognitive scores in the second year. AHLS was generally accompanied by stereotyped leg movements.

AIMS

To examine in a standardized way whether AHLS with or without stereotyped leg movements in the general population is associated with prenatal, perinatal, neonatal and socio-economic risk factors or with lower scores on concurrent infant tests.

STUDY DESIGN

Cross-sectional study SUBJECTS: 1700 infants aged 2-18 months representative of the Dutch population.

OUTCOME MEASURES

Infant Motor Profile (IMP) and Standardized Infant NeuroDevelopmental Assessment (SINDA). Assessments were video-recorded and included at the youngest ages 3min of behaviour in supine. AHLS and the presence of stereotyped leg movements were recorded. Standardized information on early risk factors was available.

RESULTS

AHLS occurred at 4-9 months (prevalence per months: 1-14%; highest prevalence at 6 months). It was not associated with early risk factors or scores on infant tests. When AHLS was accompanied by stereotyped leg movements it was associated with a higher prevalence of an IMP-variation score < P15 (Odds Ratio (OR) 2.472 [95%CI 1.017; 6.006]). Stereotyped leg movements irrespective of AHLS were associated with more unfavourable total IMP scores and IMP performance scores (B coefficients -3.212 [-4.065; -2.360], -2.521 [-3.783; -1.259]) and IMP variation and SINDA neurological scores (ORs 5.432 [3.409; 8.655], 3.098 [1.548; 6.202]).

CONCLUSIONS

The data suggest that AHLS is not a red flag. Rather its co-occurring stereotyped leg movements may signal less favourable neurodevelopment.

Care pathway for fetal joint contractures, Fetal Akinesia Deformation Sequence and Arthrogryposis Multiplex Congenita

Introduction The majority of arthrogryposis multiplex congenita (AMC) and lethal forms of AMC such as fetal akinesia deformation sequence (FADS) cases are missed prenatally. We have demonstrated the additional value of fetal motor assessment and evaluation in a multidisciplinary team for the period 2007-2016. An applied care pathway for fetuses presenting with joint contracture(s) in one anatomic region (e.g. talipes equinovares), more than one body part with non-progressive contractures and motility (AMC) and with deterioration over time (FADS). Methods The multidisciplinary team of Amsterdam University Medical Centre Expertise Centre FADS and AMC developed the care pathway. Additional tools are provided including a motor assessment by ultrasound examination and postmortem assessment form. Results An eight-step care pathway is presented with a proposed timing for prenatal sonographic examination, genetic examinations, multidisciplinary meetings, prenatal and postnatal counselling of the parents by specialist also treating after birth, follow-up of prenatal and postnatal findings with counselling for future pregnancies. Discussion/conclusion The scheduled serial structural and motor sonograpahic assessment together with follow-up examinations and genetic analysis, should be tailored per prenatal centre per available resources. The multidisciplinary care pathway may pave the way to increase detection rate and diagnosis of isolated contracture(s), talipes equinovares with underlying genetic causes and the rare phenotypes AMC/FADS and prompt treatment after birth within expertise teams.

Kinematic Comparison on Lower Limb Kicking Action of Fetuses in Different Gestational Weeks: A Pilot Study

The fetal movements during different gestational weeks are essential for normal musculoskeletal development. The kinematic characteristics of fetuses with small differences in gestational weeks may be different and important. Ultrasonographic videos of fetal kicking action and plantarflexion action were collected from three healthy pregnant women (24, 27, and 30 gestational weeks) with normal fetal development. The kinematic characteristics, including angular range and angular velocity, were analyzed. These kinematic parameters were measured using simi motion. The final knee angle was found to decrease with progressive gestational weeks. Compared with 24 w, the knee joint angle at 27 w and 30 w was significantly reduced at the end of a kick-type movement (p < 0.01). Except for the mean angular velocity of the knee joint, there were no significant differences in the other conditions. The value at 30 w for mean angular velocity was significantly higher than that at 24 w (p = 0.02). In the ankle joint, no significant differences were observed between different conditions. Therefore, we can conclude that there was no significant difference in the kinematic characteristics of the ankle joint for small gestational age gaps, but there was a significant difference in the knee joint. As the gestation weeks increase, the range of kicking motion tends to decrease. The reason may be that with the increase of gestational weeks, fetal lower limb musculoskeletal development is gradually enhanced; the slower growth rate indicates that development reaches a peak level in weeks 24 to 30.

Indications for Outpatient Antenatal Fetal Surveillance: ACOG Committee Opinion, Number 828

ABSTRACT

The purpose of this Committee Opinion is to offer guidance about indications for and timing and frequency of antenatal fetal surveillance in the outpatient setting. Antenatal fetal surveillance is performed to reduce the risk of stillbirth. However, because the pathway that results in increased risk of stillbirth for a given condition may not be known and antenatal fetal surveillance has not been shown to improve perinatal outcomes for all conditions associated with stillbirth, it is challenging to create a prescriptive list of all indications for which antenatal fetal surveillance should be considered. This Committee Opinion provides guidance on and suggests surveillance for conditions for which stillbirth is reported to occur more frequently than 0.8 per 1,000 (the false-negative rate of a biophysical profile) and which are associated with a relative risk or odds ratio for stillbirth of more than 2.0 compared with pregnancies without the condition. Table 1 presents suggestions for the timing and frequency of testing for specific conditions. As with all testing and interventions, shared decision making between the pregnant individual and the clinician is critically important when considering or offering antenatal fetal surveillance for individuals with pregnancies at high risk for stillbirth or with multiple comorbidities that increase the risk of stillbirth. It is important to emphasize that the guidance offered in this Committee Opinion should be construed only as suggestions; this guidance should not be construed as mandates or as all encompassing. Ultimately, individualization about if and when to offer antenatal fetal surveillance is advised.

Canadian Association of Radiologists Recommendations for the Safe Use of MRI During Pregnancy

The use of magnetic resonance imaging (MRI) during pregnancy is associated with concerns among patients and health professionals with regards to fetal safety. In this work, the Canadian Association of Radiologists (CAR) Working Group on MRI in Pregnancy presents recommendations for the use of MRI in pregnancy, derived from literature review as well as expert panel opinions and discussions. The working group, which consists of academic subspecialty radiologists and obstetrician-gynaecologists, aimed to provide updated, evidence-based recommendations addressing safety domains related to energy deposition, acoustic noise, and gadolinium-based contrast agent use based on magnetic field strength (1.5T and 3T) and trimester scanned, in addition to the effects of sedative use and occupational exposure.

Sleep-wake regulation in preterm and term infants

Study Objectives

In adults, wakefulness can be markedly prolonged at the expense of sleep, e.g. to stay vigilant in the presence of a stressor. These extra-long wake bouts result in a heavy-tailed distribution (highly right-skewed) of wake but not sleep durations. In infants, the relative importance of wakefulness and sleep are reversed, as sleep is necessary for brain maturation. Here, we tested whether these developmental pressures are associated with the unique regulation of sleep–wake states.

Methods

In 175 infants of 28–40 weeks postmenstrual age (PMA), we monitored sleep–wake states using electroencephalography and behavior. We constructed survival models of sleep–wake bout durations and the effect of PMA and other factors, including stress (salivary cortisol), and examined whether sleep is resilient to nociceptive perturbations (a clinically necessary heel lance).

Results

Wake durations followed a heavy-tailed distribution as in adults and lengthened with PMA and stress. However, differently from adults, active sleep durations also had a heavy-tailed distribution, and with PMA, these shortened and became vulnerable to nociception-associated awakenings.

Conclusions

Sleep bouts are differently regulated in infants, with especially long active sleep durations that could consolidate this state’s maturational functions. Curtailment of sleep by stress and nociception may be disadvantageous, especially for preterm infants given the limited value of wakefulness at this age. This could be addressed by environmental interventions in the future.

Fetal Movement Counting Using Optical Fibre Sensors

Daily fetal movement counting based on maternal perception is widely deployed to monitor fetal wellbeing. However, the counting performed by the mother is prone to errors for various reasons. There are limited devices on the market that can provide reliable and automatic counting. This paper presents a prototype of a novel fetal movement monitoring device based on fibre Bragg grating sensors. Deformation of the skin caused by a fetal movement can lead to a change of the strain and stress on the optical fibre sensors, therefore can induce distortions to the breathing pattern of the mother. In the study data was gathered by the sensors through strain measurement and was post-processed using independent component analysis (ICA) and high-pass filtering to show the instances of the fetal movements. Information gathered during user trials with the prototype suggests that the system detects significantly higher numbers of fetus movements than that observed based on the mother's perception. Among the various techniques available for fetal movement monitoring, fibre optic sensing provides many advantages including multiplex capability, flexibility and minimal size, making the concept an attractive solution for reliable monitoring of antenatal fetal movements.

Development of motor circuits: From neuronal stem cells and neuronal diversity to motor circuit assembly

In this review, we discuss motor circuit assembly starting from neuronal stem cells. Until recently, studies of neuronal stem cells focused on how a relatively small pool of stem cells could give rise to a large diversity of different neuronal identities. Historically, neuronal identity has been assayed in embryos by gene expression, gross anatomical features, neurotransmitter expression, and physiological properties. However, these definitions of identity are largely unlinked to mature functional neuronal features relevant to motor circuits. Such mature neuronal features include presynaptic and postsynaptic partnerships, dendrite morphologies, as well as neuronal firing patterns and roles in behavior. This review focuses on recent work that links the specification of neuronal molecular identity in neuronal stem cells to mature, circuit-relevant identity specification. Specifically, these studies begin to address the question: to what extent are the decisions that occur during motor circuit assembly controlled by the same genetic information that generates diverse embryonic neuronal diversity? Much of the research addressing this question has been conducted using the Drosophila larval motor system. Here, we focus largely on Drosophila motor circuits and we point out parallels to other systems. And we highlight outstanding questions in the field. The main concepts addressed in this review are: (1) the description of temporal cohorts-novel units of developmental organization that link neuronal stem cell lineages to motor circuit configuration and (2) the discovery that temporal transcription factors expressed in neuronal stem cells control aspects of circuit assembly by controlling the size of temporal cohorts and influencing synaptic partner choice.

A Novel Fetal Movement Simulator for the Performance Evaluation of Vibration Sensors for Wearable Fetal Movement Monitors

Fetal movements (FM) are an important factor in the assessment of fetal health. However, there is currently no reliable way to monitor FM outside clinical environs. While extensive research has been carried out using accelerometer-based systems to monitor FM, the desired accuracy of detection is yet to be achieved. A major challenge has been the difficulty of testing and calibrating sensors at the pre-clinical stage. Little is known about fetal movement features, and clinical trials involving pregnant women can be expensive and ethically stringent. To address these issues, we introduce a novel FM simulator, which can be used to test responses of sensor arrays in a laboratory environment. The design uses a silicon-based membrane with material properties similar to that of a gravid abdomen to mimic the vibrations due to fetal kicks. The simulator incorporates mechanisms to pre-stretch the membrane and to produce kicks similar to that of a fetus. As a case study, we present results from a comparative study of an acoustic sensor, an accelerometer, and a piezoelectric diaphragm as candidate vibration sensors for a wearable FM monitor. We find that the acoustic sensor and the piezoelectric diaphragm are better equipped than the accelerometer to determine durations, intensities, and locations of kicks, as they have a significantly greater response to changes in these conditions than the accelerometer. Additionally, we demonstrate that the acoustic sensor and the piezoelectric diaphragm can detect weaker fetal movements (threshold wall displacements are less than 0.5 mm) compared to the accelerometer (threshold wall displacement is 1.5 mm) with a trade-off of higher power signal artefacts. Finally, we find that the piezoelectric diaphragm produces better signal-to-noise ratios compared to the other two sensors in most of the cases, making it a promising new candidate sensor for wearable FM monitors. We believe that the FM simulator represents a key development towards enabling the eventual translation of wearable FM monitoring garments.

Prognostic significance of prenatal ultrasound in fetal arthrogryposis multiplex congenita

Purpose

Fetal arthrogryposis multiplex congenita (AMC) describes a heterogeneous disease entity characterized by multiple contractures affecting at least two different body areas. The aim of our study was to identify additional sonographic abnormalities in fetuses with AMC Type I–III associated with an unfavorable prognosis and to describe when those signs were first detected.

Methods

This retrospective study included 41 pregnancies of suspected AMC diagnosed 1999–2017 at our tertiary referral center. The affected pregnancies were divided into the 3 AMC subgroups; the time of detection and outcome were analyzed. Prenatal sonograms, pediatric charts, genetic tests, and autopsy reports were studied.

Results

Pregnancy outcome data were verifiable in 34 out of 41 cases; in 27 cases, AMC was confirmed. Hydrops was present in 50% of postnatally deceased fetuses, 53% of cases resulting in termination of pregnancy vs. 0% of the surviving 8 children. Absent stomach filling was found in 67% of the children with neonatal death. After subcategorization, the limb-involvement-only-group, 8% showed hydrops vs. 100% in system anomaly group vs. 70% in neuromuscular dysfunction cohort (p = 0.001). Scoliosis, nuchal edema, and absent stomach filling were significantly indicating for a neurological etiology.

Conclusion

In addition to disease-defining sonographic findings, those with prognostic significance were identified. Hydrops, nuchal edema, scoliosis and absent stomach filling were associated with unfavorable outcomes implicating a neuromuscular etiology. This knowledge can help to predict the further course of the disease and support patient counseling.

Effect of umbilical cord length on early fetal biomechanics

The umbilical cord suspends the fetus within the amniotic cavity, where fetal dynamics is one of its many functions. Hence, the umbilical cord is a viable index in determining fetal activity. Fetal movements result in mechanical loads that are fundamental for fetal growth. At present, mechanical environment during early human fetal development is still largely unknown. To determine early fetal movement dynamics at given physiological (0.060 m) and pathological umbilical cord lengths (0.030 m, 0.020 m, 0.017 m and 0.014 m) a 2D computational model was created to simulate dynamic movement conditions. Main findings of this computational model revealed the shortest umbilical cord length (0.014 m) with a 6(10-6)N, twitch force amplitude had a two-fold increase on linear velocity (0.12 m/s) in comparison with other lengths (0.05m/s). Moreover, umbilical cord length effect presented an increasing exponential tension on the fetus body wall from longest to shortest, from 0 N in the control length to 0.05 N for the shortest umbilical cord. Last, tension was always present over a period of time for the shortest cord (0.03 N to 0.08 N). Collectively, for all variables evaluated the shortest umbilical cord (0.014 m) presented remarkable differences with other lengths in particular with the second shortest umbilical cord (0.017 m), suggesting a 0.003 m difference represents a greater biomechanical effect. In conclusion, this computational model brings new insights required by clinicians, where the magnitude of these loads could be associated with different pathologies found in the clinic.

In vitro chondral culture under compression and shear stimuli. From mesenchymal stem cells to hyaline cartilage

INTRODUCTION

The in vitro creation of hyaline joint cartilage is a challenge since, to date, the ex vivo synthesis of a structured tissue with the same biomechanical and histological properties of the joint cartilage has not been achieved. To simulate the physiological conditions we have designed an in vitro culture system that reproduces joint movement.

MATERIAL AND METHOD

We have developed a cell culture bioreactor that prints a mechanical stimulus on an elastin matrix, in which mesenchymal stem cells (MSC) are embedded. The first phase of study corresponds to the development of a bioreactor for hyaline cartilage culture and the verification of cell viability in the elastin matrix in the absence of stimulus. The second phase of the study includes the MSC culture under mechanical stimulus and the analysis of the resulting tissue.

RESULTS

After culture under mechanical stimulation we did not obtain hyaline tissue due to lack of cellularity and matrix destructuring.

CONCLUSION

The stimulus pattern used has not been effective in generating hyaline cartilage, so other combinations should be explored in future research.

Long-range temporal organisation of limb movement kinematics in human neonates

OBJECTIVE

Movement provides crucial sensorimotor information to the developing brain, evoking somatotopic cortical EEG activity. Indeed, temporal-spatial organisation of these movements, including a diverse repertoire of accelerations and limb combinations (e.g. unilateral progressing to bilateral), predicts positive sensorimotor outcomes. However, in current clinical practice, movements in human neonates are qualitatively characterised only during brief periods (a few minutes) of wakefulness, meaning that the vast majority of sensorimotor experience remains unsampled. Here our objective was to quantitatively characterise the long-range temporal organisation of the full repertoire of newborn movements, over multi-hour recordings.

METHODS

We monitored motor activity across 2-4 h in 11 healthy newborn infants (median 1 day old), who wore limb sensors containing synchronised tri-axial accelerometers and gyroscopes. Movements were identified using acceleration and angular velocity, and their organisation across the recording was characterised using cluster analysis and spectral estimation.

RESULTS

Movement occurrence was periodic, with a 1-hour cycle. Peaks in movement occurrence were associated with higher acceleration, and a higher proportion of movements being bilateral.

CONCLUSIONS

Neonatal movement occurrence is cyclical, with periods consistent with sleep-wake behavioural architecture. Movement kinematics are organised by these fluctuations in movement occurrence. Recordings that exceed 1-hour are necessary to capture the long-range temporal organisation of the full repertoire of newborn limb movements.

SIGNIFICANCE

Future work should investigate the prognostic value of combining these movement recordings with synchronised EEG, in at-risk infants.

Impact of prematurity on neurodevelopment

The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.

Event-related potentials following contraction of respiratory muscles in pre-term and full-term infants

OBJECTIVE

Involuntary isolated body movements are prominent in pre-term and full-term infants. Proprioceptive and tactile afferent feedback following limb muscle contractions is associated with somatotopic EEG responses. Involuntary contractions of respiratory muscles, primarily the diaphragm - hiccups - are also frequent throughout the human perinatal period during active behavioural states. Here we tested whether diaphragm contraction provides afferent input to the developing brain, as following limb muscle contraction.

METHODS

In 13 infants on the neonatal ward (30-42 weeks corrected gestational age), we analysed EEG activity (18-electrode recordings in six subjects; 17-electrode recordings in five subjects; 16-electrode recordings in two subjects), time-locked to diaphragm contractions (n = 1316) recorded with a movement transducer affixed to the trunk.

RESULTS

All bouts of hiccups occurred during wakefulness or active sleep. Each diaphragm contraction evoked two initial event-related potentials with negativity predominantly across the central region, and a third event-related potential with positivity maximal across the central region.

CONCLUSIONS

Involuntary contraction of the diaphragm can be encoded by the brain from as early as ten weeks prior to the average time of birth.

SIGNIFICANCE

Hiccups - frequently observed in neonates - can provide afferent input to developing sensory cortices in pre-term and full-term infants.

Fronto-central slow cortical activity is attenuated during phasic events in rapid eye movement sleep at full-term birth

Delta and theta power across fronto-central regions is lower during phasic (saccadic eye movements) than tonic rapid eye movement (active) sleep in full-term infants (n = 15). This indicates that the behavioural-electrophysiological pillars of rapid eye movement sleep micro-architecture are in place at birth.

Human embryonic ribs all progress through common morphological forms irrespective of their position on the axis

BACKGROUND

We aimed to analyze the morphogenesis of all ribs from 1st to 12th rib pairs plus vertebrae to compare their differences and features according to the position along the cranial-caudal axis during the human embryonic period.

RESULTS

Rib pair formation was analyzed using high-resolution digitalized imaging data (n = 29) between Carnegie stage (CS) 18 and CS23 (corresponding to ED13-14 in mouse; HH29-35 in chick). A total of 348 rib pairs, from 1st to 12th rib pairs of each sample were subjected to Procrustes and principal component (PC) analyses. PC1 and PC2 accounted for 76.3% and 16.4% (total 92.7%) of the total variance, respectively, indicating that two components mainly accounted for the change in shape. The distribution of PC1 and PC2 values for each rib showed a "fishhook-like shape" upon fitting to a quartic equation. PC1 and PC2 value position for each rib pair moved along the fitted curve according to the development. Thus, the change in PC1 and PC2 could be expressed by a single parameter using a fitted curve as a linear scale for shape.

CONCLUSION

Human embryonic ribs all progress through common morphological forms irrespective of their position on the axis.

Early stages of development of the alar fascia (human specimens at 6-12 weeks of development)

In recent years, there has been much discussion concerning the cervical fasciae. The aim of this study is to confirm and to describe the development of the alar fascia as well as its relationship with nearby structures. Histological preparations of 25 human embryos (6-8 weeks of development) and 25 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. Our study confirms the existence of the alar fascia and permits three stages to be established during its development. The initial stage (1st), corresponding to the 6th week of development (Carnegie stages 18-19), is characterized by the beginning of the alar fascia primordium in the retroesophageal space at the level of C7-T1. In the formation stage (2nd), corresponding to the 7th and 8th weeks of development (Carnegie stages 20-23), the alar fascia primordium grows upwards and reaches the level of C2-C3. In the maturation stage (3rd), beginning in the 9th week of development, the visceral, alar and prevertebral fasciae can be identified. The alar fascia divides the retrovisceral space (retropharyngeal and retroesophageal) into two spaces: one anterior (between the alar fascia and the visceral fascia and extending from C1 to T1, named retropharyngeal or retroesophageal space according to the level) and the other posterior (between the alar fascia and the prevertebral fascia, named danger space). We suggest that this latter space be named the retroalar space. This study suggests that alar fascia development is related to mechanical factors and that the alar fascia permits the sliding of the pharynx and the oesophagus during swallowing.

Decreased fetal movements: Perinatal and long-term neurological outcomes

BACKGROUND

While maternal perception of decreased fetal movements during advanced stages of pregnancy may be an indicator for adverse perinatal outcome, the long-term neurological outcome of offspring of affected pregnancies remains largely unknown.

OBJECTIVE

To examine whether maternal complaint of decreased fetal movements is associated with adverse perinatal outcomes, and to assess the implications of decreased fetal movements on long-term neurological morbidity of the offspring.

STUDY DESIGN

A single center cohort analysis including deliveries between the years 1991-2014 was conducted. The association between decreased fetal movements and adverse perinatal outcome was evaluated using a general estimation equation (GEE) multivariable analyses. Incidence of hospitalizations (up to age 18 years) due to various neurological conditions was compared between offspring of affected pregnancies, and those who were not, using a Kaplan-Meyer survival curve. A Cox proportional hazards model was used to control for confounders.

RESULTS

439 (0.18%) of 242,342 deliveries included in this study were accompanied by maternal complaint of decreased fetal movements. Perinatal outcome was comparable between the groups, with no cases of perinatal mortality observed among the exposed group. Total neurological-related hospitalization rate of the offspring, as well as hospitalizations due to movement disorders, were higher among the exposed group (Kaplan-Meyer log-rank test P < 0.05). This association between decreased fetal movements and increased long-term neurological hospitalization proved to be independent of potential confounders with an adjusted hazard ratio of 1.54 (95% CI 1.0-2.37).

CONCLUSION

Maternal complaint of decreased fetal movements does not predict adverse perinatal outcome but is associated with an elevated risk for long-term neurological morbidity of the offspring.

Jaw-neck movement integration in 6-year-old children differs from that of adults

BACKGROUND

A functional integration between the jaw and neck regions during purposive jaw movements is well described in adults, but there is a lack of knowledge of such integration during jaw function in children.

OBJECTIVES

To determine the movement integration between the jaw and neck during jaw motor tasks in 6-year-olds, whether there is a difference between children and adults.

METHODS

Jaw and neck movements were recorded with an optoelectronic 3D system in 25 healthy 6-year-olds (12 girls, 13 boys) and 24 healthy adults (12 women, 12 men) during paced jaw opening-closing and self-paced gum chewing. Jaw and neck movement amplitudes, intra-individual variation in movement amplitude, ratio between neck-jaw movement amplitudes and movement cycle time were analysed. Differences between children and adults were evaluated with Mann-Whitney U test for independent samples.

RESULTS

Compared to adults, 6-year-old children showed larger neck movement amplitudes (P = .008) during chewing, higher intra-individual variability in amplitudes of jaw (P = .008) and neck (P = .001) movements, higher ratio between neck-jaw movement amplitudes for jaw opening-closing (P = .026) and chewing (P = .003), and longer jaw movement cycle time (P ≤ .0001) during the jaw opening-closing task.

CONCLUSION

Despite integrated jaw-neck movements in 6-year-old children, the movement pattern differs from that of adults and may be interpreted as an immature programming of jaw-neck motor behaviour. The well-integrated movements observed in adults most likely develop over years, perhaps into adolescence, and needs further research including well-controlled longitudinal studies to map this development in order to provide appropriate age-related clinical treatment for functional disorders.

Fetal arthrogryposis: Challenges and perspectives for prenatal detection and management

Antenatal identification of fetuses with multiple congenital contractures or arthrogryposis multiplex congenita (AMC) may be challenging. The first clinical sign is often reduced fetal movement and/or contractures, as seen on prenatal ultrasounds. This can be apparent at any point, from early to late pregnancy, may range from mild to severe involvement, with or without associated other structural anomalies. Possible etiologies and their prognosis need to be interpreted with respect to developmental timing. The etiology of AMC is highly heterogeneous and making the specific diagnosis will guide prognosis, counseling and prenatal and perinatal management. Current ultrasound practice identifies only approximately 25% of individuals with arthrogryposis prenatally before 24 weeks of pregnancy in a general obstetrics care population. There are currently no studies and guidelines that address the question of when and how to assess for fetal contractures and movements during pregnancy. The failure to identify fetuses with arthrogryposis before 24 weeks of pregnancy means that physicians and families are denied reproductive options and interventions that may improve outcome. We review current practice and recommend adjusting the current prenatal imaging and genetic diagnostic strategies to achieve early prenatal detection and etiologic diagnosis. We suggest exploring options for in utero therapy to increase fetal movement for ongoing pregnancies.

Stresses and strains on the human fetal skeleton during development

Mechanical forces generated by fetal kicks and movements result in stimulation of the fetal skeleton in the form of stress and strain. This stimulation is known to be critical for prenatal musculoskeletal development; indeed, abnormal or absent movements have been implicated in multiple congenital disorders. However, the mechanical stress and strain experienced by the developing human skeleton in utero have never before been characterized. Here, we quantify the biomechanics of fetal movements during the second half of gestation by modelling fetal movements captured using novel cine-magnetic resonance imaging technology. By tracking these movements, quantifying fetal kick and muscle forces, and applying them to three-dimensional geometries of the fetal skeleton, we test the hypothesis that stress and strain change over ontogeny. We find that fetal kick force increases significantly from 20 to 30 weeks' gestation, before decreasing towards term. However, stress and strain in the fetal skeleton rises significantly over the latter half of gestation. This increasing trend with gestational age is important because changes in fetal movement patterns in late pregnancy have been linked to poor fetal outcomes and musculoskeletal malformations. This research represents the first quantification of kick force and mechanical stress and strain due to fetal movements in the human skeleton in utero, thus advancing our understanding of the biomechanical environment of the uterus. Further, by revealing a potential link between fetal biomechanics and skeletal malformations, our work will stimulate future research in tissue engineering and mechanobiology.

Muscles of Breathing: Development, Function, and Patterns of Activation

This review is a comprehensive description of all muscles that assist lung inflation or deflation in any way. The developmental origin, anatomical orientation, mechanical action, innervation, and pattern of activation are described for each respiratory muscle fulfilling this broad definition. In addition, the circumstances in which each muscle is called upon to assist ventilation are discussed. The number of "respiratory" muscles is large, and the coordination of respiratory muscles with "nonrespiratory" muscles and in nonrespiratory activities is complex-commensurate with the diversity of activities that humans pursue, including sleep (8.27). The capacity for speech and adoption of the bipedal posture in human evolution has resulted in patterns of respiratory muscle activation that differ significantly from most other animals. A disproportionate number of respiratory muscles affect the nose, mouth, pharynx, and larynx, reflecting the vital importance of coordinated muscle activity to control upper airway patency during both wakefulness and sleep. The upright posture has freed the hands from locomotor functions, but the evolutionary history and ontogeny of forelimb muscles pervades the patterns of activation and the forces generated by these muscles during breathing. The distinction between respiratory and nonrespiratory muscles is artificial, as many "nonrespiratory" muscles can augment breathing under conditions of high ventilator demand. Understanding the ontogeny, innervation, activation patterns, and functions of respiratory muscles is clinically useful, particularly in sleep medicine. Detailed explorations of how the nervous system controls the multiple muscles required for successful completion of respiratory behaviors will continue to be a fruitful area of investigation. © 2019 American Physiological Society. Compr Physiol 9:1025-1080, 2019.

Towards the Womb of Neonatal Intensive Care

Within the mother's womb, life finds its first stirrings. The womb shelters the fetus, the growing child within. We recognize the existential traces of a wombed existence when a newborn calms in response to being held; when a newborn stills in response to his or her mother's heartbeat; and, when a newborn startles in the presence of bright light. Yet, how does experiential human life begin within another human being? What are the conditions and paths of becoming for the fetus within the womb? And for the child born early, what "womb" welcomes the premature child in neonatal intensive care?

How Early Can a Seizure Happen? Pathophysiological Considerations of Extremely Premature Infant Brain Development

Seizures in neonates represent a neurologic emergency requiring prompt recognition, determination of etiology, and treatment. Yet, the definition and identification of neonatal seizures remain challenging and controversial, in part due to the unique physiology of brain development at this life stage. These issues are compounded when considering seizures in premature infants, in whom the complexities of brain development may engender different clinical and electrographic seizure features at different points in neuronal maturation. In extremely premature infants (< 28 weeks gestational age), seizure pathophysiology has not been explored in detail. This review discusses the physiological and structural development of the brain in this developmental window, focusing on factors that may lead to seizures and their consequences at this early time point. We hypothesize that the clinical and electrographic phenomenology of seizures in extremely preterm infants reflects the specific pathophysiology of brain development in that age window.

Developmental trajectories of general and breathing movements in fetal twins

This study examined the developmental trajectories of general and breathing movements in fetal twins. Fetal movement patterns were assessed from real-time ultrasound recordings performed at 12-15, 20-23, and 28-32 weeks of gestation in 42 twin pairs. Results indicated that both general movements and breathing movements followed a curvilinear, inverted U-shaped curve. Developmental trajectories were unrelated within pairs of twins and were not associated with gestational age at birth and birth weight. However, sex differences were found for general movements with males displaying more time making general movements at 21 weeks and a steeper decline in time spent making general movements during the second half of pregnancy than females. These age-related changes in fetal movements may reflect CNS development. These findings also suggest that twins' behavioral development is largely independent of co-twin development, gestational age at birth, and birth weight, but not of fetal sex.

Correlation between human nervous system development and acquisition of fetal skills: An overview

Understanding the association between fetal nervous system structure and functioning should be an important goal in neurodevelopmental sciences, especially when considering the emerging knowledge regarding the importance of prenatal onset. Intrauterine development of the human central nervous system consists of specific processes: neurogenesis, neuronal migration, synaptogenesis, and myelination. However, as extensively shown by the neurobehavioral studies in the last century, the development of the central nervous system involves both structure and functioning. It is now recognised that the developing motor and sensory systems are able to function long before they have completed their neural maturation and that the intrauterine experience contributes to neurobehavioral development. This review analyzes the recent literature, looking at the association between the human nervous system maturation and fetal behavior. This article will follow the development and skill acquisition of the anatomical nervous system across the three trimesters of the gestation period.

Are sensorimotor experiences the key for successful early intervention in infants with congenital brain lesion?

Living with a congenital brain lesion may have detrimental effects on the ability to do everyday activities, but contrary to acquired brain lesions, people and in particular children, with congenital brain lesions may have limited or no experience of how their bodies work. This absence of experience gives rise to challenges for habilitation of sensorimotor abilities and derived cognitive abilities. How can motor and cognitive abilities be achieved and trained in an individual with no experience of potential abilities? In this article, we aim to review the existing knowledge about the development of sensorimotor integration. Further, we will discuss this knowledge in the light of two neurocognitive theories: embodied cognition and predictive coding. Moreover, using developmental knowledge and theory in combination, we will argue that early sensorimotor development serves as a foundation for later cognitive development. Finally, we try to use these elements in a strategy to make interventions as early as possible, with the purpose of improving sensorimotor and cognitive abilities in children with congenital brain lesions.

Ultrasound assessment of fetal hearing response to vibroacoustic stimulation

Background: Assessment of fetal responses to external stimuli could be a vital clue for understanding development of fetal neurophysiology, which is extremely challenging to explore. To study hearing development in growing human fetus, we assessed sonographic fetal movement responses to external auditory stimulus at increasing period of gestation.Method: In 123 normal pregnant women between 16 and 40 weeks' gestation, sonographic assessment of fetal movements (gross body movement, isolated limb movement, breathing movement and startle response) was carried out before and after administering vibroacoustic stimulation (VAS). Types and number of fetal movements during 5-min period each - immediately before and after application of VAS - were compared.Results: With increasing gestational age, spontaneous gross body movement decreased significantly between 16-28 and 29-40 weeks of gestation (93.3 versus 66.6%; p < .001). However, VAS significantly increased gross body movement at 29-40 weeks of gestation (66.6 versus 93.6%; p < .001). Incidence of isolated limb movement was inversely related to increasing gestational age. However, VAS was associated with significantly increase in isolated limb movement during 29-40 weeks' gestation (57.1 versus 80.9%; p = .007). VAS induced almost similar pattern of response for both fetal startle and breathing movements.Conclusions: Fetal movement responses to VAS are consistent after 28 weeks' gestation. These findings suggest fetal hearing develops at or before 28 weeks of intrauterine life.

Developmental trajectory of movement-related cortical oscillations during active sleep in a cross-sectional cohort of pre-term and full-term human infants

In neonatal animal models, isolated limb movements during active sleep provide input to immature somatomotor cortex necessary for its development and are somatotopically encoded by alpha-beta oscillations as late as the equivalent of human full-term. Limb movements elicit similar neural patterns in very pre-term human infants (average 30 corrected gestational weeks), suggesting an analogous role in humans, but it is unknown until when they subserve this function. In a cohort of 19 neonates (31-42 corrected gestational weeks) we showed that isolated hand movements during active sleep continue to induce these same somatotopically distributed oscillations well into the perinatal period, but that these oscillations decline towards full-term and fully disappear at 41 corrected gestational weeks (equivalent to the end of gestation). We also showed that these highly localised alpha-beta oscillations are associated with an increase in delta oscillations which extends to the frontal area and does not decline with age. These results suggest that isolated limb movements during active sleep could have an important role in experience-dependent somatomotor development up until normal birth in humans.