New insights into fetal pain

A comparison of the effect of procedural pain on cerebral oxygen saturation between late preterm and term infants

OBJECTIVES

We prospectively compared cerebral oxygen saturation (CrSO2) and pain score changes during procedures in late preterm (LPT) versus term infants.

METHODS

Near-infrared spectroscopy, pulse oximetry, Neonatal Infant Pain Scale (NIPS) and Premature Infant Pain Profile-Revised (PIPP-R) scores were assessed and CrSO2 data analyzed.

RESULTS

Thirty infants in each group were evaluated. LPT infants displayed a milder significant drop in Minimum post-procedural CrSO2 and smaller Maximum-Minimum post-procedural CrSO2 disparity. CrSO2 minute changes between the groups were non-significant. Moderate correlations were observed in both groups between NIPS and Minimum post-procedural CrSO2, and a moderate correlation was found in the Maximum-Minimum post-procedural CrSO2 difference in LPT infants. No correlation between PIPP-R and CrSO2 values was noted.

CONCLUSION

LPT and term infants demonstrated decreased CrSO2 in response to painful procedures. Correlations between CrSO2 and PIPP-R or NIPS scores were poor to moderate, reflecting the complex nature of these associations relative to gestational age.

An Evidence-Based Discussion of Fetal Pain and Stress

BACKGROUND

The concept of fetal pain results from procedures conducted without anesthesia in preterm newborns and fetuses, which indicate that it is possible to examine fetal pain based on stress hormone, metabolic, and behavioral changes. Anatomical and physiological data suggest that fetuses become capable of processing nociceptive stimuli around midgestation, although the associated changes in fetal brain development remain unclear. What constitutes fetal pain remains controversial in the light of the definition of pain adopted by the International Association for the Study of Pain (IASP), which posits pain as an "unpleasant sensory and emotional experience."

SUMMARY

Here, we examine the notion that human fetuses cannot "experience" pain and potential implications of this claim. We highlight the key scientific evidence related to fetal pain, including clinical studies on pain in fetuses and preterm newborns. We argue that consistent patterns of stress hormones, metabolic changes, body movements, hemodynamic changes, and pain-related facial expressions in fetuses exposed to invasive procedures overcome the need for subjective proof of pain as articulated in the IASP definition. No study to date has conclusively proven the absence of fetal pain beyond the age of viability.

KEY MESSAGES

Based on the current evidence, we propose that all fetuses receive anesthesia regardless of the invasive procedures being performed to guarantee the least possible pain and physiological, behavioral, or hormonal responses without exposing the mother or her baby to unnecessary complications.

Potentiality switches and epistemic uncertainty: the Argument from Potential in times of human embryo-like structures

Recent advancements in developmental biology enable the creation of embryo-like structures from human stem cells, which we refer to as human embryo-like structures (hELS). These structures provide promising tools to complement-and perhaps ultimately replace-the use of human embryos in clinical and fundamental research. But what if these hELS-when further improved-also have a claim to moral status? What would that imply for their research use? In this paper, we explore these questions in relation to the traditional answer as to why human embryos should be given greater protection than other (non-)human cells: the so-called Argument from Potential (AfP). According to the AfP, human embryos deserve special moral status because they have the unique potential to develop into persons. While some take the development of hELS to challenge the very foundations of the AfP, the ongoing debate suggests that its dismissal would be premature. Since the AfP is a spectrum of views with different moral implications, it does not need to imply that research with human embryos or hELS that (may) have 'active' potential should be completely off-limits. However, the problem with determining active potential in hELS is that this depends on development passing through 'potentiality switches' about the precise coordinates of which we are still in the dark. As long as this epistemic uncertainty persists, extending embryo research regulations to research with specific types of hELS would amount to a form of regulative precaution that as such would require further justification.

Pain-related changes in crSO2 among premature infants undergoing PICC insertion

OBJECTIVE

To evaluate the effectiveness of cerebral regional oxygen saturation (crSO₂) values, measured using near-infrared spectroscopy (NIRS), in assessing pain associated with the peripherally inserted central catheter (PICC) in premature infants.

METHODS

NIRS was used to measure the crSO₂ levels of 48 premature infants with gestational age (GA) of < 32 weeks or a birth weight of < 1500 g. Premature infant pain profile (PIPP) scores, vital signs, transcutaneous oxygen tension (TcpO₂), transcutaneous carbon dioxide tension (TcpCO₂), and crSO₂ values were monitored. One-way repeated measure analysis of variance was used to compare heart rate (HR), respiratory rate (RR), blood pressure (BP), peripheral oxygen saturation (SpO₂), TcpO₂, TcpCO₂, and crSO₂ values before (Time 1), during (Time 2), and after (Time 3) PICC insertion. The correlation between the PIPP scores at Time 2 and the fluctuations (values detected at Time 2 minus those at Time 1) of SpO_2, TcpO_2, and crSO₂ were also analyzed.

RESULTS

The PIPP score at Time 2 was significantly higher than those at Times 1 and 3. HR, RR, and BP values increased (p < .05), and SpO₂ and crSO₂ levels decreased at Time 2 (p < .05) compared with those at Time 1. Stratified analysis based on GA revealed significant differences in HR, RR, and crSO₂ values between Times 1 and 2 in infants with a GA of ≥ 32 weeks. In infants with a GA < 32 weeks, significant differences were observed in HR, RR, SpO₂, BP, and crSO₂ values between Times 1 and 2. The fluctuation of the crSO₂ level was strongly correlated with the PIPP score at Time 2 (r = -0.829, p < .001). A weak correlation was observed between the PIPP score at Time 2 and TcpO₂ level fluctuation (r = 0.375, p = .009). No correlation was observed between the PIPP score at Time 2 and SpO₂ level fluctuation (r = 0.242, p = .097).

CONCLUSION

The fluctuation of crSO₂ levels strongly correlates with PICC procedural pain. Hence, crSO₂ levels measured using NIRS may be used as an indicator for pain assessment in premature infants.

Regional Anesthesia for Neonates

Pain management in neonates and infants has many unique and important facets, particularly in former preterm infants. Untreated pain and surgical stress in neonates are associated with myriad negative sequelae, including deleterious inflammatory, autonomic, hormonal, metabolic, and neurologic effects. Meanwhile, opioid side effects are also very impactful and affect multiple systems and pathways, particularly in the neonatal and infant population. Regional anesthesia presents a unique opportunity to provide highly effective analgesia; prevent deleterious signaling cascade pathways within the endocrine, immune, and nervous systems from occurring; and create conditions to facilitate reduced reliance on opioids and other analgesics. In some cases, clinicians can completely avoid general anesthesia and systemic anesthetics. This review will discuss some of the unique aspects of pain management in neonates and infants and provide an overview of the different regional anesthetic options available, namely, spinal anesthesia, epidural anesthesia, and peripheral nerve blocks.

Nociception in Chicken Embryos, Part I: Analysis of Cardiovascular Responses to a Mechanical Noxious Stimulus

Although it is assumed that chicken embryos acquire the capacity for nociception while developing in the egg, an exact time point has not yet been specified. The present research was an exploratory study aiming to determine when the capacity of nociception emerges during embryonic development in chickens. Changes in blood pressure and heart rate (HR) in response to a noxious mechanical stimulus at the base of the beak versus a light touch on the beak were examined in chicken embryos between embryonic days (EDs) 7 and 18. Mean arterial pressure (MAP) was the most sensitive parameter for assessing cardiovascular responses. Significant changes in MAP in response to a noxious stimulus were detected in embryos at ED16 to ED18, whereas significant changes in HR were observed at ED17 and ED18. Infiltration anesthesia with the local anesthetic lidocaine significantly reduced the response of MAP on ED18, so the measured cardiovascular changes may be interpreted as nociceptive responses.

Narrative Review of the Complex Interaction between Pain and Trauma in Children: A Focus on Biological Memory, Preclinical Data, and Epigenetic Processes

The incidence and collective impact of early adverse experiences, trauma, and pain continue to increase. This underscores the urgent need for translational efforts between clinical and preclinical research to better understand the underlying mechanisms and develop effective therapeutic approaches. As our understanding of these issues improves from studies in children and adolescents, we can create more precise preclinical models and ultimately translate our findings back to clinical practice. A multidisciplinary approach is essential for addressing the complex and wide-ranging effects of these experiences on individuals and society. This narrative review aims to (1) define pain and trauma experiences in childhood and adolescents, (2) discuss the relationship between pain and trauma, (3) consider the role of biological memory, (4) decipher the relationship between pain and trauma using preclinical data, and (5) examine the role of the environment by introducing the importance of epigenetic processes. The ultimate scope is to better understand the wide-ranging effects of trauma, abuse, and chronic pain on children and adolescents, how they occur, and how to prevent or mitigate their effects and develop effective treatment strategies that address both the underlying causes and the associated physiological and psychological effects.

The fetal pain paradox

Controversy exists as to when conscious pain perception in the fetus may begin. According to the hypothesis of cortical necessity, thalamocortical connections, which do not form until after 24-28 weeks gestation, are necessary for conscious pain perception. However, anesthesiologists and neonatologists treat age-matched neonates as both conscious and pain-capable due to observable and measurable behavioral, hormonal, and physiologic indicators of pain. In preterm infants, these multimodal indicators of pain are uncontroversial, and their presence, despite occurring prior to functional thalamocortical connections, has guided the use of analgesics in neonatology and fetal surgery for decades. However, some medical groups state that below 24 weeks gestation, there is no pain capacity. Thus, a paradox exists in the disparate acknowledgment of pain capability in overlapping patient populations. Brain networks vary by age. During the first and second trimesters, the cortical subplate, a unique structure that is present only during fetal and early neonatal development, forms the first cortical network. In the third trimester, the cortical plate assumes this function. According to the subplate modulation hypothesis, a network of connections to the subplate and subcortical structures is sufficient to facilitate conscious pain perception in the fetus and the preterm neonate prior to 24 weeks gestation. Therefore, similar to other fetal and neonatal systems that have a transitional phase (i.e., circulatory system), there is now strong evidence for transitional developmental phases of fetal and neonatal pain circuitry.

Parasympathetic evaluation for procedural pain assessment in neonatology

INTRODUCTION

The Newborn Infant Parasympathetic Evaluation (NIPE) index is an instrument that enables continuous, fast and objective assessment of neonatal discomfort. The aim of the study was to analyse changes in NIPE values after performance of blood draws and the factors involved in this variation.

MATERIAL AND METHODS

We conducted a prospective observational study. We included infants admitted to the neonatal intensive care unit between June and December 2021 who underwent blood draws. We recorded demographic data, aspects related to the procedure, the NIPE index and the heart rate at baseline and 1, 2, 3, 4, 5, 10 and 15 min after the procedure.

RESULTS

The study included 86 records for 49 patients. In the first 4 min after the procedure, there was a significant decrease in the NIPE index, with a maximum decrease of 22.8% relative to baseline and the nadir at 2.79 min. The decrease in NIPE values was greater in infants born preterm, male, with lower 5-min Apgar scores and following procedures that had been performed previously, after caesarean section or in the morning. There were no differences when the blood draw was obtained during kangaroo care. The correlation between the NIPE index and the heart rate was weak.

CONCLUSIONS

After a painful procedure, such as a blood draw, the NIPE monitor showed a significant decrease in the first 4 min, which was more pronounced in preterm infants, in repeated procedures or after caesarean delivery. The NIPE index could help identify infants experiencing acute procedural pain, complementing clinical rating scales.

Evaluation and Treatment of Pain in Fetuses, Neonates and Children

The perception of pain is individual and differs between children and adults. The structures required to feel pain are developed at 24 weeks of gestation. However, pain assessment is complicated, especially in neonates, infants and preschool-age children. Clinical scales adapted to age are the most used methods for assessing and monitoring the degree of pain in children. They evaluate several behavioral and/or physiological parameters related to pain. Some monitors detect the physiological changes that occur in association with painful stimuli, but they do not yet have a clear clinical use. Multimodal analgesia is recommended for pain treatment with non-pharmacological and pharmacological interventions. It is necessary to establish pharmacotherapeutic protocols for analgesia adjusted to the acute or chronic, type and intensity of pain, as well as age. The most used analgesics in children are paracetamol, ibuprofen, dipyrone, opioids (morphine and fentanyl) and local anesthetics. Patient-controlled analgesia is an adequate alternative for adolescent and older children in specific situations, such as after surgery. In patients with severe or persistent pain, it is very important to consult with specific pain services.

Clinical Assessment of Fetal Well-Being and Fetal Safety Indicators

Delivering safe clinical trials of novel therapeutics is central to enable pregnant women and their babies to access medicines for better outcomes. This review describes clinical monitoring of fetal well‐being and safety. Current pregnancy surveillance includes regular antenatal checks of blood pressure and urine for signs of gestational hypertension. Fetal and placental development is assessed routinely using the first‐trimester “dating” and mid‐trimester “anomaly” ultrasound scans, but the detection of fetal anomalies can continue throughout pregnancy using targeted sonography or magnetic resonance imaging (MRI). Serial sonography can be used to assess fetal size, well‐being, and placental function. Carefully defined reproducible imaging parameters, such as the head circumference (HC), abdominal circumference (AC), and femur length (FL), are combined to calculate an estimate of the fetal weight. Doppler analysis of maternal uterine blood flow predicts placental insufficiency, which is associated with poor fetal growth. Fetal doppler analysis can indicate circulatory decompensation and fetal hypoxia, requiring delivery to be expedited. Novel ways to assess fetal well‐being and placental function using MRI, computerized cardiotocography (CTG), serum circulating fetoplacental proteins, and mRNA may improve the assessment of the safety and efficacy of maternal and fetal interventions. Progress has been made in how to define and grade clinical trial safety in pregnant women, the fetus, and neonate. A new system for improved safety monitoring for clinical trials in pregnancy, Maternal and Fetal Adverse Event Terminology (MFAET), describes 12 maternal and 18 fetal adverse event (AE) definitions and severity grading criteria developed through an international modified Delphi consensus process. This fills a vital gap in maternal and fetal translational medicine research.

Addressing Animal Welfare Issues in Fetal Blood Collection for Fetal Bovine Serum Production

There is ethical debate over whether fetal calves suffer when their dam is slaughtered and fetal blood extracted by cardiac puncture for fetal bovine serum (FBS) production. Yet, the serum industry does not follow best practice, as recommended by the European Food Standards Agency (EFSA), to avoid fetal distress. We discuss the key elements of this debate, and recommend how the serum industry can alter its practices to improve animal welfare.

Improving Development of Drug Treatments for Pregnant Women and the Fetus

The exclusion of pregnant populations, women of reproductive age, and the fetus from clinical trials of therapeutics is a major global public health issue. It is also a problem of inequity in medicines development, as pregnancy is a protected characteristic. The current regulatory requirements for drugs in pregnancy are being analyzed by a number of agencies worldwide. There has been considerable investment in developing expertise in pregnancy clinical trials (for the pregnant person and the fetus) such as the Obstetric-Fetal Pharmacology Research Centers funded by the National Institute of Child Health and Human Development. Progress has also been made in how to define and grade clinical trial safety in pregnant women, the fetus, and neonate. Innovative methods to model human pregnancy physiology and pharmacology using computer simulations are also gaining interest. Novel ways to assess fetal well-being and placental function using magnetic resonance imaging, computerized cardiotocography, serum circulating fetoplacental proteins, and mRNA may permit better assessment of the safety and efficacy of interventions in the mother and fetus. The core outcomes in women’s and newborn health initiative is facilitating the consistent reporting of data from pregnancy trials. Electronic medical records integrated with pharmacy services should improve the strength of pharmacoepidemiologic and pharmacovigilance studies. Incentives such as investigational plans and orphan disease designation have been taken up for obstetric, fetal, and neonatal diseases. This review describes the progress that is being made to better understand the extent of the problem and to develop applicable solutions.

Pregnancy in Slaughtered Lambs and Sheep—A Cross-Sectional Study in Three Abattoirs in Switzerland

Simple Summary

The slaughtering of pregnant livestock and its relevance to animal welfare has become an ethically controversial topic. In this study, the prevalence of sheep and lambs being slaughtered while pregnant in Switzerland was assessed as well as the stage of pregnancy and the life signs of the fetuses. Data collection was carried out over one year in three Swiss abattoirs. Overall, 7.6% of the female animals were pregnant at slaughter, and 25.5% of them were in the third trimester of pregnancy, where 81.1% of the fetuses showed signs of life, such as a heartbeat or umbilical artery pulsation. To assess the relevance of animal welfare, it is discussed whether fetuses feel pain and stress. Even though science disagrees as to whether fetuses are capable of feeling conscious pain, it cannot certainly be ruled out, which is why the slaughter of pregnant sheep and lambs should be minimized as much as possible.

Abstract

The slaughter of pregnant sheep and goats is not restricted in Switzerland. The aim of this study was to assess the prevalence of pregnant sheep and lambs being slaughtered in Switzerland and to determine the state of gestation and vital signs of the fetuses in order to assess the need to take measures and raise awareness of this issue. The data collection was carried out from March 2021 to February 2022, comprising 115 days in three abattoirs. A total of 18,702 sheep and lambs were included in this cross-sectional study, and 8770 were female (46.9%), 663 of which were pregnant at slaughter (7.6%). The pregnancy rate varied by age category: 404 lambs (6.1%) and 259 sheep (11.9%) were pregnant. The highest pregnancy rate was found in winter (25.7%). Among the 663 pregnancies, more than a quarter were multiple pregnancies (28.2%). A total of 169 animals were in the third trimester of pregnancy (25.5%), where living fetuses were mainly found (81.1%). As it cannot be definitively ruled out that fetuses feel conscious pain, the data from this study underline that, from an ethical point of view, there is a need for action and that measures must be taken to reduce the number of pregnant slaughtered animals.

Fetal Pain in the First Trimester

Fetal pain perception has important implications for fetal surgery, as well as for abortion. Current neuroscientific evidence indicates the possibility of fetal pain perception during the first trimester (<14 weeks gestation). Evidence for this conclusion is based on the following findings: (1) the neural pathways for pain perception via the cortical subplate are present as early as 12 weeks gestation, and via the thalamus as early as 7–8 weeks gestation; (2) the cortex is not necessary for pain to be experienced; (3) consciousness is mediated by subcortical structures, such as the thalamus and brainstem, which begin to develop during the first trimester; (4) the neurochemicals in utero do not cause fetal unconsciousness; and (5) the use of fetal analgesia suppresses the hormonal, physiologic, and behavioral responses to pain, avoiding the potential for both short- and long-term sequelae. As the medical evidence has shifted in acknowledging fetal pain perception prior to viability, there has been a gradual change in the fetal pain debate, from disputing the existence of fetal pain to debating the significance of fetal pain. The presence of fetal pain creates tension in the practice of medicine with respect to beneficence and nonmaleficence.

Society for Maternal-Fetal Medicine Consult Series #59: The use of analgesia and anesthesia for maternal-fetal procedures

Pain is a complex phenomenon that involves more than a simple physical response to external stimuli. In maternal-fetal surgical procedures, fetal analgesia is used primarily to blunt fetal autonomic responses and minimize fetal movement. The purpose of this Consult is to review the literature on what is known about the potential for fetal awareness of pain and to discuss the indications for and the risk-benefit calculus involved in the use of fetal anesthesia and analgesia. The recommendations by the Society for Maternal-Fetal Medicine are as follows: (1) we suggest that fetal paralytic agents be considered in the setting of intrauterine transfusion, if needed, for the purpose of decreasing fetal movement (GRADE 2C); (2) although the fetus is unable to experience pain at the gestational age when procedures are typically performed, we suggest that opioid analgesia should be administered to the fetus during invasive fetal surgical procedures to attenuate acute autonomic responses that may be deleterious, avoid long-term consequences of nociception and physiological stress on the fetus, and decrease fetal movement to enable the safe execution of procedures (GRADE 2C); and (3) due to maternal risk and a lack of evidence supporting benefit to the fetus, we recommend against the administration of fetal analgesia at the time of pregnancy termination (GRADE 1C).

Society for Maternal-Fetal Medicine Consult Series #59: The use of analgesia and anesthesia for maternal-fetal procedures

Pain is a complex phenomenon that involves more than a simple physical response to external stimuli. In maternal-fetal surgical procedures, fetal analgesia is used primarily to blunt fetal autonomic responses and minimize fetal movement. The purpose of this Consult is to review the literature on what is known about the potential for fetal awareness of pain and to discuss the indications for and the risk-benefit calculus involved in the use of fetal anesthesia and analgesia. The recommendations by the Society for Maternal-Fetal Medicine are as follows: (1) we suggest that fetal paralytic agents be considered in the setting of intrauterine transfusion, if needed, for the purpose of decreasing fetal movement (GRADE 2C); (2) although the fetus is unable to experience pain at the gestational age when procedures are typically performed, we suggest that opioid analgesia should be administered to the fetus during invasive fetal surgical procedures to attenuate acute autonomic responses that may be deleterious, avoid long-term consequences of nociception and physiological stress on the fetus, and decrease fetal movement to enable the safe execution of procedures (GRADE 2C); and (3) due to maternal risk and a lack of evidence supporting benefit to the fetus, we recommend against the administration of fetal analgesia at the time of pregnancy termination (GRADE 1C).

Doppler changes in umbilical artery, middle cerebral artery, cerebroplacental ratio and ductus venosus during open fetal microneurosurgery for intrauterine open spina bifida repair

OBJECTIVE

To describe changes in fetal Doppler parameters during a novel technique for open fetal microneurosurgery for open spina bifida (OSB) repair.

METHODS

This was a prospective study of 44 fetuses undergoing open fetal surgery for OSB repair using a novel microneurosurgery approach that is characterized by a mini-hysterotomy (diameter of 15 mm), minimal fetal manipulation and maintenance of a constant normal amniotic fluid volume throughout the procedure. Doppler velocimetry of the umbilical artery (UA), fetal middle cerebral artery (MCA) and ductus venosus (DV) was performed before the start of surgery and at prespecified timepoints during fetal surgery. UA pulsatility index (PI) > 95^th percentile, DV-PI > 95^th percentile, MCA-PI < 5^th percentile and cerebroplacental ratio (CPR) < 5^th percentile were considered abnormal.

RESULTS

Median gestational age at fetal surgery was 25.2 weeks (range, 22.9-27.9 weeks). Doppler recordings were successfully obtained in all cases during all timepoints throughout the surgery. As compared with Doppler values before surgery, there was a significant increase in the proportion of fetuses with MCA-PI < 5^th percentile (63.6% vs 13.6%; P < 0.001), CPR < 5^th percentile (65.9% vs 15.9%; P < 0.001) and DV-PI > 95^th percentile (22.7% vs 0%; P = 0.01) and a non-significant increase in the proportion of fetuses with UA-PI > 95^th percentile (11.4% vs 0%; P = 0.12) during fetal surgery. None of the fetuses showed absent or reversed end-diastolic velocity in the UA or absent or reversed DV a-wave at any stage during OSB repair. All abnormal Doppler parameters returned to normal after surgery.

CONCLUSIONS

During open fetal surgery for OSB repair, a small hysterotomy, reduced fetal manipulation and maintenance of a normal amniotic fluid volume seem to prevent severe fetal Doppler abnormalities. The mild Doppler changes observed during fetal surgery could be a manifestation of fetal adaptation to the stress of fetal surgery. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Sedoanalgesia in neonatal units

Pain recognition and management continues to be a challenge for health professionals in Neonatal Intensive Care Units. Many of the patients are routinely exposed to repeated painful experiences with demonstrated short- and long-term consequences. Preterm babies are a vulnerable high-risk population. Despite international recommendations, pain remains poorly assessed and managed in many Neonatal Intensive Care Units. Due to there being no general protocol, there is significant variability as regards the guidelines for the approach and treatment of pain between the different Neonatal Intensive Care Units. The objective of this article is to review and assess the general principles of pain in the initial stages of development, its recognition through the use of standardised scales. It also includes its prevention and management with the combination of pharmacological and non-pharmacological measures, as well as to establish recommendations that help alleviate pain in daily clinical practice by optimising pain and stress control in the Neonatal Intensive Care Units.

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.

Analgesia for fetal pain during prenatal surgery: 10 years of progress

Some doubts on the necessity and safety of providing analgesia to the fetus during prenatal surgery were raised 10 years ago. They were related to four matters: fetal sleep due to neuroinhibitors in fetal blood, the immaturity of the cerebral cortex, safety, and the need for fetal direct analgesia. These objections now seem obsolete. This review shows that neuroinhibitors give fetuses at most some transient sedation, but not a complete analgesia, that the cerebral cortex is not indispensable to feel pain, when subcortical structures for pain perception are present, and that maternal anesthesia seems not sufficient to anesthetize the fetus. Current drugs used for maternal analgesia pass through the placenta only partially so that they cannot guarantee a sufficient analgesia to the fetus. Extraction indices, that is, how much each analgesic drug crosses the placenta, are provided here. We here report safety guidelines for fetal direct analgesia. In conclusion, the human fetus can feel pain when it undergoes surgical interventions and direct analgesia must be provided to it. IMPACT: Fetal pain is evident in the second half of pregnancy. Progress in the physiology of fetal pain, which is reviewed in this report, supports the notion that the fetus reacts to painful interventions during fetal surgery. Evidence here reported shows that it is an error to believe that the fetus is in a continuous and unchanging state of sedation and analgesia. Data are given that disclose that drugs used for maternal analgesia cross the placenta only partially, so that they cannot guarantee a sufficient analgesia to the fetus. Safety guidelines are given for fetal direct analgesia.

Longitudinal study on steroid hormone variations during the second trimester of gestation: a useful tool to confirm adequate foetal development

Background

The interaction of hormonal factors are crucial for good foetal development. During the second trimester of gestation, most of the main physiological processes of foetal development occur. Therefore, the aim of this study was to determine the variations in the physiological levels of cortisol, estriol, estrone sulphate, and progesterone during the second trimester (weeks 12–26) in order to establish normal ranges that can serve as indicators of foetal well-being and good functioning of the foetal-placental unit.

Methods

Saliva samples from 106 pregnant women were collected weekly (from week 12 to week 26 of gestation), and hormonal measurements were assayed by an enzyme immunoassay. The technique used for hormone measurements was highly sensitive and served as a non-invasive method for sample collection.

Results

The results revealed a statistically significant (p<0.05) difference between cortisol, progesterone, and oestrogens throughout the second trimester, with a more substantial relationship between oestrogens and progesterone [P4-E3 (r=0.427); P4-E1SO4 (r=0.419)]. By analysing these hormone concentrations, statistically significant (p<0.05) elevations in progesterone, cortisol, and estriol levels were found at the 16^th [(P4 (0.78±0.088), C(1.99±0.116), E3(2.513±0.114)]; 18th [(P4 (1.116±0.144), C(3.409±0.137), E3(3.043±0.123)] and 23rd week of gestation [(P4(1.36±0.153), C(1.936±0.11), E3(2.657±0.07)]. Estrone sulphate levels appeared to increase progressively throughout the second trimester [from 1.103±0.03 to 2.244±0.09].

Conclusion

The 18th week of gestation seems to constitute a very important week during foetal adrenal development, and the analysis of the main hormones involved in foetal development, provided more precise information regarding the proper functioning of the foetal unit and foetal development.

Fetal Pain: The Science Behind Why It Is the Medical Standard of Care

Despite pain as the fifth vital sign in adult and pediatric care, many still dismiss the fact that immature human beings (whether a fetus, a preterm, or term baby) are capable of being affected by pain. Studies have demonstrated that avoiding, minimizing, and treating pain in babies, particularly when premature, improves their outcomes. Informed by the evidence, treating neonatal pain has become the medical standard of care for physicians in neonatology and anesthesiology. This article provides a brief overview of relevant publications that explain the clinical evolution that has led to the treatment of neonatal pain. This article also examines three arguments against the existence of fetal pain and presents evidence that refutes them. Informed by the research, a revised definition of pain is offered.