Self-reported respiratory and gastrointestinal outcomes in children with isolated congenital diaphragmatic hernia: A prospective multicentre study.

OBJECTIVE: To evaluate medium-term self-reported respiratory and gastrointestinal (GI) outcomes in children with congenital diaphragmatic hernia (CDH). DESIGN: Self-reported respiratory and GI outcomes correlated with prenatal severity indicators. SETTING: Prospective study at three fetal medicine units. POPULATION: Families of children prenatally diagnosed with isolated, left-sided CDH surviving for >1 year. METHODS: Families received validated questionnaires for GI outcomes (Infant Gastroesophageal Reflux Questionnaire Revised, I-GERQ-R, for infants aged <2 years, or Paediatric Gastro-oesophageal Symptom and Quality of Life Questionnaire, PGSQ, for children aged aged 2-8 years or >9 years) and respiratory outcomes (preschool respiratory outcome questionnaire, for children aged ≤5 years, or the International Study of Asthma and Allergies in Childhood asthma questionnaire, for children aged 6-8 years or ≥9 years). Prenatal data collected from the medical records included lung size (percentage observed/expected lung-to-head ratio, O/E LHR %), liver position, fetal endoluminal tracheal occlusion (FETO) gestational age (GA) at delivery, and perinatal data included birthweight, location, patch repair and respiratory support. MAIN OUTCOME MEASURES: The GI and respiratory scores were correlated with O/E LHR using linear and logistic regression models. Univariate analysis was used to evaluate associations with perinatal variables. RESULTS: We obtained 142 responses from 342 families (representing a response rate of 45%). The baseline characteristics of participants and non-participants were comparable. No correlations between perinatal variables and respiratory or GI scores were identified. Children aged ≤5 years with lower O/E LHR values reported higher respiratory scores (P = 0.0175); this finding was not reported in older children. Overall, the children who underwent FETO (n = 51) had GI (P = 0.290) and respiratory (P = 0.052) scores that were comparable with those of children who were expectantly managed. CONCLUSIONS: Families and children with prenatally diagnosed CDH reported fewer respiratory symptoms with increasing age. There was no correlation between O/E LHR or the use of FETO and self-reported outcomes.

Abnormal fetal ultrasound leading to the diagnosis of ADNP syndrome.

ADNP syndrome, also known as the Helsmoortel-Van der Aa syndrome (HVDAS), is a neurodevelopmental disorder characterized by hypotonia, developmental delay, and intellectual disability. Diagnosis is typically made postnatally, and little is known about prenatal presentation of the disorder. We report a child who presented with intrauterine growth restriction, proportionate microcephaly, and an abnormal skull shape on fetal ultrasound. Whole exome sequencing performed on amniotic fluid cells showed a de novo pathogenic variant in the ADNP gene, corresponding to a diagnosis of ADNP syndrome.

Placenta-associated adverse pregnancy outcomes in women experiencing mild or severe hyperemesis gravidarum - a systematic review and meta-analysis.

BACKGROUND: Nausea and vomiting in pregnancy (NVP) affects 50-80% of pregnant women and is correlated to the level of human chorionic gonadotropin (hCG). Hyperemesis gravidarum (HG) is a severe condition, with an incidence of 0.2-1.5%, characterized by consistent nausea, vomiting, weight loss and dehydration continuing after the second trimester. AIM: The aim of this systematic review was to investigate a potential correlation between NVP or HG with adverse pregnancy outcomes and hCG levels. METHOD: A systematic search in PubMed, Embase and CINAHL Complete was conducted. Studies on pregnant women with nausea in the first or second trimester, reporting either pregnancy outcomes or levels of hCG were included. The primary outcomes were preterm delivery (PTD), preeclampsia, miscarriage, and fetal growth restriction. Risk of bias was assessed using ROBINS-I. The overall certainty of evidence was assessed using GRADE. RESULTS: The search resulted in 2023 potentially relevant studies; 23 were included. The evidence was uncertain for all outcomes, however women with HG had a tendency to have an increased risk for preeclampsia [odds ratio (OR) 1.18, 95% confidence of interval (CI) 1.03 to 1.35], PTD [OR 1.35, 95% CI 1.13 to 1.61], small for gestational age (SGA) [OR 1.24, 95% CI 1.13 to 1.35], and low birth weight (LBW) [OR 1.35, 95% CI 1.26 to 1.44]. Further, a higher fetal female/male ratio was observed [OR 1.36, 95% CI 1.15 to 1.60]. Meta-analyses were not performed for women with NVP; however, most of these studies indicated that women with NVP have a lower risk for PTD and LBW and a higher risk for SGA, and a higher fetal female/male ratio. CONCLUSION: There may be an increased risk in women with HG and a decreased risk in women with NVP for adverse placenta-associated pregnancy outcomes, however the evidence is very uncertain. TRIAL REGISTRATION: PROSPERO: CRD42021281218.

Brain development is altered in rabbit fetuses with congenital diaphragmatic hernia.

INTRODUCTION: Children with congenital diaphragmatic hernia (CDH) are at risk for neurodevelopmental delay. Some changes are already present prenatally. Herein, we further examined how the brain develops in fetal rabbits with surgically created DH. METHODS: Two fetuses underwent surgical DH creation on day 23 (term = d31). DH pups and littermate controls were harvested at term. Ten DH pups and 11 controls underwent transcardial perfusion for brain fixation and measurement of brain volume, brain folding, neuron and synaptic density, pre-oligodendrocyte count, proliferation, and vascularization. Twelve other DH and 11 controls had echocardiographic assessment of cardiac output and aortic and cerebral blood flow, magnetic resonance imaging (9.4 T) for cerebral volumetry, and molecular assessment of vascularization markers. RESULTS: DH pups had lower lung-to-body weight ratio (1.3 ± 0.3 vs. 2.4 ± 0.3%; p < 0.0001) and lower heart-to-body weight ratio (0.007 ± 0.001 vs. 0.009 ± 0.001; p = 0.0006) but comparable body weight and brain-to-body weight ratio. DH pups had a lower left ventricular ejection fraction, aortic and cerebral blood flow (39 ± 8 vs. 54 ± 15 mm/beat; p = 0.03) as compared to controls but similar left cardiac ventricular morphology. Fetal DH-brains were similar in volume but the cerebellum was less folded (perimeter/surface area: 25.5 ± 1.5 vs. 26.8 ± 1.2; p = 0.049). Furthermore, DH brains had a thinner cortex (143 ± 9 vs. 156 ± 13 µm; p = 0.02). Neuron densities in the white matter were higher in DH fetuses (124 ± 18 vs. 104 ± 14; p = 0.01) with comparable proliferation rates. Pre-oligodendrocyte count was lower, coinciding with the lower endothelial cell count. CONCLUSION: Rabbits with DH had altered brain development compared to controls prenatally, indicating that brain development is already altered prenatally in CDH.

Effects of cumulative duration of repeated anaesthesia exposure on foetal brain development in the ovine model.

OBJECTIVE: Anaesthesia is required in 0.4-1% of pregnant women, and prolonged and repeated exposures to anaesthesia may be required. It is unknown whether these exposures may result in foetal neurotoxicity in humans. As sheep have a gestation comparable to that of humans, the objective of this study was to analyse the neurodevelopmental outcome of ovine foetuses that had been exposed in utero to repeated and prolonged anaesthesia. DESIGN: Randomized controlled preclinical study. SETTING: Anaesthesia for non-obstetric surgery during pregnancy. ANIMALS: Twenty-four healthy pregnant Swifter ewes. INTERVENTIONS: The ewes were randomized to no anaesthesia exposure (control-group), single exposure (at gestational age 68-70 days), or repeated exposure (at gestational age 68-70 days and 96-98 days) to 2.5 h of sevoflurane anaesthesia and maternal laparotomy. All lambs were delivered at approximately term gestation (gestational age: 140-143 days). MEASUREMENTS: The primary outcome was neuron density in the frontal cortex 24 h after birth for the control-group versus the repeated-exposure-group. Key secondary outcome was the time needed to achieve the milestone of standing. Secondary outcomes included other neurobehavioural assessments (e.g., motoric milestones) and histological parameters quantified in multiple brain regions (neuron density, total cell density, proliferation, inflammation, synaptogenesis, astrocytes and myelination). MAIN RESULTS: Neuron density in the frontal cortex did not differ between groups (mean ±â€¯standard deviation: control-group: 403 ±â€¯39, single-exposure group: 436 ±â€¯23 and repeated-exposure-group: 403 ±â€¯40 neurons/mm2, control-group versus repeated-exposure-group: p = 0.986, control-group versus single-exposure-group: p = 0.097). No significant difference was observed for the time needed to achieve the milestone of standing. Only very limited differences were observed for other histological outcome parameters and neurobehavioural assessments. CONCLUSIONS: There is no evidence for foetal neuronal injury or neurobehavioural impairments after a cumulative duration of 5 h repetitive prenatal anaesthesia in sheep.

Placental vascular alterations are associated with early neurodevelopmental and pulmonary impairment in the rabbit fetal growth restriction model.

Fetal growth restriction is one of the leading causes of perinatal mortality and morbidity and has consequences that extend well beyond the neonatal period. Current management relies on timely delivery rather than improving placental function. Several prenatal strategies have failed to show benefit in clinical trials after promising results in animal models. Most of these animal models have important developmental and structural differences compared to the human and/or are insufficiently characterized. We aimed to describe placental function and structure in an FGR rabbit model, and to characterize the early brain and lung developmental morbidity using a multimodal approach. FGR was induced in time-mated rabbits at gestational day 25 by partial uteroplacental vessel ligation in one horn. Umbilical artery Doppler was measured before caesarean delivery at gestational day 30, and placentas were harvested for computed microtomography and histology. Neonates underwent neurobehavioral or pulmonary functional assessment the day after delivery, followed by brain or lung harvesting, respectively. Neuropathological assessment included multiregional quantification of neuron density, apoptosis, astrogliosis, cellular proliferation, and oligodendrocyte progenitors. Brain region volumes and diffusion metrics were obtained from ex-vivo brain magnetic resonance imaging. Lung assessment included biomechanical tests and pulmonary histology. Fetal growth restriction was associated with labyrinth alterations in the placenta, driven by fetal capillary reduction, and overall reduced vessels volume. FGR caused altered neurobehavior paralleled by regional neuropathological deficits and reduced fractional anisotropy in the cortex, white matter, and hippocampus. In addition, FGR kittens presented functional alterations in the peripheral lung and structurally underdeveloped alveoli. In conclusion, in a uteroplacental insufficiency FGR rabbit model, placental vascular alterations coincide with neurodevelopmental and pulmonary disruption.

Neurodevelopmetal effects of maternal blood pressure management with noradrenaline during general anaesthesia for nonobstetric surgery in the pregnant rabbit model.

In pregnant women, anaesthesia-induced hypotension is commonly treated using phenylephrine or noradrenaline, the rationale being to maintain uterine perfusion pressure and thereby uterine blood flow. Evidence for this strategy during general anaesthesia for nonobstetric surgery is absent. To analyse the effects of treating anaesthesia-induced hypotension with noradrenaline on brain development of rabbit foetuses of mothers subjected to general anaesthesia for nonobstetric surgery. We hypothesised that treatment of maternal hypotension would improve foetal outcomes. Randomised controlled laboratory study using 21 pregnant rabbits (does) at 28 days of gestation. Two hours of sevoflurane anaesthesia for a laparotomy without treatment of anaesthesia-induced hypotension (hypotension group) or with maintaining maternal mean arterial pressure above 80% of the awake value using noradrenaline (noradrenaline group). In the control group, does remained untouched. At term, all pups were delivered by caesarean section. One day later, the neurobehaviour of the pups was assessed and brains were harvested. Neuron density in the frontal cortex for the comparison of noradrenaline groups versus hypotension groups was the primary outcome; the neurobehavioural scores and other histological outcomes were secondary outcomes. In the noradrenaline groups and hypotension groups, neuron density in the frontal cortex was similar (1181 ±â€Š162 versus 1189 ±â€Š200 neurons mm-2, P  = 0.870). However, significantly less foetal survival, lower sensory scores in neurobehavioural assessment and less proliferation were observed in the noradrenaline group when compared with the hypotension group. Neuron densities in other regions, total cell densities, biometrics and synaptogenesis were not affected. There were no differences between the control group and hypotension group. During general anaesthesia for nonobstetric surgery in rabbits, treatment of anaesthesia-induced hypotension using noradrenaline did not affect neuron densities but was associated with impaired foetal outcomes according to several secondary outcome parameters. Further studies are needed to investigate any clinical relevance and to determine the target blood pressure in pregnant women during general anaesthesia.KEY POINTSIn pregnant women, anaesthesia-induced hypotension is commonly treated using phenylephrine or noradrenaline, with the rationale to maintain uterine perfusion pressure and thereby uterine blood flow.Evidence for this strategy during general anaesthesia for nonobstetric surgery is absent.We investigated the effects of treating anaesthesia-induced hypotension with noradrenaline on the brain development of rabbit foetuses, of mothers subjected to general anaesthesia for nonobstetric surgery.We hypothesised that treatment of maternal hypotension would improve foetal outcomes.Neuron densities were similar but significantly less foetal survival, impaired neurobehaviour and less proliferation were observed after treatment of anaesthesia-induced hypotension with noradrenaline, compared with untreated hypotension.

Fetoscopic insufflation of heated-humidified carbon dioxide during simulated spina bifida repair is safe under controlled anesthesia in the fetal lamb.

OBJECTIVE: To assess the safety of Partial-Amniotic-Insufflation-of-heated-humidified-CO2 (hPACI) during fetoscopic spina bifida repair (fSB-repair). METHOD: A simulated fSB-repair through an exteriorized uterus under hPACI was performed in 100-day fetal lambs (term = 145 days) under a laboratory anesthesia protocol (n = 5; group 1) which is known to induce maternal-fetal acidosis and hypercapnia. Since these may not occur clinically, we applied a clinical anesthesia protocol (n = 5; group 2), keeping maternal parameters within physiological conditions, that is, controlled maternal arterial carbon dioxide (CO2) pressure (pCO2  = 30 mmHg), blood pressure (≥67 mmHg), and temperature (37.1-39.8°C). Our superiority study used fetal pH as the primary outcome. RESULTS: Compared to group 1, controlled anesthesia normalized fetal pH (7.23 ± 0.02 vs. 7.36 ± 0.02, p < 0.001), pCO2 (70.0 ± 9.1 vs. 43.0 ± 1.0 mmHg, p = 0.011) and bicarbonate (27.8 ± 1.1 vs. 24.0 ± 0.9 mmol/L, p = 0.071) at baseline. It kept them within clinically acceptable limits (pH ≥ 7.23, pCO2  ≤ 70 mmHg, bicarbonate ≤ 30 mm/L) for ≥120 min of hPACI as opposed to ≤30 min in group one. Fetal pO2 and lactate were comparable between groups and generally within normal range. Fetal brain histology demonstrated fewer apoptotic cells and higher neuronal density in the prefrontal cortex in group two. There was no difference in fetal membrane inflammation, which was mild. CONCLUSION: Fetoscopic insufflation of heated-humidified CO2 during simulated fSB-repair through an exteriorized uterus can be done safely under controlled anesthesia.

Neurodevelopmental outcomes in children with isolated congenital diaphragmatic hernia: A systematic review and meta-analysis.

BACKGROUND: Congenital diaphragmatic hernia (CDH) reportedly has neurologic consequences in childhood however little is known about the impact in isolated CDH. AIMS: Herein we aimed to describe the risk of neurodevelopmental complications in children born with isolated CDH. MATERIALS & METHODS: We systematically reviewed literature for reports on the neurological outcome of infants born with isolated CDH. The primary outcome was neurodevelopmental delay. Secondary outcomes included, motor skills, intelligence, vision, hearing, language and behavior abnormalities. RESULTS: Thirteen out of 87 (15%) studies reported on isolated CDH, including 2624 out of 24,146 children. Neurodevelopmental delay was investigated in four studies and found to be present in 16% (3-34%) of children. This was mainly attributed to motor problems in 13% (2-30%), whereas cognitive dysfunction only in 5% (0-20%) and hearing in 3% (1-7%). One study assessed the effect of fetal surgery. When both isolated and non-isolated children were included, these numbers were higher. DISCUSSION: This systematic review demonstrates that only a minority of studies focused on isolated CDH, with neurodevelopmental delay present in 16% of children born with CDH. CONCLUSION: To accurately counsel patients, more research should focus on isolated CDH cases and examine children that underwent fetal surgery.

Fetal surgery has no additional effect to general anesthesia on brain development in neonatal rabbits.

BACKGROUND: Fetal surgery is part of modern fetal medicine, and some procedures, such as fetal spina bifida repair, are performed under general anesthesia. Fetuses are operated on in a time window when the developing brain is extremely vulnerable to external, potentially harmful factors. To date, little is known about the effect of fetal surgery on fetal brain development. OBJECTIVE: This study aimed to assess the effect of fetal surgery on the developing fetal brain in the rabbit model. STUDY DESIGN: This was a randomized, sham-controlled study in time-mated pregnant does at 28 days' gestation (term, 31 days), which corresponds to the start of the peak of brain development and end of the second trimester of pregnancy in humans. We included 4 different groups in this experiment: no-surgery, general anesthesia, general anesthesia+hysterotomy, and general anesthesia+fetal surgery. In 11 does, anesthesia was induced using propofol and maintained for 75 minutes with 3.6 vol% (4% is the equivalent of 1 minimum alveolar concentration) sevoflurane. Maternal blood pressure, heart rate, oxygen saturation, temperature, end-tidal CO2 were continuously monitored. For each operated doe, 6 fetuses were part of the experiment. Randomization determined which cornual sac and what opposing third sac were assigned to fetal surgery: hysterotomy, fetal injection (atropine, fentanyl, and cisatracurium), fetal skin incision, and suturing. Only hysterotomy was performed on the opposing cornual and third amniotic sacs of the does. The fetus in these experimental sacs was used as internal unmanipulated control (general anesthesia). All fetuses (n=38) from unmanipulated does (n=4) served as external controls (no-surgery). At term, the does were delivered by cesarean delivery under ketamine-medetomidine sedation and local anesthesia. The pups underwent standardized motoric and sensory neurologic testing on day 1 followed by euthanasia and brain harvesting for histologic assessment of neurons, synapses, proliferation, and glial cells. RESULTS: Maternal vital signs were stable during surgery. Survival was similar in the 4 groups (75%-94%), and brain-to-body weight ratio was comparable; only the no-surgery pups had a higher brain weight. On postnatal day 1, the pups in the 4 groups had a comparable neurobehavioral outcome on both motoric and sensory testing. In the prefrontal cortex, no-surgery pups had significantly higher neuron density than pups who underwent maternal surgery, but there was no difference among pups that underwent general anesthesia, hysterotomy, or fetal surgery. The measurements of proliferation had a similar outcome: a higher proliferation rate in the prefrontal cortex of no-surgery pups. Moreover, synaptic density values were higher in the no-surgery pups, but there was no difference observed among pups who underwent general anesthesia, hysterotomy, and fetal surgery. Lastly, there was no difference in gliosis among the 4 groups. CONCLUSION: In rabbits, fetal surgery through hysterotomy under maternal general anesthesia did not affect brain development, in addition to the effects of general anesthesia per se.

Prenatal cerebellar growth is altered in congenital diaphragmatic hernia on ultrasound.

OBJECTIVE: Children with congenital diaphragmatic hernia (CDH) are at risk for neurodevelopmental delay. Herein we report on prenatal changes in biometry and brain perfusion in fetuses with isolated CDH. STUDY DESIGN: This retrospective study evaluated fetuses with isolated, left-sided CDH in three European referral centers. Abdominal circumference (AC), femur length (FL), head circumference (HC), transcerebellar diameter (TCD), middle cerebral artery (MCA) Doppler, and ventricular width (VW) were assessed during four gestational periods (<24 weeks, 25-28 weeks, 29-32 weeks, >33 weeks). Z-scores were calculated, and growth curves were created based on longitudinal data. RESULTS: In 367 fetuses, HC, AC and FL were within normal ranges throughout gestation. The TCD diminished with advancing gestational age to fall below the fifth percentile after 32 weeks. A less pronounced but similar trend was seen in VW. The peak systolic velocity of the MCA was consistently approximately 10% lower than normal. Disease severity was correlated to TCD (p = 0.002) and MCA doppler values (p = 0.002). There were no differences between fetuses treated with FETO and those managed expectantly. CONCLUSION: Fetuses with isolated left-sided CDH have a small cerebellum and reduced MCA peak systolic velocity. Follow up studies are necessary to determine the impact of these changes on neurodevelopment.

Neurocognitive sequelae of antenatal corticosteroids in a late preterm rabbit model.

BACKGROUND: Late preterm birth is associated with short-term respiratory and adaptive problems. Although antenatal corticosteroids seem to reduce the respiratory burden, this may come at the cost of adverse neuropsychological outcomes later in life. This impact has not been investigated. OBJECTIVE: Herein, we investigate what the short- and long-term neurodevelopmental effects of a single course of betamethasone in simulated late preterm birth. STUDY DESIGN: Time-mated pregnant does received 0.1 mg/kg betamethasone (n=8) or 1 mL saline intramuscular (n=6) at the postconceptional ages of 28 and 29 days. The antenatal corticosteroid dose and scheme were based on previous studies and were comparable with routine clinical use. Cesarean delivery was done on postconceptional age 30 days (term=31 days), and new-born rabbits were foster-cared for 28 days and were thereafter cared for in group housing. Neonatal lung function testing and short-term neurobehavioral testing was done. Open field, spontaneous alternation, and novel object recognition tests were subsequently performed at 4 and 8 weeks of age. On postnatal day 1 and at 8 weeks, a subgroup was euthanized and transcardially perfuse fixated. Ex vivo high-resolution Magnetic Resonance Imaging was used to calculate the Diffusion Tensor Imaging-derived fractional anisotropy and mean diffusivity. Fixated brains underwent processing and were serial sectioned, and a set of 3 coronal sections underwent anti-NeuN, Ki67, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. RESULTS: Antenatal corticosteroid exposure was associated with improved neonatal lung function, yet resulted in a long-term growth deficit that coincided with a persistent neurobehavioral deficit. We demonstrated lower neonatal motor scores; a persistent anxious behavior in the open field test with more displacements, running, and self-grooming episodes; persistent lower alternation scores in the T-Maze test; and lower discriminatory indexes in the novel object recognition. On neuropathological assessment, antenatal corticosteroid exposure was observed to result in a persistent lower neuron density and fewer Ki67+ cells, particularly in the hippocampus and the corpus callosum. This coincided with lower diffusion tensor imaging-derived fractional anisotropy scores in the same key regions. CONCLUSION: Clinical equivalent antenatal corticosteroid exposure in this late preterm rabbit model resulted in improved neonatal lung function. However, it compromised neonatal and long-term neurocognition.

The effect of xenon on fetal neurodevelopment following maternal sevoflurane anesthesia and laparotomy in rabbits.

BACKGROUND: There is concern that maternal anesthesia during pregnancy impairs brain development of the human fetus. Xenon is neuroprotective in pre-clinical models of anesthesia-induced neurotoxicity in neonates. It is not known if xenon also protects the developing fetal brain when administered in addition to maternal sevoflurane-anesthesia during pregnancy. OBJECTIVE: To investigate the effects of sevoflurane and xenon on neurobehaviour and neurodevelopment of the offspring in a pregnant rabbit model. METHODS: Pregnant rabbits on post-conception day 28 (term = 31d) underwent two hours of general anesthesia with 1 minimum alveolar concentration (MAC) of sevoflurane in 30% oxygen (n = 17) or 1 MAC sevoflurane plus 50-60 % xenon in 30% oxygen (n = 10) during a standardized laparotomy while receiving physiological monitoring. A sham-group (n = 11) underwent monitoring alone for two hours. At term, the rabbits were delivered by caesarean section. On the first postnatal day, neonatal rabbits underwent neurobehavioral assessment using a validated test battery. Following euthanasia, the brains were harvested for neurohistological analysis. A mixed effects-model was used for statistical analysis. RESULTS: Maternal cardiopulmonary parameters during anesthesia were within the reference range. Fetal survival rates were significantly higher in the sham-group as compared to the sevoflurane-group and the fetal brain/body weight ratio was significantly lower in the sevoflurane-group as compared with the sham- and xenon-group. Pups antenatally exposed to anesthesia had significantly lower motor and sensory neurobehavioral scores when compared to the sham-group (mean ± SD; sevo: 22.70 ± 3.50 vs. sevo+xenon: 22.74 ± 3.15 vs. sham: 24.37 ± 1.59; overall p = 0.003; sevo: 14.98 ± 3.00 vs. sevo+xenon: 14.80 ± 2.83 vs. sham: 16.43 ± 2.63; overall p = 0.006; respectively). Neuron density, neuronal proliferation and synaptic density were reduced in multiple brain regions of the exposed neonates. The co-administration of xenon had no measurable neuroprotective effects in this model. CONCLUSIONS: In rabbits, sevoflurane anesthesia for a standardized laparotomy during pregnancy resulted in impaired neonatal neurobehavior and a decreased neuron count in several regions of the neonatal rabbit brain. Co-administration of xenon did not prevent this effect.

Effects of general anaesthesia during pregnancy on neurocognitive development of the fetus: a systematic review and meta-analysis.

BACKGROUND: The US Food and Drug Administration warned that exposure of pregnant women to general anaesthetics may impair fetal brain development. This review systematically evaluates the evidence underlying this warning. METHODS: PubMed, EMBASE, and Web of Science were searched from inception until April 3, 2020. Preclinical and clinical studies were eligible. Exclusion criteria included case reports, in vitro models, chronic exposures, and exposure only during delivery. Meta-analyses were performed on standardised mean differences. The primary outcome was overall effect on learning/memory. Secondary outcomes included markers of neuronal injury (apoptosis, synapse formation, neurone density, and proliferation) and subgroup analyses. RESULTS: There were 65 preclinical studies included, whereas no clinical studies could be identified. Anaesthesia during pregnancy impaired learning and memory (standardised mean difference -1.16, 95% confidence interval -1.46 to -0.85) and resulted in neuronal injury in all experimental models, irrespective of the anaesthetic drugs and timing in pregnancy. Risk of bias was high in most studies. Rodents were the most frequently used animal species, although their brain development differs significantly from that in humans. In a minority of studies, anaesthesia was combined with surgery. Monitoring and strict control of physiological homeostasis were below preclinical and clinical standards in many studies. The duration and frequency of exposure and anaesthetic doses were often much higher than in clinical routine. CONCLUSION: Anaesthesia-induced neurotoxicity during pregnancy is a consistent finding in preclinical studies, but translation of these results to the clinical situation is limited by several factors. Clinical observational studies are needed. PROSPERO REGISTRATION NUMBER: CRD42018115194.

Fetally-injected drugs for immobilization and analgesia do not modify fetal brain development in a rabbit model.

OBJECTIVE: During fetal surgery, fetuses receive medication (atropine-fentanyl-curare) to prevent fetal pain, movement and bradycardia. Although essential there has been no detailed review of potential side effects. Herein we aimed to assess the effects of this medication cocktail on fetal brain development in a rabbit model. METHODS: Pregnant does underwent laparotomy at 28 days of gestation. Two pups of each horn were randomized to an ultrasound guided injection with medication (atropine-cisatracurium-fentanyl, as clinically used) or saline (sham). The third pup was used as control. At term, does were delivered by cesarean. Outcome measures were neonatal biometry, neuromotoric functioning and neuro-histology (neuron density, synaptic density and proliferation). RESULTS: Maternal vital parameters remained stable during surgery. Fetal heart rates did not differ before and after injection, and were comparable for the three groups. At birth, neonatal body weights and brain-to-body weight ratios were also comparable. Both motor and sensory neurobehavioral scores were comparable. There were no differences in neuron density or proliferation. Sham pups, had a lower synaptic density in the hippocampus as compared to the medication group, however there was no difference in the other brain areas. CONCLUSION: In the rabbit model, fetal medication does not appear to lead to short-term neurocognitive effects.

Effects of Maternal Abdominal Surgery on Fetal Brain Development in the Rabbit Model.

INTRODUCTION: Anesthesia during pregnancy can impair fetal neurodevelopment, but effects of surgery remain unknown. The aim is to investigate effects of abdominal surgery on fetal brain development. Hypothesis is that surgery impairs outcome. METHODS: Pregnant rabbits were randomized at 28 days of gestation to 2 h of general anesthesia (sevoflurane group, n = 6) or to anesthesia plus laparoscopic appendectomy (surgery group, n = 13). On postnatal day 1, neurobehavior of pups was assessed and brains harvested. Primary outcome was neuron density in the frontal cortex, and secondary outcomes included neurobehavioral assessment and other histological parameters. RESULTS: Fetal survival was lower in the surgery group: 54 versus 100% litters alive at birth (p = 0.0442). In alive litters, pup survival until harvesting was 50 versus 69% (p = 0.0352). No differences were observed for primary outcome (p = 0.5114) for surviving pups. Neuron densities were significantly lower in the surgery group in the caudate nucleus (p = 0.0180), but not different in other regions. No differences were observed for secondary outcomes. Conclusions did not change after adjustment for mortality. CONCLUSION: Abdominal surgery in pregnant rabbits at a gestational age corresponding to the end of human second trimester results in limited neurohistological changes but not in neurobehavioral impairments. High intrauterine mortality limits translation to clinical scenario, where fetal mortality is close to zero.

Earlier preterm birth is associated with a worse neurocognitive outcome in a rabbit model.

BACKGROUND: Preterm birth (PTB) and particularly late preterm PTB has become a research focus for obstetricians, perinatologists, neonatologists, pediatricians and policy makers alike. Translational models are useful tools to expedite and guide clinical but presently no model exists that contextualizes the late PTB scenario. Herein we aimed to develop a rabbit model that echo's the clinical neurocognitive phenotypes of early and late PTB. METHODS: Time mated rabbit does underwent caesarean delivery at a postconceptional age (PCA) of either 28 (n = 6), 29 (n = 5), 30 (n = 4) or 31 (n = 4) days, term = 31 d. Newborn rabbits were mixed and randomly allocated to be raised by cross fostering and underwent short term neurobehavioral testing on corrected post-natal day 1. Open field (OFT), spontaneous alteration (TMT) and novel object recognition (NORT) tests were subsequently performed at 4 and 8 weeks of age. RESULTS: PTB was associated with a significant gradient of short-term mortality and morbidity inversely related to the PCA. On postnatal day 1 PTB was associated with a significant sensory deficit in all groups but a clear motor insult was only noted in the PCA 29d and PCA 28d groups. Furthermore, PCA 29d and PCA 28d rabbits had a persistent neurobehavioral deficit with less exploration and hyperanxious state in the OFT, less alternation in TMT and lower discriminatory index in the NORT. While PCA 30d rabbits had some anxiety behavior and lower spontaneous alteration at 4 weeks, however at 8 weeks only mild anxiety driven behavior was observed in some of these rabbits. CONCLUSIONS: In this rabbit model, delivery at PCA 29d and PCA 28d mimics the clinical phenotype of early PTB while delivery at PCA 30d resembles that of late PTB. This could serve as a model to investigate perinatal insults during the early and late preterm period.

Long-term neurological effects of neonatal caffeine treatment in a rabbit model of preterm birth.

BACKGROUND: Neonatal caffeine treatment might affect brain development. Long-term studies show conflicting results on brain-related outcomes. Herein we aimed to investigate the long-term effects of neonatal caffeine administration in a rabbit model of preterm birth. METHODS: Preterm (born day 29) and term (day 32) pups were raised by wet nurses and allocated to treatment with saline or caffeine for 7 or 17 days. At pre-puberty, neurobehavioral tests were performed and brains were harvested for immunostaining of neurons, synapses, myelin, and astrocytes. RESULTS: Survival was lower in preterm saline pups than in controls, whereas caffeine-treated preterm pups did not differ from term control pups. Preterm saline pups covered less distance compared to controls and were more likely to stay in the peripheral zone of the open field. Corresponding differences were not seen in preterm caffeine pups. Preterm animals had lower neuron density compared to controls, which was not influenced by caffeine treatment. Synaptic density, astrocytes, and myelin were not different between groups. CONCLUSION: Caffeine appeared to be safe. All preterm rabbits had lower neuron density but anxious behavior seen in preterm saline rabbits was not seen in caffeine-treated preterm pups.

Publisher Correction: Early neuropathological and neurobehavioral consequences of preterm birth in a rabbit model.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.