Clinical validation of the Neonatal Infant Stressor Scale with preterm infant salivary cortisol

Effect of Routine Nurse Caregiving on the Stress Responses and Behavior State in Preterm Infants: A Systematic Review

BACKGROUND

Although routine nurse caregiving is vital for the overall health of preterm infants, variations in approaches may exert distinct effects on preterm infants' stress responses and behavior state.

PURPOSE

The purpose of this systematic review was to examine routine nurse caregiving in the neonatal intensive care unit and its effect on stress responses and behavior state in preterm infants.

DATA SOURCES

A systematic search was conducted using PubMed, Embase, and CINAHL for studies published between 2013 and 2023.

STUDY SELECTION

Included studies enrolled preterm infants born <37 weeks gestational age and investigated nurse caregiving practices and effects on stress responses and/or behavior state.

DATA EXTRACTION

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, data about study design, methods, findings, and limitations were extracted and summarized. Included studies were evaluated for bias using the National Health, Lung, and Blood Institute quality assessment tools.

RESULTS

All 13 studies included in the review received a fair quality rating. Nurse caregiving activities, including suctioning, diaper changes, bathing, and weighing, were associated with increases in heart and respiratory rates, blood pressure, energy expenditure, and motor responses, lower oxygen saturations, and fewer sleep states.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Adapting nurse caregiving frequency and duration, aligning caregiving with infant state, and integrating developmental care strategies may reduce infant stress responses and support behavioral rest. Further research is needed to understand how caregiving activities affect stress responses and behavior state in preterm infants, aiding in identifying modifiable caregiving stressors to promote optimal development.

Deep learning to quantify care manipulation activities in neonatal intensive care units

Early-life exposure to stress results in significantly increased risk of neurodevelopmental impairments with potential long-term effects into childhood and even adulthood. As a crucial step towards monitoring neonatal stress in neonatal intensive care units (NICUs), our study aims to quantify the duration, frequency, and physiological responses of care manipulation activities, based on bedside videos and physiological signals. Leveraging 289 h of video recordings and physiological data within 330 sessions collected from 27 neonates in 2 NICUs, we develop and evaluate a deep learning method to detect manipulation activities from the video, to estimate their duration and frequency, and to further integrate physiological signals for assessing their responses. With a 13.8% relative error tolerance for activity duration and frequency, our results were statistically equivalent to human annotations. Further, our method proved effective for estimating short-term physiological responses, for detecting activities with marked physiological deviations, and for quantifying the neonatal infant stressor scale scores.

Identification of Inflammatory Mediators in Saliva Samples From Hospitalized Newborns: Potential Biomarkers?

Saliva measurements serve as a noninvasive tool for clinically monitoring newborns (NB) and children, a vulnerable population with promising potential for both research and clinical practice. Saliva acts as a repository for various inflammatory biomarkers involved in diverse biological functions. Particularly for children, it offers numerous advantages when compared to plasma and urine sampling. Nevertheless, there is a significant knowledge gap regarding detectable levels of cytokines in the saliva of newborns and children, as well as studies aiming to assess the relationship of this content with physiological and pathological processes.

OBJECTIVES

To characterize the levels of 11 inflammatory mediators (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF) in saliva samples from NB on the first and second day of hospitalization in the Neonatal Intensive Care Unit (NICU).

METHOD

Exploratory study, descriptive, nested within a primary clinical, observational, and prospective study, conducted in the NICU of a public hospital in São Paulo, Brazil. Demographic data and vital signs were recorded in the clinical records of 90 NB, and five saliva samples from 5 NB were collected between the first and second day of life (D1-D2) at approximately 8-hr intervals (8-9 am, 4-5 pm, and 11-12 pm). Saliva samples were used for the measurement of 11 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF).

RESULTS

Five NBs participated in this exploratory study, and the vital signs showed variability from the first (D1) to the second day (D2) of hospitalization, variability similar to that of the total population of the primary study. The presence and levels of the 11 cytokines were detected in the saliva samples, as well as a statistical correlation between 10 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL10, IL12, IL17, TNF, and VEGF) and vital signs.

CONCLUSIONS

The novelty of measuring inflammatory mediators in saliva samples from hospitalized NBs in the NICU is highlighted, providing support and new perspectives for the development of clinical and experimental research and an opportunity for developing and implementing new salivary biomarkers in different population segments.

Impact of Parent Presence and Engagement on Stress in NICU Infants

BACKGROUND

Infants in neonatal intensive care units (NICUs) are exposed to frequent stressors that impact their neurodevelopmental outcomes. Parent presence and engagement are considered critical to improving infant outcomes, yet associations between cumulative NICU parent presence, engagement, and infant stress are infrequently examined.

PURPOSE

To examine associations between NICU infant stress and the amount (hours per week) or frequency (days per week) of parent presence and skin-to-skin care (SSC).

METHODS

A secondary analysis of a data set representing 78 NICU families was conducted. Infant acuity was measured using Neonatal Medical Index (NMI) scores. Parent presence and SSC data were collected from electronic medical records. Infant stress was measured using resting salivary cortisol levels collected at NICU discharge (median = 33 days of life).

RESULTS

More cumulative SSC was associated with lower discharge cortisol in NICU infants for SSC measured in hours per week (P = .03) or days per week (P = .05). Cumulative parent presence was not significantly associated with infant cortisol at discharge. Hierarchical regression analyses examining timing of parent presence supported a model including admission cortisol, NMI score, and parent presence during weeks 1 to 4 of life for explaining infant stress at discharge (R2 = 0.44, P = .004). Analyses examining timing of SSC supported a model including admission cortisol, NMI score, and frequency of SSC during week 1 for explaining infant stress at discharge (R2 = 0.21, P = .04).

IMPLICATIONS FOR PRACTICE AND RESEARCH

Early, frequent SSC to mitigate stress in NICU infants was supported. Results suggested that timing of parent presence impacts NICU infant stress; however, additional study is recommended.

Health disparities in preterm births

Introduction

Black African American (B/AA) women have a 2-fold to 3-fold elevated risk compared with non-Hispanic White (W) women for preterm birth. Further, preterm birth is the leading cause of mortality among B/AA infants, and among survivors, preterm infant adverse health outcomes occur disproportionately in B/AA infants. Racial inequities in maternal and infant health continue to pose a public health crisis despite the discovery >100 years ago. The purpose of this study was to expand on reported preterm infant outcome disparities. A life-course approach, accumulation of lifelong stress, including discrimination, may explain social factors causing preterm birth rate and outcome inequities in B/AA mothers.

Methods

Anthropometric measures and clinical treatment information for 197 consented participants were milled from electronic health records across 4 years. The Neonatal Infant Stressor Scale was used to tally acute and chronic painful/stressful procedures. Neurobehavioral differences were investigated using the Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scale.

Results

B/AA mothers gave birth to preterm infants earlier than W mothers. NICU hospitalization stays were extended more than 2 weeks for the significantly smaller B/AA preterm infants in comparison to the age-matched W preterm infants. A higher number of chronic lifesaving procedures with demonstrated altered stress response patterns were recorded for B/AA preterm infants.

Discussion

This cross-sectional analysis of preterm birth rates and preterm infant developmental and neurodevelopmental outcomes are presented in the context of NICU stress and pain, with attendant implications for infant mortality and future health disparities. Preterm birth rate and outcome inequities further support the need to develop interventions and policies that will reduce the impact of discrimination and improve social determinants of health for Black, Indigenous, and other People of Color.

The effect of the swaddling method on stress levels in newborns administered nasal CPAP

BACKGROUND

This study aims to investigate the effects of the swaddling method on the stress levels in newborns receiving nasal continuous positive airway pressure (nCPAP).

METHODS

The study was conducted between 1 June 2022 and 1 October 2022 with 40 newborns who underwent nCPAP in the second-level Neonatal Intensive Care Unit (NICU) of a city hospital in the Central Anatolia Region of Turkey. Data were collected using a descriptive form, including the characteristics of newborns, a patient follow-up chart, and the Newborn Stress Scale (NSS). The descriptive form, the patient follow-up chart, and the NSS were completed by the researcher 30 min after the nCPAP was started and the first saliva sample was taken. The patient follow-up chart and NSS were completed 30 min after applying the swaddling method and the second saliva sample was collected. The data were analyzed using IBM SPSS Statistics 25.0 package software and presented with number, percentage, mean, standard deviation, min-max, and t-test.

RESULTS

The study found that the mean score of the NSS after the intervention (3.52 ± 2.57) was lower than that before the intervention (10.02 ± 2.05) (p < 0.05). The mean saliva cortisol levels of the newborns after the intervention (4.99 ± 1.89) were lower than before the intervention (5.51 ± 1.65) (p < 0.05). The mean heart (135.50 ± 14.15) and respiratory rates (68.07 ± 10.16) of the newborns after the intervention were lower than those before the intervention (140.82 ± 18.11; 72.95 ± 9.06, respectively) (p < 0.05). There was no difference between the mean oxygen saturation of newborns before and after the intervention (p > 0.05).

CONCLUSIONS

The study showed that the swaddling method played a role in reducing the stress levels in newborns who underwent nCPAP. It is recommended that randomized controlled trials examining the effect of swaddling on the stress levels of newborns who underwent nCPAP be conducted.

Feasibility of Stress Research in Premature Infant-Maternal Dyads During and After Neonatal Intensive Care Unit Hospitalization

BACKGROUND

Stress from preterm infant admission to the neonatal intensive care unit (NICU) is associated with infant and maternal physiologic changes, including endocrine and epigenetic alterations. Little is known about the mechanisms connecting NICU stress to biologic changes, and whether preterm infant and maternal stress are reciprocal. As a preliminary step, feasibility and acceptability of measuring indicators of stress are required.

PURPOSE

This study evaluated the feasibility and acceptability of research examining perceptions and biologic markers of stress in premature infant-maternal dyads during and after NICU hospitalization.

METHODS

We evaluated study feasibility using a longitudinal descriptive design. Acceptability was measured via a maternal questionnaire. Exploratory data regarding hospitalization, perceptions of stress, social support and social determinants of health, and biologic markers of stress were collected during the first week of life and again 3 months after NICU.

RESULTS

Forty-eight mothers were eligible for the study, 36 mothers were approached, 20 mothers consented to participate, and 14 mothers completed data collection. Mothers reported high levels of study acceptability despite also voicing concern about the sharing of genetic data. Exploration of DNA methylation of SLC6A4 in preterm infants was significant for a strong correlation with perception of total chronic stress.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Clinical practice at the bedside in the NICU should include standardized screening for and early interventions to minimize stress. Complex research of stress is feasible and acceptable. Future research should focus on linking early life stress with epigenetic alterations and evaluation of the dyad for reciprocity.

Neonatal stress and behavior problems in preschool children born preterm

The aim of the present longitudinal study was to examine the effect of preterm childbirth, acute neonatal stress, and child behavior at 18-36 months of age on later behavior outcomes in 4-5-year-old children. The sample comprised of 70 children who were born preterm. The neonatal characteristics of children were assessed during hospitalization by reviewing their medical records and utilizing the Neonatal Infant Stressor Scale. Behavior problems were evaluated by the maternal-report in the Child Behavior Checklist 1½-5 years. A multiple linear regression analysis was conducted. Also, the repeated measures analysis of variance and the McNemar test for paired samples were performed. Daily exposure of the infants to high neonatal acute stress during NICU hospitalization and more behavior problems at 18-36 months of age was associated with more total and externalizing behavior problems at 4-5 years of age. Lower gestational age at childbirth and more internalizing behavior problems at 18-36 months was associated with more internalizing problems at 4-5 years old. The present study showed the combination of predictors of neonatal conditions and behavioral problems at childhood, highlighting the relevance of the implementation of developmental care in the NICU and follow-up the preterm infants after discharge programs.

Environmental influences on child health outcomes: cohorts of individuals born very preterm

The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) Program was designed to address solution-oriented research questions about the links between children's early life environment and their risks of pre-, peri-, and post-natal complications, asthma, obesity, neurodevelopmental disorders, and positive health. Children born very preterm are at increased risk for many of the outcomes on which ECHO focuses, but the contributions of environmental factors to this risk are not well characterized. Three ECHO cohorts consist almost exclusively of individuals born very preterm. Data provided to ECHO from cohorts can be used to address hypotheses about (1) differential risks of chronic health and developmental conditions between individuals born very preterm and those born at term; (2) health disparities across social determinants of health; and (3) mechanisms linking early-life exposures and later-life outcomes among individuals born very preterm. IMPACT: The National Institutes of Health's Environmental Influences on Child Health Outcomes Program is conducting solution-oriented research on the links between children's environment and health. Three ECHO cohorts comprise study participants born very preterm; these cohorts have enrolled, to date, 1751 individuals born in 14 states in the U.S. in between April 2002 and March 2020. Extensive data are available on early-life environmental exposures and child outcomes related to neurodevelopment, asthma, obesity, and positive health. Data from ECHO preterm cohorts can be used to address questions about the combined effects of preterm birth and environmental exposures on child health outcomes.

Cortisol awakening response and developmental outcomes at 6-7 years in children born extremely preterm

BACKGROUND

Extremely preterm (EPT) birth has been related to dysregulation of stress responses and behavioral/learning problems at school age. Early adverse experiences can blunt HPA axis reactivity. We hypothesized that an attenuated cortisol awakening response would be associated with developmental and behavioral problems at school age in EPT children.

METHODS

This secondary analysis of a sub-cohort of the SUPPORT study included children born between 24 and 27 weeks, evaluated at 6-7 years with a neurodevelopmental battery and cortisol measures. Differences were tested between EPT and a term-born group. Relationships of cortisol awakening response to test scores were analyzed.

RESULTS

Cortisol was measured in 110 EPT and 29 term-born 6-7 year olds. Unadjusted WISC-IV and NEPSY-II scores were significantly worse among EPT children only. Conners Parent Rating Scale behavior scores were significantly worse among EPT children. After adjusting for covariates, blunted cortisol awakening responses were found to be associated with poorer scores on memory tests and greater problems with inattention for the EPT group (p < 0.05) only.

CONCLUSIONS

Among children born EPT, we identified an association of blunted cortisol awakening response with memory and inattention problems. This may have implications related to stress reactivity and its relationship to learning problems in children born EPT.

CLINICALTRIALS

GOV ID

Extended Follow-up at School Age for the SUPPORT Neuroimaging and Neurodevelopmental Outcomes (NEURO) Cohort: NCT00233324.

IMPACT

In children born EPT, stress reactivity may have a relationship to learning problems. Cortisol awakening response should be a component for follow-up in EPT born children. Components of executive function, such as memory and attention, are related to stress reactivity.

Quantification of stress exposure in very preterm infants: Development of the NeO-stress score

BACKGROUND

Stress during treatment at the Neonatal Intensive Care Unit (NICU) has long-term negative consequences on preterm infants' development.

AIMS

We developed an instrument suited to validly determine the cumulative stress exposure for preterm infants in a NICU.

STUDY DESIGN

This survey study made use of two consecutive questionnaires.

SUBJECTS

NICU nurses and physicians from the nine NICUs in the Netherlands.

OUTCOME MEASURES

First, respondents rated the relevance of 77 items encompassing potentially stressful procedures, commented on their comprehensibility and the comprehensiveness of the list. We calculated the content validity per item (CVI-I) and included only the relevant items in a second questionnaire in which the participants rated the stressfulness from 0 (not stressful) to 10 (extremely stressful). A stressfulness index - representing the median score - was calculated for each included item.

RESULTS

Based on the CVI-I of the 77 items, step 1 resulted in 38 items considered relevant to quantify stress in preterm infants during the first 28 days of life. This list of 38 items exists of 34 items with a CVI-I if 0.78 or higher, one of these items was split into two items, and three items were added to improve comprehensiveness. The stressfulness index ranged from five to nine.

CONCLUSIONS

The NeO-stress score consists of stressful items including their severity index and was developed to determine cumulative stress exposure of preterm infants. Evaluating the cross-cultural validity, correlating it to behavioural and biological stress responses, and evaluating its ability to predict preterm infants at risk for the negative effects following stress might expand the possibilities for this instrument.

Trends of fecal calprotectin levels and associations with early life experience in preterm infants

Background

Preterm infants are at risk for severe infections due to their immature immune systems. Factors such as early life pain/stress experiences and feeding may influence immune activation and maturation of immune systems. However, the underlying mechanism remains unclear. Fecal calprotectin (FCP) is a noninvasive surrogate biomarker of mucosal inflammation in the gastrointestinal tract and has been used in detecting intestinal inflammation in specific pediatric gastrointestinal disorders.

Objective

To describe the longitudinal trajectory of FCP levels in preterm infants and investigate the contributing factors that are associated with FCP levels.

Design

A longitudinal study design was used.

Settings

Preterm infants were recruited from 2 neonatal intensive care units (NICU) of a children's medical center in the North-eastern US.

Methods

Preterm infants were followed during their first 4 weeks of NICU hospitalization. Stool samples were collected twice per week to quantify the FCP levels. Cumulative pain/stress experiences and feeding types were measured daily. A linear mixed-effect model was used to examine the associations between FCP levels and demographic and clinical characteristics, cumulative pain/stress, and feeding over time.

Results

Forty-nine preterm infants were included in the study. Infants' FCP levels varied largely with a mean of 268.7±261.3 µg/g and increased over time. Preterm infants experienced an average of 7.5±5.0 acute painful procedures and 15.3±20.8 hours of chronic painful procedures per day during their NICU stay. The mean percentage of mother's own milk increased from the first week (57.1±36.5%) to the fourth week (60.7±38.9%) after birth. Elevated FCP concentration was associated with acute and cumulative (chronic) pain/stress levels, mother's own milk, non-White race, and higher severity of illness score.

Conclusions

FCP levels were elevated in preterm infants with wide interindividual and intraindividual variations. Cumulative pain/stress during the NICU hospitalization, feeding, race, and health status may influence FCP concentrations in early life that may be associated with inflammatory gut processes.

NICU-based stress response and preterm infant neurobehavior: exploring the critical windows for exposure

BACKGROUND

Exposure to maternal stress in utero negatively impacts cognitive and behavioral outcomes of children born at term. The neonatal intensive care unit (NICU) can be stressful for preterm infants during a developmental period corresponding to the third trimester of gestation. It is unknown whether stress in the NICU contributes to adverse neurodevelopment among NICU graduates. The aim was to examine the association between salivary cortisol and early neurodevelopment in preterm infants.

METHODS

We examined the association between cortisol levels during the NICU hospitalization and subsequent performance on the NICU Network Neurobehavioral Scales (NNNS), estimating time-specific associations and considering sex differences.

RESULTS

Eight hundred and forty salivary cortisol levels were measured from 139 infants. Average cortisol levels were inversely associated with NNNS Regulation scores for both male and female infants (β = -0.19; 95% CI: -0.44, -0.02). Critical developmental windows based on postmenstrual age were identified, with cortisol measured <30 weeks PMA positively associated with Habituation and Lethargy scores (β = 0.63-1.04). Critical developmental windows based on chronological age were identified, with cortisol measured in the first week of life inversely associated with Attention score (β = -1.01 for females; -0.93 for males).

CONCLUSIONS

Stress in the NICU at specific developmental time points may impact early preterm infant neurodevelopment.

IMPACT

Stress in the neonatal intensive care unit can impact the neurodevelopmental trajectory of premature infants. The impact of stress is different at different points in development. The impact of stress is sexually dimorphic.

Perinatal and early childhood biomarkers of psychosocial stress and adverse experiences

The human brain develops through a complex interplay of genetic and environmental influences. During critical periods of development, experiences shape brain architecture, often with long-lasting effects. If experiences are adverse, the effects may include the risk of mental and physical disease, whereas positive environments may increase the likelihood of healthy outcomes. Understanding how psychosocial stress and adverse experiences are embedded in biological systems and how we can identify markers of risk may lead to discovering new approaches to improve patient care and outcomes. Biomarkers can be used to identify specific intervention targets and at-risk children early when physiological system malleability increases the likelihood of intervention success. However, identifying reliable biomarkers has been challenging, particularly in the perinatal period and the first years of life, including in preterm infants. This review explores the landscape of psychosocial stress and adverse experience biomarkers. We highlight potential benefits and challenges of identifying risk clinically and different sub-signatures of stress, and in their ability to inform targeted interventions. Finally, we propose that the combination of preterm birth and adversity amplifies the risk for abnormal development and calls for a focus on this group of infants within the field of psychosocial stress and adverse experience biomarkers. IMPACT: Reviews the landscape of biomarkers of psychosocial stress and adverse experiences in the perinatal period and early childhood and highlights the potential benefits and challenges of their clinical utility in identifying risk status in children, and in developing targeted interventions. Explores associations between psychosocial stress and adverse experiences in childhood with prematurity and identifies potential areas of assessment and intervention to improve outcomes in this at-risk group.

Quality Improvement Initiative in the NICU for Improved Practice of Cuff Blood Pressure Measurements

BACKGROUND

Extreme preterm infants face lengthy hospitalizations and are often subjected to painful stimuli. These stimuli may be related to routine caregiving that may negatively impact long-term developmental outcomes. Frequently obtained cuff blood pressure (BP) measurements are an example of a potentially noxious stimulus to preterm infants that may have a cumulating impact on development.

PURPOSE

The primary aim was to explore the frequency of cuff BP measurements obtained in hemodynamically stable extreme preterm infants in the neonatal intensive care unit (NICU). Our secondary aim was to reduce the number of cuff BP measurements obtained in hemodynamically stable extreme preterm infants in the NICU.

METHODS

Quality improvement methodologies per the Institute for Healthcare Improvement were used combined with a multidisciplinary approach. Participants were infants born less than 27 weeks of gestation and discharged home. The baseline period was 2015 through Q2-2018 and the intervention period was Q3-2018 through Q1-2020. The electronic medical record was used to collect data and Minitab Statistical Software was used for data analysis.

FINDINGS/RESULTS

A baseline of 5.0% of eligible patients received the desired number of cuff BP measurements and increased to 63.2% after the intervention period.

IMPLICATIONS FOR PRACTICE

Findings demonstrate that using quality improvement methodology can improve clinical care. Findings suggest the feasibility and safety of reducing the number of cuff BP measurements obtained on hemodynamically stable infants in the NICU.

IMPLICATIONS FOR RESEARCH

Future endeavors should aim to reduce the quantity of painful stimuli in the NICU. Long-term developmental outcomes should be correlated in these patients.

Descriptive Longitudinal Pilot Study: Behaviors Surrounding Feeding of Preterm Infants Who Received Extended Tube Feedings

Purpose

Seventy percent of preterm infants experience challenges with oral feeding and commonly require tube feedings. Yet it is not well understood how these behaviors change over time while infants are receiving tube feedings only and through the transition to oral feedings. The purpose of this pilot study was to describe the change in behaviors surrounding feeding and with respect to advancing Post Menstrual Age (PMA) for preterm infants who received extended tube feedings during hospitalization in the Neonatal Intensive Care Unit (NICU).

Methods and measures

A prospective pilot study was conducted in a NICU. We recruited thirty-five infants who were born between 28 to 32 weeks gestational age and expected to have at least two weeks of tube feedings. Infant health status and feeding progression were obtained from the medical record. Behaviors surrounding feeding included infant state, social interactive behaviors, orally directed behaviors, and hunger/satiation cues were evaluated via weekly recorded videos.

Results

During the pre-feeding segment, we noted an increase over time for awake, facial gaze, gaze aversion, tongue protrusion, fussing, mouthing, vocalization, and interest in the pacifier. During the intra-feeding segment, we found an increase over time for fussing, and a decrease for eye widening, eye searching, and vocalization.

Conclusion

To our knowledge, this was the first pilot study to comprehensively describe the changes in behaviors surrounding feeding over time and with respect to advancing PMA for preterm infants who received extended tube feedings during the NICU hospitalization. Infants demonstrated distinct behaviors surrounding feeding as young as 28 weeks post menstrual age. These behaviors may vary among infants and change significantly with advancing post-menstrual age. Assessment of subtle behaviors surrounding feeding is important to ensure oral feeding readiness.

Stabilization of Salivary Biomarkers

The use of saliva as a diagnostic biofluid has been increasing in recent years, thanks to the identification and validation of new biomarkers and improvements in test accuracy, sensitivity, and precision that enable the development of new noninvasive and cost-effective devices. However, the lack of standardized methods for sample collection, treatment, and storage contribute to the overall variability and lack of reproducibility across analytical evaluations. Furthermore, the instability of salivary biomarkers after sample collection hinders their translation into commercially available technologies for noninvasive monitoring of saliva in home settings. The present review aims to highlight the status of research on the challenges of collecting and using diagnostic salivary samples, emphasizing the methodologies used to preserve relevant proteins, hormones, genomic, and transcriptomic biomarkers during sample handling and analysis.

Maternal Anxiety, Infant Stress, and the Role of Live-Performed Music Therapy during NICU Stay in The Netherlands

Having an infant in the neonatal intensive care unit (NICU) elicits maternal anxiety, which may hamper parent-child bonding. We performed a prospective cohort study to describe anxiety in mothers of infants born before 30 weeks of gestation during NICU stay in The Netherlands, and investigated the influence of infant stress and gestational age. Second, we performed a randomized-controlled live-performed music therapy trial (LPMT trial) to investigate whether music therapy applied to the infant alleviated maternal anxiety. The relation between infant stress, gestational age, and maternal anxiety was measured in 45 mother-infant dyads, using the Neonatal Infant Stressor Scale and the State-Trait Anxiety Inventory (STAI). The effect of LPMT on anxiety was assessed in 21 mothers whose infants were assigned to either LPMT (n = 12) or waitlist (n = 9). Mothers completed the STAI before and after this period. Maternal anxiety decreased over time in all mothers, and was strongly related with infant stress (r = 0.706, p < 0.001), but not with gestational age. Anxiety scores decreased by 12% after LMPT, and increased by 1% after a waitlist period (p = 0.30). Our results indicate that LPMT in the weeks after birth may accelerate the reduction of maternal anxiety. Further research should focus on the effects on mother-child bonding.

Mothers' voices and white noise on premature infants' physiological reactions in a neonatal intensive care unit: A multi-arm randomized controlled trial

BACKGROUND

A few positive effects of mothers' voice on physiological outcomes have been studied and limited studies have focused on the level of cortisol. In addition, white noise has recently been found to be beneficial for human sleep, but studies in premature infants were limited and no study has compared the effects of mothers' voice and white noise on premature infants.

OBJECTIVE

To examine the effects of mothers' voice and white noise on sleep-wake patterns, salivary cortisol levels, weight gain, heart rate, and oxygen saturation of premature infants in a neonatal intensive care unit (NICU).

METHODS

This was a three-group randomized controlled trial. A total of 103 medically stable premature infants in incubators were recruited from the NICU of a women's and children's hospital in China between March and December 2017 and were randomized into three groups: the mothers' voice group (n = 34), the white noise group (n = 34), and the routine care group (n = 35). Mothers' voice, white noise, and no voice were provided to the three groups for 20 min at a time, three times a day for four consecutive days. The sound levels of the mothers' voice and white noise were controlled between 50 and 55 dB. Sleep-wake patterns, salivary cortisol level, and weight were measured at pre-test and post-test whereas heart rate and oxygen saturation were measured every five-minute at 11am, 2pm, 5pm for four-consecutive days.

RESULTS

A group difference was found only in weight gain (p = 0.003), with weight gain in the white noise group being significantly higher than the mothers' voice group (Z=-3.447, p = 0.001). Significant declines in total sleep time and sleep efficiency and increases in wake time after sleep onset and average awakening time were only found in the routine-care group between the pre-test and post-test (p<0.05). No significant differences were found in the salivary cortisol levels, heart rates, and oxygen saturation levels among the three groups (p>0.05). A significant increase in oxygen saturation during the 20-min intervention was found in white noise group. Non-significant decreases in the heart rate during the 20-min intervention and salivary cortisol levels at post test were noted in all the three groups.

CONCLUSION

White noise is more useful for encouraging weight gain in preterm infants compared with mothers' voices. White noise might be introduced for use in the care of premature infants in NICUs, and more high-quality randomized controlled trials are needed to confirm these findings. Trial Registration No: ChiCTR-INR-17012755.