The relationship of salivary and cord blood cortisol in preterm infants

Environmental stress and salivary cortisol levels in preterm infants

BACKGROUND

Preterm infants are exposed to numerous environmental stressors during their Neonatal Intensive Care Unit (NICU) stay, particularly during the first week after birth. The aim of this study is to assess whether salivary cortisol levels are correlated with Neonatal Infant Stressor Scale (NISS) scores in preterm infants during the first week of life. We also quantified the changes in both NISS scores and cortisol levels in the first week, and whether cortisol levels are associated with gestational age.

METHODS

Preterm infants (n = 38, birth weight <1250 g and/or gestational age <29 weeks) were included. Saliva samples were collected on day 0-3 (early) and day 4-7 (late), and cortisol concentrations were measured by immunoassay. NISS scores were assessed retrospectively for the six hours preceding each saliva collection.

RESULTS

NISS scores were not significantly correlated with salivary cortisol levels at either time point. However, infants born at <28 weeks gestation had higher median cortisol levels than infants born at >28 weeks (p = 0.0068), and there was also a significant inverse relationship between NISS score and gestational age (p = 0.04). There was no significant difference between the early and late time points for either NISS scores or cortisol levels.

CONCLUSIONS

Cortisol levels are elevated in infants <28 weeks gestation but do not correlate with NISS scores. NISS scores are inversely related to gestational age, likely reflecting increased exposure to interventions and invasive procedures for the smallest infants.

Benefits of Kangaroo Mother Care on the Physiological Stress Parameters of Preterm Infants and Mothers in Neonatal Intensive Care

It is well documented that the stress of separation of mother and baby can lead to short-term physiological instability as well as neurological, sociological or psychological consequences that may last a lifetime. Objective: The goal was to estimate the effect of kangaroo mother care (KMC) on physiological and biochemical parameters of preterm infant stress and maternal stress in neonatal intensive care. Methods: The investigation involved 112 preterm infants. Two groups were compared according to the mean duration of KMC during 12 days of study: the KMC group (mean duration more than 90 min daily) and the control group (less than 90 min). Results: Kangaroo mother care for more than 90 min on average per day in preterm infants is associated 12 days after the intervention with lower mean cortisol levels (p = 0.02), greater weight gain and less need for parenteral nutrition in preterm infants, as well as less postpartum depression (p = 0.02) and lower cortisol levels (p = 0.002) in the mothers of preterm infants. Conclusions: This study suggests that KMC can be used to improve the stress of preterm infants and their mothers, and that the greater weight gain observed in these preterm infants could contribute to a shorter average hospital stay and lower healthcare expenditure.

Effects of smelling amniotic fluid on preterm infant's pain and stress during peripheral cannulation: A randomized controlled trial

AIM

To investigate the effect of smelling amniotic fluid on preterm infants' pain and stress caused by peripheral cannulation.

METHODS

This was a randomized controlled trial. The study sample consisted of 80 preterm infants meeting the case selection criteria and infants were randomly assigned to each group. However, in addition to the infants excluded from the study, total number of the infants in all the groups was 61. Infants in the amniotic fluid group smelled amniotic fluid for 15 min before, during, and after the application of peripheral cannulation while those in the control group received routine care during the procedure. The Premature Infant Pain Profile was used to assess their pain levels, and salivary cortisol analysis was performed to evaluate stress levels.

RESULTS

Preterm infants in the amniotic fluid and control groups had similar baseline characteristics. However, the pain levels of infants in the amniotic fluid group were significantly lower than of those in the control group during and after the procedure. After the procedure, cortisol levels of the infants in the amniotic fluid group were lower than of those in the control group, although this difference was not significant.

CONCLUSION

The intervention of smelling amniotic fluid is a practice that can be used for reducing pain and stress of preterm infants during peripheral cannulation.

Realising the Potential of Urine and Saliva as Diagnostic Tools in Sport and Exercise Medicine

Accurate monitoring of homeostatic perturbations following various psychophysiological stressors is essential in sports and exercise medicine. Various biomarkers are routinely used as monitoring tools in both clinical and elite sport settings. Blood collection and muscle biopsies, both invasive in nature, are considered the gold standard for the analysis of these biomarkers in exercise science. Exploring non-invasive methods of collecting and analysing biomarkers that are capable of providing accurate information regarding exercise-induced physiological and psychological stress is of obvious practical importance. This review describes the potential benefits, and the limitations, of using saliva and urine to ascertain biomarkers capable of identifying important stressors that are routinely encountered before, during, or after intense or unaccustomed exercise, competition, over-training, and inappropriate recovery. In particular, we focus on urinary and saliva biomarkers that have previously been used to monitor muscle damage, inflammation, cardiovascular stress, oxidative stress, hydration status, and brain distress. Evidence is provided from a range of empirical studies suggesting that urine and saliva are both capable of identifying various stressors. Although additional research regarding the efficacy of using urine and/or saliva to indicate the severity of exercise-induced psychophysiological stress is required, it is likely that these non-invasive biomarkers will represent "the future" in sports and exercise medicine.

Correlation between maternal and infant cortisol varies by breastfeeding status

OBJECTIVE

The objective of this study was to examine associations of mother and infant salivary cortisol, measured three times over the course of a day, and assess whether these varied by breastfeeding status.

METHODS

We conducted a cross-sectional study of 54 mothers and their infants aged 4-11 months. Mothers collected their own saliva and that of their infants upon awakening, 30min after waking and at bedtime. Breastfeeding status was reported by mothers and cortisol level was measured in saliva in μg/dl using standard techniques. We used generalized linear models to evaluate relationships between maternal and infant cortisol levels, and assessed whether the relationship differed by breastfeeding status: formula only compared to partial and full breastfeeding, adjusting for infant sex, race, age, maternal education, and family income.

RESULTS

Thirty-four infants received formula only and 20 were either partially or fully breastfed. Breastfeeding was associated with higher household income, higher maternal education, and white race. Cortisol levels were higher among breastfed infants at all three time points. After adjustment, maternal cortisol levels were related with infant cortisol at bedtime only (regression estimate 0.06; 95% CI: 0.10, 1.1; p=0.02). The adjusted association between bedtime maternal and infant cortisol was stronger among breastfeeding dyads than among formula-feeding dyads (regression estimate 1.0; 95% CI: 0.1, 2.0; p=0.04 vs. 0.6; CI: -0.1, 1.3; p=0.10). In addition, we assessed the influence of maternal education and household income in our adjusted model; income strengthened the observed association, whereas maternal education did not change the estimate.

CONCLUSIONS

Breastfeeding mothers and infants had significant correlations for cortisol at bedtime, while formula-feeding dyads did not. These data suggest that several factors may contribute to cortisol synchrony observed in mother/infant dyads, including the transfer of cortisol in human milk, physical interaction such as skin-to-skin contact, and shared environment. In addition, our findings support household income as a possible contributor.

Effect of holding on co-regulation in preterm infants: a randomized controlled trial

OBJECTIVE

To determine whether kangaroo holding of healthy preterm infants over the first eight weeks of an infant's life facilitates co-regulation of salivary cortisol between mother and infant.

STUDY DESIGN

Randomized control trial. Infants were assigned to receive 1h of daily kangaroo (skin-to-skin contact on the chest of mother) or blanket holding (dressed and held in mother's arms). A registered nurse visited mothers weekly for eight weeks to encourage holding and provide information about infant development. A control group had no holding restrictions and received weekly brief social visits.

SUBJECTS

The study included 79 preterm infants, born between 32 and 35weeks gestational age and were a mean of 15days (±5.7) at enrollment.

OUTCOME MEASURES

Co-regulation was conceptualized as progressive reduction in the absolute difference between mother and infant cortisol levels across 60min of holding at each holding session. Mother and infant cortisol levels were measured before holding and at 30 and 60min after holding began during three holding sessions (baseline and at two and eight weeks after study initiation). Primary analyses were conducted using hierarchical linear models.

RESULTS

There was much variability in cortisol levels. Levels of mother and infant cortisol decreased during holding. No significant co-regulation occurred in any group at any holding session or over time.

CONCLUSIONS

Decreasing level of cortisol in both mothers and infants suggests that holding promoted the expected decline in stress hormone levels. However, supported holding methods did not differentially affect co-regulation compared to controls. Holding is pleasurable and stress may need to be present in order for mothers and infants to demonstrate co-regulation in cortisol levels.

Retrospective study of factors related to preterm labor in Yasuj, Iran

INTRODUCTION

Premature labor is a serious worldwide problem that can cause neonatal death and other serious disorders. This study aimed to determine the most important factors related to preterm labor in Yasuj, Iran.

METHOD

This case-control study was conducted in the maternity ward of Imam Sajjad Hospital, the obstetrics and gynecology center of Yasuj, in 2010. Among eligible samples, mothers with preterm labor were selected as the case group, and for each sample in the case group, one mother with full-term labor was selected by using clipper-matched sampling to make up the control group. Data were collected by a researcher-made questionnaire and the 28-item General Health Questionnaire. Finally, after deleting imperfect questionnaires, collected data of 52 subjects of case group and the same amount in control group were analyzed.

RESULTS

Among the 5400 live birth infants in Yasuj in 2010, 130 infants were premature (2.4%). The preterm labor risk in women with two or more pregnancies was 5.5 times more than women with less than two pregnancies, its risk in women with low general health status was 2.9 times more than in women with normal general health status, and the preterm labor risk in women with a history of diabetes mellitus/thyroid dysfunction/cardiac disease was 2.3 times more than healthy mothers (P < 0.01).

CONCLUSION

With respect to the above and due to the role and importance of mother-infant health in community health, it is necessary that the health-care system improve health education with regard to the appropriate number of pregnancies, diagnose and cure disease during pregnancy, especially diabetes and cardiovascular disease (hypertension and/or eclampsia), and recognize pregnant mothers with mental pressure or lack of sufficient support and help them.

Intercorrelations between serum, salivary, and hair cortisol and child-reported estimates of stress in elementary school girls

To evaluate the impact of stress on children's well-being, it is important to have valid and reliable stress assessment methods. Nevertheless, selection of an appropriate method for a particular research question may not be straightforward, as there is currently no consensus on a reference method to measure stress in children. This article examined to what extent childhood stress can be estimated accurately by stressor questionnaires (i.e., Coddington life events scale) and biological markers (serum, salivary, and hair cortisol) using the Triads (a triangulation) method in 272 elementary school girls. Salivary cortisol was shown to most accurately indicate true childhood stress for short periods in the past (i.e., last 3 months), whereas hair cortisol may be preferred above salivary measurements for periods more distant and thus for chronic stress assessment. However, applicability should be confirmed in larger and more heterogeneous populations.