Antenatal betamethasone treatment has a persisting influence on infant HPA axis regulation

Early life corticosteroid overexposure: Epigenetic and fetal origins of adult diseases

The relationship between events occurring during intrauterine development and later-life predisposition to long-term disease, has been described. The fetus responds to excess intrauterine exposure to high levels of corticosteroids, modifying their physiological development and stopping their growth. Fetal exposure to elevated levels of either endogenous (alterations in fetal hypothalamic-pituitary-adrenal axis) or synthetic corticosteroids, is one model of early-life adversity; to developing adult disease. At the molecular level, there are transcriptional changes in metabolic and growth pathways. Epigenetic mechanisms participate in transgenerational inheritance, not genomic. Exposures that change 11β-hydroxysteroid dehydrogenase type 2 enzyme methylation status in the placenta can result in transcriptional repression of the gene, causing the fetus to be exposed to higher levels of cortisol. More precise diagnosis and management of antenatal corticosteroids for preterm birth, would potentially decrease the risk of long-term adverse outcomes. More studies are needed to understand the potential roles of factors to alter fetal corticosteroid exposure. Long-term infant follow-up is required to determine whether methylation changes in placenta may represent useful biomarkers of later disease risk. This review, summarize recent advances in the programming of fetal effects of corticosteroid exposure, the role of corticosteroids in epigenetic gene regulation of placental 11β-hydroxysteroid dehydrogenase type 2 enzyme expression and transgenerational effects.

The effect of antenatal corticosteroid use on offspring cardiovascular function: A systematic review

BACKGROUND

Antenatal corticosteroids (ACS) are recommended in threatened preterm labour to improve short-term neonatal outcome. Preclinical animal studies suggest detrimental effects of ACS exposure on offspring cardiac development; their effects in humans are unknown.

OBJECTIVES

To systematically review the human clinical literature to determine the effects of ACS on offspring cardiovascular function.

SEARCH STRATEGY

A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines in MEDLINE, EMBASE and Cochrane databases.

SELECTION CRITERIA

Offspring who had been exposed to ACS during fetal life, in comparison with those not receiving steroids, those receiving a placebo or population data, were included. Studies not performed in humans or that did not assess cardiovascular function were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the studies, extracted the data and assessed the quality of the studies. Results were combined descriptively and analysed using a standardised Excel form.

MAIN RESULTS

Twenty-six studies including 1921 patients were included, most of which were cohort studies of mixed quality. The type of ACS exposure, gestational age at exposure, dose and number of administrations varied widely. Offspring cardiovascular outcomes were assessed from 1 day to 36 years postnatally. The most commonly assessed parameter was arterial blood pressure (18 studies), followed by echocardiography (eight studies), heart rate (five studies), electrocardiogram (ECG, three studies) and cardiac magnetic resonance imaging (MRI, one study). There were no clinically significant effects of ACS exposure on offspring blood pressure. However, there were insufficient studies assessing cardiac structure and function using echocardiography or cardiac MRI to be able to determine an effect.

CONCLUSIONS

The administration of ACS is not associated with long-term effects on blood pressure in exposed human offspring. The effects on cardiac structure and other measures of cardiac function were unclear because of the small number, heterogeneity and mixed quality of the studies. Given the preclinical and human evidence of potential harm following ACS exposure, there is a need for further research to assess central cardiac function in human offspring exposed to ACS.

Exposure to antenatal corticosteroids and infant cortisol regulation

Administration of antenatal corticosteroids (AC) is the standard of care during pregnancy for women who are at risk of early delivery. Evidence indicates that AC improve survival and reduce morbidity for preterm infants. However, research suggests that infants whose mothers receive AC have an altered hypothalamic-pituitary-axis (HPA) response to stressors in early life. Results are mixed regarding the nature of these effects, with studies showing both suppressed and augmented HPA activity. In addition, research is very limited beyond the 4th month of life. The purpose of this study was to determine if AC exposure was associated with infant cortisol levels in a resting state or in response to a stressor at 1, 6 and 12 months postnatal. We also evaluated the moderating role of preterm birth in this association. 181 women and their infants participated in the study. Women were recruited during the 3rd trimester of pregnancy; at this time, they completed the Perceived Stress Scale and provided 8 salivary samples over a 2-day period for cortisol assay. They provided these data again at 6 and 12 months postnatal. At 1, 6, and 12 months postnatal, salivary samples were collected from infants to examine their cortisol levels before and after participation in a 'stressor protocol'. Data were extracted from the medical record on AC exposure, gestational age, maternal obstetric risk, and neonatal morbidity. Mixed effects multilevel regression modeling was used to examine the aims. Infants whose mothers received AC had significantly lower resting state (B = -2.47, CI: -3.691, -0.0484) and post-stressor (B = -2.51, CI: -4.283, -0.4276) cortisol levels across the first year of life than infants whose mothers did not receive AC. There was no moderating effect of preterm birth on the relationship between AC exposure and cortisol. Results indicate a state of dampened HPA activation and cortisol hypo-arousal that persists across the first year of life among infants who were exposed to corticosteroids in utero. Further research is needed to examine mechanisms responsible for any alterations that occur during development of the fetal HPA axis, including epigenetic and biochemical factors that control hormonal secretion, negative feedback, and glucocorticoid receptor function throughout the HPA axis. Findings warrant careful consideration by obstetric clinicians of the benefits and risks of prescribing AC.

Antenatal Glucocorticoids Reduce the Incidence of Refractory Hypotension in Low Birthweight Infants during the Early Neonatal Period, but Do Not Affect It beyond This Time

OBJECTIVE

This study aimed to clarify the effect of antenatal glucocorticoids (AGs) on the incidence of refractory hypotension (RH) in very low birthweight (VLBW) infants after the first week of life.

STUDY DESIGN

We included VLBW infants born at a gestational age of <30 weeks and divided them into three groups: the complete group (born within 7 days of completing a single course [two doses] of AGs), the incomplete group (born without complete course), and the late delivery group (born at ≥8 days after a single course). We compared the incidence and period of onset of RH among the three groups.

RESULTS

A total of 115 infants were enrolled. The incidence of RH in the first week of life was significantly lower in the complete group than in the other groups. However, there was no significant difference in the incidence of RH after the first week of life among the groups.

CONCLUSION

AGs contribute to circulatory stabilization during the first week of life, but this effect does not last after 1 or 2 weeks of administration. In infants who receive AGs, physicians should consider that the risk of RH after the first week of life is not low.

Clinical risk factors for the development of late-onset circulatory collapse in premature infants

BACKGROUND

Very low birth weight (VLBW) infants may be at risk for late-onset circulatory collapse (LCC) where otherwise stable infants develop hypotension resistant to vasoactive agents. The risk factors for LCC development are poorly defined, and it has been theorized that it may be in part due to withdrawal from exogenous prenatal steroids. The goal of this study was to define the clinical characteristics of LCC and investigate its association with antenatal steroid administration.

METHODS

This is a retrospective cohort study of infants born ≤1500 g. LCC was retrospectively diagnosed in infants requiring glucocorticoids for circulatory instability at >1 week of life. Demographic and clinical characteristics were compared between groups using Mann-Whitney test.

RESULTS

Three hundred and ten infants were included; 19 (6.1%) developed LCC. Infants with LCC were born at a median 4.6 weeks' lower gestation, 509 g lower birth weight than those without LCC. There was no difference in antenatal steroid delivery between the groups.

CONCLUSIONS

LCC occurs in a distinct subset of VLBW infants, suggesting the need for monitoring in this high-risk population. Antenatal steroids did not significantly increase the risk of LCC development in this study.

IMPACT

Late-onset circulatory collapse (LCC) is a life-threatening clinical entity occurring in around 6% in VLBW infants and is likely underdiagnosed in the United States. Targeting specific demographic characteristics such as birth weight (<1000 g) and gestational age at birth (<26 weeks) may allow for early identification of high-risk infants, allowing close monitoring and prompt treatment of LCC. No significant association was found between antenatal steroid administration and LCC development, suggesting that the theoretical risks of antenatal steroids on the fetal HPA axis does not outweigh the benefits of antenatal steroids in fetal lung maturity. To date, no studies characterizing LCC have originated outside of Asia. Therefore, providing a description of LCC in a U.S.-based cohort will provide insight into both its prevalence and presentation to inform clinicians about this potentially devastating disorder and foster early diagnosis and treatment. This study validates LCC characteristics and prevalence previously outlined by Asian studies in a single-center U.S.-based cohort while also identifying potential risk factors for LCC development. This manuscript will provide education for U.S. physicians about the risk factors and clinical presentation of LCC to facilitate early diagnosis and treatment, potentially decreasing neonatal mortality. With prompt recognition and treatment of LCC, infants may have decreased exposure to vasoactive medications that have significant systemic effects.

First-Trimester Prenatal Dexamethasone Treatment Is Associated With Alterations in Brain Structure at Adult Age

CONTEXT

Prenatal treatment of human disease is rare. Dexamethasone (DEX) is used in pregnancies at risk for congenital adrenal hyperplasia (CAH) to prevent virilization in an affected female fetus. The safety and long-term consequences of prenatal DEX exposure on the brain are largely unknown.

OBJECTIVE

We investigate whether first-trimester prenatal DEX treatment is associated with alterations in brain structure at adult age, and if these alterations are associated with DNA methylation, mood, and cognitive abilities.

DESIGN, SETTING, AND PARTICIPANTS

T1-weighted and diffusion-weighted imaging scans, from a single research institute, are compared between 19 (9 women) first-trimester DEX-treated individuals, at risk of CAH but not having CAH, and 43 (26 women) controls (age range, 16.0-26.4 years).

RESULTS

DEX-treated participants showed bilateral enlargement of the amygdala, increased surface area and volume of the left superior frontal gyrus, and widespread increased radial, mean, and axial diffusivity of white matter, in particular in the superior longitudinal fasciculi and corticospinal tracts. In the DEX-treated group, increased mean and radial diffusivity correlated with increased methylation of the promotor region of the FKBP5 gene. There were no group differences in cognition or in scales assessing depression or anxiety, and the relationship between brain structure and cognition did not differ between DEX-treated and controls.

CONCLUSIONS

First-trimester prenatal DEX treatment is associated with structural alterations of the brain at adult age, with an accompanying change in gene methylation. The findings add to the safety concerns of prenatal DEX treatment in the context of CAH.

Effects of early rearing enrichments on modulation of brain monoamines and hypothalamic-pituitary-interrenal axis (HPI axis) of fish mahseer (Tor putitora)

Enriching rearing environment is the strategy suggested for improving the post release survivorship of captive-reared animals. Here, an attempt has been made to evaluate the impact of early rearing enrichment on the hypothalamic-pituitary-interrenal axis (HPI axis), blood glucose, and brain dopaminergic and serotonergic systems of Tor putitora. Fifteen-day-old hatchlings of T. putitora were reared up to advanced fry stage in barren, semi-natural, and physically enriched environments and compared them with regard to pre-stress and post-stress levels of whole-body cortisol, blood glucose, brain serotonergic activity (5HIAA/5HT ratio), dopaminergic activity (DOPAC/DA and HVA/DA ratios) and norepinephrine (NE) levels. Significantly low basal whole-body cortisol, glucose and brain NE levels were observed in a physically enriched group of fish as compared to the other two groups. However, after acute stress, all rearing groups showed elevated levels of cortisol, blood glucose, brain 5HIAA/5HT, DOPAC/DA and HVA/DA ratios and NE levels but the magnitude of response was different among different rearing groups. The barren reared group showed a higher magnitude of response as compared to semi-natural and physically enriched groups. Similarly, the recovery rate of whole-body cortisol, blood glucose, and whole-brain monoamines were long-lasting in barren-reared mahseer. We illustrate that increased structural complexity (physical enrichment) during the early rearing significantly modulates various physiological and stress-coping mechanisms of mahseer.

No Association of Antenatal Synthetic Glucocorticoid Exposure and Hair Steroid Levels in Children and Adolescents

CONTEXT

Antenatal synthetic glucocorticoid (sGC) treatment constitutes a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. Previous findings from our group revealed long-term changes in cortisol stress reactivity following antenatal sGC therapy. However, the few prior studies exclusively relied on spot measurements of phasic HPA axis activity, which may not adequately capture cortisol output over prolonged periods of time.

OBJECTIVE

To address this gap, the current study utilized hair steroid concentrations, a valid marker of integrated long-term HPA-axis activity, to investigate endocrine changes in individuals treated with antenatal sGC.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study comprised 76 term-born children (7-12 years) and 58 adolescents (14-18 years). Cumulated hormonal secretion in scalp hair over a 3-month period was determined for different biomarkers of tonic HPA axis activity by liquid chromatography coupled with tandem mass spectrometry. Hair steroid levels were compared between participants with antenatal sGC therapy (dexamethasone or betamethasone) and different control groups.

RESULTS

Findings from this study provide no evidence for a significant effect of antenatal sGCs on long-term hair steroid concentrations. Participants treated with antenatal sGC exhibited comparable levels of hair cortisol, cortisone, dehydroepiandrosterone, and cortisol/dehydroepiandrosterone ratios compared to those of mothers who had been admitted to hospital for pregnancy complications but had never received sGC therapy and controls from physiological pregnancies.

CONCLUSION

In conjunction with data from previous studies, it is thus tempting to speculate that sGC may affect the capacity of dynamic changes and flexible adaption of an individual's HPA axis rather than changes in tonic steroid output.

The development of the hypothalamus-pituitary-adrenal axis during infancy may be affected by antenatal glucocorticoid therapy

BACKGROUND

Developmental changes in the hypothalamus-pituitary-adrenal (HPA) axis during infancy have been reported in term infants, but those in preterm infants have yet to be elucidated. If developmental changes in the HPA axis of preterm infants are modulated by any factors, it may affect their future health. Few studies have examined the lasting consequences of antenatal glucocorticoids on the development of the HPA axis.

METHODS

We measured pre- and post-palivizumab vaccination salivary cortisol values in two conforming periods of three-months intervals during infancy, and compared cortisol values and the response of cortisol secretion between groups with and without antenatal glucocorticoid (AG) therapy.

RESULTS

Although the strength of the response of cortisol secretion to palivizumab fell age-dependently (until late infancy) in the Non-AG group, the opposite pattern was exhibited in the AG group. The changes of the delta cortisol values between the 2 groups were significant.

CONCLUSIONS

This study suggests that the HPA axis of preterm infants whose mothers receive AG therapy may be upregulated during infancy, possibly leading to long lasting health problems.

Combined Antioxidant and Glucocorticoid Therapy for Safer Treatment of Preterm Birth

Ante- and postnatal glucocorticoid therapy reduces morbidity and mortality in the preterm infant, and it is therefore one of the best examples of the successful translation of basic experimental science into human clinical practice. However, accruing evidence derived from human clinical studies and from experimental studies in animal models raise serious concerns about potential long-term adverse effects of treatment on growth and neurological and cardiovascular function in the offspring. This review explores whether combined antioxidant and glucocorticoid therapy may be safer than glucocorticoid therapy alone for the treatment of preterm birth.

Persistent Effects of Antenatal Synthetic Glucocorticoids on Endocrine Stress Reactivity From Childhood to Adolescence

CONTEXT

Antenatal synthetic glucocorticoid (sGC) therapy has been identified as a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. We previously observed significantly increased cortisol stress responses in 6- to 11-year-old, term-born children exposed to antenatal sGCs compared with controls. These findings call for longitudinal follow-up studies to evaluate long-term effects of antenatal sGCs, given that adolescence is marked by a substantial shift of HPA axis functioning.

OBJECTIVE

This study aimed to longitudinally investigate the stability of antenatal sGC-related effects on cortisol stress reactivity from childhood to adolescence.

DESIGN, SETTING, AND PARTICIPANTS

To evaluate long-term trajectories of antenatal sGCs, we longitudinally followed a subsample (n = 44) of our children's cohort into adolescence (14 to 18 years old) for a second assessment. To this end, 22 adolescents with antenatal sGC exposure and 22 untreated controls underwent a standardized laboratory stressor [Trier Social Stress Test (TSST)].

RESULTS

Besides a general increase in HPA axis reactivity from childhood to adolescence (P < 0.05), participants treated with antenatal sGCs showed significantly higher cortisol levels in response to the TSST compared with controls during both developmental stages (P < 0.05). Furthermore, we observed a moderating effect of sGCs on rank-order stability of cortisol stress reactivity from childhood to adolescence (P < 0.05) with a trend (P = 0.07) for higher rank-order stability in sGC-exposed individuals (r = 0.37) compared with controls (r = -0.20).

CONCLUSION

These findings suggest that antenatal sGCs yield long-term changes of HPA axis reactivity that persist into adolescence and may confer increased vulnerability for developing stress-related disorders.

Can Placental Corticotropin-Releasing Hormone Inform Timing of Antenatal Corticosteroid Administration?

CONTEXT

Antenatal corticosteroids are commonly administered to pregnant women at risk for delivering between 23 and 34 gestational weeks; they provide crucial benefits to fetal lung maturation and reduce risk for neonatal morbidity and mortality. Corticosteroids are maximally efficacious for lung maturation when administered within 2 to 7 days of delivery. Accurately identifying the timing of preterm delivery is thus critical to ensure that antenatal corticosteroids are administered within a week of delivery and to avoid unnecessary administration to women who will deliver at term. A plausible biomarker for predicting time of delivery is placental corticotropin-releasing hormone (pCRH).

OBJECTIVE

To assess whether pCRH concentrations predict time to delivery and specifically which women will deliver within a week of treatment.

DESIGN

pCRH concentrations were evaluated before administration of the corticosteroid betamethasone, and timing of delivery was recorded.

PARTICIPANTS

A total of 121 women with singleton pregnancies who were prescribed betamethasone.

RESULTS

Elevated pCRH concentrations were associated with a shorter time from treatment to delivery. Receiver-operating characteristic curves revealed that pCRH may improve the precision of predicting preterm delivery.

CONCLUSIONS

In the current sample, pCRH concentrations predicted the likelihood of delivering within 1 week of corticosteroid treatment. Current findings suggest that pCRH may be a diagnostic indicator of impending preterm delivery. Increasing the precision in predicting time to delivery could inform when to administer antenatal corticosteroids, thus maximizing benefits and reducing the likelihood of exposing fetuses who will be delivered at term.

Influence of Low Protein Diet-Induced Fetal Growth Restriction on the Neuroplacental Corticosterone Axis in the Rat

Objectives: Placental steroid metabolism is linked to the fetal hypothalamus-pituitary-adrenal axis. Intrauterine growth restriction (IUGR) might alter this cross-talk and lead to maternal stress, in turn contributing to the pathogenesis of anxiety-related disorders of the offspring, which might be mediated by fetal overexposure to, or a reduced local enzymatic protection against maternal glucocorticoids. So far, direct evidence of altered levels of circulating/local glucocorticoids is scarce. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) allows quantitative endocrine assessment of blood and tissue. Using a rat model of maternal protein restriction (low protein [LP] vs. normal protein [NP]) to induce IUGR, we analyzed fetal and maternal steroid levels via LC-MS/MS along with the local expression of 11beta-hydroxysteroid-dehydrogenase (Hsd11b). Methods: Pregnant Wistar dams were fed a low protein (8%, LP; IUGR) or an isocaloric normal protein diet (17%, NP; controls). At E18.5, the expression of Hsd11b1 and 2 was determined by RT-PCR in fetal placenta and brain. Steroid profiling of maternal and fetal whole blood, fetal brain, and placenta was performed via LC-MS/MS. Results: In animals with LP-induced reduced body (p < 0.001) and placental weights (p < 0.05) we did not observe any difference in the expressional Hsd11b1/2-ratio in brain or placenta. Moreover, LP diet did not alter corticosterone (Cort) or 11-dehydrocorticosterone (DH-Cort) levels in dams, while fetal whole blood levels of Cort were significantly lower in the LP group (p < 0.001) and concomitantly in LP brain (p = 0.003) and LP placenta (p = 0.002). Maternal and fetal progesterone levels (whole blood and tissue) were not influenced by LP diet. Conclusion: Various rat models of intrauterine stress show profound alterations in placental Hsd11b2 gatekeeper function and fetal overexposure to corticosterone. In contrast, LP diet in our model induced IUGR without altering maternal steroid levels or placental enzymatic glucocorticoid barrier function. In fact, IUGR offspring showed significantly reduced levels of circulating and local corticosterone. Thus, our LP model might not represent a genuine model of intrauterine stress. Hypothetically, the observed changes might reflect a fetal attempt to maintain anabolic conditions in the light of protein restriction to sustain regular brain development. This may contribute to fetal origins of later neurodevelopmental sequelae.

Prenatal stress and models explaining risk for psychopathology revisited: Generic vulnerability and divergent pathways

The present review revisits three hypothesized models that potentially could explain how prenatal maternal stress influences fetal development, birth outcomes, and subsequent developmental psychopathology. These models were mostly based on animal models, and new evidence for these models from human studies is evaluated. Furthermore, divergent trajectories from prenatal exposure to adversities to offspring affected outcomes are reviewed, including the comparison of studies on prenatal maternal stress with research on maternal substance use and maternal malnutrition during pregnancy. Finally, new directions in research on the mechanism underlying prenatal stress effects on human offspring is summarized. While it is concluded that there is abundant evidence for the negative associations between prenatal maternal stress and offspring behavioral, brain, and psychopathological outcomes in humans, there is no consistent evidence for specific mechanisms or specific outcomes in relation to stress exposure in utero. Rather, principles of multifinality and equifinality best describe the consequences for the offspring, suggesting a generic vulnerability and different pathways from prenatal adversities to developmental psychopathology, which complicates the search for underlying mechanisms. New and promising directions for research are provided to get a better understanding of how prenatal stress gets under the skin to affect fetal development.

Prenatal Maternal Cortisol Has Sex-Specific Associations with Child Brain Network Properties

Elevated maternal cortisol concentrations have the potential to alter fetal development in a sex-specific manner. Female brains are known to show adaptive behavioral and anatomical flexibility in response to early-life exposure to cortisol, but it is not known how these sex-specific effects manifest at the whole-brain structural networks. A prospective longitudinal study of 49 mother child dyads was conducted with serial assessments of maternal cortisol levels from 15 to 37 gestational weeks. We modeled the structural network of typically developing children (aged 6-9 years) and examined its global connectome properties, rich-club organization, and modular architecture. Network segregation was susceptible only for girls to variations in exposure to maternal cortisol during pregnancy. Girls generated more connections than boys to maintain topologically capable and efficient neural circuits, and this increase in neural cost was associated with higher levels of internalizing problems. Maternal cortisol concentrations at 31 gestational weeks gestation were most strongly associated with altered neural connectivity in girls, suggesting a sensitive period for the maternal cortisol-offspring brain associations. Our data suggest that girls exhibit an adaptive response by increasing the neural network connectivity necessary for maintaining homeostasis and efficient brain function across the lifespan.

Negative Temperature Differential in Preterm Infants Less Than 29 Weeks Gestational Age: Associations With Infection and Maternal Smoking

BACKGROUND

Hypothermia is related to increased morbidity and mortality in very preterm infants; continuous temperature monitoring is necessary. Thermoregulation is limited in preterm infants.

OBJECTIVES

The purpose of the research was to assess and describe negative temperature differential (NTD) and assess the associations of NTD with infant demographic characteristics, medical history, and clinical events.

METHODS

An exploratory, case study design was used. Abdominal and foot temperature was measured every minute over the first 2 weeks of life in 22 preterm infants at less than 29 weeks gestational age.

RESULTS

All infants experienced NTD. Daily NTD in all infants across all study days ranged from 0 to 70.7%; 2-week mean NTD over all infants ranged from 7.3% to 38.5%. Four infants treated for late onset of infection had a higher NTD than 18 infants without infection (M = 27.8%, SD = 9.52 vs. M = 16.4%, SD = 5.34, p < .05). Although not statistically significant, higher mean percentage of NTD was noted in infants having early onset infection (24.1% vs. 16.4%), African American race (20.0% vs. 15.3%), and/or being born to a mother who smoked during pregnancy (26.6% vs. 16.7%).

DISCUSSION

A larger study is needed to examine associations between NTD and race, maternal smoking history, and infection. NTD might be used as a biomarker to guide acute clinical care and identify infants at risk for acute and chronic morbidity.

Developmental origins of the human hypothalamic-pituitary-adrenal axis

INTRODUCTION

The developmental origins of disease or fetal programming model predicts that intrauterine exposures have life long consequences for physical and psychological health. Prenatal programming of the fetal hypothalamic-pituitary-adrenal (HPA) axis is proposed as a primary mechanism by which early experiences are linked to later disease risk. Areas covered: This review describes the development of the fetal HPA axis, which is determined by an intricately timed cascade of endocrine events during gestation and is regulated by an integrated maternal-placental-fetal steroidogenic unit. Mechanisms by which stress-induced elevations in hormones of maternal, fetal, or placental origin influence the structure and function of the emerging fetal HPA axis are discussed. Recent prospective studies documenting persisting associations between prenatal stress exposures and altered postnatal HPA axis function are summarized, with effects observed beginning in infancy into adulthood. Expert commentary: The results of these studies are synthesized, and potential moderating factors are discussed. Promising areas of further research highlighted include epigenetic mechanisms and interactions between pre and postnatal influences.

Failure of Saliva Sampling in the QF2011 Queensland Flood Study Examining the Effects of Prenatal Maternal Stress on Neonatal Stress Reactivity

The study was designed to investigate the impact of disaster-related prenatal maternal stress on neonates’ reactivity to the routinely administered, painful, newborn screen procedure (heelstick or heel prick). We hypothesized that pregnancy exposure to a flood stressor would affect fetal developmental pathways and subsequently neonatal responses to other stressful events, including the newborn screen. The pregnant women we recruited were affected by sudden onset floods in Queensland, Australia in 2011. Using methods similar to those described in the literature, we collected neonatal saliva immediately prior to the newborn screen and +20 and +40 min afterwards. Saliva sampling was halted after failed saliva collection attempts by trained research staff on 17 newborns. This article discusses reasons for our failure, including the influence of bioethical concerns and the requirement that research activities are compliant with hospital policies as well as the necessity of publishing studies that fail to replicate prior research.

Enduring, Sexually Dimorphic Impact of In Utero Exposure to Elevated Levels of Glucocorticoids on Midbrain Dopaminergic Populations

Glucocorticoid hormones (GCs) released from the fetal/maternal glands during late gestation are required for normal development of mammalian organs and tissues. Accordingly, synthetic glucocorticoids have proven to be invaluable in perinatal medicine where they are widely used to accelerate fetal lung maturation when there is risk of pre-term birth and to promote infant survival. However, clinical and pre-clinical studies have demonstrated that inappropriate exposure of the developing brain to elevated levels of GCs, either as a result of clinical over-use or after stress-induced activation of the fetal/maternal adrenal cortex, is linked with significant effects on brain structure, neurological function and behaviour in later life. In order to understand the underlying neural processes, particular interest has focused on the midbrain dopaminergic systems, which are critical regulators of normal adaptive behaviours, cognitive and sensorimotor functions. Specifically, using a rodent model of GC exposure in late gestation (approximating human brain development at late second/early third trimester), we demonstrated enduring effects on the shape and volume of the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) (origins of the mesocorticolimbic and nigrostriatal dopaminergic pathways) on the topographical organisation and size of the dopaminergic neuronal populations and astrocytes within these nuclei and on target innervation density and neurochemical markers of dopaminergic transmission (receptors, transporters, basal and amphetamine-stimulated dopamine release at striatal and prefrontal cortical sites) that impact on the adult brain. The effects of antenatal GC treatment (AGT) were both profound and sexually-dimorphic, not only in terms of quantitative change but also qualitatively, with several parameters affected in the opposite direction in males and females. Although such substantial neurobiological changes might presage marked behavioural effects, in utero GC exposure had only a modest or no effect, depending on sex, on a range of conditioned and unconditioned behaviours known to depend on midbrain dopaminergic transmission. Collectively, these findings suggest that apparent behavioural normality in certain tests, but not others, arises from AGT-induced adaptations or compensatory mechanisms within the midbrain dopaminergic systems, which preserve some, but not all functions. Furthermore, the capacities for molecular adaptations to early environmental challenge are different, even opponent, in males and females, which may account for their differential resilience or failure to perform adequately in behavioural tests. Behavioural "normality" is thus achieved by the midbrain dopaminergic network operating outside its normal limits (in a state of allostasis), rendering it at greater risk to malfunction when challenged in later life. Sex-specific neurobiological programming of midbrain dopaminergic systems may, therefore, have psychopathological relevance for the sex bias commonly found in brain disorders associated with these systems, and which have a neurodevelopmental component, including schizophrenia, ADHD (attention/deficit hyperactivity disorders), autism, depression and substance abuse.

Prenatal betamethasone exposure and psychopathology risk in extremely low birth weight survivors in the third and fourth decades of life

BACKGROUND

Mortality rates among extremely low birthweight (ELBW) infants have declined since the advent of antenatal glucocorticoid use. However, the long term neuropsychiatric effects of exposure are not well understood. We utilized the world's oldest longitudinally followed cohort of ELBW survivors to compare psychopathology over two decades in adulthood in those exposed to prenatal betamethasone and those who were not.

METHODS

ELBW survivors (n=179) and matched normal birth weight (NBW) controls (n=145) completed the Young Adult Self-Report questionnaire at 22-26 and 29-36 years, and the Beck Depression and Anxiety Inventories at 29-36 years. Symptom levels and rates of clinically significant psychiatric problems were compared in ELBW survivors whose mothers were administered steroids during pregnancy (ELBW-S n=63), ELBW participants who were not (ELBW-NS, n=79), and NBW controls.

RESULTS

At 22-26, ELBW-S had higher levels of anxiety, depressive, and avoidant personality symptoms, and a 3 to 5-fold increase in the odds of clinically significant levels of these problems compared to NBW controls, whereas ELBW-NS did not. These associations were maintained at 29-36, when ELBW-S participants exhibited a 3 to 10-fold increase in the odds of clinically significant anxiety and avoidant personality problems compared to NBW controls. At both time points, the odds of clinically significant anxiety problems were more than 3 times higher among ELBW-S than in ELBW-NS.

CONCLUSION

ELBW adults exposed to prenatal betamethasone manifest higher levels of anxiety and depression than those who were not, and may represent a group of preterm survivors at particularly high psychiatric risk.

Antenatal glucocorticoid treatment is associated with diurnal cortisol regulation in term-born children

Due to the rapid developmental changes that occur during the fetal period, prenatal influences can affect the developing central nervous system with lifelong consequences for physical and mental health. Glucocorticoids are one of the proposed mechanisms by which fetal programing occurs. Glucocorticoids pass through the blood-brain barrier and target receptors throughout the central nervous system. Unlike endogenous glucocorticoids, synthetic glucocorticoids readily pass through the placental barrier to reach the developing fetus. The synthetic glucocorticoid, betamethasone, is routinely given prenatally to mothers at risk for preterm delivery. Over 25% of the fetuses exposed to betamethasone will be born at term. Few studies have examined the lasting consequences of antenatal treatment of betamethasone on the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. The purpose of this study is to examine whether antenatal exposure to betamethasone alters circadian cortisol regulation in children who were born full term. School-aged children prenatally treated with betamethasone and born at term (n=19, mean (SD)=8.1 (1.2) years old) were compared to children not treated with antenatal glucocorticoids (n=61, mean (SD)=8.2 (1.4) years old). To measure the circadian release of cortisol, saliva samples were collected at awakening; 30, 45, and 60min after awakening; and in the evening. Comparison children showed a typical diurnal cortisol pattern that peaked in the morning (the cortisol awakening response) and gradually decreased throughout the day. In contrast, children exposed to antenatal betamethasone lacked a cortisol awakening response and had a flatter diurnal slope (p's<0.01). These data suggest that antenatal glucocorticoid treatment may disrupt the circadian regulation of the HPA axis among children born at term. Because disrupted circadian regulation of cortisol has been linked to mental and somatic health problems, future research is needed to determine whether children exposed to antenatal synthetic glucocorticoids are at risk for poor mental and physical health.

Maternal cortisol during pregnancy is related to infant cardiac vagal control

BACKGROUND

Prenatal exposure to maternal psychological distress and glucocorticoids result in neurobiological adaptations within the fetus that increase risk for developing exaggerated emotional, behavioral, and stress responses to novelty and challenges in childhood. The current study investigated the influence of maternal depressed mood and cortisol during pregnancy on infant cardiac vagal control (CVC) to standardized laboratory challenge tasks.

METHODS

The sample comprised 194 women and their infants. Maternal reports of depressed mood and salivary cortisol were assessed at 14 and 32 weeks gestational age. Linear regression was used to examine associations between maternal measures during early and late pregnancy, and infant CVC indexed via respiratory sinus arrhythmia (RSA) at rest and in response to laboratory tasks designed to elicit frustration when infants were 6 months of age. It was hypothesized that maternal depressed mood and cortisol would be associated with lower basal RSA and smaller decreases in RSA from baseline to challenge.

RESULTS

A significant decrease in infant RSA from baseline to frustration tasks indicated that laboratory tasks elicited a reliable decrease in RSA from baseline to frustration among infants which is characterized by reduction in vagal efferent activity on the heart in response to challenge. Higher maternal cortisol, but not depressed mood, was associated with lower basal RSA and greater decrease in RSA from baseline to frustration. Associations between maternal cortisol and infant basal RSA were observed for both early and late pregnancy whereas the associations between prenatal cortisol and decrease in RSA from baseline to frustration were observed for early, but not late, pregnancy.

CONCLUSIONS

Maternal cortisol during pregnancy was associated with infant CVC at 6-months of age. Such influences may have enduring impacts on the child and important implications for the development of physical and mental health outcomes.

Multidimensional response to vaccination pain in very preterm, moderate- to-late preterm and full-term infants at age three months

BACKGROUND

Very early life pain exposure and stress induces alterations in the developing brain and leads to altered pain sensitivity. In premature infants with a history of numerous early postnatal adverse events, behavioral responsiveness and hypothalamic-pituitary-adrenal (HPA) axis reactivity may show alterations as well.

AIMS

We compared a multidimensional response to a painful situation (vaccination) in three month old infants. The study involved very preterm, moderate to late preterm infants and full-term infants with varying exposure to pain and stress within the first weeks of life.

STUDY DESIGN

At the age of three months, we evaluated the infants' reactivity to intramuscular injections for immunization.

SUBJECTS

The study included 61 very preterm infants, 30 moderate to late preterm infants and 30 full-term infants.

OUTCOME MEASURES

We assessed heart rate recovery, Bernese pain Score and increase of salivary cortisol following vaccination. We also evaluated the flexor withdrawal reflex threshold as well as Prechtl's General Movements. Secondly, we assessed factors potentially influencing pain reactivity such as exposure to pain/stress, gender, use of steroids or opioids and mechanical ventilation.

RESULTS

Very preterm, moderate to late preterm and full-term infants showed different reactivity to pain in all analyzed aspects. Very preterm infants showed a lower level of behavioral and physiologic reactivity and exposure to pain/stress predicted lower cortisol increase.

CONCLUSION

At three months of age, very preterm infants show an altered level of HPA axis reactivity. Efforts aiming at minimizing pain and stress in premature infants should be taken.

Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood

BACKGROUND

Maternal depression is one of the most common prenatal complications. The consequences of fetal exposure to maternal depression are poorly understood. The aim of this study is to examine the association between fetal exposure to maternal depressive symptoms and cortical thickness in children 6-9 years old.

METHODS

A prospective, longitudinal study of maternal depressive symptoms at 19, 25, and 31 weeks' gestation was followed by acquisition of a structural magnetic resonance imaging scan in 81 children (age, 86.1 ± 9.9 months).

RESULTS

Significant (p < .01) cortical thinning in children primarily in the right frontal lobes was associated with exposure to prenatal maternal depression. The strongest association was at 25 weeks' gestation; exposure to maternal depression at 25 gestational weeks was associated with cortical thinning in 19% of the whole cortex and 24% of the frontal lobes, primarily in the right superior, medial orbital, and frontal pole regions of the prefrontal cortex (p < .01). The significant association between prenatal maternal depression and child externalizing behavior (p < .05) was mediated by cortical thinning in prefrontal areas of the right hemisphere.

CONCLUSIONS

The pattern of cortical thinning in children exposed to prenatal maternal depression is similar to patterns in depressed patients and in individuals with risk for depression. Exposure to prenatal depression coupled with subsequent cortical thinning was associated with presence of externalizing behavior in preadolescent children and may be prodromal markers of risk for dysphoria. Vulnerability to prenatal influences at 25 gestational weeks may result from the enormous growth and dramatic structural changes in the nervous system.

Effects of Antenatal Corticosteroids on Cortisol and Heart Rate Reactivity of Preterm Infants

Administration of glucocorticoids (GCs) during pregnancy is an established practice for reducing morbidity and mortality of fetuses at risk of preterm delivery. However, preliminary research indicates that exposure to exogenous GCs in utero may be associated with suppressed hypothalamic–pituitary–adrenal axis activity. The aim of this study was to determine whether preterm neonates who are exposed to antenatal corticosteroids show evidence of a suppressed stress-response system during their first few weeks of life, in contrast to infants who are not exposed. The sample (51% female) included 57 neonates, with 74% exposed to steroids. Mean gestational ages (GAs) were 32.6 weeks for exposed and 34.7 weeks for nonexposed infants. Although neonates in the two groups differed in gender, birth weight, and morbidity, these factors were controlled for in data analyses. Infants’ salivary cortisol and heart rate (HR) were measured before and after they received a standardized caregiving “stressor” while in the newborn intensive care unit. Infants exposed to GCs in utero had lower basal cortisol levels and higher HRs than their nonexposed peers. In contrast to infants who received no GCs, they also exhibited minimal HR or cortisol reactivity to the stressor. Findings suggest that preterm infants who were exposed to antenatal corticosteroids experience a suppressed response to stress. As preterm children develop, this dysregulation has numerous implications for later development of stress-related cardiovascular and mental health problems. Further research is needed to determine whether these postnatal effects of antenatal corticosteroids persist over time.

Early-life glucocorticoid exposure: the hypothalamic-pituitary-adrenal axis, placental function, and long-term disease risk

An adverse early-life environment is associated with long-term disease consequences. Adversity early in life is hypothesized to elicit developmental adaptations that serve to improve fetal and postnatal survival and prepare the organism for a particular range of postnatal environments. These processes, although adaptive in their nature, may later prove to be maladaptive or disadvantageous if the prenatal and postnatal environments are widely discrepant. The exposure of the fetus to elevated levels of either endogenous or synthetic glucocorticoids is one model of early-life adversity that contributes substantially to the propensity of developing disease. Moreover, early-life glucocorticoid exposure has direct clinical relevance because synthetic glucocorticoids are routinely used in the management of women at risk of early preterm birth. In this regard, reports of adverse events in human newborns have raised concerns about the safety of glucocorticoid treatment; synthetic glucocorticoids have detrimental effects on fetal growth and development, childhood cognition, and long-term behavioral outcomes. Experimental evidence supports a link between prenatal exposure to synthetic glucocorticoids and alterations in fetal development and changes in placental function, and many of these alterations appear to be permanent. Because the placenta is the conduit between the maternal and fetal environments, it is likely that placental function plays a key role in mediating effects of fetal glucocorticoid exposure on hypothalamic-pituitary-adrenal axis development and long-term disease risk. Here we review recent insights into how the placenta responds to changes in the intrauterine glucocorticoid environment and discuss possible mechanisms by which the placenta mediates fetal hypothalamic-pituitary-adrenal development, metabolism, cardiovascular function, and reproduction.

Antenatal glucocorticoid exposure enhances the inhibition of adrenal steroidogenesis by leptin in a sex-specific fashion

Antenatal treatment with glucocorticoids (GC) poses long-lasting effects on endocrine and cardiovascular function. Given that leptin attenuates adrenal function and the reported sex differences in plasma leptin concentration, we hypothesized that antenatal GC will affect leptin levels and leptin modulation of adrenal function in a sex-specific manner. Pregnant sheep were randomly given betamethasone or vehicle at 80 days of gestational age, and offspring were allowed to deliver at term. Adrenocortical cells (ADC) were studied from male and female animals at 1.5 yr of age. Plasma leptin was increased 66% in male and 41% in female GC-treated animals (P < 0.05), but adrenal leptin mRNA was increased only in GC-treated males (P < 0.05). Whereas mRNA expression of adrenal leptin receptor isoforms showed sex (Ob-Ra and Ob-Rb) and treatment-dependent (Ob-Rb) differences, protein expression remained unchanged. GC-treated females showed greater plasma cortisol and greater ACTH-stimulated cortisol production (P < 0.05) in ADC. Leptin exerted a greater inhibitory effect on basal and stimulated cortisol by ADC from GC-treated males (P < 0.05), with no differences in females. Similarly, greater inhibitory effects on basal and ACTH-stimulated StAR and ACTH-R mRNA expression by leptin were observed in cells from GC males (P < 0.05), with no changes in females. Persistent effects of antenatal GC on leptin levels and leptin modulation of adrenal function are expressed in a sex-specific manner; males are more sensitive than females to the inhibitory influences of leptin on adrenal function, and this effect appears to be mediated by a greater inhibition of StAR and ACTH-R expression in adrenals of adult GC-treated males.

Effects of antenatal corticosteroids on the hypothalamic-pituitary-adrenocortical axis of the fetus and newborn: experimental findings and clinical considerations

The hypothalamic-pituitary-adrenocortical (HPA) axis is a major neuroendocrine pathway that modulates the stress response. The glucocorticoid, cortisol, is the principal end product of the HPA axis in humans and plays a fundamental role in maintaining homeostasis and in fetal maturation and development. Antenatal administration of synthetic glucocorticoids (GCs) accelerates fetal lung maturation and has significantly decreased neonatal mortality and morbidity in infants born before 34 weeks of gestation. Exposure to excess levels of endogenous GCs and exogenous GCs (betamethasone and dexamethasone) has been shown to alter the normal development trajectory. The development and regulation of the fetal HPA axis is discussed and the experimental animal evidence presented suggests long-term adverse consequences of altered HPA function. The clinical data in infants exposed to GCs also suggest altered HPA axis function over the short term. The longer-term consequences of antenatal GC exposure on HPA axis function and subtler neurodevelopmental outcomes including adaptation to stress, cognition, behavior, and the cardiovascular and immune responses are poorly understood. Emerging clinical strategies and interventions may help in the selection of mothers at risk for preterm delivery who would benefit from existing or future formulations of antenatal GCs with a reduction in the associated risk to the fetus and newborn. Detailed longitudinal long-term follow-up of those infants exposed to synthetic GCs are needed.

Epigenetic effects of prenatal stress on 11β-hydroxysteroid dehydrogenase-2 in the placenta and fetal brain

Maternal exposure to stress during pregnancy is associated with significant alterations in offspring neurodevelopment and elevated maternal glucocorticoids likely play a central role in mediating these effects. Placental 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) buffers the impact of maternal glucocorticoid exposure by converting cortisol/corticosterone into inactive metabolites. However, previous studies indicate that maternal adversity during the prenatal period can lead to a down-regulation of this enzyme. In the current study, we examined the impact of prenatal stress (chronic restraint stress during gestational days 14–20) in Long Evans rats on HSD11B2 mRNA in the placenta and fetal brain (E20) and assessed the role of epigenetic mechanisms in these stress-induced effects. In the placenta, prenatal stress was associated with a significant decrease in HSD11B2 mRNA, increased mRNA levels of the DNA methyltransferase DNMT3a, and increased DNA methylation at specific CpG sites within the HSD11B2 gene promoter. Within the fetal hypothalamus, though we find no stress-induced effects on HSD11B2 mRNA levels, prenatal stress induced decreased CpG methylation within the HSD11B2 promoter and increased methylation at sites within exon 1. Within the fetal cortex, HSD11B2 mRNA and DNA methylation levels were not altered by prenatal stress, though we did find stress-induced elevations in DNMT1 mRNA in this brain region. Within individuals, we identified CpG sites within the HSD11B2 gene promoter and exon 1 at which DNA methylation levels were highly correlated between the placenta and fetal cortex. Overall, our findings implicate DNA methylation as a mechanism by which prenatal stress alters HSD11B2 gene expression. These findings highlight the tissue specificity of epigenetic effects, but also raise the intriguing possibility of using the epigenetic status of placenta to predict corresponding changes in the brain.

Single course of antenatal steroids did not alter cortisol in preterm infants up to 18 months

AIMS

To determine whether a single course of antenatal dexamethasone alters resting cortisol at 3, 8 and 18 months corrected age in preterm infants.

METHODS

Preterm infants born ≤32 weeks gestational age were recruited during 2001-2004 from a single neonatal intensive care unit. Resting salivary cortisol was collected at least once at 3, 8 and 18 months corrected age in a longitudinal cohort. A mixed-effects repeated measures analysis was used to accommodate cases with less than complete follow-up.

RESULTS

One hundred and thirty three infants were included in the present study, contributing 266 cortisol samples. Of these, 107 infants had been exposed to a single course of antenatal dexamethasone and 26 not exposed to antenatal steroids. There was no significant main effect of antenatal steroids on resting cortisol at any age. This result was not altered after adjusting for gestational age at birth, neonatal cumulative pain, morphine exposure, mechanical ventilation days and post-natal steroid exposure.

CONCLUSIONS

No effect of a single course of dexamethasone on resting salivary cortisol, an indicator of hypothalamic-pituitary-adrenal axis function, was found in infancy up to 18 months corrected age in infants born very preterm.

Maternal cortisol over the course of pregnancy and subsequent child amygdala and hippocampus volumes and affective problems

Stress-related variation in the intrauterine milieu may impact brain development and emergent function, with long-term implications in terms of susceptibility for affective disorders. Studies in animals suggest limbic regions in the developing brain are particularly sensitive to exposure to the stress hormone cortisol. However, the nature, magnitude, and time course of these effects have not yet been adequately characterized in humans. A prospective, longitudinal study was conducted in 65 normal, healthy mother-child dyads to examine the association of maternal cortisol in early, mid-, and late gestation with subsequent measures at approximately 7 y age of child amygdala and hippocampus volume and affective problems. After accounting for the effects of potential confounding pre- and postnatal factors, higher maternal cortisol levels in earlier but not later gestation was associated with a larger right amygdala volume in girls (a 1 SD increase in cortisol was associated with a 6.4% increase in right amygdala volume), but not in boys. Moreover, higher maternal cortisol levels in early gestation was associated with more affective problems in girls, and this association was mediated, in part, by amygdala volume. No association between maternal cortisol in pregnancy and child hippocampus volume was observed in either sex. The current findings represent, to the best of our knowledge, the first report linking maternal stress hormone levels in human pregnancy with subsequent child amygdala volume and affect. The results underscore the importance of the intrauterine environment and suggest the origins of neuropsychiatric disorders may have their foundations early in life.

Glucocorticoid exposure of sheep at 0.7 to 0.75 gestation augments late-gestation fetal stress responses

OBJECTIVES

Exposure to glucocorticoid levels inappropriately high for current maturation alters fetal hypothalamo-pituitary-adrenal axis (HPAA) development. In an established fetal sheep model, we determined whether clinical betamethasone doses used to accelerate fetal lung maturation have persistent effects on fetal HPAA hypotensive-stress responses.

STUDY DESIGN

Pregnant ewes received saline (n = 6) or betamethasone (n = 6); 2 × 110 μg/kg body weight doses injected 24 hours apart (106/107 and 112/113 days' gestational age, term 150 days). Basal adrenocorticotropin (ACTH) and cortisol and responses to fetal hypotension were measured before and 5 days after the first course and 14 days after the second course.

RESULTS

Basal ACTH and cortisol were similar with treatment. HPAA responses to hypotension increased after the second but not first course and ACTH/cortisol ratio increased indicating central HPAA effects.

CONCLUSIONS

Results demonstrate latency in the emergence of fetal HPAA hyperresponsiveness following betamethasone exposure that may explain hyperresponsiveness in full-term but not preterm neonates.

Psychobiological effects of prenatal glucocorticoid exposure in 10-year-old-children

BACKGROUND

Prenatal stress seems to have long-lasting effects on biological and psychological processes of the offspring. However, to date, there have been no studies investigating the effects of prenatal glucocorticoid exposure on psychological, endocrine, and autonomic responses to a standardized psychosocial stress test in children.

METHODS

A sample of 115 healthy, 10-year-old children was examined. The Glucocorticoids + Tocolytics group was characterized by tocolytic treatment of the mothers due to preterm labor (n = 43). In addition, the pregnant women received glucocorticoid treatment in order to accelerate fetal lung maturation in case of preterm birth. The first comparison group (Tocolytics) consisted of children whose mothers also experienced preterm labor, but did not receive glucocorticoid treatment (n = 35). In the second comparison group (CONTROL), children whose mothers had a complication-free pregnancy were assessed (n = 37). Psychological parameters (stress appraisal and mood) using self-report questionnaires as well as salivary cortisol, salivary alpha-amylase, and heart rate were measured during a standardized psychosocial stress test (Trier Social Stress Test for Children).

RESULTS

Group comparisons revealed that a subscale of stress appraisal, control expectancies, significantly differed in children who were prenatally exposed to glucocorticoids as compared to both comparison groups (F = 4.889, p = 0.009). Furthermore, significant differences between the groups were revealed for salivary cortisol. With respect to overall stress appraisal and heart rate, trends toward significance were observed between the three groups.

CONCLUSION

At the age of ten, those children who have been exposed to prenatal maternal glucocorticoids show changed psychobiological stress reactivity to a standardized psychosocial stress test as compared to control children.

Mood disorders and their pharmacological treatment during pregnancy: is the future child affected?

Nearly half the US population will meet criteria for a neuropsychiatric disorder at some point in their lives, and 1 in 17 has a seriously debilitating illness. Although not all affected adults had an identified disorder as a child, increasingly these psychopathologies are conceptualized as the late-stage culmination of aberrant developmental processes shaped by a complex interplay of genes and experience, including experiences in utero. Decades of studies with pregnant animals demonstrate that stress-elicited perturbations in maternal biology affect offspring neurodevelopment. Studies of stress in pregnant women largely mirror these findings. Pregnant women with anxiety and/or depression experience greater life stress, and illness-related alterations in their neurobiology, with a potential to impact fetal neurobehavioral development via associated changes in the intrauterine environment and/or pharmacologic interventions. This article critically reviews findings on child development (including fetal neurobehavior) related to maternal depression, anxiety, and pharmacological treatments, primarily selective serotonin reuptake inhibitors (SSRIs). The hypothesis under review is that, in addition to genetics and characteristics of the postnatal environment, the familial transmission of risk for neuropsychiatric disorders involves a "third path"-prenatal exposure to psychiatric illness and its treatment.

The link between perinatal glucocorticoids exposure and psychiatric disorders

The perinatal period is particularly sensitive to a variety of insults during which stress-regulating systems can be permanently altered and psychopathologies ensue. The programming of physiological, endocrinological, and behavioral functions by perinatal adversities is mediated by altered levels of glucocorticoids or the hypothalamic-pituitary-adrenal axis activity in either the mother or offspring. In this article, I review the integrated data from human studies and from animal models that suggest the programming effects of perinatal glucocorticoids exposure. Finally, the concept of developmental origins of psychiatric disorders is discussed.

Prenatal corticosteroid exposure alters early developmental seizures and behavior

In humans, corticosteroids are often administered prenatally to improve lung development in preterm neonates. Studies in exposed children as well as in children, whose mothers experienced significant stress during pregnancy indicate behavioral problems and possible increased occurrence of epileptic spasms. This study investigated whether prenatal corticosteroid exposure alters early postnatal seizure susceptibility and behaviors. On gestational day 15, pregnant rats were injected i.p. with hydrocortisone (2×10mg/kg), betamethasone (2×0.4mg/kg) or vehicle. On postnatal day (P)15, seizures were induced by flurothyl or kainic acid (3.5 or 5.0mg/kg). Horizontal bar holding was determined prior to seizures and again on P17. Performance in the elevated plus maze was assessed on P20-22. Prenatal exposure to betamethasone decreased postnatal susceptibility to flurothyl-induced clonic seizures but not to kainic acid-induced seizures. Prenatal hydrocortisone decreased postnatal weight but did not affect seizure susceptibility. Hydrocortisone alone did not affect performance in behavioral tests except for improving horizontal bar holding on P17. A combination of prenatal hydrocortisone and postnatal seizures resulted in increased anxiety. Prenatal exposure to mineralocorticoid receptor blocker canrenoic acid did not attenuate, but surprisingly amplified the effects of hydrocortisone on body weight and significantly worsened horizontal bar performance. Thus, prenatal exposure to excess corticosteroids alters postnatal seizure susceptibility and behaviors. Specific effects may depend on corticosteroid species.

Corticosteroid regulation of P-glycoprotein in the developing blood-brain barrier

The early fetal brain is susceptible to teratogens in the maternal circulation, because brain microvessel expression of drug efflux transporter, P-glycoprotein (P-gp), is very low. However, there is a dramatic up-regulation of brain microvessel P-gp in late gestation. This study investigated the role of cortisol and dexamethasone in this up-regulation of fetal brain microvessel P-gp expression. Primary brain endothelial cell (BEC) cultures derived from gestational d (GD)40, GD50, GD65 (term, ∼68 d) and postnatal d 14 male guinea pigs were treated with varying doses (10(-8) to 10(-5) m) of cortisol, dexamethasone, and aldosterone. After treatment, P-gp function was assessed using calcein-acetoxymethyl ester (P-gp substrate; 1 μm for 1 h) and measuring BEC accumulation of calcein. Corticosteroid treatment of BECs derived from postnatal d 14 resulted in increased P-gp activity. BECs derived from GD65 (near term) responded similarly, but these cells were extremely sensitive to the effects of mineralocorticoid receptor agonists (cortisol and aldosterone). BECs derived from GD50 displayed dose-dependent increases in P-gp function with dexamethasone (P < 0.05) and a trend towards increased function with cortisol. Cells derived from GD40 were unresponsive to all treatments. In conclusion, P-gp function in BECs is more responsive to glucocorticoids (GCs) in late gestation. Therefore, the late gestational surge in fetal plasma GCs, which parallels the increase in brain microvessel P-gp expression, may contribute to this P-gp up-regulation. Further, synthetic GCs (administered to pregnant women at risk of preterm delivery) may increase the protective capacity of the developing fetal blood-brain barrier, depending on the timing of GC exposure.

Prenatal treatment with glucocorticoids sensitizes the hpa axis response to stress among full-term infants

The objective of this study was to determine the consequences for HPA axis functioning among healthy full-term newborns of prenatal treatment with the synthetic glucocorticoid (GC), betamethasone, which is the routine treatment for threatened preterm delivery. Ninety full-term infants were recruited into two study groups (30 betamethasone treated; 60 comparison group matched for GA at birth and sex). The cortisol and behavioral response to the painful stress of a heel-stick blood draw was assessed 24 hr after birth. Full-term infants exposed to prenatal betamethasone displayed a larger cortisol response to the heel-stick procedure, despite no differences in baseline levels. Further, within the recommended window of betamethasone administration (24-34 gestational weeks), infants exposed to betamethasone earlier in gestation displayed the largest cortisol response to the heel-stick. These data add to accumulating evidence that prenatal exposure to elevated GCs programs the development of the HPA axis.

Prenatal maternal stress programs infant stress regulation

OBJECTIVE

Prenatal exposure to inappropriate levels of glucocorticoids (GCs) and maternal stress are putative mechanisms for the fetal programming of later health outcomes. The current investigation examined the influence of prenatal maternal cortisol and maternal psychosocial stress on infant physiological and behavioral responses to stress.

METHODS

The study sample comprised 116 women and their full term infants. Maternal plasma cortisol and report of stress, anxiety and depression were assessed at 15, 19, 25, 31 and 36 + weeks' gestational age. Infant cortisol and behavioral responses to the painful stress of a heel-stick blood draw were evaluated at 24 hours after birth. The association between prenatal maternal measures and infant cortisol and behavioral stress responses was examined using hierarchical linear growth curve modeling.

RESULTS

A larger infant cortisol response to the heel-stick procedure was associated with exposure to elevated concentrations of maternal cortisol during the late second and third trimesters. Additionally, a slower rate of behavioral recovery from the painful stress of a heel-stick blood draw was predicted by elevated levels of maternal cortisol early in pregnancy as well as prenatal maternal psychosocial stress throughout gestation. These associations could not be explained by mode of delivery, prenatal medical history, socioeconomic status or child race, sex or birth order.

CONCLUSIONS

These data suggest that exposure to maternal cortisol and psychosocial stress exerts programming influences on the developing fetus with consequences for infant stress regulation.

Effects of maternal breathing rate, psychiatric status, and cortisol on fetal heart rate

Women's experiences during pregnancy are predictive of variation in neurobehavioral profiles in their children. Few studies have assessed these relationships during the prenatal period. In 113 women in the 36(th) -38(th) gestational week (mean age 26.3 ± 5.4 years), electrocardiogram, blood pressure, respiration, salivary cortisol, and fetal heart rate (HR) were measured during baseline, a psychological challenge (Stroop color-word matching task), and a standardized paced breathing protocol. Subjects underwent the Structured Clinical Interview for DSM-IV prior to testing and were grouped as: depressed, co-morbid for depression and anxiety, anxiety disorder only, and control. There was a significant main effect of maternal diagnostic group on fetal HR only during the Stroop task: fetuses of women in the co-morbid group had a greater HR increase compared to controls (p < .05). Overall, fetuses showed robust increases in HR during paced breathing (p < .0001), and there was no significant difference by maternal diagnosis. For both tasks, changes in fetal HR were independent of women's concurrent cardiorespiratory activity. Finally, although cortisol was higher in the co-morbid group (p < .05), across all participants, there was a trend for maternal baseline cortisol to be positively associated with average fetal HR (p = .06). These findings indicate that variation in fetal HR reactivity-an index of emerging regulatory capacities-is likely influenced by multiple acute and chronic factors associated with women's psychobiology.

Effect of antenatal betamethasone administration on neonatal cardiac autonomic balance

Beneficial effects of antenatal glucocorticoid treatment in pregnancies at risk for preterm delivery may entail long-term consequences for the establishment of sympathoadrenergic system balance. We analyzed the cardiac autonomic system activity in neonates with a single course of antenatal betamethasone (2 × 12 mg) treatment by calculating heart rate variability (HRV) time-domain parameters from 24 h ECG recordings and short-term frequency-domain parameters during infant active and resting states. In addition, resting and challenged salivary α-amylase levels were measured in 23 betamethasone-exposed neonates and compared with controls. Indicators for overall HRV (SDNN: p = 0.258; triangular index: p = 0.179) and sympathovagal balance [low- to high-frequency power (LF/HF): p = 0.82 (resting state)] were not significantly different in neonates of the betamethasone treatment group. Parameters mostly influenced by sympathetic activity [SD of the average of valid NN intervals (SDANN): p = 0.184 and SDs of all NN intervals (SDNNi): p = 0.784] and vagal tone [RMSSD: p = 1.0; NN50: p = 0.852; HF: p = 0.785 (resting state)] were unaltered. Resting α-amylase levels were not significantly different in the betamethasone treatment group (p = 0.304); however, α-amylase release after a neonatal challenge was slightly reduced (p = 0.045). Thus, cardiac autonomic balance seems to be preserved in neonates exposed to a single course of antenatal betamethasone treatment.

The timing of prenatal exposure to maternal cortisol and psychosocial stress is associated with human infant cognitive development

The consequences of prenatal maternal stress for development were examined in 125 full-term infants at 3, 6, and 12 months of age. Maternal cortisol and psychological state were evaluated 5 times during pregnancy. Exposure to elevated concentrations of cortisol early in gestation was associated with a slower rate of development over the 1st year and lower mental development scores at 12 months. Elevated levels of maternal cortisol late in gestation, however, were associated with accelerated cognitive development and higher scores at 12 months. Elevated levels of maternal pregnancy-specific anxiety early in pregnancy were independently associated with lower 12-month mental development scores. These data suggest that maternal cortisol and pregnancy-specific anxiety have programming influences on the developing fetus.

Dose-response effects of betamethasone on maturation of the fetal sheep lung

OBJECTIVE

Glucocorticoid administration to women in preterm labor improves neonatal mortality and morbidity. Fetal exposure to glucocorticoid levels higher than those appropriate to the current gestational stage has multiple organ system effects. Some, eg, fetal hypertension, are maximal at lower than the clinical dose. We hypothesized that the clinical dose has supramaximal lung maturational effects.

STUDY DESIGN

We evaluated the full, half, and quarter clinical betamethasone dose (12 mg/70 kg or 170 microg/kg intramuscularly twice 24 hours apart) on fetal sheep lung pressure volume curves (PVC) after 48 hours' exposure at 0.75 gestation. We measured key messenger RNAs and protein products that affect lung function and total lung dipalmitoyl phosphatidyl choline.

RESULTS

Full and half doses had similar PVC and total lung dipalmitoyl phosphatidyl choline effects. Messenger RNA for surfactant proteins A, B, and D and elastin increased in a dose-dependent fashion.

CONCLUSION

Half the clinical betamethasone dose produces maximal PVC improvement in fetal sheep at 0.75 gestation.

Effects of intrauterine exposure to synthetic glucocorticoids on fetal, newborn, and infant hypothalamic-pituitary-adrenal axis function in humans: a systematic review

BACKGROUND

Synthetic glucocorticoids are commonly used in reproductive medicine. Fetal organ systems are highly sensitive to changes in the intrauterine environment, including overexposure to glucocorticoids. Structural and functional alterations resulting from such changes may persist throughout life and have been associated with diverse diseases. One system that could be particularly sensitive to fetal glucocorticoid overexposure is the hypothalamic-pituitary-adrenal (hpa) axis. Many human studies have investigated this possibility, but a systematic review to identify consistent, emergent findings is lacking.

METHODS

We systematically review 49 human studies, assessing the effects of intrauterine exposure to synthetic glucocorticoids on fetal, neonate, and infant hpa function.

RESULTS

Study quality varied considerably, but the main findings held true after restricting the analyses to higher-quality studies: intrauterine exposure to synthetic glucocorticoids reduces offspring hpa activity under unstimulated conditions after pain but not pharmacological challenge. Although reduced unstimulated hpa function appears to recover within the first 2 wk postpartum, blunted hpa reactivity to pain is likely to persist throughout the first 4 months of life. There is some evidence that the magnitude of the effects is correlated with the total amount of glucocorticoids administered and varies with the time interval between glucocorticoid exposure and hpa assessment.

CONCLUSIONS

This systematic review has allowed the demonstration of the way in which intrauterine exposure to various regimens of synthetic glucocorticoids affects various forms of hpa function. As such, it guides future studies in terms of which variables need to be focused on in order to further strengthen the understanding of such therapy, whilst continuing to profit from its clinical benefits.

Effect of antenatal betamethasone use on adrenal gland size and endogenous cortisol and 17-hydroxyprogesterone in preterm neonates

AIM

To assess the effect of antenatal betamethasone use on adrenal gland size and adrenal hormones in preterm neonates who had gestational ages of 27-36 weeks.

INFANTS AND METHODS

Sixty-six neonates divided into two groups: betamethasone group, whose mothers received betamethasone 12 mg two times 24 h apart, and no betamethasone group, whose mothers did not receive any steroid agent during the antenatal period. Serum 17-hydroxyprogesterone (17-OHP) levels and cortisol levels were measured during the first six hours of life. In addition, adrenal gland length and width were determined on the first day of life. Hormone tests and ultrasonographic evaluation were repeated on the fifth day of life.

RESULTS

We found statistically significant reductions in 17-OHP and cortisol levels at birth in corticosteroid-exposed neonates (p < 0.05). There was no significant difference between the study groups with regard to adrenal gland length and width (p > 0.05).

CONCLUSIONS

This study demonstrates that betamethasone use in preterm neonates reduces endogenous 17-OHP and cortisol levels; however, it has no effect on adrenal gland size.

Early life experience alters behavioral responses to sweet food and accumbal dopamine metabolism

Neonatal handling in rats persistently alters behavioral parameters and responses to stress. Such animals eat more sweet food in adult life, without alterations in lab chow ingestion. Here, we show that neonatally handled rats display greater incentive salience to a sweet reward in a runway test; however they are less prone to conditioned place preference and show less positive hedonic reactions to sweet food. When injected with methylphenidate (a dopamine mimetic agent), non-handled rats increase their sweet food ingestion in the fasted state, while neonatally handled rats do not respond. We did not observe any differences regarding baseline general ambulatory activity between the groups. A lower dopamine metabolism in the nucleus accumbens was observed in handled animals, without differences in norepinephrine content. We suggest that early handling leads to a particular response to positive reinforcers such as palatable food, in a very peculiar fashion of higher ingestion but lower hedonic impact, as well as higher incentive salience, but diminished dopaminergic metabolism in the nucleus accumbens.