Effect of prenatal glucocorticoid treatment on size at birth among infants born at term gestation

Antenatal corticosteroids in Singapore: a clinical and scientific assessment

ABSTRACT

Preterm birth (PTB; delivery prior to 37 weeks' gestation) is the leading cause of early childhood death in Singapore today. Approximately 9% of Singaporean babies are born preterm; the PTB rate is likely to increase given the increased use of assisted reproduction technologies, changes in the incidence of gestational diabetes/high body mass index and the ageing maternal population. Antenatal administration of dexamethasone phosphate is a key component of the obstetric management of Singaporean women who are at risk of imminent preterm labour. Dexamethasone improves preterm outcomes by crossing the placenta to functionally mature the fetal lung. The dexamethasone regimen used in Singapore today affords a very high maternofetal drug exposure over a brief period of time. Drawing on clinical and experimental data, we reviewed the pharmacokinetic profile and pharmacodynamic effects of dexamethasone treatment regimen in Singapore, with a view to creating a development pipeline for optimising this critically important antenatal therapy.

Antenatal steroids elicited neurodegenerative-associated transcriptional changes in the hippocampus of preterm fetal sheep independent of lung maturation

BACKGROUND

Antenatal steroid therapy for fetal lung maturation is routinely administered to women at risk of preterm delivery. There is strong evidence to demonstrate benefit from antenatal steroids in terms of survival and respiratory disease, notably in infants delivered at or below 32 weeks' gestation. However, dosing remains unoptimized and lung benefits are highly variable. Current treatment regimens generate high-concentration, pulsatile fetal steroid exposures now associated with increased risk of childhood neurodevelopmental diseases. We hypothesized that damage-associated changes in the fetal hippocampal transcriptome would be independent of preterm lung function.

METHODS

Date-mated ewes carrying a single fetus at 122 ± 2dGA (term = 150dGA) were randomized into 4 groups: (i) Saline Control Group, 4×2ml maternal saline intramuscular(IM) injections at 12hr intervals (n = 11); or (ii) Dex High Group, 2×12mg maternal IM dexamethasone phosphate injections at 12hr intervals followed by 2×2ml IM saline injections at 12hr intervals (n = 12; representing a clinical regimen used in Singapore); or (iii) Dex Low Group, 4×1.5mg maternal IM dexamethasone phosphate injections 12hr intervals (n = 12); or (iv) Beta-Acetate Group, 1×0.125mg/kg maternal IM betamethasone acetate injection followed by 3×2ml IM sterile normal saline injections 12hr intervals (n = 8). Lambs were surgically delivered 48hr after first maternal injection at 122-125dGA, ventilated for 30min to establish lung function, and euthanised for necropsy and tissue collection.

RESULTS

Preterm lambs from the Dex Low and Beta-Acetate Groups had statistically and biologically significant lung function improvements (measured by gas exchange, lung compliance). Compared to the Saline Control Group, hippocampal transcriptomic data identified 879 differentially significant expressed genes (at least 1.5-fold change and FDR < 5%) in the steroid-treated groups. Pulsatile dexamethasone-only exposed groups (Dex High and Dex Low) had three common positively enriched differentially expressed pathways related in part to neurodegeneration ("Prion Disease", "Alzheimer's Disease", "Arachidonic Acid metabolism"). Adverse changes were independent of respiratory function during ventilation.

CONCLUSIONS

Our data suggests that exposure to antenatal steroid therapy is an independent cause of damage- associated transcriptomic changes in the brain of preterm, fetal sheep. These data highlight an urgent need for careful reconsideration and balancing of how antenatal steroids are used, both for patient selection and dosing regimens.

Corticotropin-releasing hormone and obesity: From fetal life to adulthood

Obesity is among the most common chronic disorders, worldwide. It is a complex disease that reflects the interactions between environmental influences, multiple genetic allelic variants, and behavioral factors. Recent developments have also shown that biological conditions in utero play an important role in the programming of energy homeostasis systems and might have an impact on obesity and metabolic disease risk. The corticotropin-releasing hormone (CRH) family of neuropeptides, as a central element of energy homeostasis, has been evaluated for its role in the pathophysiology of obesity. This review aims to summarize the relevance and effects of the CRH family of peptides in the pathophysiology of obesity spanning from fetal life to adulthood.

Prenatal maternal glucocorticoid exposure modifies sperm miRNA profiles across multiple generations in the guinea-pig

Maternal stress and glucocorticoid exposure during pregnancy have multigenerational effects on neuroendocrine function and behaviours in offspring. Importantly, effects are transmitted through the paternal lineage. Altered phenotypes are associated with profound differences in transcription and DNA methylation in the brain. In the present study, we hypothesized that maternal prenatal synthetic glucocorticoid (sGC) exposure in the F0 pregnancy will result in differences in miRNA levels in testes germ cells and sperm across multiple generations, and that these changes will associate with modified microRNA (miRNA) profiles and gene expression in the prefrontal cortex (PFC) of subsequent generations. Pregnant guinea-pigs (F0) were treated with multiple courses of the sGC betamethasone (Beta) (1 mg kg-1; gestational days 40, 41, 50, 51, 60 and 61) in late gestation. miRNA levels were assessed in testes germ cells and in F2 PFC using the GeneChip miRNA 4.0 Array and candidate miRNA measured in epididymal sperm by quantitative real-time PCR. Maternal Beta exposure did not alter miRNA levels in germ cells derived from the testes of adult male offspring. However, there were significant differences in the levels of four candidate miRNAs in the sperm of F1 and F2 adult males. There were no changes in miRNA levels in the PFC of juvenile F2 female offspring. The present study has identified that maternal Beta exposure leads to altered miRNA levels in sperm that are apparent for at least two generations. The fact that differences were confined to epididymal sperm suggests that the intergenerational effects of Beta may target the epididymis. KEY POINTS: Paternal glucocorticoid exposure prior to conception leads to profound epigenetic changes in the brain and somatic tissues in offspring, and microRNAs (miRNAs) in sperm may mediate these changes. We show that there were significant differences in the miRNA profile of epididymal sperm in two generations following prenatal glucocorticoid exposure that were not observed in germ cells derived from the testes. The epididymis is a probable target for intergenerational programming. The effects of prenatal glucocorticoid treatment may span multiple generations.

A comparison of 2 doses of antenatal dexamethasone for the prevention of respiratory distress syndrome: an open-label, noninferiority, pragmatic randomized trial

BACKGROUND

Antenatal corticosteroids have been used for the prevention of respiratory complications, intraventricular hemorrhage, necrotizing enterocolitis, and other adverse neonatal outcomes for over 50 years, with limited evidence about their optimal doses. Higher steroid doses or frequencies of antenatal corticosteroids in preterm newborns pose adverse effects such as prolonged adrenal suppression, negative effects on fetal programming and metabolism, and increased risks of neurodevelopmental and neuropsychological impairments. Conversely, lower doses of antenatal corticosteroids may be an effective alternative to induce fetal lung maturation with less risk to the fetus. Late preterm births represent the largest population of all preterm neonates, with a respiratory distress syndrome risk of 8.83%. Therefore, determining the optimal antenatal corticosteroid dosage is of particular importance for this population.

OBJECTIVE

This study aimed to compare the efficacy of 5-mg and 6-mg dexamethasone in preventing neonatal respiratory distress syndrome in women with preterm births at 320 to 366 weeks of gestation.

STUDY DESIGN

This was an open-label, randomized, controlled, noninferiority trial. Singleton pregnant women (n=370) at 320 to 366 weeks of gestation with spontaneous preterm labor or preterm premature rupture of membranes were enrolled. They were randomly assigned (1:1) to a 5-mg or 6-mg dexamethasone group. Dexamethasone was administered intramuscularly every 12 hours for 4 doses or until delivery. The primary outcome was the reduction in neonatal respiratory distress syndrome cases, whereas the secondary outcomes were any adverse maternal or neonatal events.

RESULTS

Between December 2020 and April 2022, 370 eligible women, anticipating deliveries within the gestational range of 32 0/7 to 36 6/7 weeks, willingly participated in the study. They were evenly split, with 185 women assigned to the 5-mg group and 185 to the 6-mg group. The study revealed that the demographic profiles of the participants in the 2 groups were remarkably similar, with no statistically significant disparities (P>.05). It is noteworthy that most of these women gave birth after 34 weeks of gestation. Despite a substantial proportion not completing the full course of steroid treatment, the 5-mg dose exhibited noninferiority compared with the 6-mg dose of dexamethasone, as indicated by a modest proportional difference of 0.5% (95% confidence interval, -2.8 to 43.9). Neonatal respiratory distress syndrome occurred in a relatively low percentage of newborns in both groups, affecting 2.2% in the 5-mg group and 1.6% in the 6-mg group. Notably, the risk difference of 0.6% fell comfortably within the predefined noninferiority threshold of 10%.

CONCLUSION

Our study suggests that a 5-mg dexamethasone dose is noninferior to a standard 6-mg dose in preventing neonatal respiratory distress syndrome in preterm births.

Genomic glucocorticoid action in embryonic mouse neural stem cells

Prenatal exposure to synthetic glucocorticoids (sGCs) reprograms brain development and predisposes the developing fetus towards potential adverse neurodevelopmental outcomes. Using a mouse model of sGC administration, previous studies show that these changes are accompanied by sexually dimorphic alterations in the transcriptome of neural stem and progenitor cells (NSPCs) derived from the embryonic telencephalon. Because cell type-specific gene expression profiles tightly regulate cell fate decisions and are controlled by a flexible landscape of chromatin domains upon which transcription factors and enhancer elements act, we multiplexed data from four genome-wide assays: RNA-seq, ATAC-seq (assay for transposase accessible chromatin followed by genome wide sequencing), dual cross-linking ChIP-seq (chromatin immunoprecipitation followed by genome wide sequencing), and microarray gene expression to identify novel relationships between gene regulation, chromatin structure, and genomic glucocorticoid receptor (GR) action in NSPCs. These data reveal that GR binds preferentially to predetermined regions of accessible chromatin to influence gene programming and cell fate decisions. In addition, we identify SOX2 as a transcription factor that impacts the genomic response of select GR target genes to sGCs (i.e., dexamethasone) in NSPCs.

Maternal prenatal cortisol trajectories predict accelerated growth in infancy

Higher maternal cortisol in pregnancy has been linked to childhood obesity. Much of the previous research has been limited in that cortisol in pregnancy is only measured at one time-point, precluding the ability to examine critical timing effects of prenatal maternal cortisol. To fill this gap, this longitudinal study measured maternal plasma cortisol at 15, 19, 25, and 31 weeks of pregnancy, and assessed infant body mass index percentile (BMIP)1 at birth, 3, 6, 12, and 24 months in 189 mother-infant pairs. Three distinct patterns of maternal cortisol in pregnancy (typical, steep, and flat trajectories) were identified using general growth mixture modeling (GGMM)2 and then used to predict child growth patterns using multilevel modeling. Infants of mothers who had flat cortisol trajectories, characterized by relatively high cortisol in early gestation that plateaus by mid-gestation, experienced more rapid increases in BMIP from birth to 6 months, and had higher BMIPs at 3 and 6 months, than infants whose mothers had the typical slow cortisol rise over gestation, or steep (rapidly accelerating) trajectories. These results suggest that it is not just the total amount of maternal cortisol in pregnancy that shapes early infant growth, but instead the timing and trajectory of prenatal cortisol exposure. To better understand the early origins of obesity risk, future research is needed to investigate the factors that shape mothers' prenatal cortisol trajectories.

Neurological implications of antenatal corticosteroids on late preterm and term infants: a scoping review

The objective of this study was to synthesize the body of knowledge on the association between ACS exposure for risk of preterm birth and brain development in infants ultimately born late preterm and term. Three databases and eight conference proceedings were systematically searched (1972-2021). Selection criteria included ACS administration for risk of preterm delivery, cohort of late preterm and term infants, and assessment of brain development. Data on study characteristics, ACS administration, and neurological outcomes were extracted and qualitatively synthesized according to themes. Neurological outcomes of the included studies (n = 27) were grouped into four themes. The most common adverse outcomes were reduced neonatal head circumference, structural cortical differences on MRI, increased prevalence of psychiatric problems, and increased risk of neurodevelopmental delays in ACS-exposed late preterm and term infants. Our scoping review demonstrated that ACS exposure for risk of preterm delivery may have important neurological implications in infants ultimately born late preterm and term. Given that the existing research is at serious risk for bias, further research that accounts for confounders such as preterm labor, maternal stress, and the number of ACS courses is needed to better establish the long-term neurological effects of ACS on late preterm and term infants. IMPACT: Due to the difficulty in predicting preterm birth, approximately 40% of fetuses exposed to antenatal corticosteroids (ACS) are born at term (≥37 weeks' gestation). This scoping review summarizes the knowledge on the association between ACS exposure for risk of preterm birth and brain development in late preterm and term infants. The majority of studies reported that ACS exposure was associated with adverse brain development outcomes across various domains, such as reduced neonatal head circumference, cortical differences on MRI, and increased prevalence of psychiatric problems and neurodevelopmental delays in late preterm and term infants.

Timing of Antenatal Steroid Administration and Effects on the Newborn Infant: A Retrospective Study

OBJECTIVE

The timing of antenatal steroids (ANS) on short- and long-term effects on newborn infants was evaluated.

STUDY DESIGN

This study was conducted at the University of Cincinnati Medical Center Level-III Neonatal Intensive Care Unit by reviewing the medical records of all women with history of ANS exposure from January 2015 to December 2018. We compared outcomes of newborns delivered within the ideal therapeutic window of 24 hours to 7 days (within window [WW]) after administration to those exposed and delivered outside the therapeutic window (outside window primary group [OWP]). Outcomes included anthropometrics, blood sugars, thyroid hormone profile, and neonatal morbidities.

RESULTS

A total of 669 patients were identified as having received at least two doses of ANS. Two-thirds of them delivered within the ideal therapeutic window. Significant differences were found in anthroprometrics including lower birth weight, shorter length, and smaller head circumferences in those born within the window compared with those outside the window. Derangements in glucose homeostasis requiring treatment and elevations of thyroid stimulating hormone (TSH) were seen in infants born outside the ideal therapeutic window compared with those born within the therapeutic window. No differences were found in neonatal morbidities including severe intraventricular hemorrhage (sIVH), necrotizing enterocolitis (NEC), need for resuscitation, exogenous surfactant administration, continuous positive airway pressure (CPAP), mechanical ventilation, bronchopulmonary dysplasia (BPD), or periventricular leukomalacia (PVL). After controlling for selected covariates, only birth length was different between the groups.

CONCLUSION

Effects on anthropometrics, glucose homeostasis, and thyroid function support the need to develop new or refine existing risk stratification systems to time the administration of antenatal steroids. Better targeting of women and fetuses may confer the benefits of systemic corticosteroids while mitigating the risks of adverse effects.

KEY POINTS

· The timing of antenatal steroids on short and long-term effects on newborn infants was evaluated.. · Differences were found in anthroprometrics, glucoses, and thyroid function.. · No differences were found in neonatal morbidities..

1% of the clinical dose used for antenatal steroid therapy is sufficient to induce lung maturation when administered directly to the preterm ovine fetus

INTRODUCTION

Antenatal steroids (ANS) are standard of care for women at imminent risk of preterm delivery. ANS accelerate functional maturation of the preterm fetal lung. Current dosing regimens expose the mother and fetus to high steroid levels with increased risk of adverse outcomes. Using a sheep model of pregnancy, we aimed to demonstrate that direct fetal administration would be sufficient to elicit functional maturation of the fetal lung.

STUDY DESIGN

Ewes and fetuses at 122d gestation underwent recovery surgery to install a fetal jugular catheter. Animals were then immediately randomised to either: i) fetal intravenous betamethasone phosphate infusion of 2ng/ml for 26 hours (fetal low-dose group; n=16); ii) fetal intravenous saline infusion for 26 hours and two maternal intramuscular injections of 0.25mg/kg betamethasone-phosphate + betamethasone-acetate (maternal clinical treatment group; n=12); or iii) fetal intravenous saline infusion for 26 hours (negative control group; n=10). Fetuses were delivered 48 hours after surgery, ventilated for 30 min to allow collection of physiological data, and euthanised.

RESULTS

The average betamethasone dose for the fetal low-dose group was 1% (0.3mg) of that used in the maternal clinical treatment group (30mg). At 30 minutes of ventilation, arterial paCO2, pH, heart rate and VEI were significantly (p<0.05) and equivalently improved in both the fetal low-dose and maternal clinical treatment group relative to negative control.

CONCLUSION

Maternal steroid administration was not required to elicit fetal lung maturation. Targeted fetal ANS treatments may allow the use of materially reduced antenatal steroid exposures, significantly reducing the risk of adverse outcomes.

Impact of natural and artificial prenatal stimulations on the behavioural profile of Japanese quail

As the sensory systems of vertebrates develop prenatally, embryos perceive many environmental stimuli that can influence the ontogeny of their behaviour. Whether the nature and intensity of prenatal stimuli affect differently this ontogeny remains to be investigated. In this context, this study aimed to analyse the effects of prenatal auditory stimulations (natural stimulations "NS": predator vocalisations, or artificial stimulations "AS": metallic sounds) on the subsequent behaviour of young Japanese quail (Coturnix coturnix japonica). For that, behavioural variables recorded during ethological tests evaluating emotional and social reactivity were analysed using a principal component analysis. This analysis revealed significant differences between the behavioural profile of stimulated chicks and that of non-exposed chicks. Indeed, chicks exposed to NS expressed more intense emotional responses in fearful situations, but less neophobia in the presence of a novel environment or object, whereas chicks exposed to AS appeared more sensitive to social isolation. Our original results show that the acoustic environment of embryos can influence the way young birds subsequently interact with their social and physical environment after hatching, and face challenges in changing living conditions.

Human Milk Glucocorticoid Levels Are Associated With Infant Adiposity and Head Circumference Over the First Year of Life

Human milk (HM) is a complex and dynamic biological fluid, which contains appreciable concentrations of the glucocorticoids, cortisol and cortisone. Experimental studies in non-human primates suggest the HM glucocorticoids' impact on infant growth and body composition. In this current study, analysis is made of the relationships between HM glucocorticoid concentrations and the infant growth and development over the first year of life. HM was collected by lactating healthy women (n = 18), using a standardized protocol, at 2, 5, 9, and 12 months after childbirth. Cortisol and cortisone concentrations in the HM were measured using liquid chromatography mass spectrometry. Infant weight, length and head circumference were measured by standard protocols and percentage fat mass (% FM) determined by whole body bioimpedance. Cortisol and cortisone concentrations were unaltered over the analyzed lactation period (2–12 months), and were altered by infant sex. Although, HM cortisol was positively associated with infant percentage fat mass (% FM) (p = 0.008) and cortisone positively associated with infant head circumference (p = 0.01). For the first 12 months of life, the concentration of HM glucocorticoids levels was positively associated with infant adiposity (%FM) and head circumference. This preliminary evidence provides insight to a possible relationship between ingested HM glucocorticoids and infant body composition. Further studies are required to determine the mechanisms regulating HM glucocorticoids.

Antenatal Corticosteroids for Fetal Lung Maturity - Too Much of a Good Thing?

BACKGROUND

Between 5-15% of babies are born prematurely worldwide, with preterm birth defined as delivery before 37 completed weeks of pregnancy (term is at 40 weeks of gestation). Women at risk of preterm birth receive antenatal corticosteroids as part of standard care to accelerate fetal lung maturation and thus improve neonatal outcomes in the event of delivery. As a consequence of this treatment, the entire fetal organ system is exposed to the administered corticosteroids. The implications of this exposure, particularly the long-term impacts on offspring health, are poorly understood.

AIMS

This review will consider the origins of antenatal corticosteroid treatment and variations in current clinical practices surrounding the treatment. The limitations in the evidence base supporting the use of antenatal corticosteroids and the evidence of potential harm to offspring are also summarised.

RESULTS

Little has been done to optimise the dose and formulation of antenatal corticosteroid treatment since the first clinical trial in 1972. International guidelines for the use of the treatment lack clarity regarding the recommended type of corticosteroid and the gestational window of treatment administration. Furthermore, clinical trials cited in the most recent Cochrane Review have limitations which should be taken into account when considering the use of antenatal corticosteroids in clinical practice. Lastly, there is limited evidence regarding the long-term effects on the different fetal organ systems exposed in utero, particularly when the timing of corticosteroid administration is sub-optimal.

CONCLUSION

Further investigations are urgently needed to determine the most safe and effective treatment regimen for antenatal corticosteroids, particularly regarding the type of corticosteroid and optimal gestational window of administration. A clear consensus on the use of this common treatment could maximise the benefits and minimise potential harms to offspring.

Prenatal drug exposure and neurodevelopmental programming of glucocorticoid signalling

Prenatal neurodevelopment is dependent on precise functioning of multiple signalling pathways in the brain, including those mobilised by glucocorticoids (GC) and endocannabinoids (eCBs). Prenatal exposure to drugs of abuse, including opioids, alcohol, cocaine and cannabis, has been shown to not only impact GC signalling, but also alter functioning of the hypothalamic-pituitary-adrenal (HPA) axis. Such exposures can have long-lasting neurobehavioural consequences, including alterations in the stress response in the offspring. Furthermore, cannabis contains cannabinoids that signal via the eCB pathway, which is linked to some components of GC signalling in the adult brain. Given that GCs are frequently used in pregnancy to prevent complications of prematurity, and also that rates of cannabis use in pregnancy are increasing, the likelihood of foetal co-exposure to these compounds is high and may have additional implications for long-term neurodevelopment. Here, we present a discussion of GC signalling and the HPA axis, as well as the effects of prenatal drug exposure on these pathways and the stress response, and we explore the interactions between GC and EC signalling in the developing brain and potential for neurodevelopmental consequences.

A Transcriptomic Model of Postnatal Cardiac Effects of Prenatal Maternal Cortisol Excess in Sheep

In utero treatment with glucocorticoids have been suggested to reprogram postnatal cardiovascular function and stress responsiveness. However, little is known about the effects of prenatal exposure to the natural corticosteroid, cortisol, on postnatal cardiovascular system or metabolism. We have demonstrated an increased incidence of stillbirth in sheep pregnancies in which there is mild maternal hypercortisolemia caused by infusion of 1 mg/kg/d cortisol. In order to model corticosteroid effects in the neonate, we created a second model in which cortisol was infused for 12 h per day for a daily infusion of 0.5 mg/kg/d. In this model we had previously found that neonatal plasma glucose was increased and plasma insulin was decreased compared to those in the control group, and that neonatal ponderal index and kidney weight were reduced and left ventricular wall thickness was increased in the 2 week old lamb. In this study, we have used transcriptomic modeling to better understand the programming effect of this maternal hypercortisolemia in these hearts. This is a time when both terminal differentiation and a shift in the metabolism of the heart from carbohydrates to lipid oxidation are thought to be complete. The transcriptomic model indicates suppression of genes in pathways for fatty acid and ketone production and upregulation of genes in pathways for angiogenesis in the epicardial adipose fat (EAT). The transcriptomic model indicates that RNA related pathways are overrepresented by downregulated genes, but ubiquitin-mediated proteolysis and protein targeting to the mitochondria are overrepresented by upregulated genes in the intraventricular septum (IVS) and left ventricle (LV). In IVS the AMPK pathway and adipocytokine signaling pathways were also modeled based on overrepresentation by downregulated genes. Peroxisomal activity is modeled as increased in EAT, but decreased in LV and IVS. Our results suggest that pathways for lipids as well as cell proliferation and cardiac remodeling have altered activity postnatally after the in utero cortisol exposure. Together, this model is consistent with the observed increase in cardiac wall thickness at necropsy and altered glucose metabolism observed in vivo, and predicts that in utero exposure to excess maternal cortisol will cause postnatal cardiac hypertrophy and altered responses to oxidative stress.

Challenges in Prenatal Treatment with Dexamethasone

Classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency causes elevated androgen levels, which can lead to virilization of female external genitalia. Prenatal dexamethasone treatment has been shown to be effective in preventing virilization of external genitalia when started prior to 7-9 weeks of gestation in females with classic CAH. However, CAH cannot be diagnosed prenatally until the end of the first trimester. Treating pregnant women with a fetus at risk of developing classic CAH exposes a significant proportion of fetuses unnecessarily, because only 1 in 8 would benefit from treatment. Consequently, prenatal dexamethasone treatment has been met with much controversy due to the potential adverse outcomes when exposed to high-dose steroids in utero. Here, we review the short- and long-term outcomes for fetuses and pregnant women exposed to dexamethasone treatment, the ethical considerations that must be taken into account, and current practice recommendations.

Prenatal programming of stress responsiveness and behaviours: Progress and perspectives

Parental exposure to stress or glucocorticoids either before or during pregnancy can have profound influences on neurodevelopment, neuroendocrine function and behaviours in offspring. Specific outcomes are dependent on the nature, intensity and timing of the exposure, as well as species, sex and age of the subject. Most recently, it has become evident that outcomes are not confined to first-generation offspring and that there may be intergenerational and transgenerational transmission of effects. There has been intense focus on the mechanisms by which such early exposure leads to long-term and potential transgenerational outcomes, and there is strong emerging evidence that epigenetic processes (histone modifications, DNA methylation, and small non-coding RNAs) are involved. New knowledge in this area may allow the development of interventions that can prevent, ameliorate or reverse the long-term negative outcomes associated with exposure to early adversity. This review will focus on the latest research, bridging human and pre-clinical studies, and will highlight some of the limitations, challenges and gaps that exist in the field.

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.

Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline

Objective

To update the congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency clinical practice guideline published by the Endocrine Society in 2010.

Conclusions

The writing committee presents updated best practice guidelines for the clinical management of congenital adrenal hyperplasia based on published evidence and expert opinion with added considerations for patient safety, quality of life, cost, and utilization.

Developmental programming of the female neuroendocrine system by steroids

Developmental programming refers to processes that occur during early life that may have long-term consequences, modulating adult health and disease. Complex diseases, such as diabetes, cancer and cardiovascular disease, have a high prevalence in different populations, are multifactorial, and may have a strong environmental component. The environment interacts with organisms, affecting their behaviour, morphology and physiology. This interaction may induce permanent or long-term changes, and organisms may be more susceptible to environmental factors during certain developmental stages, such as the prenatal and early postnatal periods. Several factors have been identified as responsible for inducing the reprogramming of various reproductive and nonreproductive tissues. Among them, both natural and synthetic steroids, such as endocrine disruptors, are known to have either detrimental or positive effects on organisms depending on the dose of exposure, stage of development and biological sexual background. The present review focuses on the action of steroids and endocrine disruptors as agents involved in developmental programming and on their modulation and effects on female neuroendocrine functions.

Efficacy and safety of antenatal steroids

Antenatal steroids (ANS) are among the most important and widely utilized interventions to improve outcomes for preterm infants. A significant body of evidence demonstrates improved outcomes in preterm infants (24-34 wk) delivered between 1 and 7 days after the administration of a single course of ANS. Moreover, ANS have the advantage of being widely available, low cost, and easily administered via maternal intramuscular injection. The use of ANS to mature the fetal lung is, however, not without contention. Their use in pregnancy is not FDA approved, and treatment doses and regimens remain largely unoptimized. Their mode of use varies considerably between countries, and there are lingering concerns regarding the safety of exposing the fetus to high doses of exogenous steroids. A significant proportion of women deliver outside the 1- to 7-day therapeutic window after ANS treatment, and this delay may be associated with an increased risk of adverse outcomes for both mother and baby. Today, animal-based studies are one means by which key questions of dosing and safety relating to ANS may be resolved, allowing for further refinement(s) of this important therapy. Complementary approaches using nonhuman primates, sheep, and rodents have provided invaluable advances to our understanding of how exogenous steroid exposure impacts fetal development. Focusing on these three major model groups, this review highlights the role of three key animal models (sheep, nonhuman primates, rodents) in the development of antenatal steroid therapy, and provides an up-to-date synthesis of current efforts to refine this therapy in an era of personalised medicine.

The efficacy of antenatal steroid therapy is dependent on the duration of low-concentration fetal exposure: evidence from a sheep model of pregnancy

BACKGROUND

Antenatal corticosteroids are among the most important and widely used interventions to improve outcomes for preterm infants. Antenatal corticosteroid dosing regimens remain unoptimized and without maternal weight-adjusted dosing. We, and others, have hypothesized that, once a low concentration of maternofetal steroid exposure is achieved and maintained, the duration of the steroid exposure determines treatment efficacy. Using a sheep model of pregnancy, we tested the relationship among steroid dose, duration of exposure, and treatment efficacy.

OBJECTIVE

The study was conducted to investigate the relative importance of duration and magnitude of fetal corticosteroid exposure to mature the preterm fetal ovine lung.

STUDY DESIGN

Ewes with single fetuses at 120 days gestation received an intravenous bolus (loading dose) followed by a maintenance infusion of betamethasone phosphate to target 12-hour fetal plasma betamethasone concentrations of (1) 20 ng/mL, (2) 10 ng/mL, or (3) 2 ng/mL. In a subsequent experiment, fetal plasma betamethasone concentrations were targeted at 2 ng/mL for 26 hours. Negative control animals received sterile saline solution. Positive control animals received 2 intramuscular injections of 0.25 mg/kg Celestone Chronodose (betamethasone phosphate + betamethasone acetate) spaced at 24 hours. Preterm lambs were delivered surgically and ventilated 48 hours after treatment commenced. Maternal and fetal plasma betamethasone concentrations were confirmed by mass spectrometry in a parallel study of chronically catheterized, corticosteroid-treated ewes and fetuses.

RESULTS

The loading and maintenance doses were achieved and maintained the desired fetal plasma betamethasone concentrations of approximately 20, 10, and 2 ng/mL for 12 hours. Compared with the 12-hour infusion-treated animals, lambs from the positive control (2 intramuscular doses of 0.25 mg/kg Celestone Chronodose) group had the greatest functional lung maturation (compliance, gas exchange, arterial pH) and molecular evidence of maturation (glucocorticoid receptor signaling activation), despite having maximum fetal plasma betamethasone concentrations 2.5 times lower than animals in the 20 ng/mL betamethasone infusion group. Lambs from the 12-hour 2-ng/mL betamethasone infusion group had little functional lung maturation. In contrast, lambs from the 26-hour 2-ng/mL betamethasone infusion group had functional lung maturation equivalent to lambs from the positive control group.

CONCLUSION

In preterm lambs that were exposed to antenatal corticosteroids, high maternofetal plasma betamethasone concentrations did not correlate with improved lung maturation. The largest and most consistent improvements in lung maturation were in animals that were exposed to either the clinical course of Celestone Chronodose or a low-dose betamethasone phosphate infusion to achieve a fetal plasma betamethasone concentration of approximately 2 ng/mL for 26 hours. The duration of low-concentration maternofetal steroid exposure, not total dose or peak drug exposure, is a key determinant for antenatal corticosteroids efficacy. These findings underscore the need to develop an optimized steroid dosing regimen that may improve both the efficacy and safety of antenatal corticosteroids therapy.

Antenatal Corticosteroid Exposure Disrupts Myelination in the Auditory Nerve of Preterm Sheep

BACKGROUND

Antenatal corticosteroids (ACS) improve preterm neonatal outcomes. However, uncertainty remains regarding the safety of ACS exposure for the developing fetus, particularly its neurosensory development.

OBJECTIVES

We investigated the effect of single and multiple ACS exposures on auditory nerve development in an ovine model of pregnancy.

METHODS

Ewes with a single fetus (gestational age [GA] 100 days) received an intramuscular injection of 150 mg medroxyprogesterone-acetate, followed by intramuscular (i) betamethasone (0.5 mg/kg) on days 104, 111, and 118 GA; (ii) betamethasone on day 104 and saline on days 111 and 118 GA; or (iii) saline on days 104, 111, and 118 GA, with delivery on day 125 GA. Transmission electron microscope images of lamb auditory nerve preparations were digitally analyzed to determine auditory nerve morphology and myelination.

RESULTS

Relative to the control, mean auditory nerve myelin area was significantly increased in the multiple-treatment group (p < 0.001), but not in the single-treatment group. Increased myelin thickness was significantly changed only in a subgroup analysis for those axons with myelin thickness greater than the median value (p < 0.001). Morphological assessments showed that the increased myelin area was due to an increased likelihood of decompacted areas (p = 0.005; OR = 2.14, 95% CI 1.26-3.63; 31.6 vs. 18.2% in controls) and irregular myelin deposition (p = 0.001; OR = 5.91, 95% CI 2.16-16.19; 49.0 vs. 16.8% in controls) in the myelin sheath.

CONCLUSIONS

In preterm sheep, ACS exposure increased auditory nerve myelin area, potentially due to disruption of normal myelin deposition.

Low-dose betamethasone-acetate for fetal lung maturation in preterm sheep

BACKGROUND

Antenatal steroids are standard of care for women who are at risk of preterm delivery; however, antenatal steroid dosing and formulation have not been evaluated adequately. The standard clinical 2-dose treatment with betamethasone-acetate+betamethasone-phosphate is more effective than 2 doses of betamethasone-phosphate for the induction of lung maturation in preterm fetal sheep. We hypothesized that the slowly released betamethasone-acetate component induces similar lung maturation to betamethasone-phosphate+betamethasone-acetate with decreased dose and fetal exposure.

OBJECTIVE

The purpose of this study was to investigate pharmacokinetics and fetal lung maturation of antenatal betamethasone-acetate in preterm fetal sheep.

STUDY DESIGN

Groups of 10 singleton-pregnant ewes received 1 or 2 intramuscular doses 24 hours apart of 0.25 mg/kg/dose of betamethasone-phosphate+betamethasone-acetate (the standard of care dose) or 1 intramuscular dose of 0.5 mg/kg, 0.25 mg/kg, or 0.125 mg/kg of betamethasone-acetate. Fetuses were delivered 48 hours after the first injection at 122 days of gestation (80% of term) and ventilated for 30 minutes, with ventilator settings, compliance, vital signs, and blood gas measurements recorded every 10 minutes. After ventilation, we measured static lung pressure-volume curves and sampled the lungs for messenger RNA measurements. Other groups of pregnant ewes and fetuses were catheterized and treated with intramuscular injections of betamethasone-phosphate 0.125 mg/kg, betamethasone-acetate 0.125 mg/kg, or betamethasone-acetate 0.5 mg/kg. Maternal and fetal betamethasone concentrations in plasma were measured for 24 hours.

RESULTS

All betamethasone-treated groups had increased messenger RNA expression of surfactant proteins A, B, and C, ATP-binding cassette subfamily A member 3, and aquaporin-5 compared with control animals. Treatment with 1 dose of intramuscular betamethasone-acetate 0.125mg/kg improved dynamic and static lung compliance, gas exchange, and ventilation efficiency similarly to the standard treatment of 2 doses of 0.25 m/kg of betamethasone-acetate+betamethasone-phosphate. Betamethasone-acetate 0.125 mg/kg resulted in lower maternal and fetal peak plasma concentrations and decreased fetal exposure to betamethasone compared with betamethasone-phosphate 0.125 mg/kg.

CONCLUSION

A single dose of betamethasone-acetate results in similar fetal lung maturation as the 2-dose clinical formulation of betamethasone-phosphate+betamethasone-acetate with decreased fetal exposure to betamethasone. A lower dose of betamethasone-acetate may be an effective alternative to induce fetal lung maturation with less risk to the fetus.

Antenatal dexamethasone exposure differentially affects distinct cortical neural progenitor cells and triggers long-term changes in murine cerebral architecture and behavior

Antenatal administration of synthetic glucocorticoids (sGC) is the standard of care for women at risk for preterm labor before 34 gestational weeks. Despite their widespread use, the type of sGC used and their dose or the dosing regimens are not standardized in the United States of America or worldwide. Several studies have identified neural deficits and the increased risk for cognitive and psychiatric disease later in life for children administered sGC prenatally. However, the precise molecular and cellular targets of GC action in the developing brain remain largely undefined. In this study, we demonstrate that a single dose of glucocorticoid during mid-gestation in mice leads to enhanced proliferation in select cerebral cortical neural stem/progenitor cell populations. These alterations are mediated by dose-dependent changes in the expression of cell cycle inhibitors and in genes that promote cell cycle re-entry. This leads to changes in neuronal number and density in the cerebral cortex at birth, coupled to long-term alterations in neurite complexity in the prefrontal cortex and hippocampus in adolescents, and changes in anxiety and depressive-like behaviors in adults.

Prenatal maternal cortisol concentrations predict neurodevelopment in middle childhood

Glucocorticoids (cortisol in humans) are the end product of the hypothalamic-pituitary-adrenocortical (HPA) axis and are proposed as a key mechanism for programming fetal brain development. The present prospective longitudinal study evaluates the association between prenatal maternal cortisol concentrations and child neurodevelopment. Participants included a low risk sample of 91 mother-child pairs. Prenatal maternal plasma cortisol concentrations were measured at 19 and 31 gestational weeks. Brain development and cognitive functioning were assessed when children were 6-9 years of age. Structural magnetic resonance imaging scans were acquired and cortical thickness was determined. Child cognitive functioning was evaluated using standardized measures (Wechsler Intelligence Scale for Children IV and Expressive Vocabulary Test, Second Edition). Higher maternal cortisol concentrations during the third trimester were associated with greater child cortical thickness primarily in frontal regions. No significant associations were observed between prenatal maternal cortisol concentrations and child cortical thinning. Elevated third trimester maternal cortisol additionally was associated with enhanced child cognitive performance. Findings in this normative sample of typically developing children suggest that elevated maternal cortisol during late gestation exert lasting benefits for brain development and cognitive functioning 6-9 years later. The benefits of fetal exposure to higher maternal cortisol during the third trimester for child neurodevelopment are consistent with the role cortisol plays in maturation of the human fetus. It is plausible that more extreme elevations in maternal cortisol concentrations late in gestation, as well as exposure to pharmacological levels of synthetic glucocorticoids, may have neurotoxic effects on the developing fetal brain.

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.

Cortisol in human milk predicts child BMI

OBJECTIVE

Breastfeeding has been linked to lower rates of childhood obesity. Human milk contains cortisol, known to regulate glucose storage and metabolism. The aim of this study was to to test the hypothesis that early exposure to cortisol in human breast milk helps to modulate infant body mass index (BMI) trajectories over the first 2 years of life.

METHODS

Growth curve modeling was used to examine whether infant exposure to cortisol in human milk at 3 months predicted changes in child body mass index percentile (BMIP) at 6, 12, and 24 months of age in 51 breastfeeding mother-child pairs.

RESULTS

Infants exposed to higher milk cortisol levels at 3 months were less likely to exhibit BMIP gains over the first 2 years of life, compared with infants exposed to lower milk cortisol. By age 2, infants exposed to higher milk cortisol levels had lower BMIPs than infants exposed to lower milk cortisol. Milk cortisol was a stronger predictor of BMIP change in girls than boys.

CONCLUSIONS

Cortisol exposure through human milk may help to program metabolic functioning and childhood obesity risk. Further, because infant formula contains only trace amounts of glucocorticoids, these findings suggest that cortisol in milk is a novel biological pathway through which breastfeeding may protect against later obesity.

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.

Fetal endocrine therapy for congenital adrenal hyperplasia should not be done

Prenatal treatment of congenital adrenal hyperplasia by administering dexamethasone to a woman presumed to be carrying an at-risk fetus remains a controversial experimental treatment. Review of data from animal experimentation and human trials indicates that dexamethasone cannot be considered safe for the fetus. In animals, prenatal dexamethasone decreases birth weight, affects renal, pancreatic beta cell and brain development, increases anxiety and predisposes to adult hypertension and hyperglycemia. In human studies, prenatal dexamethasone is associated with orofacial clefts, decreased birth weight, poorer verbal working memory, and poorer self-perception of scholastic and social competence. Numerous medical societies have cautioned that prenatal treatment of adrenal hyperplasia with dexamethasone is not appropriate for routine clinical practice and should only be done in Institutional Review Board approved, prospective clinical research settings with written informed consent. The data indicate that this treatment is inconsistent with the classic medical ethical maxim to 'first do no harm'.

Trends in optimal, suboptimal, and questionably appropriate receipt of antenatal corticosteroid prophylaxis

OBJECTIVE

To conduct a population-based study to assess rates of optimal, suboptimal, and questionably appropriate administration of antenatal corticosteroid (betamethasone or dexamethasone) use.

METHODS

All live births in Nova Scotia, Canada, from 1988 to 2012 were included in the study. Temporal trends in optimal (proportion of live births at 24-34 weeks of gestation exposed to antenatal corticosteroids between 24 hours and 7 days before delivery), suboptimal (proportion of live births at 24-34 weeks of gestation exposed to antenatal corticosteroids less than 24 hours or more than 7 days before delivery), and questionably appropriate exposure to antenatal corticosteroids (proportion of live births 35 weeks of gestation or greater exposed to antenatal corticosteroids) were quantified using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Among 246,459 live births between 1988 and 2012, 2.5% received a partial or a full course of antenatal corticosteroids. The rate of antenatal corticosteroid exposure for neonates born between 28 and 32 weeks of gestation increased from 39.5% in 1988-1992 to 79.3% in 2008-2012, whereas exposure for those born at 33-34 weeks of gestation increased from 14.3 to 49.7%. Optimal antenatal corticosteroid receipt increased from 10% in 1988 to 23% in 2012 (OR 2.7, 95% CI 1.6-4.5), suboptimal administration increased from 7 to 34% (OR 6.7, 95% CI 3.9-11.6), and questionably appropriate administration increased from 0.2% in 1988 to 1.7% in 2012 (OR 7.5, 95% CI 4.9-11.3). Of the women who received antenatal corticosteroids in 2012, 52% delivered at 35 weeks of gestation or greater.

CONCLUSION

Temporal increases in optimal exposure to antenatal corticosteroids have been matched by increases in suboptimal and questionably appropriate receipt of antenatal corticosteroids, highlighting the need for accurate preterm delivery prognostic models.

Fetal programming of children's obesity risk

OBJECTIVE

Childhood obesity affects nearly 17% of children and adolescents in the United States. Increasing evidence indicates that prenatal maternal stress signals influence fetal growth, child obesity, and metabolic risk. Children exhibiting catch-up growth, a rapid and dramatic increase in body size, within the first two years of life are also at an increased risk for developing metabolic disorder and obesity. We evaluate the potential role of the maternal hypothalamic-pituitary-adrenal (HPA) and placental axis in programming risk for child obesity.

METHOD

This prospective longitudinal study measured placental corticotropin-releasing hormone (pCRH) and maternal plasma cortisol at 15, 19, 25, 30, and 37 gestational weeks and collected child body mass index (BMI) at birth, 3, 6, 12, and 24 months. Participants included 246 mothers and their healthy children born full term. Each child's BMI percentile (BMIP) was determined using World Health Organization (WHO) standards based on age and sex. Child BMIP profiles from birth to two years of age were characterized using general growth mixture modeling (GGMM). We evaluated whether fetal exposure to placental CRH and maternal cortisol are associated with BMIP profiles.

RESULTS

Placental CRH at 30 gestational weeks was highly associated with both BMIP (p<.05) and weight (p<.05) at birth when accounting for gestational age at birth and used as a predictor in modeling BMIP profiles. Maternal cortisol was not associated with child BMIP. GGMM analyses identified four distinct BMIP profiles: typical, rapid increase, delayed increase, and decreasing (See Fig. 2). The typical profile comprised the majority of the sample and maintained BMIP across the first two years. The rapid and delayed increase profiles each exhibit a period of reduced body size followed by BMI catch-up growth. The rapid increase profile exhibited catch-up within the first 12 months while the delayed group showed an initial decrease in BMIP at 3 months and a dramatic increase from 12 to 24 months. The decreasing profile exhibited normal birth weight and BMIP followed by persisting, low BMIP. The members of the rapid and delayed increase profiles were exposed to the highest concentrations of placental CRH at 30 gestational weeks compared to those in the typical profile group (Fig. 3).

CONCLUSIONS

Exposure to elevated placental CRH concentrations during the third trimester is associated with catch-up growth. An early period of small body size followed by rapid catch-up growth is a profile associated with increased metabolic risk and increased obesity risk. Our findings suggest that placental CRH exposure makes a unique contribution to fetal programming of obesity risk.

Synthetic glucocorticoid reduces human placental system a transport in women treated with antenatal therapy

CONTEXT

Synthetic glucocorticoids (sGCs) are routinely given to women with threatened preterm labor and have been linked to fetal growth restriction and developmental programming. Reductions in fetal growth are likely to be mediated by placental dysfunction, including altered nutrient transport. sGCs modify the system A neutral amino acid transporter in vitro, but there are no in vivo comparable data in human placenta.

OBJECTIVE

Because ∼ 30% of women who receive sGCs carry to term, our objective was to examine the short- and longer-term consequences of antenatal sGCs on placental system A transport.

METHODS AND PATIENTS

Placental tissue was collected from women treated with sGCs between 24 hours and 14 days before delivery (24h-14d), 14 days after treatment but before term (14d-term), or at term, compared with healthy term (control) deliveries to measure system A-mediated activity (Na(+)-dependent [(14)C]methylaminoisobutyric acid uptake per gram placenta) and mRNA expression.

RESULTS

After sGC treatment, system A activity was significantly reduced at term compared with both sGC placentas delivered 24h-14d and compared with controls. Placentae from women treated with sGCs who delivered between 14d-term also had significantly reduced system A activity compared with 24h-14d placentas. SLC38A1 and SLC38A2 mRNA expression was unaffected. However, SLC38A4 was significantly reduced by sGCs at term compared with placentas delivered between 14d-term.

CONCLUSION

We conclude that women who are at risk of preterm labor and receive sGCs but deliver at term have significantly reduced placental system A amino acid transporter activity. Altered placental transporter function could affect fetal growth and may contribute to developmental programming reported in both animal and clinical studies.

Second-trimester maternal distress increases the risk of small for gestational age

BACKGROUND

The effect of prenatal distress on the risk of a small for gestational age (SGA) infant is uncertain. We have addressed the influences of prenatal stress, anxiety and depression on the risk of SGA. We also examined the effects of infant sex and timing of distress during pregnancy on any observed associations.

METHOD

The study population comprised 5606 healthy nulliparous pregnant women who participated in the international prospective Screening for Obstetric and Pregnancy Endpoints (SCOPE) study. Women completed the Perceived Stress Scale (PSS), the short form of the Spielberger State-Trait Anxiety Inventory (STAI) and the Edinburgh Postnatal Depression Scale (EPDS) at 15 ± 1 and 20 ± 1 weeks' gestation. SGA was defined as birthweight below the 10th customized percentile. Logistic regression was used for data analysis, adjusting for several potential confounders such as maternal age, body mass index (BMI), smoking, socio-economic status and physical exercise.

RESULTS

The risk of SGA was increased in relation to mild [adjusted odds ratio (aOR) 1.35, 95% confidence interval (CI) 1.07-1.71], moderate (aOR 1.26, 95% CI 1.06-1.49), high (aOR 1.45, 95% CI 1.08-1.95) and very high stress scores (aOR 1.56, 95% CI 1.03-2.37); very high anxiety score (aOR 1.45, 95% CI 1.13-1.86); and very high depression score (aOR 1.14, 95% CI 1.05-1.24) at 20 ± 1 weeks' gestation. Sensitivity analyses showed that very high anxiety and very high depression increases the risk of SGA in males but not in females whereas stress increases the risk of SGA in both males and females.

CONCLUSIONS

These findings suggest that prenatal stress, anxiety and depression measured at 20 weeks' gestation increase the risk of SGA. The effects of maternal anxiety and depression on SGA were strongest in male infants.

Association between gestational age at birth, antenatal corticosteroids, and outcomes at 5 years: multiple courses of antenatal corticosteroids for preterm birth study at 5 years of age (MACS-5)

Background

The Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study (MACS) showed no benefit in the reduction of major neonatal mortality/morbidity or neurodevelopment at 2 and 5 years of age. Using the data from the randomized controlled trial and its follow-up, the aim of this study was to evaluate the association between gestational ages at birth in children exposed to single versus multiple courses of antenatal corticosteroid (ACS) therapy in utero and outcomes at 5 years of age.

Method

A total of 1719 children, with the breakdown into groupings of <30, 30–36, and ≥ 37 weeks gestation at birth, contributed to the primary outcome: death or survival with a disability in one of the following domains: neuromotor, neurosensory, and neurobehavioral/emotional disability and were included in this analysis.

Results

Gestational age at birth was strongly associated with the primary outcome, p < 0.001. Overall, the interaction between ACS groups and gestational age at birth was not significant, p = 0.064. Specifically, in the 2 preterm categories, there was no difference in the primary outcome between single vs. multiple ACS therapy. However, for infants born ≥37 weeks gestation, there was a statistically significant increase in the risk of the primary outcome in multiple ACS therapy, 48/213 (22.5%) compared to 38/249 (15.3%) in the single ACS therapy; OR = 1.69 [95% CI: 1.04, 2.77]; p = 0.037.

Conclusion

Preterm birth (<37 weeks gestation) remained the primary factor contributing to an adverse outcome regardless of the number of courses of ACS therapy. Children born ≥ 37 weeks and exposed to multiple ACS therapy may have an increased risk of neurodevelopmental/neurosensory impairment by 5 years of age. To optimize outcomes for infants/children, efforts in reducing the incidence of preterm birth should remain the primary focus in perinatal research.

Trial registration

This study has been registered at (identifier NCT00187382)

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2393-14-272) contains supplementary material, which is available to authorized users.

Fetal glucocorticoid exposure is associated with preadolescent brain development

BACKGROUND

Glucocorticoids play a critical role in normative regulation of fetal brain development. Exposure to excessive levels may have detrimental consequences and disrupt maturational processes. This may especially be true when synthetic glucocorticoids are administered during the fetal period, as they are to women in preterm labor. This study investigated the consequences for brain development and affective problems of fetal exposure to synthetic glucocorticoids.

METHODS

Brain development and affective problems were evaluated in 54 children (56% female), aged 6 to 10, who were full term at birth. Children were recruited into two groups: those with and without fetal exposure to synthetic glucocorticoids. Structural magnetic resonance imaging scans were acquired and cortical thickness was determined. Child affective problems were assessed using the Child Behavior Checklist.

RESULTS

Children in the fetal glucocorticoid exposure group showed significant and bilateral cortical thinning. The largest group differences were in the rostral anterior cingulate cortex (rACC). More than 30% of the rACC was thinner among children with fetal glucocorticoid exposure. Furthermore, children with more affective problems had a thinner left rACC.

CONCLUSIONS

Fetal exposure to synthetic glucocorticoids has neurologic consequences that persist for at least 6 to 10 years. Children with fetal glucocorticoid exposure had a thinner cortex primarily in the rACC. Our data indicating that the rACC is associated with affective problems in conjunction with evidence that this region is involved in affective disorders raise the possibility that glucocorticoid-associated neurologic changes increase vulnerability to mental health problems.

The negative predictive value of cervical interleukin-6 for the risk assessment of preterm birth

OBJECTIVE

To determine the potential clinical use of cervical interleukin-6 (IL-6) as a negative predictor of preterm birth in symptomatic women.

STUDY DESIGN

Observational prospective study carried out in a tertiary hospital.

PATIENTS AND METHODS

We studied 100 singleton pregnant women with threatened preterm delivery and intact membranes, between 24 and 34 weeks, recruited during the period 2006-2008. A cervical swab for IL-6 detection was taken and a transvaginal ultrasound scan was performed for measuring the cervical length.

RESULTS

Five women delivered within 2 d and six women within 7 d. A high cervical IL-6 concentration was found in these women. The area under the ROC curve for cervical IL-6 was 0.97 for deliveries within 2 d after the test, and 0.85 for deliveries within 7 d. The optimal cut-off point was a cervical IL-6 concentration of 210 pg/ml. The negative predictive value (NPV) was 100% for deliveries within 2 d, and 98.5% for deliveries within 7 d (when considering a prevalence of preterm birth of 8%). Cervical IL-6 and sonographic measurement of cervical length showed similar NPV.

CONCLUSION

A low-cervical IL-6 concentration can accurately identify symptomatic women with a very low chance to progress to preterm birth within 2-7 d.

Neurobehavioral risk is associated with gestational exposure to stress hormones

The developmental origins of disease or fetal programming model predict that early exposures to threat or adverse conditions have lifelong consequences that result in harmful outcomes for health. The maternal endocrine 'fight or flight' system is a source of programming information for the human fetus to detect threats and adjust their developmental trajectory for survival. Fetal exposures to intrauterine conditions including elevated stress hormones increase the risk for a spectrum of health outcomes depending on the timing of exposure, the timetable of organogenesis and the developmental milestones assessed. Recent prospective studies, reviewed here, have documented the neurodevelopmental consequences of fetal exposures to the trajectory of stress hormones over the course of gestation. These studies have shown that fetal exposures to biological markers of adversity have significant and largely negative consequences for fetal, infant and child emotional and cognitive regulation and reduced volume in specific brain structures.

On the function of placental corticotropin-releasing hormone: a role in maternal-fetal conflicts over blood glucose concentrations

Throughout the second and third trimesters, the human placenta (and the placenta in other anthropoid primates) produces substantial quantities of corticotropin-releasing hormone (placental CRH), most of which is secreted into the maternal bloodstream. During pregnancy, CRH concentrations rise over 1000-fold. The advantages that led selection to favour placental CRH production and secretion are not yet fully understood. Placental CRH stimulates the production of maternal adrenocorticotropin hormone (ACTH) and cortisol, leading to substantial increases in maternal serum cortisol levels during the third trimester. These effects are puzzling in light of widespread theory that cortisol has harmful effects on the fetus. The maternal hypothalamic-pituitary-adrenal (HPA) axis becomes less sensitive to cortisol during pregnancy, purportedly to protect the fetus from cortisol exposure. Researchers, then, have often looked for beneficial effects of placental CRH that involve receptors outside the HPA system, such as the uterine myometrium (e.g. the placental clock hypothesis). An alternative view is proposed here: the beneficial effect of placental CRH to the fetus lies in the fact that it does stimulate the production of cortisol, which, in turn, leads to greater concentrations of glucose in the maternal bloodstream available for fetal consumption. In this view, maternal HPA insensitivity to placental CRH likely reflects counter-adaptation, as the optimal rate of cortisol production for the fetus exceeds that for the mother. Evidence pertaining to this proposal is reviewed.

Cardio-renal and metabolic adaptations during pregnancy in female rats born small: implications for maternal health and second generation fetal growth

Intrauterine growth restriction caused by uteroplacental insufficiency increases risk of cardiovascular and metabolic disease in offspring. Cardio-renal and metabolic responses to pregnancy are critical determinants of immediate and long-term maternal health. However, no studies to date have investigated the renal and metabolic adaptations in growth restricted offspring when they in turn become pregnant. We hypothesised that the physiological challenge of pregnancy in growth restricted females exacerbates disease outcome and compromises next generation fetal growth. Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham surgery (Control) on day 18 of gestation in WKY rats and F1 female offspring birth and postnatal body weights were recorded. F1 Control and Restricted females were mated at 4 months and blood pressure, renal and metabolic parameters were measured in late pregnancy and F2 fetal and placental weights recorded. Age-matched non-pregnant Control and Restricted F1 females were also studied. F1 Restricted females were born 10-15% lighter than Controls. Basal insulin secretion and pancreatic β-cell mass were reduced in non-pregnant Restricted females but restored in pregnancy. Pregnant Restricted females, however, showed impaired glucose tolerance and compensatory glomerular hypertrophy, with a nephron deficit but normal renal function and blood pressure. F2 fetuses from Restricted mothers exposed to physiological measures during pregnancy were lighter than Controls highlighting additive adverse effects when mothers born small experience stress during pregnancy. Female rats born small exhibit mostly normal cardio-renal adaptations but altered glucose control during late pregnancy making them vulnerable to lifestyle challenges.

Antenatal dexamethasone treatment in midgestation reduces system A-mediated transport in the late-gestation murine placenta

Clinically, approximately 30% of women who receive synthetic glucocorticoids (sGC) for risk of preterm labor carry to term. In vitro studies have shown that sGC acutely regulate the placental system A amino acid transporter, but there are no comparable data in vivo. Hence, the objective of our study was to examine the acute [embryonic day (E)15.5] and longer-term (E17.5 and E18.5) consequences of midgestation antenatal sGC [dexamethasone (DEX); 0.1 mg/kg on E13.5 and E14.5] on placental system A-mediated transfer in the mouse (measured in vivo as maternal-fetal unidirectional (14)C-methylaminoisobutyric acid transfer per gram of placenta). System A transfer and Slc38a mRNA expression significantly increased from E12.5 to E18.5 (P < 0.05), corresponding to increased fetal growth. DEX treatment had no acute effect at E15.5 or longer-term effect at E17.5 but significantly decreased system A-mediated transfer before term (E18.5; P < 0.05) in placentae of male and female fetuses. There was no effect of DEX on Slc38a gene expression. Administration of DEX in this regime had no effect on birth weight. We conclude that sGC treatment in midgestation leads to a substantial decrease in placental system A-mediated transport in late gestation, suggesting that prenatal sGC therapy may lead to a reduction in availability of neutral amino acids to the fetus if gestation persists to term.

Exaggerated sympathetic mediated responses to behavioral or pharmacological challenges following antenatal betamethasone exposure

Glucocorticoid administration to women at risk for preterm delivery is standard practice to enhance neonatal survival. However, antenatal betamethasone exposure (β-exposure) increases mean arterial pressure (MAP) in adult sheep (1.8 yr old) and results in impaired baroreflex sensitivity (BRS) for control of heart rate (HR). In the current studies we tested the hypothesis that enhanced sympathetic nervous system and hypothalamo-pituitary-adrenal (HPA) axis-mediated responses are evident at an early age in β-exposed sheep. Pregnant ewes were administered betamethasone (0.17 mg/kg twice over 24 h) or vehicle (Veh-control) on the 80th day of gestation, and offspring were delivered at full term. Female β-exposed and control offspring instrumented at age 42 ± 3 days for conscious continuous recording of MAP and HR had similar resting values at baseline. However, BRS was ~45% lower in β-exposed offspring. β-Exposed lambs allowed to suckle for 10 min had a greater elevation in MAP than Veh-control lambs (19 ± 1 vs 12 ± 2 mmHg; n = 4-5, P < 0.05). MAP was reduced by 20% from baseline via sodium nitroprusside infusion (SNP) over 10 min, which triggered a rebound increase in MAP only in β-exposed lambs. HR increased with the reduction in MAP during SNP infusion in Veh-control lambs, whereas there was no change in HR with the reduction in MAP in β-exposed lambs. Combined vasopressin-CRF injection caused greater increases in MAP in the β-exposed lambs. Cortisol and ACTH responses were higher in response to SNP hypotension in the β-exposed lambs. The data reveal enhanced sympathetic and HPA axis responses associated with impaired BRS preceding differences in resting MAP in preweanling female lambs exposed in utero to glucocorticoids. The consequences of these alterations at an early age include eventual development of higher blood pressure in this ovine model of fetal programming.

Role of pelvic sensory signaling during delivery in postpartum mental health

BACKGROUND: Animal research demonstrates that pelvic sensory signaling at parturition initiates behavioral and emotional changes that are protective for mother and offspring. In contrast, research with humans has found no effect of cesarean delivery (i.e., procedure that blocks pelvic signaling) on mother's mental health. The lack of effect may reflect little consideration for the use of epidurals, another intervention that blocks pelvic signaling. The following study examines whether blocking pelvic signaling during delivery predicts postpartum depression symptomatology. METHOD: Longitudinal mental health data were collected prospectively from 142 primiparous women who had a cesarean delivery and/or received epidural anesthesia (Intervention) or delivered vaginally without anesthesia (No-Intervention). Measurements began in late pregnancy and continued through the first postpartum year. RESULTS: Intervention mothers reported more depressive symptoms at the end of the first postpartum year compared to those in the No-Intervention group. This effect was independent of socio-cultural factors known to predict levels of depressive symptoms. CONCLUSION: These results suggest that pelvic sensory signaling may help to prepare women for the postpartum period. Considering there are many factors influencing the mental health of mothers, the present finding suggest that populations vulnerable to postpartum depression should consider a delivery without intervention, when medically permissible.