The Impact of Early Maternal Presence on Child Development and the Stress Response System

Neonatal stress exposure and DNA methylation of stress-related and neurodevelopmentally relevant genes: An exploratory study

BACKGROUND

Stress exposure during Neonatal Intensive Care Unit (NICU) stay may have long-lasting effects on neurodevelopmental outcomes in extremely preterm infants. Altered DNA methylation of stress-related and neurodevelopmentally relevant genes may be an underlying mechanism.

AIMS

This exploratory study aimed to investigate the association between neonatal stress exposure and DNA methylation in these genes at two different time points: early during the NICU stay (7-14 days after birth) and later, at discharge from the NICU.

SUBJECTS

We included 45 extremely preterm infants in this prospective cohort study, gestational age 24-30 weeks.

OUTCOME MEASURES

We collected fecal samples at days 7-14 (n = 44) and discharge (n = 28) and determined DNA methylation status in predefined regions of NR3C1, SLC6A4, HSD11B2, OPRM1, SLC7A5, SLC1A2, IGF2, NNAT, BDNF and GABRA6 using pyrosequencing. Because of low DNA concentrations in some fecal samples, we could do so in 25-50 % of collected samples. We prospectively quantified daily neonatal stress exposure using the Neonatal Infant Stressor Scale (NISS) and explored associations between cumulative NISS scores and average DNA methylation status.

RESULTS

Rates of methylation of most genes were not statistically different between day 7-14 and discharge, except for OPRM1. We found moderately high and mostly negative correlation coefficients upon discharge with the cumulative NISS for the NR3C1, SLC6A4, SLC1A2, IGF2, BDNF and OPRM1 genes, albeit not statistically significant.

CONCLUSIONS

Findings suggest that expression of stress-related and neurodevelopmentally relevant genes may be differently regulated following higher neonatal stress exposure. Larger studies should challenge the findings of this study and ideally test the effects on gene expression.

Neonatal Stress, Health, and Development in Preterms: A Systematic Review

CONTEXT

An overview of the full range of neonatal stressors and the associated clinical, laboratory, and imaging outcomes regarding infants' health and development may contribute to the improvement of neonatal care.

OBJECTIVE

To systematically review existing literature on the associations between all kinds of neonatal stressors and the health and development of preterm infants.

DATA SOURCES

Data sources included Embase, Medline, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature, and reference lists.

STUDY SELECTION

Studies were eligible if they included a measure of neonatal stress during the NICU stay, reported clinical, laboratory, and/or imaging outcomes regarding health and/or development on discharge from the NICU or thereafter, included preterm infants, and were written in English or Dutch.

DATA EXTRACTION

Two reviewers independently screened the sources and extracted data on health and development. Study quality was assessed by using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

We identified 20 articles that reported on neonatal stress associated negatively with clinical outcomes, including cognitive, motor, and emotional development, and laboratory and imaging outcomes, including epigenetic alterations, hypothalamic-pituitary-adrenal axis functioning, and structural brain development. We found no evidence regarding associations with growth, cardiovascular health, parent-infant interaction, the neonatal immune system, and the neonatal microbiome.

LIMITATIONS

The studies were all observational and used different definitions of neonatal stress.

CONCLUSIONS

Neonatal stress has a profound impact on the health and development of preterm infants, and physicians involved in their treatment and follow-up should be aware of this fact.

Kangaroo mother care and infant biopsychosocial outcomes in the first year: A meta-analysis

AIM

A systematic review and meta-analysis was conducted to examine the relationship between KMC and infant/toddler biopsychosocial outcomes.

METHOD

PubMed, MEDLINE (OvidSP), MEDLINE in Process (OvidSP), Embase (OvidSP), PsycINFO (OvidSP), and AMED (OvidSP) were searched. Observational studies and randomized control trials through October 2015 that investigated the association between KMC intervention and infant/toddler biopsychosocial outcomes were included. Studies with <10 participants, those using skin-to-skin only during painful procedures or only on the day of birth, and those that did not report quantitative outcomes were excluded. Data were extracted by two coders and estimates were examined using random-effects.

RESULTS

3177 studies were screened with 13 meeting inclusion criteria and representing 5 child outcomes (cognitive, motor, self-regulation, socio-emotional and temperament). Among LBW/premature neonates, KMC compared to conventional care was associated with improved infant self-regulation. Moderated effects were identified for cognitive (duration of KMC) and motor development (duration of KMC, country-level mortality ratio, and infant gender).

INTERPRETATIONS

KMC administered to vulnerable neonates during a sensitive period of brain development has a lasting impact on self-regulation skills later in infancy. Further research examining the longer-term effect of KMC on cognitive and motor development, socioemotional skills, and temperament is needed.