Carolina de Weerth

Physiological stress reactivity in human pregnancy—a review

Prenatal maternal stress has been found to have long-lasting effects on the behavioral and physiological development of the offspring. These programming effects on the fetus would be physiologically mediated through heightened and/or abnormal activity of the maternal sympathetic-adrenal-medullary system (SAM) and especially of her hypothalamic-pituitary-adrenocortical axis (HPA-axis). The abnormalities in maternal physiology could be present in her basal functioning, but also in her physiological reactivity to stressors, which constitutes the topic of this paper. This article reviews studies that have used laboratory challenges to study physiological stress reactivity in pregnant women. It concentrates on stress tests designed to produce pain or discomfort, or cognitive and psychological stress, and that assess changes in blood pressure, heart rate and/or cortisol as reactivity measures. The general conclusion is that physiological stress reactivity appears to be dampened during pregnancy. Nonetheless, the physiological responses to laboratory challenges are clearly present and display enough inter-individual variability to enable the study of links between responsivity patterns, psychosocial variables, fetal behavior, pregnancy outcome and offspring development. This paper also looks into the methodological limitations present in the reviewed studies. Options for sound design of stress test protocols are discussed and recommendations for future studies are presented. These methodological points are general and can therefore also be of use for researchers studying human stress reactivity in other populations and ages.

Prenatal stress and children's cortisol reaction to the first day of school

Maternal prenatal stress has been found to be related to over-activity and/or dysregulation of the HPA-system in the offspring. These effects are more readily apparent in response to novel situations. The aim of the present report was to examine whether pregnancy stress predicted HPA-axis reactions of children to the first day of school after the summer break. Children of mothers with more prenatal stress were compared to those of mothers with less stress. Habituation was studied by comparisons between the first school day and a second school day a week later. Finally, cortisol levels at school were compared to those of a weekend day. The participants were 29 mother-child pairs (20 girls and nine boys, mean age 5.31 years, SD = 0.50). The childrens cortisol levels were determined in saliva. Multilevel analysis (hierarchical linear modelling) was used to analyze the data. Both prenatal cortisol and pregnancy anxiety were related to the childrens cortisol levels as a reaction to the first school day. Children whose mothers had higher levels of morning cortisol during pregnancy, and more fear of bearing a handicapped child showed higher levels of cortisol on school days. In addition, the circadian rhythm of cortisol on school days appeared to have a steeper slope as compared to that of the circadian curve on a weekend day.

The effects of prenatal stress on temperament and problem behavior of 27-month-old toddlers

AimTo examine, in a prospective study, the influence of prenatal stress on infant temperament and problem behavior.MethodSelf-report data on stress and anxiety, and levels of cortisol in saliva were collected from nulli-parous women during pregnancy. Temperament of the child was measured at 27 months by parent report on the Infant Characteristics Questionnaire. Behavior of the child was assessed by direct observation during the administration of the Bayley Scales of Development 2–30, and by parent report on the Child Behavior Checklist 2–3.ResultsComplete data were available for 103 healthy toddlers. Logistic regression analyses were performed and results were adjusted for possible prenatal, perinatal and postnatal confounders. Perceived stress during pregnancy was a predictor of lower levels of restless/disruptive temperament (OR=0.77), more total behavioral problems (OR=1.17), and more externalizing behavioral problems (OR=1.12) in 2-year-olds. Fear of bearing a handicapped child was a predictor of higher levels of restless/disruptive temperament (OR=1.39) and more attention regulation problems in toddlers (OR=1.46).ConclusionsIncreased levels of maternal prenatal stress appear to be associated with temperamental and behavioral problems in toddlers.

Intestinal Microbiota of Infants With Colic: Development and Specific Signatures

OBJECTIVES: To provide a comprehensive analysis of the fecal microbiota in infants with colic, as compared with control infants, during their first 100 days of life. METHODS: Microbial DNA of >200 samples from 12 infants with colic and 12 age-matched control infants was extracted and hybridized to a phylogenetic microarray. RESULTS: Microbiota diversity gradually increased after birth only in the control group; moreover, in the first weeks, the diversity of the colic group was significantly lower than that of the control group. The stability of the successive samples also appeared to be significantly lower in the infants with colic for the first weeks. Further analyses revealed which bacterial groups were responsible for colic-related differences in microbiota at age 1 or 2 weeks, the earliest ages with significant differences. Proteobacteria were significantly increased in infants with colic compared with control infants, with a relative abundance that was more than twofold. In contrast, bifidobacteria and lactobacilli were significantly reduced in infants with colic. Moreover, the colic phenotype correlated positively with specific groups of proteobacteria, including bacteria related to Escherichia, Klebsiella, Serratia, Vibrio, Yersinia, and Pseudomonas, but negatively with bacteria belonging to the Bacteroidetes and Firmicutes phyla, the latter of which includes some lactobacilli and canonical groups known to produce butyrate and lactate. CONCLUSIONS: The results indicate the presence of microbial signatures in the first weeks of life in infants who later develop colic. These microbial signatures may be used to understand the excessive crying. The results offer opportunities for early diagnostics as well as for developing specific therapies.

Do We Recover from Vacation? Meta-analysis of Vacation Effects on Health and Well-being

Do We Recover from Vacation? Meta‐analysis of Vacation Effects on Health and Wellbeing: Jessica de Bloom, et al. Department of Work & Organizational Psychology, Behavioural Science Institute, Radboud University Nijmegen, The Netherlands

Mechanisms underlying the effects of prenatal psychosocial stress on child outcomes: beyond the HPA axis

Abstract Accumulating evidence from preclinical and clinical studies indicates that maternal psychosocial stress and anxiety during pregnancy adversely affect child outcomes. However, knowledge on the possible mechanisms underlying these relations is limited. In the present paper, we review the most often proposed mechanism, namely that involving the HPA axis and cortisol, as well as other less well-studied but possibly relevant and complementary mechanisms. We present evidence for a role of the following mechanisms: compromised placental functioning, including the 11β-HSD2 enzyme, increased catecholamines, compromised maternal immune system and intestinal microbiota, and altered health behaviors including eating, sleep, and exercise. The roles of (epi)genetics, the postnatal environment and the fetus are also discussed. We conclude that maternal prenatal psychosocial stress is a complex phenomenon that affects maternal emotions, behavior and physiology in many ways, and may influence the physiology and functioning of the fetus through a network of different pathways. The review concludes with recommendations for future research that helps our understanding of the mechanisms by which maternal prenatal stress exerts its effect on the fetus.

Cortisol reactivity in young infants

In this systematic review on empirical studies of cortisol reactivity to acute stressors in infants, we specifically focus on the role of infant age in the early development of cortisol reactivity to stressors. Our findings indicate that many psychological stressors do not provoke a cortisol reaction, but in response to physical stressors, the infant HPA-axis mostly reacts with a moderate increase in post-stressor cortisol. Furthermore, for physical stressors only, cortisol reactivity effect sizes decrease with infant age, although relatively little is known for infants older than 6 months. These data provide more insight in the role of infant age in the development of cortisol reactivity in response to acute stressors. We discuss the role of caregivers in buffering the cortisol response to both psychological and physical stressors, and recommend extending the current knowledge on infant cortisol reactivity.

Moderation of distress-induced eating by emotional eating scores.

Earlier studies assessing the possible moderator effect of self-reported emotional eating on the relation between stress and actual food intake have obtained mixed results. The null findings in some of these studies might be attributed to misclassification of participants due to the use of the median splits and/or insufficient participants with extreme scores. The objective of the two current studies was to test whether it is possible to predict distress-induced eating with a self-report emotional eating scale by using extreme scorers. In study 1 (n=45) we used a between-subjects design and emotional eating was assessed after food intake during a negative or a neutral mood (induced by a movie). In study 2 (n=47) we used a within-subjects design and emotional eating was assessed well before food intake, which occurred after a control or stress task (Trier Social Stress Task). The main outcome measure was actual food intake. In both studies self-reported emotional eating significantly moderated the relation between distress and food intake. As expected, low emotional eaters ate less during the sad movie or after stress than during the neutral movie or after the control task, whereas high emotional eaters ate more. No such moderator effect was found for emotional eating in the entire sample (n=124) of study 1 using the median-split procedure or the full range of emotional eating scores. We conclude that it is possible to predict distress-induced food intake using self-reports of emotional eating provided that the participants have sufficiently extreme emotional eating scores.

Cortisol awakening response in pregnant women

In this study, basal saliva cortisol was determined in women at 32 weeks of pregnancy and again at 9 months post-partum. During pregnancy, the cortisol levels of the 119 subjects were found to be elevated, with noon and evening levels more than twice as high as during the non-pregnant state. Despite the hypercortisolism, the cortisol awakening response was still present during pregnancy. Although the absolute mean increase in cortisol at 30 min post-awakening was larger during pregnancy, the relative mean increase was around 40% of the awakening level in both cases. The cortisol awakening response was not correlated between pregnancy and the post-partum, showing a lack of stability over the 11-month period. Finally, both in the pregnant and non-pregnant states, the magnitude of the cortisol awakening response was not related to time of awakening, nor to anticipation of a working vs. non-working day. In conclusion, the free cortisol awakening response is present during pregnancy, and is potentially a useful marker to study the association between prenatal psychosocial stress and offspring development.

Does Early-Life Exposure to Stress Shape or Impair Cognition?

A predominant view in psychology is that early psychosocial adversity (e.g., abuse) impairs cognition, because children from stressful backgrounds (e.g., violent households) score lower on standard tests of intelligence, language, memory, inhibition, and other abilities. However, recent studies indicate that these people may exhibit improved detection, learning, and memory on tasks involving stimuli that are ecologically relevant to them (e.g., dangers), compared with safely nurtured peers. These findings contradict the view that cognition of stressed people is generally impaired; they suggest, rather, that these people’s minds are developmentally specialized toward local environmental conditions. Here, we review recent research supporting this hypothesis. In addition, we propose that novel studies should examine whether stressed children show not only improved detection but also improved memory and reasoning on tasks involving stimuli that are ecologically relevant to them. Finally, we discuss clinical implications of switching from conceptualizing stressed minds as “adapted” rather than “impaired.”