Effects of nutritive and non-nutritive sucking on infant heart rate variability during the first 6 months of life

Soothing touch matters: Patterns of everyday mother-infant physical contact and their real-time physiological implications

Physical contact between infants and caregivers is crucial for attachment development. Previous research shows that skin-to-skin contact after birth and frequent baby wearing in the first year predict secure attachment at 12-months. This relationship is thought to be mediated by the activation of infants' parasympathetic nervous system through caregiver touch. However, little is known about everyday touch behaviors and their impact on infants' real-time parasympathetic activity. Laboratory observations may not accurately represent real-world interactions, highlighting the need for ecologically valid studies. To address this, we examined everyday dyadic touch behaviors and their real-time effects on infant parasympathetic activation. We video recorded N = 28 infants (1-10 months old) and their mothers at home for behavioral analyses. All infants wore wireless ECG sensors (1024 Hz) during video recordings, and n = 21 infants had high-quality ECG data that could be used for Respiratory Sinus Arrhythmia analyses. We used a dynamic measure of RSA (updated every 200 ms) as an index for real-time parasympathetic activation. We found that dyads touch interactions at home involve short, though highly variable bouts of physical contact, that change with infant age. Younger infants spent more time remaining stationary during contact and receiving more soothing touch compared to older infants. Only soothing touch - i.e., rocking, patting, bouncing, or stroking- led to immediate, significant increases in parasympathetic activity (RSA), and this effect was driven by younger infants. This study provides new insights into the ecological patterns of touch in early development and the biobehavioral mechanisms promoting secure attachment.

Breastfeeding duration and vagal regulation of infants and mothers

BACKGROUND

Vagal regulation within the parasympathetic nervous system supports self-regulation and social engagement. Research has suggested that early feeding practices may influence mother-infant vagal functioning.

AIM

We aimed to examine the association between breastfeeding duration and mother-infant vagal regulation during an interaction. We hypothesized that breastfeeding duration would be positively associated with adaptive vagal regulation in infants and mothers.

METHOD

204 mother-infant dyads (infant mean age 6 months) completed the face-to-face still-face (FFSF) task. During the task, vagal regulation indexed by respiratory sinus arrhythmia (RSA, a component of heart rate variability) was calculated through continuously recorded electrocardiogram signals. Breastfeeding duration and demographic information were reported by mothers. Linear mixed models were adopted to estimate the associations between breastfeeding duration and repeated measures of RSA in infants and mothers throughout the FFSF.

RESULTS

Infants breastfed for a longer duration demonstrated lower RSA throughout the FFSF (B = -0.06, 95 % CI: -0.09 to -0.03), suggesting active physiological mobilization to engage in interaction and regulate distress. Mothers with longer breastfeeding duration displayed higher baseline RSA and higher overall RSA levels (higher vagal control) during the FFSF (B = 0.06, 95 % CI: 0.02 to 0.09), indicating a calmer and regulated state.

CONCLUSION

Longer breastfeeding duration was associated with more adaptive mother-infant vagal regulation during the interaction, indicating a positive dose-response association. This finding reveals breastfeeding practice as a factor contributing to infant effective vagal regulation and further supports WHO recommendation on exclusive breastfeeding for the first 6 months and continuing breastfeeding to 24 months and beyond.

Impact of umbilical cord arterial pH, gestational age, and birth weight on neurodevelopmental outcomes for preterm neonates

Background

The aim of this study was to determine the impact of umbilical cord arterial pH, gestational age, and birth weight on neurodevelopmental outcomes for preterm neonates.

Methods

We examined 112 neonates. Inclusion criteria were: Saturations greater than 88%, and heart rates between 100–205 beats per minute.

Measurements

We assessed several neurodevelopmental factors as part of the Brazelton Neonatal Behavioral Assessment Scale (NBAS), 4th edition, such as asymmetric tonic neck reflex (ATNR), motor maturity, response to sensory stimuli, habituation, and state regulation. Initial assessment parameters such as APGAR score and umbilical cord arterial pH were used to assess neonates.

Results

We found a strong correlation between the presence of the sucking reflex and umbilical cord arterial pH (r = 0.32; p = 0.018981). Umbilical cord arterial pH was also correlated with the presence of asymmetric tonic neck reflex (r = 0.27; p = 0.047124), cost of attention (r = 0.31; p = 0.025381) and general motor maturity (r = 0.34; p = 0.011741).

Conclusions

We found that the sucking reflex may be affected in infants with low umbilical cord arterial pH values. Practitioners and parents can use the NBAS to help determine neurodevelopmental factors and outcomes in preterm infants, possibly leading to safer and more effective feeding practices and interventions.

Improving neurodevelopment in infants with complex congenital heart disease

Worldwide, more than 400,000 infants are born each year with complex congenital heart disease (CCHD) requiring surgical intervention within the first months of life. Although improvements in perioperative care have resulted in increased rates of survival, more than half of infants with CCHD have neurodevelopmental impairments affecting subsequent educational achievements, job opportunities, and mental health. Brain maturity and impaired outcomes in infants with CCHD are similar to those of prematurely born infants. Developmentally supportive care, including foundational application of kangaroo care (KC), improves neurodevelopment in premature infants. Provision of developmentally supportive care with KC during the early hospitalization of infants with CCHD has the potential to similarly improve neurodevelopment. The purposes of the article are to describe common congenital heart defects, describe developmentally supportive care with an emphasis on KC, and to offer specific recommendations for KC and research in infants with CCHD.

Autonomic Nervous System Function After a Skin-to-Skin Contact Intervention in Infants With Congenital Heart Disease

BACKGROUND

Infants with complex congenital heart disease (CCHD) demonstrate impaired autonomic nervous system (ANS) regulation, which may contribute to commonly observed impairments in feeding, growth, and development. Close mother-infant physical contact improves ANS function in other high-risk infant populations.

OBJECTIVE

Our purposes were to examine feasibility of a 2-week daily skin-to-skin contact (SSC) intervention and to describe change in ANS function in response to the intervention.

METHODS

Feasibility was assessed by recruitment and retention rates, safety, and acceptability. Autonomic nervous system function was measured with linear and nonlinear measures of heart rate variability (HRV) during a feeding before the 14-day SSC intervention and 3 times during a 4-week follow-up.

RESULTS

Recruitment rate was 72%; retention rate was 55.5%. Mothers were universally positive about SSC. Ten mothers and infants completed a daily mean of 77.05 minutes of SSC during the 14-day intervention with no adverse events. Baseline high-frequency HRV, reactivity to challenge, and recovery after challenge improved during the 6-week study. Nonlinear measures demonstrated abnormally high sympathetic activity, especially after feeding, in most infants.

CONCLUSIONS

Skin-to-skin contact is feasible in infants with CCHD. Linear measures of HRV suggested improvements in ANS function with this intervention. This article is one of the first to describe nonlinear HRV measures in infants with CCHD. Additional research is needed to identify variations in linear and nonlinear effects based on specific cardiac conditions and with varying intervention doses and timing. This low-cost, low-risk intervention has the potential to improve outcomes in infants with CCHD.

Cardiovascular autonomic dysfunction in sudden infant death syndrome

A failure of cardiorespiratory control mechanisms, together with an impaired arousal response from sleep, are believed to play an important role in the final event of sudden infant death syndrome (SIDS). The 'triple risk model' describes SIDS as an event that results from the intersection of three overlapping factors: (1) a vulnerable infant, (2) a critical developmental period in homeostatic control and (3) an exogenous stressor. In an attempt to understand how the triple risk hypothesis is related to infant cardiorespiratory physiology, many researchers have examined how the known risk and protective factors for SIDS alter infant cardiovascular control during sleep. This review discusses the association between the three components of the triple risk hypothesis and major risk factors for SIDS, such as prone sleeping, maternal smoking, together with three "protective" factors, and cardiovascular control during sleep in infants, and discusses their potential involvement in SIDS.

Psychoanalytic Thoughts on the European Refugee Crisis and the Other

There are many aspects-political, economic, legal, medical, cultural, religious-of the present refugee crisis in Europe. Difficulties at border crossings, settlement programs, life-saving issues, and security measures come to mind immediately, but the refugee crisis also needs to be examined from a psychological angle. This paper outlines psychoanalytic findings on voluntary and forced immigration and human responses to the Other. Change in the twenty-first century is occurring at an unprecedented pace and scale. Globalization, incredible advances in communication technology, fast travel, recourse limitations, terrorist activities, and now the refugee crisis in Europe make psychoanalytic investigation of the Other a necessity.

Heart Rate Variability as a Feeding Intervention Outcome Measure in the Preterm Infant

BACKGROUND

Feeding interventions for preterm infants aim to reduce the physiologic stress of feeding to promote growth. Heart rate variability (HRV) is a potential noninvasive measure of physiologic stress that may be useful for evaluating efficacy of feeding interventions.

PURPOSE

To evaluate whether HRV is a sensitive measure of physiologic stress compared with standard physiologic outcomes in the context of a feeding intervention study.

METHODS

This was a secondary analysis of a within-subjects, cross-over design study comparing usual care feeding with a gentle, coregulated (CoReg) feeding approach in 14 infants born less than 35 weeks' postmenstrual age. HRV indices were calculated from electrocardiogram data and compared with standard physiologic outcomes, including oxygen saturation (Spo2), respiratory rate (RR), apnea, heart rate (HR), and bradycardia. Data were analyzed using linear mixed modeling.

RESULTS

Infants fed using the CoReg approach had fewer apneic events and higher RR, suggesting they were able to breathe more during feeding. No statistically significant differences were found in SpO2, HR, bradycardia, or high frequency power (the most commonly reported measure of HRV). Infants fed using the usual care approach had significantly higher SD12, a measure of HRV indicating randomness in the HR, which is a potential indicator of elevated stress.

IMPLICATIONS FOR PRACTICE

SD12 was more sensitive to stress than SpO2, HR, and bradycardia. The utility of HRV as a measure of feeding outcomes in clinical practice needs further exploration.

IMPLICATIONS FOR RESEARCH

Further exploration of HRV as an intervention outcome measure is needed, particularly evaluating nonlinear indices, such as SD12.

Nutritive sucking induces age-specific EEG-changes in 0-24 week-old infants

Little is known how the brain of the newborn infant responds to the postnatal nutrition and care. No systematic studies exist in which the effects of nutritional and non-nutritional sucking on the brain activity of the infant were compared. We recorded the EEG activity of 40 infants at the ages of 0,6,12 and 24 weeks in four successive behavioral stages: while the infants were hungry and waiting for sucking, during non-nutritional and nutritional sucking, and during satiation after completed feeding. Quantitative EEG analysis was performed using occipital, parietal and central EEG channels. In the newborn infants, a significant reduction in the EEG power was found after nutritional sucking in the all EEG frequency bands studied (1-10Hz), which was paralleled by a significant behavioral alertness decline. This response decayed during the subsequent neonatal period and was completely absent at the age of 12 weeks. In 24-week-old infants, nutritional sucking was accompanied with an increase in rhythmic theta activity during which no significant alertness change took place. Non-nutritional sucking was connected with minor and non-significant effects on the EEG. We conclude that in newborn infants nutritional sucking has a direct effect on the EEG, which has a soothing character and is connected with an alertness decline. In 24-week-old infants the response to nutritional sucking is of a different type and consists of an organized, rhythmical theta activity in the EEG not directly linked with alertness change. Our findings suggest a developmental relationship between nursing and infant brain function with plausible affective and cognitive implications.

Suck-Swallow-Breathe Dynamics in Breastfed Infants

Despite the importance of the suck-swallow-breathe reflex during breastfeeding, a large proportion of our understanding is derived from bottle-feeding studies. Given the differences in the delivery of milk during breast and bottle feeding, it is imperative that a more general view of the suck-swallow-breathe and milk removal process during breastfeeding is available. This systematic review aimed to assess the evidence for the mechanism of milk removal during breastfeeding; evaluate how the term infant coordinates sucking, swallowing, breathing (SSwB) and cardiorespiratory patterns; and how these patterns change with maturation during breastfeeding. A literature search of PubMed and MEDLINE was performed to assess the mechanism of milk removal and patterns of sucking, swallowing, breathing, and cardiorespiratory control during breastfeeding in healthy term infants. Seventeen studies were selected and a narrative synthesis was performed. Nine studies assessing the infant sucking mechanism consistently provided evidence that vacuum is essential to milk removal from the breast. The limited data on swallowing and breathing and cardiorespiratory control showed mixed results. Overall, results highlighted the high variability in breastfeeding studies and suggested that swallowing, breathing, and cardiorespiratory patterns change with maturation, and within a breastfeed. These findings show potential for devising breastfeeding interventions for populations at risk of SSwB problems. However, consistent methods and definitions of breastfeeding parameters are required before interventions can be adequately developed and tested.

A pilot study: the role of the autonomic nervous system in cardiorespiratory regulation in infant feeding

AIM

The purpose of this pilot study was to examine the interplay between the parasympathetic (PNS) and sympathetic nervous systems' (SNS) contributions to prefeeding, feeding and satiation in young, healthy infants.

METHOD

This prospective study was completed on eleven full-term infants, less than 6 months old. Respiratory rate, heart rate, heart rate variability (HRV), electrodermal activity and low-frequency/high-frequency heart rate variability ratio were sampled from the infant during prefeeding, feeding and satiation periods.

RESULTS

A repeated-measures ANOVA revealed a significant difference in respiratory patterning during the three feeding phases (p = .049); however, none of the other physiological measures reached significance. An emerging trend across physiological measures suggests that the feeding phase was influenced by the SNS with increasing respiratory rate, heart rate, low-frequency HRV, electrodermal activity and decreasing high-frequency HRV compared to the prefeeding and satiation phases, which were influenced predominantly by the PNS.

CONCLUSION

Respiration rate increased significantly during the feeding phase compared to prefeeding and postfeeding phases. Emerging trends indicate a pattern of alternating relative tone in PNS versus SNS across feeding phases - with SNS predominating the feeding phase. More clinical research examining the SNS and PNS contributions to feeding should be completed across patient populations.

Maternal regulation of infant brain state

Patterns of neural activity are critical for sculpting the immature brain, and disrupting this activity is believed to underlie neurodevelopmental disorders [1-3]. Neural circuits undergo extensive activity-dependent postnatal structural and functional changes [4-6]. The different forms of neural plasticity [7-9] underlying these changes have been linked to specific patterns of spatiotemporal activity. Since maternal behavior is the mammalian infant's major source of sensory-driven environmental stimulation and the quality of this care can dramatically affect neurobehavioral development [10], we explored, for the first time, whether infant cortical activity is influenced directly by interactions with the mother within the natural nest environment. We recorded spontaneous neocortical local field potentials in freely behaving infant rats during natural interactions with their mother on postnatal days ∼12-19. We showed that maternal absence from the nest increased cortical desynchrony. Further isolating the pup by removing littermates induced further desynchronization. The mother's return to the nest reduced this desynchrony, and nipple attachment induced a further reduction but increased slow-wave activity. However, maternal simulation of pups (e.g., grooming and milk ejection) consistently produced rapid, transient cortical desynchrony. The magnitude of these maternal effects decreased with age. Finally, systemic blockade of noradrenergic beta receptors led to reduced maternal regulation of infant cortical activity. Our results demonstrate that during early development, mother-infant interactions can immediately affect infant brain activity, in part via a noradrenergic mechanism, suggesting a powerful influence of the maternal behavior and presence on circuit development.

Longitudinal changes in suck-swallow-breathe, oxygen saturation, and heart rate patterns in term breastfeeding infants

BACKGROUND

Despite the differences in breastfeeding and bottle-feeding, our understanding of how suck-swallow-breathe (SSwB), oxygenation, and heart rate patterns change as the infant ages is based predominantly on bottle-feeding studies. Therefore, this study aimed to measure how SSwB, oxygenation, and heart rate patterns changed during the first 4 months of lactation in term breastfeeding infants.

METHODS

Infants less than 1 month postpartum (n = 15) were monitored early in lactation and again later in lactation (2-4 months postpartum). Simultaneous recordings of vacuum, tongue movement, respiration, swallowing, oxygen saturation, and heart rate were made during both nutritive sucking and non-nutritive sucking during breastfeeding.

RESULTS

Infants transferred a similar amount of milk (P = .15) over a shorter duration later in lactation (P = .04). Compared to early lactation, suck bursts became longer (P < .001), pauses became shorter (P < .001), vacuum levels decreased (all P < .05), oxygen saturation increased (P < .001), and heart rate decreased (P < .001) later in lactation.

CONCLUSION

This study confirmed that term infants become more efficient at breastfeeding as they age, primarily by extending their suck bursts and pausing less. Although infants demonstrated satisfactory SSwB coordination during early lactation, they showed a level of adaption or conditioning at later lactation by applying weaker vacuum levels and demonstrating improved cardiorespiratory responses.

Autonomic nervous system function following prenatal opiate exposure

In utero exposure to opiates may affect autonomic functioning of the fetus and newborn. We investigated heart rate variability (HRV) as a measure of autonomic stability in prenatal opiate-exposed neonates (n = 14) and in control term infants (n = 10). Electrocardiographic data during both non-nutritive and nutritive sucking were evaluated for RR intervals, heart rate (HR), standard deviation of the consecutive RR intervals (SDRR), standard deviation of the differences of consecutive RR intervals (SDDRR), and the power spectral densities in low and high frequency bands. In controls, mean HR increased significantly, 143-161 per min (p = 0.002), with a trend toward a decrease in RR intervals from non-nutritive to nutritive sucking; these measures did not change significantly among exposed infants. Compared to controls, exposed infants demonstrated significantly greater HRV or greater mean SDRR and SDDRR during non-nutritive period (p < 0.01), greater mean SDDRR during nutritive sucking (p = 0.02), and higher powers in the low and high frequency bands during nutritive feedings. Our findings suggest that prenatal opiate exposure may be associated with changes in autonomic nervous system (ANS) functioning involving both sympathetic and parasympathetic branches. Future studies are needed to examine the effects of prenatal opiate exposure on ANS function.

Autonomic nervous system function in infants with transposition of the great arteries

The ability to maintain and respond to challenges to homeostasis is primarily a function of the autonomic nervous system (ANS). In infants with complex congenital heart defects this ability may be impaired. This study described change in ANS function before and after surgical correction in infants with transposition of the great arteries (TGA) and in healthy infants. A total of 15 newborn infants with TGA were matched with 16 healthy infants on age, gender, and feeding type. The ANS function was measured using heart rate variability (HRV). Data were collected preoperatively in the 1st week of life and postoperatively before, during, and after feeding at 2 weeks and 2 months of age. Infants with TGA demonstrated significantly lower high-frequency and low-frequency HRV preoperatively (p < .001) when compared with healthy infants. At 2 weeks, infants with TGA were less likely than healthy infants to demonstrate adaptive changes in high-frequency HRV during feeding (Wald Z = 2.002, p = .045), and at 2 months, 40% of TGA infants exhibited delayed postfeeding recovery. Further research is needed to more thoroughly describe mechanisms of a physiologically adaptive response to feeding and to develop nursing interventions supportive of these high-risk infants.

Trajectories of parasympathetic nervous system function before, during, and after feeding in infants with transposition of the great arteries

BACKGROUND

Compromised parasympathetic response to stressors may underlie feeding difficulties in infants with complex congenital heart defects, but little is known about the temporal pattern of parasympathetic response across phases of feeding.

OBJECTIVES

The aim of this study was to describe initial data exploration of trajectories of parasympathetic response to feeding in 15 infants with surgically corrected transposition of the great arteries and to explore the effects of feeding method, feeding skill, and maternal sensitivity on trajectories.

METHOD

In this descriptive, exploratory study, parasympathetic function was measured using high-frequency heart rate variability (HF HRV), feeding skill was measured using the Early Feeding Skills assessment, and maternal sensitivity was measured using the Parent-Child Early Relational Assessment. Data were collected before, during, and after feeding at 2 weeks and 2 months of age. Trajectories of parasympathetic function and relationships with possible contributing factors were examined graphically.

RESULTS

Marked between-infant variability in HF HRV across phases of feeding was apparent at both ages, although it was attenuated at 2 months. Four patterns of HF HRV trajectories across phases of feeding were identified and associated with feeding method, feeding skill, and maternal sensitivity. Developmental increases in HF HRV were apparent in most breast-fed, but not bottle-fed, infants.

DISCUSSION

This exploratory data analysis provides critical information in preparation for a larger study in which varying trajectories and potential contributing factors can be modeled in relationship to infant outcomes. Findings support inclusion of feeding method, feeding skill, and maternal sensitivity in modeling parasympathetic function across feeding.

Cardiovascular control during sleep in infants: Implications for Sudden Infant Death Syndrome

In infants the cardiorespiratory system undergoes significant functional maturation after birth and these changes are sleep-state dependent. Given the immaturity of these systems it is not surprising that infants are at risk of cardiorespiratory instability, especially during sleep. A failure of cardiovascular control mechanisms in particular is believed to play a role in the final event of Sudden Infant Death Syndrome (SIDS). The "triple risk model" describes SIDS as an event that results from the intersection of three overlapping factors: (1) a vulnerable infant, (2) a critical development period in homeostatic control, and (3) an exogenous stressor. This review summarises normal development of cardiovascular control during sleep in infants and describes the association of impaired cardiovascular control with the three overlapping factors proposed to be involved in SIDS pathogenesis.

Heart rate variability responses to nipple feeding for preterm infants with bronchopulmonary dysplasia: three case studies

Preterm infants with bronchopulmonary dysplasia (BPD) have cardiorespiratory compromise that prolongs the transition time from gavage to nipple feeding. Heart rate variability (HRV) provides an indirect measure of the autonomic nervous system's influence on heart rate and cardiorespiratory stability. The purpose of this case study was to describe HRV responses of three preterm infants with BPD during the transition from gavage to nipple feeding. The infants responded to nipple feeding with increases in sympathetic influence on heart rate, and the increase continued in the 10-minute postfeeding. The infants were capable of balancing sympathetic and parasympathetic influences on heart rate related to the work of feeding.

Effect of maternal behavior on regulation during feeding in healthy infants and infants with transposition

OBJECTIVE

To compare physiological regulation and the effect of maternal sensitive caregiving during feeding on physiological regulation in healthy infants and in infants with transposition of the great arteries.

DESIGN

Descriptive, 2 groups, repeated measures.

SETTING

Three children's hospitals in the Midwest.

PARTICIPANTS

A convenience sample of 15 infants with transposition of the great arteries matched with 16 healthy infants.

METHODS

Measures of physiological regulation before, during, and after feeding and quality of maternal affect and behavior during feeding were collected postoperatively at 2 weeks and 2 months of age.

RESULTS

At 2 weeks, infants with transposition of the great arteries demonstrated impaired physiological regulation with feedings when compared with healthy infants. Healthy infants of more sensitive mothers were more likely to demonstrate a physiologically adaptive response during feeding. Maternal effect on physiological regulation was not observed in infants with transposition of the great arteries. No differences between groups were found at 2 months.

CONCLUSIONS

For infants with transposition of the great arteries, effects of surgical recovery and limited contact with their mothers relative to healthy infants may have outweighed the supportive effect of maternal sensitivity during feeding in the early weeks of life. Further research is needed to identify ways of enhancing the regulatory effect of maternal behavior on infants with heart defects.