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

Mild maternal stress disrupts associative learning and increases aggression in offspring

Maternal stress has been shown to affect behaviour of offspring in a wide range of animals, but this evidence has come from studies that exposed gestating mothers to acute or severe stressors, such as restraint or exposure to synthetic stress hormones. Here we show that exposure of mothers to even a mild stressor reduces associative learning and increases aggression in offspring. Female guppies were exposed to routine husbandry procedures that produced only a minimal, non-significant, elevation of the stress hormone cortisol. In contrast to controls, offspring from mothers that experienced this mild stress failed to learn to associate a colour cue and food reward, and showed a greater amount of inter-individual variation in behaviour compared with control offspring. This mild stress also resulted in offspring that were more aggressive towards their own mirror image than controls. While it is possible that these results could represent the transmission of beneficial maternal characteristics to offspring born into unpredictable environments, the potential for mild maternal stress to affect offspring performance also has important implications for research into the trans-generational effects of stress.

Metabolic and hormonal effects of antenatal betamethasone after 35 weeks of gestation

BACKGROUND

Antenatal corticosteroid therapy recently has been considered for term and near-term infants, in addition to preterm infants, delivered by elective cesarean section, with the aim of preventing an adverse respiratory outcome.

OBJECTIVES

The objective of this study was to investigate hormonal and metabolic effects of antenatal betamethasone when administered to term fetuses.

METHODS

Cord blood levels of cortisol, C-peptide, insulin-like growth factor I and its binding protein 3, and 5 more analytes including glucose were measured in singleton newborns of over 35 weeks of gestational age. In anticipation of a cesarean delivery, the mother was either treated or not treated with 12 mg of intramuscularly administered antenatal betamethasone approximately 24 hours prior to birth. Babies of comparable gestational age, sex, and nutritional status who were not treated antenatally served as controls.

RESULTS

Cord serum cortisol levels of the betamethasone-treated fetuses were suppressed to <10% of that of untreated controls (median levels of 11.6 nmol/L vs. 138.2 nmol/L, respectively), and their C-peptide and glucose levels were significantly higher (2.85 mcg/L vs. 1.19 mcg/L, respectively, p < 0.0001; and 62.5 mg/dL vs. 56.0 mg/dL, respectively, p = 0.01).

CONCLUSIONS

Prophylactic betamethasone therapy causes immediate hormonal alterations, which might interfere with the metabolic adaptation of the newborn. This issue deserves thorough investigation.

Modulation of GR activity does not affect the in vitro metabolism of cortisol by rainbow trout ovarian follicles

The goal of the study was to determine whether the metabolic clearance of cortisol from rainbow trout (Oncorhynchus mykiss) ovarian follicles is affected by the level of ovarian steroidogenesis, and whether it involves the activation of glucocorticoid receptors (GRs). Ovarian follicles were incubated in vitro; the adenylate cyclase activator, forskolin, was used to stimulate ovarian steroidogenesis, and the modulation of GR activity was brought about using GR agonists (cortisol and dexamethasone) or the GR antagonist, mifepristone (RU486). The follicles were co-incubated with [2, 4, 6, 7 (3)H] cortisol, and the tritium-labelled steroid products were separated by HPLC. In addition, the rates of expression of genes encoding for the two forms of GR (gr1 and gr2) were measured. Cortisone, cortisol sulphate, and cortisone sulphate were the major glucocorticoid products of cortisol metabolism, indicative of the action of 11β-hydroxysteroid dehydrogenase and glucocorticoid sulphotransferase in the follicular cells. There were no effects of RU486 or forskolin on the rates of [(3)H]cortisol metabolism suggesting that cortisol metabolism by ovarian follicles was independent of GR activation, and not influenced by increased activation of gonadal reproductive steroidogenesis.

Prematurity and programming of cardiovascular disease risk: a future challenge for public health?

There is substantial epidemiological evidence linking low birth weight with adult cardiometabolic disease risk factors. This has led to the concept of 'early life programming' or the 'developmental origins of disease' which proposes that exposure to adverse conditions during critical stages of early development results in compensatory mechanisms predicted to aid survival. There is growing evidence that preterm infants, many of whom are of low birth weight, are also at increased risk of adult cardiometabolic disease. In this article, we provide a broad overview of the evidence linking preterm birth and cardiovascular disease risk and discuss potential consequences for public health.

Risk of congenital malformations for asthmatic pregnant women using a long-acting β₂-agonist and inhaled corticosteroid combination versus higher-dose inhaled corticosteroid monotherapy

BACKGROUND

Current recommendations for managing persistent asthma during pregnancy when low-dose inhaled corticosteroids (ICSs) are insufficient include adding a long-acting β₂-agonist (LABA) or increasing the ICS dose. However, there are no data to help clinicians evaluate the safest regimen during pregnancy.

OBJECTIVE

We sought to compare the risk of major congenital malformations in asthmatic women exposed to a LABA plus ICS combination and those exposed to ICS monotherapy at higher doses during the first trimester.

METHODS

A cohort of asthmatic pregnant women exposed to ICSs during the first trimester who delivered between January 1990 and March 2009 was established. The primary outcome was major malformation recorded at birth or during the first year of life. Two subcohorts were established as follows: (1) users of a LABA plus low-dose ICS combination or users of a medium-dose ICS and (2) users of a LABA plus medium-dose ICS combination or users of a high-dose ICS. Generalized estimating equations were used to compare the risk of major malformations between the groups.

RESULTS

In one subcohort there were 643 women who used a LABA plus low-dose ICS and 305 who used a medium-dose ICS; the other subcohort included 198 users of a LABA plus medium-dose ICS and 156 users of a high-dose ICS. The prevalence of major malformations was 6.9% and 7.2%, respectively. The adjusted odds ratio for major malformations was 1.1 (95% CI, 0.6-1.9) when a LABA plus low-dose ICS was used compared with a medium-dose ICS and 1.2 (95% CI, 0.5-2.7) when a LABA plus medium-dose ICS was used compared with a high-dose ICS.

CONCLUSION

The risk of major malformations was similar with a LABA plus ICS combination and ICS monotherapy at higher doses, suggesting that both therapeutic options can be considered during pregnancy.

Glucocorticoids and fetal programming part 1: Outcomes

Fetal development is a critical period for shaping the lifelong health of an individual. However, the fetus is susceptible to internal and external stimuli that can lead to adverse long-term health consequences. Glucocorticoids are an important developmental switch, driving changes in gene regulation that are necessary for normal growth and maturation. The fetal hypothalamic-pituitary-adrenal (HPA) axis is particularly susceptible to long-term programming by glucocorticoids; these effects can persist throughout the life of an organism. Dysfunction of the HPA axis as a result of fetal programming has been associated with impaired brain growth, altered behaviour and increased susceptibility to chronic disease (such as metabolic and cardiovascular disease). Moreover, the effects of glucocorticoid-mediated programming are evident in subsequent generations, and transmission of these changes can occur through both maternal and paternal lineages.

Use of corticosteroids during pregnancy and risk of asthma in offspring: a nationwide Danish cohort study

OBJECTIVE

To examine whether in utero exposure to local and systemic corticosteroids is associated with asthma development in offspring.

DESIGN

Cohort study.

SETTING

Denmark.

PARTICIPANTS

We included all singletons born alive in Denmark between 1996 and 2009. Data on maternal corticosteroid use, asthma in offspring and covariates were obtained from medical registries.

MAIN OUTCOME MEASURES

We compared asthma risks of children prenatally exposed to corticosteroids and of children of former corticosteroid users with that of unexposed children. We computed absolute risks and used proportional-hazards regression to compute adjusted HRs (aHRs). Using logistic regression we compared exposed children with unexposed siblings in a 'within-mother-between-pregnancy' analysis. Adjustment addressed varying length of follow-up.

RESULTS

We identified 877 778 children, 3.6% of whom were prenatally exposed to systemic (n=5327) or local (n=24 436) corticosteroids. A total of 105 677 children developed asthma during follow-up with a 10-year risk of 18.4% among the exposed and 13.5% among the unexposed. The aHR was 1.54 (95% CI 1.45 to 1.65) for systemic use, 1.45 (95% CI 1.40 to 1.50) for local use and 1.32 (95% CI 1.30 to 1.34) for former use. The adjusted OR of the 'within-mother-between-pregnancy' analysis was 1.11 (95% CI 0.98 to 1.25).

CONCLUSIONS

These population-based data do not support a strong causal association between maternal corticosteroid use during pregnancy and increased asthma risk in offspring.

Inflammatory bowel disease in women of reproductive age

Management of inflammatory bowel disease in women of reproductive age requires special attention. Even though fertility in women without previous pelvis surgery is similar to the general population, active disease at conception and during pregnancy can lead to unfavorable pregnancy and fetal outcomes. In general, most medications needed to treat inflammatory bowel disease are low risk during pregnancy and breastfeeding. Achieving and maintaining disease remission, patient education, and a multidisciplinary team approach is the key to a successful pregnancy.

Glucocorticoids and foetal heart maturation; implications for prematurity and foetal programming

Glucocorticoids are steroid hormones, essential in mammals to prepare for life after birth. Blood levels of glucocorticoids (cortisol in most mammals including humans; corticosterone in rats and mice) rise dramatically shortly before birth. This is mimicked clinically in the routine administration of synthetic glucocorticoids to pregnant women threatened by a preterm birth or to preterm infants to improve neonatal survival. Whilst effects on lung are well documented and essential for postnatal survival, those on heart are less well known. In this study, we review recent evidence for a crucial role of glucocorticoids in late gestational heart maturation. Either insufficient or excessive glucocorticoid exposure before birth may alter the normal glucocorticoid-regulated trajectory of heart maturation with potential life-long consequences.

Evidence for adverse effect of perinatal glucocorticoid use on the developing brain

The use of glucocorticoids (GCs) in the perinatal period is suspected of being associated with adverse effects on long-term neurodevelopmental outcomes for preterm infants. Repeated administration of antenatal GCs to mothers at risk of preterm birth may adversely affect fetal growth and head circumference. Fetal exposure to excess GCs during critical periods of brain development may profoundly modify the limbic system (primarily the hippocampus), resulting in long-term effects on cognition, behavior, memory, co-ordination of the autonomic nervous system, and regulation of the endocrine system later in adult life. Postnatal GC treatment for chronic lung disease in premature infants, particularly involving the use of dexamethasone, has been shown to induce neurodevelopmental impairment and increases the risk of cerebral palsy. In contrast to studies involving postnatal dexamethasone, long-term follow-up studies for hydrocortisone therapy have not revealed adverse effects on neurodevelopmental outcomes. In experimental studies on animals, GCs has been shown to impair neurogenesis, and induce neuronal apoptosis in the immature brains of newborn animals. A recent study has demonstrated that dexamethasone-induced hypomyelination may result from the apoptotic degeneration of oligodendrocyte progenitors in the immature brain. Thus, based on clinical and experimental studies, there is enough evidence to advice caution regarding the use of GCs in the perinatal period; and moreover, the potential long-term effects of GCs on brain development need to be determined.

IBD medications during pregnancy and lactation

IBD often affects patients during their peak reproductive years. Several drugs are available for the treatment of IBD and new drugs are continuously in the pipeline. As long-term administration of medications is often necessary, the safety of drug therapy during pregnancy and breast-feeding needs to be considered in daily clinical practice. The aim of this Review is to summarize the latest information concerning the safety of medications used to treat IBD during pregnancy and lactation, as well as their effect on fertility. Although only thalidomide and methotrexate are absolutely contraindicated during pregnancy and breast-feeding, alternatives to ciprofloxacin, natalizumab and sodium phosphate should also be considered for pregnant women. Breast-feeding is also discouraged while on treatment with ciclosporin, metronidazole and ciprofloxacin. However, therapy with 5-aminosalicylic acid preparations, glucocorticoids, thiopurines and TNF inhibitors are acceptable during pregnancy and lactation. Pregnant women who have symptomatic IBD or who require therapy should have the opportunity to discuss any associated risks to their pregnancy and infant with the appropriate consultants. By ensuring that the patient and her family are informed, the clinical outcome might be optimized.

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.

Prenatal dexamethasone augments the neurobehavioral teratology of chlorpyrifos: significance for maternal stress and preterm labor

Glucocorticoids are the consensus treatment given in preterm labor and are also elevated by maternal stress; organophosphate exposures are virtually ubiquitous, so human developmental coexposures to these two agents are common. This study explores how prenatal dexamethasone exposure modifies the neurobehavioral teratology of chlorpyrifos, one of the most widely used organophosphates. We administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2 mg/kg); offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1 mg/kg) that produces barely-detectable (<10%) inhibition of brain cholinesterase activity. Dexamethasone did not alter brain chlorpyrifos concentrations, nor did either agent alone or in combination affect brain thyroxine levels. Assessments were carried out from adolescence through adulthood encompassing T-maze alternation, Figure 8 maze (locomotor activity, habituation), novelty-suppressed feeding and novel object recognition tests. For behaviors where chlorpyrifos or dexamethasone individually had small effects, the dual exposure produced larger, significant effects that reflected additivity (locomotor activity, novelty-suppressed feeding, novel object recognition). Where the individual effects were in opposite directions or were restricted to only one agent, we found enhancement of chlorpyrifos' effects by prenatal dexamethasone (habituation). Finally, for behaviors where controls displayed a normal sex difference in performance, the combined treatment either eliminated or reversed the difference (locomotor activity, novel object recognition). Combined exposure to dexamethasone and chlorpyrifos results in a worsened neurobehavioral outcome, providing a proof-of-principle that prenatal glucocorticoids can create a subpopulation with enhanced vulnerability to environmental toxicants.

Asthma during pregnancy and clinical outcomes in offspring: a national cohort study

BACKGROUND AND OBJECTIVE

Maternal asthma is a common pregnancy complication, with adverse short-term effects for the offspring. The objective was to determine whether asthma during pregnancy is a risk factor of offspring diseases.

METHODS

We studied pregnant women from the Danish National Birth Cohort (births: 1996-2002; prospective data) giving birth to live singletons (n = 66 712 mother-child pairs), with 4145 (6.2%) women suffering from asthma during pregnancy. We estimated the associations between asthma during pregnancy and offspring diseases (International Classification of Diseases, 10th Revision diagnoses from national registries), controlling for potential confounders and validating findings by secondary analyses.

RESULTS

Offspring median age at end of follow-up was 6.2 (3.6-8.9) years. Asthma was associated with an increased offspring risk of infectious and parasitic diseases (hazard ratio [HR] 1.34; 95% confidence interval [CI] 1.23-1.46), diseases of the nervous system (HR 1.43; CI 1.18-1.73), ear (HR 1.33; CI 1.19-1.48), respiratory system (HR 1.43; CI 1.34-1.52), and skin (HR 1.39; CI 1.20-1.60), and potentially (not confirmed in secondary analyses) of endocrine and metabolic disorders (HR 1.26; CI 1.02-1.55), diseases of the digestive system (HR 1.17; CI 1.04-1.32), and malformations (odds ratio 1.13; CI 1.01-1.26), but not of neoplasms, mental disorders, or diseases of the blood and immune system, circulatory system, musculoskeletal system, and genitourinary system.

CONCLUSIONS

To the best of our knowledge, this is the first comprehensive study of the associations between asthma during pregnancy and a wide spectrum of offspring diseases. In line with previous data on selected outcomes, asthma during pregnancy may be a risk factor for numerous offspring diseases, suggesting that careful monitoring of women with asthma during pregnancy and their offspring is important.

Cortisol awakening response in infants during the first six postnatal months and its relation to birth outcome

CONTEXT

The rise of cortisol concentrations after awakening is well documented in adults and children and commonly used as easily accessible marker of hypothalamic-pituitary-adrenal (HPA) reactivity.

OBJECTIVE

The purpose of this study was to demonstrate the existence of a salivary cortisol awakening response (CAR) in infants, and to estimate its association with birth outcome.

SETTING

The study was conducted in the general community.

PARTICIPANTS

Healthy infants up to six months age (N=64).

MAIN OUTCOME MEASURES

Mothers were instructed to collect their infant's saliva immediately and 30 min after awakening on two days within 45 days, irrespective of awakening time. Information on birth outcome was collected from medical records and questionnaires.

RESULTS

Linear mixed models analysis revealed a significant rise of infant salivary cortisol concentrations within 30 min after awakening (b=0.128, SE=0.024, t61=5.31, p<0.001), which was quite stable across the two sampling days (r=0.40, p=0.002). The infant CAR was predicted by length of gestation (t58=2.44, p=0.018).

CONCLUSIONS

The current data demonstrate the existence of a CAR in infants as early as during the first six postnatal months; its relationship with length of gestation supports its usefulness for questions related to developmental neuroscience. Therefore, the infant CAR emerges as non-invasive biomarker of HPA axis dynamics at this early stage of life, with relevance for future research and potential clinical applications.

Multigenerational effects of fetal dexamethasone exposure on the hypothalamic-pituitary-adrenal axis of first- and second-generation female offspring

OBJECTIVE

Synthetic glucocorticoid (sGC) administration to women threatening preterm delivery increases neonatal survival. Evidence shows that fetal exposure to glucocorticoid levels higher than appropriate for current maturation programs offspring development. We examined fetal sGC multigenerational effects on F1 and F2 female offspring hypothalamo-pituitary-adrenal axis (HPAA) function.

STUDY DESIGN

At 0.7 gestation, pregnant F0 ewes received 4 dexamethasone injections (2 mg, approximately 60 μg/kg(-1) per day(-1), 12 hours apart) or saline (control). F1 female offspring were bred to produce F2 female offspring. Postpubertal HPAA function was tested in F1 and F2 ewes.

RESULTS

F1 and F2 ewe lambs showed reduced birthweight and morphometrics. Dexamethasone increased baseline but reduced stimulated HPAA activity in F1 and F2 female offspring.

CONCLUSION

This is the first demonstration that sGC doses in the clinical range have multigenerational effects on hypothalamo-pituitary-adrenal activity in a precocial species, indicating the need for the study of long-term effects of fetal sGC exposure.

Nicotine-induced retardation of chondrogenesis through down-regulation of IGF-1 signaling pathway to inhibit matrix synthesis of growth plate chondrocytes in fetal rats

Previous studies have confirmed that maternal tobacco smoking causes intrauterine growth retardation (IUGR) and skeletal growth retardation. Among a multitude of chemicals associated with cigarette smoking, nicotine is one of the leading candidates for causing low birth weights. However, the possible mechanism of delayed chondrogenesis by prenatal nicotine exposure remains unclear. We investigated the effects of nicotine on fetal growth plate chondrocytes in vivo and in vitro. Rats were given 2.0 mg/kg·d of nicotine subcutaneously from gestational days 11 to 20. Prenatal nicotine exposure increased the levels of fetal blood corticosterone and resulted in fetal skeletal growth retardation. Moreover, nicotine exposure induced the inhibition of matrix synthesis and down-regulation of insulin-like growth factor 1 (IGF-1) signaling in fetal growth plates. The effects of nicotine on growth plates were studied in vitro by exposing fetal growth plate chondrocytes to 0, 1, 10, or 100 μM of nicotine for 10 days. Nicotine inhibited matrix synthesis and down-regulated IGF-1 signaling in chondrocytes in a concentration-dependent manner. These results suggest that prenatal nicotine exposure induces delayed chondrogenesis and that the mechanism may involve the down-regulation of IGF-1 signaling and the inhibition of matrix synthesis by growth plate chondrocytes. The present study aids in the characterization of delayed chondrogenesis caused by prenatal nicotine exposure, which might suggest a candidate mechanism for intrauterine origins of osteoporosis and osteoarthritis.

Prenatal dexamethasone augments the sex-selective developmental neurotoxicity of chlorpyrifos: implications for vulnerability after pharmacotherapy for preterm labor

Glucocorticoids are routinely given in preterm labor and are also elevated by maternal stress; organophosphate exposures are virtually ubiquitous, so coexposures to these two agents are pervasive. We administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2mg/kg); offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1mg/kg) that produces barely-detectable (<10%) inhibition of brain cholinesterase activity. We evaluated indices for acetylcholine (ACh) synaptic function throughout adolescence, young adulthood and later adulthood, in brain regions possessing the majority of ACh projections and cell bodies; we measured nicotinic ACh receptor binding, hemicholinium-3 binding to the presynaptic choline transporter and choline acetyltransferase activity, all known targets for the adverse developmental effects of dexamethasone and chlorpyrifos given individually. Dexamethasone did not enhance the systemic toxicity of chlorpyrifos, as evidenced by weight gain and measurements of cholinesterase inhibition during chlorpyrifos treatment. Nevertheless, it enhanced the loss of presynaptic ACh function selectively in females, who ordinarily show sparing of organophosphate developmental neurotoxicity relative to males. Females receiving the combined treatment showed decrements in choline transporter binding and choline acetyltransferase activity that were unique (not found with either treatment alone), as well as additive decrements in nicotinic receptor binding. On the other hand, males given dexamethasone showed no augmentation of the effects of chlorpyrifos. Our findings indicate that prior dexamethasone exposure could create a subpopulation that is especially vulnerable to the adverse effects of organophosphates or other developmental neurotoxicants.

Risk of childhood injuries after prenatal exposure to maternal bereavement: a Danish National Cohort Study

OBJECTIVES

The aim of this study was to assess the risk of injuries among children exposed to a stressful life exposure (defined as bereavement) before conception or during fetal life.

DESIGN

Population-based cohort study.

SETTING

Denmark.

PARTICIPANTS

All singleton births in Denmark between 1 January 1995 and 31 December 2006 were identified. These newborns were then linked to mothers, fathers, grandparents and siblings using individually assigned civil personal registration numbers.

PRIMARY AND SECONDARY OUTCOME MEASURES

We identified that data on childhood injuries were obtained from the Danish National Patient Registry, which contains data on all hospital stays and outpatient visits. Incidence rate ratios (IRRs) were estimated from birth using log-linear Poisson regression models, and person-years were used as the offset variable. Age, residence, calendar period, maternal education, maternal income and parental-cohabitation status are treated as time-dependent variables (records were extracted from the offspring's birth year).

RESULTS

Exposure to maternal bereavement due to a father's death had the strongest association with childhood injuries, especially when the cause of death was due to a traumatic event (adjusted estimates of IRR (aIRR): 1.25, 95%CI: 0.99 to 1.58). We did not find an association for childhood injuries and maternal bereavement due to grandparent's death, and we only found an association for sibling death when restricting to deaths due to traumatic events (aIRR: 1.20, 95%CI:1.03 to 1.39).

CONCLUSIONS

The aetiology of childhood injuries is complex and may be related to events that take place during prenatal life. This study suggests that exposure to a stressful life event during gestation may be linked to injury susceptibility in childhood. However, changes in postnatal family conditions related to loss or genetic factors may also play a role.

BACKGROUND

Developmental plasticity related to early life exposures leading to disease programming in offspring is a theory with substantial theoretical and empirical support. Prenatal stress exposure has been linked to neurological outcomes, such as temperament, behavioural problems, cognitive function and affective disorders. If exposure modifies risk-seeking behaviour, perceived danger and reaction time, it is also expected to modify injury risk.

Effects of early- and late-gestational maternal stress and synthetic glucocorticoid on development of the fetal hypothalamus-pituitary-adrenal axis in sheep

Prenatal maternal stress (PMS) programs dysregulation of the hypothalamus-pituitary-adrenal axis (HPAA) in postnatal life, though time periods vulnerable to PMS, are still unclear. We evaluated in pregnant sheep the effect of PMS during early gestation [30-100 days of gestation (dGA); term is 150 dGA] or late gestation (100-120 dGA) on development of fetal HPAA function. We compared the effects of endogenous cortisol with synthetic glucocorticoid (GC) exposure, as used clinically to enhance fetal lung maturation. Pregnant sheep were exposed to repeated isolation stress twice per week for 3 h in a separate box with no visual, tactile, or auditory contact with their flock-mates either during early (n = 7) or late (n = 7) gestation. Additional groups received two courses of betamethasone (BM; n = 7; 2 × 110 μg kg(- 1) body weight, 24 h apart) during late gestation (106/107 and 112/113 dGA, n = 7) or acted as controls (n = 7). Fetal cortisol responses to hypotensive challenge, a physiological fetal stressor, were measured at 112 and 129 dGA, i.e. before and during maturation of the HPAA. Hypotension was induced by fetal infusion of sodium nitroprusside, a potent vasodilator. At 112 dGA, neither PMS nor BM altered fetal cortisol responses. PMS, during early or late gestation, and BM treatment increased fetal cortisol responses at 129 dGA with the greatest increase achieved in stressed early pregnant sheep. Thus, development of the HPAA is vulnerable to inappropriate levels of GCs during long periods of fetal life, whereas early gestation is most vulnerable to PMS.

The in vitro metabolism of cortisol by ovarian follicles of rainbow trout (Oncorhynchus mykiss): comparison with ovulated oocytes and pre-hatch embryos

Mid-vitellogenic stage rainbow trout (Oncorhynchus mykiss) ovarian follicles (both intact and yolk free (YF)), ovulated oocytes and embryos were co-incubated with [2,4,6,7-3H]cortisol for 18 h to determine the degree and nature of the metabolism and biotransformation of the glucocorticoid. There was evidence of the conversion of cortisol to the less biologically potent glucocorticoid, cortisone, and the formation of glucocorticoid sulphates (both cortisol and cortisone) for all cell and tissue samples, suggesting the presence of 11β-hydroxysteroid dehydrogenase (11β-HSD) and glucocorticoid sulphotransferase (GST) activity at all stages; however, GST activity was particularly marked in both intact and YF ovarian follicles, suggesting an important role of follicles in limiting the exposure of oocyte to maternal cortisol. As there was no evidence of 11β-HSD or GST activity in ovarian fluid, the findings affirm that ovarian follicles (probably the thecal and granulosa cells) provide a barrier against the transfer of cortisol to the oocytes by forming sulphated steroids, whereas ovulated oocytes and early embryos have a more limited capacity to either metabolize or conjugate cortisol and are therefore more vulnerable at the post-ovulatory and early embryonic stages to increases in exposure to the glucocorticoid.

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.

Postnatal administration of IL-1Ra exerts neuroprotective effects following perinatal inflammation and/or hypoxic-ischemic injuries

New therapeutic strategies are needed to protect neonates, especially premature newborns, against brain injury and associated neurobehavioral deficits. The role of pro-inflammatory cytokines, especially IL-1β, in the pathophysiological pathway leading to neonatal brain damage is increasingly recognized and represents an attractive therapeutic target. We investigated the therapeutic potential of postnatal systemic administration of the interleukin (IL)-1 receptor antagonist (IL-1Ra) in an animal model of perinatal brain injury using the insults most common to human neonates, i.e. prenatal exposure to inflammation and/or postnatal hypoxia-ischaemia (HI). We found that postnatal administration of IL-1Ra preserved motor function and exploratory behavior after either prenatal exposure to inflammatory agent lipopolysaccharide (LPS) or postnatal HI insult. The deleterious effect of combined prenatal LPS and postnatal HI on brain development was also alleviated by administration of IL-1Ra, as seen by the protected neural stem cell population, prevention of myelin loss in the internal capsule, decreased gliosis, and decreased neurobehavioral impairment. This study showed the distinct pattern of functional deficits induced by prenatal inflammation as compared to postnatal HI and the therapeutic potential of IL-1Ra administration against neonatal brain injury. Furthermore, our results highlight the potential for postnatal treatment of prenatal inflammatory stressors.

Glucocorticoids as mediators of developmental programming effects

Epidemiological evidence suggests that exposure to an adverse environment in early life is associated with an increased risk of cardio-metabolic and behavioral disorders in adulthood, a phenomenon termed 'early life programming'. One major hypothesis for early life programming is fetal glucocorticoid overexposure. In animal studies, prenatal glucocorticoid excess as a consequence of maternal stress or through exogenous administration to the mother or fetus is associated with programming effects on cardiovascular and metabolic systems and on the brain. These effects can be transmitted to subsequent generations. Studies in humans provide some evidence that prenatal glucocorticoid exposure may exert similar programming effects on glucose/insulin homeostasis, blood pressure and neurodevelopment. The mechanisms by which glucocorticoids mediate these effects are unclear but may include a role for epigenetic modifications. This review discusses the evidence for glucocorticoid programming in animal models and in humans.

Chlorpyrifos developmental neurotoxicity: interaction with glucocorticoids in PC12 cells

Prenatal coexposures to glucocorticoids and organophosphate pesticides are widespread. Glucocorticoids are elevated by maternal stress and are commonly given in preterm labor; organophosphate exposures are virtually ubiquitous. We used PC12 cells undergoing neurodifferentiation in order to assess whether dexamethasone enhances the developmental neurotoxicity of chlorpyrifos, focusing on models relevant to human exposures. By themselves, each agent reduced the number of cells and the combined exposure elicited a correspondingly greater effect than with either agent alone. There was no general cytotoxicity, as cell growth was actually enhanced, and again, the combined treatment evoked greater cellular hypertrophy than with the individual compounds. The effects on neurodifferentiation were more complex. Chlorpyrifos alone had a promotional effect on neuritogenesis whereas dexamethasone impaired it; combined treatment showed an overall impairment greater than that seen with dexamethasone alone. The effect of chlorpyrifos on differentiation into specific neurotransmitter phenotypes was shifted by dexamethasone. Either agent alone promoted differentiation into the dopaminergic phenotype at the expense of the cholinergic phenotype. However, in dexamethasone-primed cells, chlorpyrifos actually enhanced cholinergic neurodifferentiation instead of suppressing this phenotype. Our results indicate that developmental exposure to glucocorticoids, either in the context of stress or the therapy of preterm labor, could enhance the developmental neurotoxicity of organophosphates and potentially of other neurotoxicants, as well as producing neurobehavioral outcomes distinct from those seen with either individual agent.

Cognitive outcome of offspring from dexamethasone-treated pregnancies at risk for congenital adrenal hyperplasia due to 21-hydroxylase deficiency

OBJECTIVES

To test whether dexamethasone (DEX) treatment in pregnancies at risk for congenital adrenal hyperplasia (CAH) impairs cognitive functioning in the offspring.

DESIGN

Observational follow-up of prenatally DEX-exposed offspring and controls.

METHODS

Study 1 included 140 children aged 512 years: 67 DEX-exposed (long-term: eight CAH girls) and 73 unexposed (with 15 CAH girls). Study 2 included 20 participants aged 11-24 years: seven DEX-exposed (long-term: one CAH woman) and 13 unexposed (with four CAH women). Neuropsychological testing was done in hospital settings or at patients' homes. Data analysis aimed at maximizing detection of the effects of DEX exposure.

RESULTS

The vast majority of group comparisons were not marginally or conventionally significant. The few significant findings on short-term prenatal DEX exposure suggested more positive than adverse outcomes. By contrast, few significant findings in females with CAH and long-term DEX exposure indicated slower mental processing than in controls on several neuropsychological variables, although partial correlations of DEX exposure duration with cognitive outcome did not corroborate this association.

CONCLUSIONS

Although our studies do not replicate a previously reported adverse effect of short-term prenatal DEX exposure on working memory, our findings on cognitive function in CAH girls with long-term DEX exposure contribute to concerns about potentially adverse cognitive after effects of such exposure. Yet, our studies are not definitive, and replications in larger samples are required.

Autonomous adrenocorticotropin reaction to stress stimuli in human fetus

The aim of the study was to determine whether human fetuses show ACTH response to stress stimuli, to define the gestational age from which these reactions may be present and to analyze the relationship between hormone concentrations and their changes, both in fetuses and in pregnant women. The study included 81 intrauterine transfusions carried out in 19 pregnant women. 52 procedures were performed directly into the umbilical vein, which is not innervated, so neutral for the fetus (the PCI group) and 29 transfusions into the intrahepatic vein -which puncture is stressful for the fetus (the IHV group). ACTH and cortisol concentrations in fetal and maternal plasma obtained during the procedures were assayed. The initial mean plasma ACTH concentration in the PCI group equaled 18.94pg/mL, but in the IHV group it was significantly higher and amounted 75.17pg/mL (p<0.001). There was no significant change in the hormone concentration during the transfusion both in the IHV group (95.8pg/mL, p>0.05) and in the PCI group (22.36pg/mL, p>0.05). The observed hormonal response in the IHV group proves the existence of fetal pituitary reaction to stress. The initial fetal ACTH concentration in the IHV group correlated with the number of transfusions performed on a single fetus (R=0.41; p=0.04). No correlation with parity, gestational weeks or the volume of transfused packed red blood cells was found. There was also no correlation between fetal and maternal ACTH concentrations in any group. Presented data suggest that the human fetus shows autonomous ACTH reaction to stress stimulation.

Inhaled glucocorticoids during pregnancy and offspring pediatric diseases: a national cohort study

RATIONALE

Glucocorticoid inhalation is the preferred asthma treatment during pregnancy. Previous studies on its safety focused on obstetric outcomes and offspring malformations.

OBJECTIVES

To determine whether glucocorticoid inhalation during pregnancy is a risk factor for offspring pediatric diseases.

METHODS

We studied offspring (live singletons) of pregnant women suffering from asthma during pregnancy (prevalence = 6.3%; n = 4,083 mother-child pairs) from the Danish National Birth Cohort (births, 1996-2002; prospective data). We estimated the associations between use of inhaled glucocorticoids for asthma treatment during pregnancy (n = 1231; 79.9% budesonide, 17.6% fluticasone, 5.4% beclomethasone, and 0.9% other or unspecified glucocorticoids) and offspring diseases (International Classification of Diseases-10th Revision, diagnoses) during childhood. We conducted Cox or logistic regression analyses for each International Classification of Diseases-10th Revision category, controlling for use of non-glucocorticoid-containing inhalants, and confirmed results by addressing confounding by treatment indication using propensity score.

MEASUREMENTS AND MAIN RESULTS

Offspring median age at end of follow-up was 6.1 (range, 3.6-8.9) years. Glucocorticoid inhalation was not associated with offspring disease risk in most categories, except for offspring endocrine, metabolic, and nutritional disorders (hazard ratio, 1.84; 95% confidence interval, 1.13-2.99). When repeating analyses with the major subgroup that used budesonide only, association estimates were of similar magnitude.

CONCLUSIONS

Regarding most disease categories, data are reassuring, supporting the use of inhaled glucocorticoids during pregnancy. In line with animal data, glucocorticoid inhalation during pregnancy may be a risk factor for offspring endocrine and metabolic disturbances, which should be considered further.

Stress during pregnancy and offspring pediatric disease: A National Cohort Study

BACKGROUND

Identifying risk factors for adverse health outcomes in children is important. The intrauterine environment plays a pivotal role for health and disease across life.

OBJECTIVES

We conducted a comprehensive study to determine whether common psychosocial stress during pregnancy is a risk factor for a wide spectrum of pediatric diseases in the offspring.

METHODS

The study was conducted using prospective data in a population-based sample of mothers with live singleton births (n = 66,203; 71.4% of those eligible) from the Danish National Birth Cohort. We estimated the association between maternal stress during pregnancy (classified based on two a priori-defined indicators of common stress forms, life stress and emotional stress) and offspring diseases during childhood (grouped into 16 categories of diagnoses from the International Classification of Diseases, 10th Revision, based on data from national registries), controlling for maternal stress after pregnancy.

RESULTS

Median age at end of follow-up was 6.2 (range, 3.6-8.9) years. Life stress (highest compared with lowest quartile) was associated with an increased risk of conditions originating in the perinatal period [odds ratio (OR) = 1.13; 95% confidence interval (CI): 1.06, 1.21] and congenital malformations (OR=1.17; CI: 1.06, 1.28) and of the first diagnosis of infection [hazard ratio (HR) = 1.28; CI: 1.17, 1.39], mental disorders (age 0-2.5 years: HR = 2.03; CI: 1.32, 3.14), and eye (age 0-4.5 years: HR = 1.27; CI: 1.06, 1.53), ear (HR = 1.36; CI: 1.23, 1.51), respiratory (HR = 1.27; CI; 1.19, 1.35), digestive (HR = 1.23; CI: 1.11, 1.37), skin (HR = 1.24; CI: 1.09, 1.43), musculoskeletal (HR = 1.15; CI: 1.01-1.30), and genitourinary diseases (HR = 1.25; CI; 1.08, 1.45). Emotional stress was associated with an increased risk for the first diagnosis of infection (HR = 1.09; CI: 1.01, 1.18) and a decreased risk for the first diagnosis of endocrine (HR = 0.81; CI; 0.67, 0.99), eye (HR = 0.84; CI; 0.71, 0.99), and circulatory diseases (age 0-3 years: HR = 0.63; CI: 0.42, 0.95).

CONCLUSIONS

Maternal life stress during pregnancy may be a common risk factor for impaired child health. The results suggest new approaches to reduce childhood diseases.

Fetal adrenal suppression due to maternal corticosteroid use: case report

During pregnancy, steroids are usually used in maternal diseases such as adrenal failure or other autoimmune diseases, e.g. idiopathic thrombocytopenic purpura (ITP), Crohn's disease, systemic lupus erythematosus, dermatomyositis, scleroderma, Addison's disease and hyperemesis gravidarum, HELLP syndrome. Endogenous or exogenousmaternal steroids are metabolized by the placental enzyme 11 beta-hydroxy steroid dehydrogenase type 2. Prednisolone and methylprednisolone are highly sensitive to this enzyme, while dexamethasone and betamethasone are less well metabolized. Steroids which can cross the placental barrier are administered in cases like fetal lupus, congenital adrenal hyperplasia and for enhancement of fetal lung maturation, whereas steroids used in maternal diseases are usually the ones with low affinity to the placenta; however, in case of long-term use or in high doses, placental enzyme saturation occurs and thus, resulting in fetal adrenal suppression. Antenatal steroids can lead to low birth weight, as observed in our patient. Here, we report a case with fetal adrenal suppression due to maternal methylprednisolone use presenting with early hypoglycaemia and late hyponatremia in neonatal period and requiring three-month replacement therapy.

Development and function of the human fetal adrenal cortex: a key component in the feto-placental unit

Continuous efforts have been devoted to unraveling the biophysiology and development of the human fetal adrenal cortex, which is structurally and functionally unique from other species. It plays a pivotal role, mainly through steroidogenesis, in the regulation of intrauterine homeostasis and in fetal development and maturation. The steroidogenic activity is characterized by early transient cortisol biosynthesis, followed by its suppressed synthesis until late gestation, and extensive production of dehydroepiandrosterone and its sulfate, precursors of placental estrogen, during most of gestation. The gland rapidly grows through processes including cell proliferation and angiogenesis at the gland periphery, cellular migration, hypertrophy, and apoptosis. Recent studies employing modern technologies such as gene expression profiling and laser capture microdissection have revealed that development and/or function of the fetal adrenal cortex may be regulated by a panoply of molecules, including transcription factors, extracellular matrix components, locally produced growth factors, and placenta-derived CRH, in addition to the primary regulator, fetal pituitary ACTH. The role of the fetal adrenal cortex in human pregnancy and parturition appears highly complex, probably due to redundant and compensatory mechanisms regulating these events. Mounting evidence indicates that actions of hormones operating in the human feto-placental unit are likely mediated by mechanisms including target tissue responsiveness, local metabolism, and bioavailability, rather than changes only in circulating levels. Comprehensive study of such molecular mechanisms and the newly identified factors implicated in adrenal development should help crystallize our understanding of the development and physiology of the human fetal adrenal cortex.

Glucocorticoids, prenatal stress and the programming of disease

An adverse foetal environment is associated with increased risk of cardiovascular, metabolic, neuroendocrine and psychological disorders in adulthood. Exposure to stress and its glucocorticoid hormone mediators may underpin this association. In humans and in animal models, prenatal stress, excess exogenous glucocorticoids or inhibition of 11β-hydroxysteroid dehydrogenase type 2 (HSD2; the placental barrier to maternal glucocorticoids) reduces birth weight and causes hyperglycemia, hypertension, increased HPA axis reactivity, and increased anxiety-related behaviour. Molecular mechanisms that underlie the 'developmental programming' effects of excess glucocorticoids/prenatal stress include epigenetic changes in target gene promoters. In the case of the intracellular glucocorticoid receptor (GR), this alters tissue-specific GR expression levels, which has persistent and profound effects on glucocorticoid signalling in certain tissues (e.g. brain, liver, and adipose). Crucially, changes in gene expression persist long after the initial challenge, predisposing the individual to disease in later life. Intriguingly, the effects of a challenged pregnancy appear to be transmitted possibly to one or two subsequent generations, suggesting that these epigenetic effects persist.

The developmental impact of prenatal stress, prenatal dexamethasone and postnatal social stress on physiology, behaviour and neuroanatomy of primate offspring: studies in rhesus macaque and common marmoset

RATIONALE

Exposure of the immature mammalian brain to stress factors, including stress levels of glucocorticoids, either prenatally or postnatally, is regarded as a major regulatory factor in short- and long-term brain function and, in human, as a major aetiological factor in neuropsychiatric disorders. Experimental human studies are not feasible and animal studies are required to demonstrate causality and elucidate mechanisms. A number of studies have been conducted and reviewed in rodents but there are relatively few studies in primates.

OBJECTIVES

Here we present an overview of our published studies and some original data on the effects of: (1) prenatal stress on hypothalamic-pituitary-adrenal (HPA) re/activity and hippocampus neuroanatomy in juvenile-adolescent rhesus macaques; (2) prenatal dexamethasone (DEX) on HPA activity, behaviour and prefrontal cortex neuroanatomy in infant-adolescent common marmosets; (3) postnatal daily parental separation stress on HPA re/activity, behaviour, sleep and hippocampus and prefrontal cortex neuroanatomy in infant-adolescent common marmoset.

RESULTS

Prenatal stress increased basal cortisol levels and reduced neurogenesis in macaque. Prenatal DEX was without effect on HPA activity and reduced social play and skilled motor behaviour in marmoset. Postnatal social stress increased basal cortisol levels, reduced social play, increased awakening and reduced hippocampal glucocorticoid and mineralocorticoid receptor expression in marmoset.

CONCLUSIONS

Perinatal stress-related environmental events exert short- and long-term effects on HPA function, behaviour and brain status in rhesus macaque and common marmoset. The mechanisms mediating the enduring effects remain to be elucidated, with candidates including increased basal HPA function and epigenetic programming.