Birth practices: Maternal-neonate separation as a source of toxic stress.

Maternal-neonate separation for human newborns has been the standard of care since the last century; low birth weight and preterm infants are still routinely separated from their mothers. With advanced technology, survival is good, but long-term developmental outcomes are very poor for these especially vulnerable newborns. The poor outcomes are similar to those described for adversity in childhood, ascribed to toxic stress. Toxic stress is defined as the absence of the buffering protection of adult support. Parental absence has been strictly enforced in neonatal care units for many reasons and could lead to toxic stress. The understanding of toxic stress comes from discoveries about our genome and epigenetics, the microbiome, developmental neuroscience and the brain connectome, and life history theory. The common factor is the early environment that gives (a) signals to epigenes, (b) sensory inputs to neural circuits, and (c) experiences for reproductive fitness. For human newborns that environment is direct skin-to-skin contact from birth. Highly conserved neuroendocrine behaviors determined by environment are described in this review. The scientific rationale underlying skin-to-skin contact is presented: autonomic development and regulation of the physiology leads to emotional connection and achieving resilience. Maternal-neonate separation prevents these critical neural processes from taking place, but also channel development into an alternative developmental strategy. This enables better coping in a stressful environment in the short term, but with permanently elevated stress systems that negatively impact mental and physical health in the long term. This may explain the increasing incidence of developmental problems in childhood, and also Developmental Origins of Health and Disease. Arguments are presented that maternal-neonate separation is indeed a source of toxic stress, and some suggestions are offered toward a "zero separation" paradigm.

Nurturescience versus neuroscience: A case for rethinking perinatal mother-infant behaviors and relationship.

Behavioral and emotional outcomes for babies who experienced maternal separation due to prematurity or birth defects have not improved significantly for the last 20 years. Current theories and treatment paradigms based on neuroscience have not generated explanatory mechanisms that work, or provided testable hypotheses. This article proposes a new field of scientific investigation, "nurturescience" within which new hypotheses can be tested with novel instruments. Key distinctions between neuroscience and nurturescience are described. Our definition of nurturescience is based on the basic needs of all newborns and of the needs of mothers and their families. This understanding is drawn from biology, anthropology, sociology, physiological, and clinical research. Mechanisms are described from studies on microbiota, epigenetics, allostasis, brain imaging, and developmental origins of health and adult disease. The converging message from these and other fields is that the mother-infant dyad should not be separated. Ongoing emotional connection is the cornerstone of development, leading to life-long resilience. This has implications for making the correct diagnosis (emotional disconnection vs. attachment disorder), providing the appropriate care (infant and family centered developmental care) in the biologically expected place (skin-to-skin contact), and potential for rehabilitation (calming cycle theory). Nurturescience has particular relevance to the care of "small and sick" infants, with profound potential for decreasing the "likelihood of developing developmental problems."

Historical background to maternal-neonate separation and neonatal care.

Maternal-neonate separation after birth is standard practice in the modern obstetric care. This is however a relatively new phenomenon, and its origins are described. Around 1890, two obstetricians in France expanded on a newly invented egg hatchery as a method of caring for preterm newborns. Mothers provided basic care, until incubators became part of commercial exhibitions that excluded them. After some 40 years hospitals accepted incubators, and adopted the strict separation of mothers from babies observed at the exhibitions. The introduction of artificial infant formula made the separation practical, and this also became normal practice rather than breastfeeding. Incubators and formula were unquestioned standard practices before randomized controlled trials were introduced, and therefore never subjected to such trials. The introduction of Kangaroo Care began 40 years ago in Colombia, now as a novel intervention. Recent trials do in fact show that maternal-neonate separation is detrimental to mothers and babies. Recent scientific discoveries such as the microbiome, epigenetics, and neuroimaging provide the scientific explanations that have not been available before, suggesting that skin-to-skin contact and breastfeeding are defining for the basic reproductive biology of human beings.

Hypothesis on supine sleep, sudden infant death syndrome reduction and association with increasing autism incidence.

AIM: To identify a hypothesis on: Supine sleep, sudden infant death syndrome (SIDS) reduction and association with increasing autism incidence. METHODS: Literature was searched for autism spectrum disorder incidence time trends, with correlation of change-points matching supine sleep campaigns. A mechanistic model expanding the hypothesis was constructed based on further review of epidemiological and other literature on autism. RESULTS: In five countries (Denmark, United Kingdom, Australia, Israel, United States) with published time trends of autism, change-points coinciding with supine sleep campaigns were identified. The model proposes that supine sleep does not directly cause autism, but increases the likelihood of expression of a subset of autistic criteria in individuals with genetic susceptibility, thereby specifically increasing the incidence of autism without intellectual disability. CONCLUSION: Supine sleep is likely a physiological stressor, that does reduce SIDS, but at the cost of impact on emotional and social development in the population, a portion of which will be susceptible to, and consequently express autism. A re-evaluation of all benefits and harms of supine sleep is warranted. If the SIDS mechanism proposed and autism model presented can be verified, the research agenda may be better directed, in order to further decrease SIDS, and reduce autism incidence.

Newly born low birthweight infants stabilise better in skin-to-skin contact than when separated from their mothers: a randomised controlled trial.

AIM: Routine care of low birthweight (LBW) neonates relies on incubators for stabilisation. An earlier study suggested that skin-to-skin contact achieves better physiological stability in the transition period when compared to incubator care. The aim of this study was to replicate that study with a larger sample. METHODS: A randomised controlled trial with LBW infants (1500-2500 g) randomised at birth, 50 to routine care and 50 to skin-to-skin contact, with stabilisation using the Stability of Cardio-Respiratory system in Preterms (SCRIP) score measured repeatedly over the first six hours of life as the primary outcome. RESULTS: Newly born infants in skin-to-skin contact showed better transition to extra-uterine life (p < 0.02), with the SCRIP score at 360 minutes in skin-to-skin contact being 5.82 (SD 0.66) and in maternal infant separation 5.24 (SD 0.72), p < 0.0001. In extended skin-to-skin contact care, infants had significantly less need for respiratory support, intravenous fluids and antibiotic use during the remainder of the hospital stay. CONCLUSION: Skin-to-skin contact was likely to be an optimal environment for neonates without life-threatening conditions who weighed 1500-2500 g at birth. By preventing instability that requires subsequent medical treatment, it may be life-saving in low-income countries.

Proposal for mechanisms of protection of supine sleep against sudden infant death syndrome: an integrated mechanism review.

UNLABELLED: Supine sleep decreases sudden infant death syndrome (SIDS) incidence, however the mechanisms for this are unclear. The triple risk model for SIDS requires that one or more underlying abnormalities of breathing or autonomic control are present; these are rare, but brainstem defects are found in most SIDS cases. Supine sleep increases sympathetic nervous system tone, and level of state organization, and may therefore act as a stressor. This is evidenced by physiological arousal, and by delayed neurodevelopment in supine compared to prone sleepers. It is argued here that prone sleep position is the biological normative standard in healthy infants, supporting autonomic regulation. During rapid eye movement (REM) sleep (and other circumstances), a parasympathetic-mediated adverse autonomic event (AAE) may be spontaneously triggered. In healthy infants, gasping initiates autoresuscitation and recovery. HYPOTHESIS: The underlying vulnerability to SIDS is specific to autoresuscitation from an AAE, the initial serotonin-dependent gasp is commonly compromised. Serotonin metabolism defects also influence sleep architecture, increasing the likelihood of AAE. The mechanism whereby supine sleep decreases SIDS may therefore be a stressor effect, disturbing sleep architecture to decrease REM and AAEs, and increasing sympathetic tone, which may prevent and counteract the purely parasympathetic-mediated AAE, thereby decreasing the risk of SIDS.

The neuroscience of birth--and the case for Zero Separation.

Currently, Western maternal and neonatal care are to a large extent based on routine separation of mother and infant. It is argued that there is no scientific rationale for this practice and a body of new knowledge now exists that makes a case for Zero Separation of mother and newborn. For the infant, the promotion of Zero Separation is based on the need for maternal sensory inputs that regulate the physiology of the newborn. There are harmful effects of dysregulation and subsequent epigenetic changes caused by separation. Skin-to-skin contact is the antithesis to such separation; the mother's body is the biologically 'normal' place of care, supporting better outcomes both for normal healthy babies and for the smallest preterm infants. In the mother, there are needed neural processes that ensure enhanced reproductive fitness, including behavioural changes (e.g. bonding and protection) and improved lactation, which are supported by the practice of Zero Separation. Zero Separation of mother and newborn should thus be maintained at all costs within health services.

Neonatal stomach volume and physiology suggest feeding at 1-h intervals.

UNLABELLED: There is insufficient evidence on optimal neonatal feeding intervals, with a wide range of practices. The stomach capacity could determine feeding frequency. A literature search was conducted for studies reporting volumes or dimensions of stomach capacity before or after birth. Six articles were found, suggesting a stomach capacity of 20 mL at birth. CONCLUSION: A stomach capacity of 20 mL translates to a feeding interval of approximately 1 h for a term neonate. This corresponds to the gastric emptying time for human milk, as well as the normal neonatal sleep cycle. Larger feeding volumes at longer intervals may therefore be stressful and the cause of spitting up, reflux and hypoglycaemia. Outcomes for low birthweight infants could possibly be improved if stress from overfeeding was avoided while supporting the development of normal gastrointestinal physiology. Cycles between feeding and sleeping at 1-h intervals likely meet the evolutionary expectations of human neonates.

Should neonates sleep alone?

BACKGROUND: Maternal-neonate separation (MNS) in mammals is a model for studying the effects of stress on the development and function of physiological systems. In contrast, for humans, MNS is a Western norm and standard medical practice. However, the physiological impact of this is unknown. The physiological stress-response is orchestrated by the autonomic nervous system and heart rate variability (HRV) is a means of quantifying autonomic nervous system activity. Heart rate variability is influenced by level of arousal, which can be accurately quantified during sleep. Sleep is also essential for optimal early brain development. METHODS: To investigate the impact of MNS in humans, we measured HRV in 16 2-day-old full-term neonates sleeping in skin-to-skin contact with their mothers and sleeping alone, for 1 hour in each place, before discharge from hospital. Infant behavior was observed continuously and manually recorded according to a validated scale. Cardiac interbeat intervals and continuous electrocardiogram were recorded using two independent devices. Heart rate variability (taken only from sleep states to control for level of arousal) was analyzed in the frequency domain using a wavelet method. RESULTS: Results show a 176% increase in autonomic activity and an 86% decrease in quiet sleep duration during MNS compared with skin-to-skin contact. CONCLUSIONS: Maternal-neonate separation is associated with a dramatic increase in HRV power, possibly indicative of central anxious autonomic arousal. Maternal-neonate separation also had a profoundly negative impact on quiet sleep duration. Maternal separation may be a stressor the human neonate is not well-evolved to cope with and may not be benign.