Oxytocin levels in the saliva of preterm infant twins during Kangaroo care

Infants' salivary oxytocin and positive affective reactions to people

Oxytocin is a neuropeptide positively associated with prosociality in adults. Here, we studied whether infants' salivary oxytocin can be reliably measured, is developmentally stable, and is linked to social behavior. We longitudinally collected saliva from 62 U.S. infants (44 % female, 56 % Hispanic/Latino, 24 % Black, 18 % non-Hispanic White, 11 % multiracial) at 4, 8, and 14 months of age and offline-video-coded the valence of their facial affect in response to a video of a smiling woman. We also captured infants' affective reactions in terms of excitement/joyfulness during a live, structured interaction with a singing woman in the Early Social Communication Scales at 14 months. We detected stable individual differences in infants' oxytocin levels over time (over minutes and months) and in infants' positive affect over months and across contexts (video-based and in live interactions). We detected no statistically significant changes in oxytocin levels between 4 and 8 months but found an increase from 8 to 14 months. Infants with higher oxytocin levels showed more positive facial affect to a smiling person video at 4 months; however, this association disappeared at 8 months, and reversed at 14 months (i.e., higher oxytocin was associated with less positive facial affect). Infant salivary oxytocin may be a reliable physiological measure of individual differences related to socio-emotional development.

Skin-to-skin contact-An effective intervention on pain and stress reduction in preterm infants

Introduction

The outcomes of pain and stress in preterm infants in the neonatal intensive care units (NICUs) compel the continued search for pain- and stress-reducing interventions.

The objective of the study

To investigate how skin-to-skin contact (SSC) influences chronic pain and stress in preterm infants in the NICU.

Materials and methods

The study included 140 preterm infants in the NICU with gestational age less than 34 weeks. The overall design was a baseline-response design. Urine and saliva were collected before (baseline) and after SSC to measure pain and stress markers by enzyme immunoassay method. The behavioral indicators of chronic pain were assessed using the EDIN (Échelle Douleur Inconfort Nouveau-Né-neonatal pain and discomfort).

Results

There was a significant decrease in the dopamine level in preterm infants after SSC in comparison with baseline values (85.99 [69.35; 112.20] pg/ml vs. 132.20 [104.80; 183.70] pg/ml), p < 0.001. The β-endorphin and serotonin levels increased after SSC (40.09 [26.81; 70.63] pg/ml vs. 29.87 [20.61; 46.94] pg/ml, p = 0.009 and 25.49 [20.45; 40.08] ng/ml vs. 22.30 [15.13; 31.65] ng/ml, p = 0.011, respectively). A significant decrease in cortisol levels in saliva and urine after SSC in comparison with baseline values (0.125 [0.079; 0.225] μg/dl vs. 0.371 [0.188; 1.002] μg/dl, p = 0.000 and 27.06 [14.59; 35.35] ng/ml vs. 35.25 [19.78; 61.94] ng/ml, p = 0.001, with a simultaneous increase of oxytocin level (57.00 [36.55; 88.49] pg/ml vs. 38.20 [28.78; 56.04] pg/ml, p = 0.009 were revealed. The total pain EDIN score in infants after SSC was below 6 points, significantly decreasing compared to the baseline (p < 0.05).

Conclusion

Preterm infants in the NICU experience stress and pain, which were confirmed by the EDIN pain scale and laboratory markers. The level of dopamine and cortisol as pain and stress hormones were reliably high, and normalized after regular SSC. Simultaneously, pain-relieving and anti-stress markers of oxytocin, β-endorphin and serotonin reliably increased in preterm infants in response to the SSC.

Oxytocin but not naturally occurring variation in caregiver touch associates with infant social orienting

Caregiver touch is crucial for infants’ healthy development, but its role in shaping infant cognition has been relatively understudied. In particular, despite strong premises to hypothesize its function in directing infant attention to social information, little empirical evidence exists on the topic. In this study, we investigated the associations between naturally occurring variation in caregiver touch and infant social attention in a group of 6‐ to 13‐month‐old infants (n = 71). Additionally, we measured infant salivary oxytocin as a possible mediator of the effects of touch on infant social attention. The hypothesized effects were investigated both short term, with respect to touch observed during parent–infant interactions in the lab, and long term, with respect to parent‐reported patterns of everyday touching behaviors. We did not find evidence that caregiver touch predicts infant social attention or salivary oxytocin levels, short term or long term. However, we found that salivary oxytocin predicted infant preferential attention to faces relative to nonsocial objects, measured in an eye‐tracking task. Our findings confirm the involvement of oxytocin in social orienting in infancy, but raise questions regarding the possible environmental factors influencing the infant oxytocin system.

Skin-to-skin contact to support preterm infants and reduce NICU-related stress

OBJECTIVE

Hospitalization in the neonatal intensive care unit (NICU) with numerous painful medical interventions, being separated from parents, leads to the high risk of chronic stress for preterm infants. Today, many NICUs use more appropriate developmental care and pain management, but the early and long-term outcomes of stress in these vulnerable infants require searching for more stress-reducing interventions in neonatal care. The objective of the study was to investigate how skin-to-skin contact (SSC) can influence the biologic stress levels in preterm infants in the NICU by assessing cortisol and oxytocin levels.

PARTICIPANTS AND METHODS

The study included 71 preterm infants with gestational age less than 34 + 0/7 weeks who were recruited from level III NICU. The overall design was a baseline-response design. Saliva and urine were collected before (baseline) and after skin-to-skin contact to measure salivary cortisol and urinary oxytocin by enzyme immunoassay method.

RESULTS

The infants' baseline hormonal status was represented by the following indicators: the level of salivary cortisol was 0.402 [0.227; 1,271] μg/dl, urinary oxytocin 48.88 [32.97; 88.11] pg/ml. There was a decrease in salivary cortisol levels to 0.157 [0.088; 0.351] μg/dl compared to baseline (p ˂ 0.001) with a simultaneous increase of the urinary oxytocin level -73.59 [45.18; 108.8] pg/ml (p = 0.028) in response to SSC.

CONCLUSION

Preterm infants in the NICU experience significant stress, characterized by hormonal imbalance: an increased level of the stress hormone cortisol and a decreased level of the anti-stress hormone oxytocin. Skin-to-skin contact helps to ameliorate the hormonal stress in preterm infants by activating the oxytocin release with simultaneous reduction of cortisol secretion.

A Systematic Review of the Effects of Skin-to-Skin Contact on Biomarkers of Stress in Preterm Infants and Parents

BACKGROUND

Premature infants and their parents experience significant stress related to separation and lifesaving procedures. While evidence suggests that skin-to-skin contact (SSC) is a stress-reducing intervention for both neonates and parents, the mechanisms that underlie its efficacy are not well understood.

OBJECTIVE

Purpose of this systematic review is to summarize the current state of knowledge on changes in biomarkers (ie, oxytocin [OT], cortisol, hypoxanthine, xanthine, uric acid, and allantoin), associated with SSC in premature infants and parents, that may reflect physiologic responses to stress.

METHODS

A comprehensive literature search was conducted from 1990 to 2020. Studies were selected using prespecified inclusion and exclusion criteria.

RESULTS

Of the 175 studies identified, only 19 are included in this review. Ten studies evaluated only infants, 2 evaluated only parents, and 7 evaluated for changes in biomarkers in both infants and parents. Cortisol was the most common biomarker evaluated. While changes in infants' cortisol levels were highly variable, in 55% of the parent studies, parent cortisol levels decreased following SSC. In both parents and infants, OT levels decreased following SSC. Only 1 study found that allantoin levels were significantly lower in infants who received SSC.

IMPLICATIONS FOR PRACTICE AND RESEARCH

While evidence suggests the numerous benefits of SSC, additional research is needed to identify the optimal biomarker to determine the mechanisms that underlie these effects. The use of novel biomarkers (eg, gene expression changes microbiome) may provide new insights into the mechanisms that underlie the efficacy of SSC.Video Abstract available at:https://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx?autoPlay=false&videoId=48.

Parent-Infant Skin-to-Skin Contact and Stress Regulation: A Systematic Review of the Literature

Several studies have focused on neonatal maternal separation (MS) to investigate behavioural and neuroendocrine reactions to lack of contact, but only a few have focused on early separation in the first days or weeks after birth. This literature review investigates the vital importance of contact and touch by exploring how skin-to-skin contact (SSC) regulates stress in the mother-infant relationship. Various databases such as PubMed, Scopus, and ScienceDirect were searched for literature published between 2015 and 2020. From 1141 articles, 22 were declared eligible. The reviewed articles showed how SSC regulates child stress by biological indicators such as the autonomic nervous system (ANS), heart rate variability (HRV), cortisol, and oxytocin. This research concludes the importance of SSC for stress regulation, especially during the COVID-19 pandemic. With no research to date indicating a possible risk of neonatal COVID-19 transmission following SSC, SSC should continue to be practiced for all women, as recommended by the WHO.

Systematic Review of the Effects of Skin-to-Skin Care on Short-Term Physiologic Stress Outcomes in Preterm Infants in the Neonatal Intensive Care Unit

BACKGROUND

Infants in the neonatal intensive care unit (NICU) are exposed to many stressors. There is growing evidence that chronic stress early in life has long-term neurodevelopmental implications. Skin-to-skin care (SSC) is an intervention used to reduce stress in the NICU.

CLINICAL QUESTION

In premature infants in the NICU, what is the available evidence that SSC improves short-term physiologic stress outcomes compared with incubator care?

SEARCH STRATEGY

PubMed and CINAHL were searched for terms related to SSC, stress, physiology, and premature infants. Of 1280 unique articles, 19 were identified that reported on research studies comparing SSC with incubator care in the NICU and reported stress-related physiologic outcome measures.

RESULTS

Although there have been some mixed findings, the research supports that SSC improves short-term cardiorespiratory stress outcomes compared with incubator care. The evidence is clearer for studies reporting stress hormone outcomes, with strong evidence that SSC reduces cortisol and increases oxytocin levels in preterm infants.

IMPLICATIONS FOR PRACTICE AND RESEARCH

SSC is safe and has stress-reducing benefits. SSC should be considered an essential component to providing optimal care in the NICU. More research is needed to determine the timing of initiation, duration, and frequency of SSC to optimize the stress-reducing benefits. Future research should include the most fragile infants, who are most likely to benefit from SSC, utilize power analyses to ensure adequate sample sizes, and use sophisticated data collection and analysis techniques to more accurately evaluate the effect of SSC on infants in the NICU.