Are we prescribing multiple courses of antenatal corticosteroids? A survey of practice in the UK

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.

Fetal glucocorticoid exposure leads to sex-specific changes in drug-transporter function at the blood-brain barrier in juvenile guinea pigs

Antenatal synthetic glucocorticoids (sGCs) are a life‐saving treatment in managing pre‐term birth. However, off‐target effects of sGCs can impact blood‐brain barrier (BBB) drug transporters essential for fetal brain protection, including P‐glycoprotein (P‐gp/Abcb1) and breast cancer resistance protein (BCRP/Abcg2). We hypothesized that maternal antenatal sGC treatment modifies BBB function in juvenile offspring in a sex‐dependent manner. Thus, the objective of this study was to determine the long‐term impact of a single or multiple courses of betamethasone on P‐gp/Abcb1 and BCRP/Abcg2 expression and function at the BBB. Pregnant guinea pigs (N = 42) received 3 courses (gestation days (GDs) 40, 50, and 60) or a single course (GD50) of betamethasone (1 mg/kg) or vehicle (saline). Cerebral microvessels and brain endothelial cells (BEC) were collected from the post‐natal day (PND) 14 offspring to measure protein, gene expression, and function of the drug transporters P‐gp/Abcb1 and BCRP/Abcg2. P‐gp protein expression was decreased (p < .05) in microvessels from male offspring that had been exposed to multiple courses and a single course of sGC, in utero. Multiple courses of sGC resulted in a significant decrease in P‐gp function in BECs from males (p < .05), but not females. There was a very strong trend for increased P‐gp function in males compared to females (p = .055). Reduced P‐gp expression and function at the BBB of young male offspring following multiple prenatal sGC exposures, is clinically relevant as many drugs administered postnatally are P‐gp substrates. These novel sex differences in drug transporter function may underlie potential sexual dimorphism in drug sensitivity and toxicity in the newborn and juvenile brain.

Prenatal dexamethasone exposure induces nonalcoholic fatty liver disease in male rat offspring via the miR-122/YY1/ACE2-MAS1 pathway

Epidemiological studies have shown that nonalcoholic fatty liver disease (NAFLD) has an intrauterine developmental origin. We aimed to demonstrate that NAFLD is caused by prenatal dexamethasone exposure (PDE) in adult male rat offspring and to investigate the intrauterine programming mechanism. Liver samples were obtained on gestational day (GD) 21 and postnatal week (PW) 28. The effects and epigenetic mechanism of dexamethasone were studied with bone marrow mesenchymal stem cells (BMSCs) hepatoid differentiated cells and other cell models. In the PDE group, lipid accumulation increased, triglyceride synthesis-related gene expression increased, and oxidation-related gene expression decreased in livers of adult male rat offspring. In utero, hepatic triglyceride synthesis increased and oxidative function decreased in PDE fetal male rats. Moreover, low hepatic miR-122 expression, high Yin Yang-1 (YY1) expression and angiotensin-converting enzyme 2 (ACE2)-Mas receptor (MAS1) signaling pathway inhibition were observed before and after birth. At the cellular level, dexamethasone (100-2500 nM) elevated the intracellular triglyceride content, increased triglyceride synthesis-related gene expression and decreased oxidation-related gene expression. Dexamethasone treatment also decreased miR-122 expression, increased YY1 expression and inhibited the ACE2-MAS1 signaling pathway. Interference or overexpression of glucocorticoid receptor (GR), miR-122, YY1 and ACE2 could reverse the changes in downstream gene expression. In summary, PDE could induce NAFLD in adult male rat offspring. The programming mechanism included inhibition of miR-122 expression after GR activation, and dexamethasone increased hepatocyte YY1 expression; these effects resulted in ACE2-MAS1 signaling pathway inhibition, which led to increased hepatic triglyceride synthesis and decreased oxidative function. The increased triglyceride synthesis and decreased oxidative function of hepatocytes caused by low miR-122 expression due to dexamethasone could continue postnatally, eventually leading to NAFLD in adult rat offspring.

Rats with prenatal dexamethasone exposure and postnatal high-fat diet exhibited insulin resistance, and spatial learning and memory impairment: effects of enriched environment

This study aimed to examine the combined effects of prenatal glucocorticoid exposure and a postnatal high-fat diet (HFD) on offspring brain development and metabolic disturbance. Besides, the effects of an enriched environment were assessed. Pregnant Sprague-Dawley rats were administered vehicle or dexamethasone between gestation days 14 and 21. Male offspring was then weaned onto either a standard chow or HFD. An enriched environment was implemented between postnatal days 22 and 180 in a subset of rats with prenatal dexamethasone and a postnatal HFD. Adult male offspring with prenatal exposure to dexamethasone and a postnatal HFD showed obesity, increased systolic blood pressure, peripheral and central insulin resistance, and spatial learning and memory impairment detected by Morris water maze. An enriched environment displayed beneficial effects in reducing body weight, decreasing systolic blood pressure, reducing insulin resistance, ameliorating brain molecular alterations, and alleviating spatial deficit in rats with prenatal dexamethasone and a postnatal HFD. In conclusion, adult male offspring with prenatal dexamethasone exposure and a postnatal HFD showed obesity, increased systolic blood pressure, peripheral and central insulin resistance, and spatial learning and memory impairment. In addition, an enriched environment had beneficial effects in this context.

Prenatal Glucocorticoid Exposure Results in Changes in Gene Transcription and DNA Methylation in the Female Juvenile Guinea Pig Hippocampus Across Three Generations

Synthetic glucocorticoids (sGC) are administered to women at risk for pre-term delivery, to mature the fetal lung and decrease neonatal morbidity. sGC also profoundly affect the fetal brain. The hippocampus expresses high levels of glucocorticoid (GR) and mineralocorticoid receptor (MR), and its development is affected by elevated fetal glucocorticoid levels. Antenatal sGC results in neuroendocrine and behavioral changes that persist in three generations of female guinea pig offspring of the paternal lineage. We hypothesized that antenatal sGC results in transgenerational changes in gene expression that correlate with changes in DNA methylation. We used RNASeq and capture probe bisulfite sequencing to investigate the transcriptomic and epigenomic effects of antenatal sGC exposure in the hippocampus of three generations of juvenile female offspring from the paternal lineage. Antenatal sGC exposure (F0 pregnancy) resulted in generation-specific changes in hippocampal gene transcription and DNA methylation. Significant changes in individual CpG methylation occurred in RNApol II binding regions of small non-coding RNA (snRNA) genes, which implicates alternative splicing as a mechanism involved in transgenerational transmission of the effects of antenatal sGC. This study provides novel perspectives on the mechanisms involved in transgenerational transmission and highlights the importance of human studies to determine the longer-term effects of antenatal sGC on hippocampal-related function.

Prenatal Glucocorticoid Exposure Modifies Endocrine Function and Behaviour for 3 Generations Following Maternal and Paternal Transmission

Fetal exposure to high levels of glucocorticoids programs long-term changes in the physiologic stress response and behaviours. However, it is not known whether effects manifest in subsequent generations of offspring following maternal (MT) or paternal (PT) transmission. We treated pregnant guinea pigs with three courses of saline or synthetic glucocorticoid (sGC) at a clinically relevant dose. Altered cortisol response to stress and behaviours transmitted to juvenile female and male F2 and F3 offspring from both parental lines. Behavioural effects of sGC in F1-F3 PT females associated with altered expression of genes in the prefrontal cortex and hypothalamic paraventricular nucleus (PVN). Exposure to sGC programmed large transgenerational changes in PVN gene expression, including type II diabetes, thermoregulation, and collagen formation gene networks. We demonstrate transgenerational programming to F3 following antenatal sGC. Transmission is sex- and generation-dependent, occurring through both parental lines. Paternal transmission to F3 females strongly implicates epigenetic mechanisms of transmission.

Consumers attitudes and beliefs towards the receipt of antenatal corticosteroids and use of clinical practice guidelines

BACKGROUND

Active participation of consumers in health care decision making, policy and clinical research is increasingly encouraged by governments, influential bodies and funders. Identifying the best way to achieve this is difficult due to the paucity of evidence. Consumers have mixed feelings towards clinical practice guidelines (CPG) demonstrating scepticism towards their purpose and applicability to their needs. There is no information pertaining to consumers' views and attitudes on the receipt of antenatal corticosteroids (ACS). The aim of this study was to examine the barriers and enablers to receiving ACS and use of CPG amongst consumers.

METHODS

Consumers were recruited from neonatal units across three district health boards (DHBs) in Auckland, New Zealand. Participants completed a semi-structured interview or questionnaire. The questions posed and analyses were informed by the Theoretical Domains Framework (TDF). Barriers and enablers were identified by the presence of conflicting beliefs within a domain; the frequency of beliefs; and the likely strength of the impact of a belief on use of CPG and receipt of ACS.

RESULTS

Twenty four consumers participated in the study. Six domains were identified as barriers to receipt of ACS and use of CPG. Key barriers to receipt of ACS included: difficulty retaining information conveyed, requiring further information in a variety of formats, and time constraints faced by consumers and health professionals in the provision and understanding of information to facilitate decision making. Barriers to use of CPG included: uncertainty about applicability of guideline use among consumers and scepticism about health professionals adhering too rigidly to guidelines. Enablers to receipt of ACS included: optimism toward ACS use, a strong knowledge of why ACS were administered, improved resilience in their pregnancy and confidence in their decision making following receipt of information about ACS. Enablers to use of CPG included: validation and standardisation of decision making among health professionals providing care and facilitating the best care for women and their babies.

CONCLUSIONS

Key barriers and enablers exist among consumers regarding receipt of ACS and use of CPG. These need to be addressed or modified in any intervention strategy to facilitate implementation of the ACS CPG.

What we have learned about antenatal corticosteroid regimens

Administration of antenatal corticosteroids has been standard of care for women between 24 and 34 weeks of gestation who are at risk for preterm delivery for more than 20 years longer in other parts of the world. Although the benefit of steroids in this population has been confirmed, there remain many questions including the frequency of dosing and whether it is possible to expand the gestational age criteria to women likely to deliver before 24 weeks or after 34 weeks. The MFMU Network has played a major role in answering some of these questions.

Prescribing patterns of antenatal corticosteroids in women with threatened preterm labor

OBJECTIVE

To assess the impact of cervical length (CL) measurement and fetal fibronectin testing (fFN) on the clinicians' decision to prescribe antenatal corticosteroids (ACS) to women with symptoms of preterm labor.

STUDY DESIGN

This is a secondary analysis of a prospective cohort study including women with symptoms of preterm labor and intact membranes between 24 and 34 weeks' gestation. We compared the proportion prescribed and completed ACS courses, preterm delivery within seven days and median intervals from ACS to delivery in four groups: group 1 CL<10 mm, group 2 CL 10-30 mm and positive fFN, group 3 CL 10-30 mm and negative fFN, group 4 CL>30 mm.

RESULTS

ACS were prescribed to 63/65 (97%) women in group 1, 176/192 (91%) in group 2, 111/172 women (65%) in group 3 and 55/242 (23%) in group 4. In group 1, 42 (65%) women delivered within seven days, compared to 34 (18%) in group 2, 6 (3%) in group 3 and 3 (1%) in group 4. Median intervals between ACS and delivery were 6 days (IQR 3-61 days), 44 days (IQR 17-69 days), 53 days (IQR 37-77 days) and 66 days (IQR 43-78 days) in group 1, 2, 3 and 4 respectively.

CONCLUSION

ACS were prescribed frequently to women with a CL of 10-30 mm and a negative fFN test or a CL>30 mm. There is room for improvement in the prescription of ACS in these low risk women.

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.

Different corticosteroids and regimens for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Despite the widespread use of antenatal corticosteroids to prevent respiratory distress syndrome in preterm infants, there is currently no consensus as to the type of corticosteroid to use; nor the dose, frequency, timing of use or the route of administration.

OBJECTIVES

To assess the effects of different corticosteroid regimens for women at risk of preterm birth.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 February 2013).

SELECTION CRITERIA

All identified published and unpublished randomised controlled trials or quasi-randomised control trials comparing any two corticosteroids (dexamethasone or betamethasone or any other corticosteroid that can cross the placenta), comparing different dose regimens (including frequency and timing of administration) in women at risk of preterm birth were included. We planned to exclude cross-over trials and cluster-randomised trials. We included studies published as abstracts only along with studies published as full-text manuscripts

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies. Data were checked for accuracy.

MAIN RESULTS

For this update, 12 trials (1557 women and 1661 infants) were included. Dexamethasone was associated with a reduced risk of intraventricular haemorrhage (IVH) compared with betamethasone (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.21 to 0.92; four trials, 549 infants). No statistically significant differences were seen for other primary outcomes: respiratory distress syndrome (RDS) (RR 1.06, 95% CI 0.88 to 1.27; five trials, 753 infants) and perinatal death (neonatal death RR 1.41, 95% CI 0.54 to 3.67; four trials, 596 infants). Similarly, very few differences were seen for secondary outcomes such as rate of admission to the neonatal intensive care unit (NICU) although in one trial, those infants exposed to dexamethasone, compared with betamethasone, had a significantly shorter length of NICU admission (mean difference (MD) -0.91 days, 95% CI -1.77 to -0.05; 70 infants). Results for biophysical parameters were inconsistent, but mostly no clinically important differences were seen.Compared with intramuscular dexamethasone, oral dexamethasone significantly increased the incidence of neonatal sepsis (RR 8.48, 95% CI 1.11 to 64.93) in one trial of 183 infants. No statistically significant differences were seen for other outcomes reported.Apart from a reduced maternal postpartum length of stay for women who received betamethasone at 12-hourly intervals compared to 24-hourly intervals in one trial (MD -0.73 days, 95% CI -1.28 to -0.18; 215 women), no differences in maternal or neonatal outcomes were seen between the different betamethasone dosing intervals assessed. Similarly, no significant differences in outcomes were seen when betamethasone acetate and phosphate was compared with betamethasone phosphate in one trial.

AUTHORS' CONCLUSIONS

It remains unclear whether one corticosteroid (or one particular regimen) has advantages over another.Dexamethasone may have some benefits compared with betamethasone such as less IVH, and a shorter length of stay in the NICU. The intramuscular route may have advantages over the oral route for dexamethasone, as identified in one small trial. Apart from the suggestion that 12-hour dosing may be as effective as 24-hour dosing of betamethasone based on one small trial, few other conclusions about optimal antenatal corticosteroid regimens were able to be made. No long-term results were available except for a small subgroup of 18 month old children in one trial. Trials comparing the commonly used corticosteroids are most urgently needed, as are trials of dosages and other variations in treatment regimens.

Australasian randomised trial to evaluate the role of maternal intramuscular dexamethasone versus betamethasone prior to preterm birth to increase survival free of childhood neurosensory disability (A*STEROID): study protocol

BACKGROUND

Both dexamethasone and betamethasone, given to women at risk of preterm birth, substantially improve short-term neonatal health, increase the chance of the baby being discharged home alive, and reduce childhood neurosensory disability, remaining safe into adulthood. However, it is unclear which corticosteroid is of greater benefit to mother and child.This study aims to determine whether giving dexamethasone to women at risk of preterm birth at less than 34 weeks' gestation increases the chance of their children surviving free of neurosensory disability at two years' corrected age, compared with betamethasone.

METHODS/DESIGN

Design randomised, multicentre, placebo controlled trial.Inclusion criteria women at risk of preterm birth at less than 34 weeks' gestation with a singleton or twin pregnancy and no contraindications to the use of antenatal corticosteroids and who give informed consent.Trial entry & randomisation at telephone randomisation eligible women will be randomly allocated to either the dexamethasone group or the betamethasone group, allocated a study number and corresponding treatment pack.Study groups women in the dexamethasone group will be administered two syringes of 12 mg dexamethasone (dexamethasone sodium phosphate) and women in the betamethasone group will be administered two syringes of 11.4 mg betamethasone (Celestone Chronodose). Both study groups consist of intramuscular treatments 24 hours apart.Primary study outcome death or any neurosensory disability measured in children at two years' corrected age.Sample size a sample size of 1449 children is required to detect either a decrease in death or any neurosensory disability from 27.0% to 20.1% with dexamethasone compared with betamethasone, or an increase from 27.0% to 34.5% (two-sided alpha 0.05, 80% power, 5% loss to follow up, design effect 1.2).

DISCUSSION

This study will provide high-level evidence of direct relevance for clinical practice. If one drug clearly results in significantly fewer deaths and fewer disabled children then it should be used consistently in women at risk of preterm birth and would be of great importance to women at risk of preterm birth, their children, health services and communities.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

ACTRN12608000631303.

Antenatal steroids and the IUGR fetus: are exposure and physiological effects on the lung and cardiovascular system the same as in normally grown fetuses?

Glucocorticoids are administered to pregnant women at risk of preterm labour to promote fetal lung surfactant maturation. Intrauterine growth restriction (IUGR) is associated with an increased risk of preterm labour. Hence, IUGR babies may be exposed to antenatal glucocorticoids. The ability of the placenta or blood brain barrier to remove glucocorticoids from the fetal compartment or the brain is compromised in the IUGR fetus, which may have implications for lung, brain, and heart development. There is conflicting evidence on the effect of exogenous glucocorticoids on surfactant protein expression in different animal models of IUGR. Furthermore, the IUGR fetus undergoes significant cardiovascular adaptations, including altered blood pressure regulation, which is in conflict with glucocorticoid-induced alterations in blood pressure and flow. Hence, antenatal glucocorticoid therapy in the IUGR fetus may compromise regulation of cardiovascular development. The role of cortisol in cardiomyocyte development is not clear with conflicting evidence in different species and models of IUGR. Further studies are required to study the effects of antenatal glucocorticoids on lung, brain, and heart development in the IUGR fetus. Of specific interest are the aetiology of IUGR and the resultant degree, duration, and severity of hypoxemia.

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.

Prenatal synthetic glucocorticoid treatment changes DNA methylation states in male organ systems: multigenerational effects

Prenatal synthetic glucocorticoids (sGC) are administered to pregnant women at risk of delivering preterm, approximately 10% of all pregnancies. Animal studies have demonstrated that offspring exposed to elevated glucocorticoids, either by administration of sGC or as a result of maternal stress, are at increased risk of developing behavioral, endocrine, and metabolic abnormalities. DNA methylation is a covalent modification of DNA that plays a critical role in long-lasting programming of gene expression. Here we tested the hypothesis that prenatal sGC treatment has both acute and long-term effects on DNA methylation states in the fetus and offspring and that these effects extend into a subsequent generation. Pregnant guinea pigs were treated with sGC in late gestation, and methylation analysis by luminometric methylation assay was undertaken in organs from fetuses and offspring across two generations. Expression of genes that modify the epigenetic state were measured by quantitative real-time PCR. Results indicate that there are organ-specific developmental trajectories of methylation in the fetus and newborn. Furthermore, these trajectories are substantially modified by intrauterine exposure to sGC. These sGC-induced changes in DNA methylation remain into adulthood and are evident in the next generation. Furthermore, prenatal sGC exposure alters the expression of several genes encoding proteins that modulate the epigenetic state. Several of these changes are long lasting and are also present in the next generation. These data support the hypothesis that prenatal sGC exposure leads to broad changes in critical components of the epigenetic machinery and that these effects can pass to the next generation.

Transgenerational effects of prenatal synthetic glucocorticoids on hypothalamic-pituitary-adrenal function

Approximately 10% of pregnant women are at risk of preterm delivery and receive synthetic glucocorticoids (sGC) to promote fetal lung development. Studies have indicated that prenatal sGC therapy modifies hypothalamic-pituitary-adrenal (HPA) function in first-generation (F(1)) offspring. The objective of this study was to determine whether differences in HPA function and behavior are evident in the subsequent (F(2)) generation. Pregnant guinea pigs (F(0)) received betamethasone (BETA; 1 mg/kg) or saline on gestational d 40/41, 50/51, and 60/61. F(1) females were mated with control males to create F(2) offspring. HPA function was assessed in juvenile and adult F(2) offspring. Locomotor activity was assessed in juvenile offspring. Analysis of HPA-related gene expression was undertaken in adult hippocampi, hypothalami, and pituitaries. Locomotor activity was reduced in F(2) BETA males (P < 0.05). F(2) BETA offspring displayed blunted cortisol response to swim stress (P < 0.05). After dexamethasone challenge, F(2) BETA males and females displayed increased and decreased negative feedback, respectively. F(2) BETA females had reduced pituitary levels of proopiomelanocortin (and adrenocorticotropic hormone), and corticotropin-releasing hormone receptor mRNA and protein (P < 0.05). F(2) BETA males displayed increased hippocampal glucocorticoid receptor (P < 0.001), whereas in BETA females, hippocampal glucocorticoid receptor and mineralocorticoid receptor mRNA were decreased (P < 0.05). In conclusion, prenatal BETA treatment affects HPA function and behavior in F(2) offspring. In F(2) BETA females, pituitary function appears to be primarily affected, whereas hippocampal glucocorticoid feedback systems appear altered in both F(2) BETA males and females. These data have clinical implication given the widespread use of repeat course glucocorticoid therapy in the management of preterm labour.

Repeat prenatal corticosteroid prior to preterm birth: a systematic review and individual participant data meta-analysis for the PRECISE study group (prenatal repeat corticosteroid international IPD study group: assessing the effects using the best level of evidence) - study protocol

BACKGROUND

The aim of this individual participant data (IPD) meta-analysis is to assess whether the effects of repeat prenatal corticosteroid treatment given to women at risk of preterm birth to benefit their babies are modified in a clinically meaningful way by factors related to the women or the trial protocol.

METHODS/DESIGN

The Prenatal Repeat Corticosteroid International IPD Study Group: assessing the effects using the best level of Evidence (PRECISE) Group will conduct an IPD meta-analysis. The PRECISE International Collaborative Group was formed in 2010 and data collection commenced in 2011. Eleven trials with up to 5,000 women and 6,000 infants are eligible for the PRECISE IPD meta-analysis. The primary study outcomes for the infants will be serious neonatal outcome (defined by the PRECISE International IPD Study Group as one of death (foetal, neonatal or infant); severe respiratory disease; severe intraventricular haemorrhage (grade 3 and 4); chronic lung disease; necrotising enterocolitis; serious retinopathy of prematurity; and cystic periventricular leukomalacia); use of respiratory support (defined as mechanical ventilation or continuous positive airways pressure or other respiratory support); and birth weight (Z-scores). For the children, the primary study outcomes will be death or any neurological disability (however defined by trialists at childhood follow up and may include developmental delay or intellectual impairment (developmental quotient or intelligence quotient more than one standard deviation below the mean), cerebral palsy (abnormality of tone with motor dysfunction), blindness (for example, corrected visual acuity worse than 6/60 in the better eye) or deafness (for example, hearing loss requiring amplification or worse)). For the women, the primary outcome will be maternal sepsis (defined as chorioamnionitis; pyrexia after trial entry requiring the use of antibiotics; puerperal sepsis; intrapartum fever requiring the use of antibiotics; or postnatal pyrexia).

DISCUSSION

Data analyses are expected to commence in 2011 with results publicly available in 2012.

Dexamethasone induces fetal developmental toxicity through affecting the placental glucocorticoid barrier and depressing fetal adrenal function

This study evaluates the neuroendocrine-interference mechanism underlying dexamethasone-induced developmental toxicity. Pregnant mice were treated with various doses of dexamethasone (0, 0.5, 2.0 and 8.0mg/kg), corticosterone levels in maternal serum, mRNA expressions of maternal and fetal adrenal steroidogenic acute regulatory protein (StAR), cytochrome P450 responsible for cholesterol side chain cleavage (P450scc) and placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD-2) were measured. And the expressions of StAR and P450scc were also measured in cultured primary human fetal adrenocortical cells treated with various concentrations of dexamethasone (0, 1, 10 and 100 μmol/L) for 24h. Mice suffered from intrauterine growth retardation (IUGR) after exposure to dexamethasone. The IUGR rate was augmented to 42.9% and 95.7% in 2.0 and 8.0mg/kg dexamethasone groups, respectively (P<0.01). The level of maternal serum corticosterone in three dexamethasone groups were decreased to 31.8%, 34.8% and 32.9%, respectively (P<0.05 or P<0.01), as compared with the control. Furthermore, the mRNA expressions of maternal and fetal adrenal StAR and P450scc in 8.0mg/kg dexamethasone groups were decreased to 19.3% and 10.8%, 11.0% and 9.9% of that in the corresponding controls, respectively (P<0.05). The mRNA expressions of placental 11β-HSD-2 were dose-dependently reduced in dexamethasone groups, particularly, the mRNA decreased to 22.2% in 8.0mg/kg dexamethasone group, as compared with the control (P=0.15). No obvious changes of StAR and P450scc in vitro after dexamethasone treatment. These suggest that prenatal dexamethasone exposure induces fetal developmental toxicity. A possible underlying mechanism is that dexamethasone may affect the placental glucocorticoid barrier and depressing fetal adrenal function.

Antenatal corticosteroids for preterm birth: dose-dependent reduction in birthweight, length and head circumference

AIM

This study was undertaken to evaluate the effects of repeated courses of antenatal corticosteroids (ACS) on foetal growth.

METHODS

We studied 94 infants exposed to 2-9 courses of ACS. Mean gestational age (GA) at first exposure was 29 and at birth 34 weeks. Exposure data were retrieved from case record files. Information on potential confounders was collected from the Swedish Medical Birth Registry. Standard deviation scores (SDS) for birthweight (BW), birthlength (BL) and head circumference (HC) were calculated and considered as outcomes.

RESULTS

GA at start of ACS did not affect outcome. BW-SDS, BL-SDS and HC-SDS were -0.21, -0.19 and +0.25 in infants exposed to two courses, compared to -1.01, -1.04 and -0.23 in infants exposed to ≥ 4 courses of ACS (p = 0.04-0.07). In multiple regression analyses, ≥ 4 courses were associated with lower BW-SDS, BL-SDS and HC-SDS (p = 0.007-0.04) compared to SDS after 2-3 courses. The effects from ≥ 4 courses on BW and BL were comparable to reduction in birth size seen in twins and on HC to that observed after maternal smoking.

CONCLUSIONS

Multiple courses of ACS are associated with a dose-dependent decline in foetal growth, which may affect later development and health.

Prenatal synthetic glucocorticoid exposure alters hypothalamic-pituitary-adrenal regulation and pregnancy outcomes in mature female guinea pigs

Preterm delivery occurs in approximately 10% of all pregnancies. Prenatal exposure to synthetic glucocorticoids (sGCs) reduces the incidence of respiratory distress syndrome (RDS) in these babies. Therefore, administration of multiple courses of sGCs became common practice. Animal and human studies have demonstrated that multiple courses of sGCs can have long-term effects. While the majority of animal studies have been undertaken in male offspring, it is emerging that there are profound sex differences in the consequences of prenatal sGC exposure. To our knowledge, no studies have determined the effects of prenatal sGC exposure on hypothalamic-pituitary-adrenal (HPA) axis function in female offspring while accounting for reproductive cycle status, or determined if there are effects on pregnancy parameters. Pregnant guinea pigs were administered three courses of betamethasone (Beta), dexamethasone (Dex) or vehicle on gestational days 40/41, 50/51 and 60/61. In adulthood (age range: postnatal days 126-165), basal and activated HPA axis function were assessed at various stages of the reproductive cycle. The female offspring were then mated and underwent an undisturbed pregnancy. Females were killed in the luteal phase of the reproductive cycle following litter weaning, and molecular analysis undertaken. In the luteal phase, Beta-exposed females exhibited significantly lower basal salivary cortisol levels (P < 0.05). Dex-exposed females also exhibited significantly lower basal salivary cortisol levels during the luteal phase (P < 0.05), but increased basal salivary cortisol levels during the ostrous phase (P < 0.01). The Beta-exposed females exhibited increased glucocorticoid receptor (GR) mRNA expression in the CA1/2 region of the hippocampus (P < 0.05) and MC2R mRNA in the adrenal cortex (P < 0.05). The Dex-exposed animals exhibited higher hippocampal GR and mineralocorticoid receptor (MR) mRNA levels (P < 0.05). Beta-exposed females showed reduced fecundity (P < 0.05). In Dex-exposed females there was a lower male to female sex ratio. In conclusion, prenatal sGC exposure affects HPA axis activity, in a cycle-dependent manner, and long-term reproductive success. The clinical implications of the findings on endocrine function and pregnancy in females are profound and further follow-up is warranted in human cohorts. Furthermore, we have shown there are considerable difference in phenotypes between the Beta- and Dex-exposed females and the specific endocrine and maternal outcome is contingent on the specific sGCs administered during pregnancy.

Blood pressure support in extremely premature infants is affected by different courses of antenatal steroids

OBJECTIVE

To examine the effects of partial, single and multiple courses of antenatal corticosteroids (ANS) on the need for blood pressure support in extremely premature infants.

METHODS

Extremely premature infants with gestational age of 24 to 28 weeks were included in this study during a 5-year period. The main outcome measure of the study was the amount of blood pressure support during the first 3 days of life.

RESULTS

The study infants (n = 163) were divided into: infants not exposed (ANS; n = 27) and exposed to ANS (ANS; n = 136). Blood pressure support was significantly lower in ANS compared with No ANS (65% vs 96%; p = 0.003) and in single course (SANS; n = 73) and >or=2 courses (MANS; n = 34) compared with partial course of ANS (PANS; n = 29) (62%, 56% vs 86%; p = 0.03). The number of infants who received volume support and the amount of volume support were significantly lower in ANS compared with that in No ANS (p < 0.001) and in SANS and MANS compared with that in PANS (p < 0.02).

CONCLUSION

Exposure to multiple courses of ANS was as beneficial as single course of ANS in decreasing the need for blood pressure support in extremely premature infants.

Impact of perinatal corticosteroids on neuromotor development and outcome: review of the literature and new meta-analysis

Perinatal corticosteroids are like a double-edged sword. On the one hand, they reduce risk for major morbidity and even mortality; on the other hand, they modify growth and development of body systems, with short- and long-term consequences. The relationship between corticosteroids and neurodevelopmental outcome has been extensively studied in randomized controlled trials, cohort and case-control studies and meta-analyses. In this article we attempt accurately to reflect current clinical equipoise on this issue by reviewing the most recent literature and adding a new meta-analysis on the relationship between postnatal dexamethasone and cerebral palsy and neurodevelopmental impairment.

Should we be prescribing repeated courses of antenatal corticosteroids?

Single-course treatment with antenatal corticosteroids has been shown to enhance fetal maturation before preterm birth and to improve outcomes for the preterm infant. Based on this success, practitioners expanded use of the treatment to repeated courses of antenatal corticosteroids ahead of evidence demonstrating benefit and excluding harm. Experiments with animals and cohort studies have provided a body of evidence suggesting that repeated doses may further improve lung maturation but may be accompanied by deleterious effects on the developing brain and other organs. Randomised controlled trials of repeated treatments to date have provided mixed evidence but in general may indicate a small benefit in terms of postnatal lung function, but this is accompanied by restricted growth which may include the brain. In view of the well-established role that corticosteroids are known to play in brain development, and the marginal difference that repeated courses may make to outcome in the context of modern neonatal care, antenatal corticosteroid treatments should be restricted to single-course treatment.

[Repeat doses of prenatal corticosteroids for women at risk of preterm birth: a difficult consensus]

A single course of antenatal corticosteroids in women at risk of preterm delivery reduces the risk of neonatal mortality and morbidity. Recent experimental and clinical studies have stated early, medium and long term consequences of single or repeated courses of antenatal corticosteroids. Betamethasone and dexamethasone are the two molecules usually used. Benefits are observed until the first 24 hours after the first injection. Single-course corticosteroids are not effective in babies born more than 7 days after initial treatment. Benefits of corticosteroids were evaluated between 22 and 35 weeks of gestation. Antenatal exposure to single-course betamethasone might result in disruption on glucose metabolism in adult offspring. Weekly courses of prenatal corticosteroids therapy are not recommended. Repeat prenatal corticosteroids given to women at continuing risk of preterm birth 7 or more days after an initial course reduced the inherent respiratory complications of prematurity and improved health outcomes of preterm infants. However, adverse outcomes have been reported concerning cognitive development. Although repeat course may have short term benefits, whether there are effects on health into childhood and beyond must await later assessment. Long term data are needed to recommend repeated courses.

Antenatal corticosteroid treatment: what's happened since Drs Liggins and Howie?

In 1972, Drs Liggins and Howie published a landmark article demonstrating that antenatal corticosteroids significantly reduced the frequency of respiratory distress syndrome and neonatal mortality. A single course of antenatal corticosteroids has become standard of care for pregnant women at risk for preterm birth. Recent studies have suggested weekly courses of antenatal corticosteroids result in improvement in the acute neonatal condition but have not supported long-term benefit. With greater understanding of the beneficial actions of corticosteroids on the fetal lung, the role for this therapy may expand. In addition to increased surfactant production and secretion, corticosteroids facilitate clearance of fetal lung fluid, as well as other maturational effects. Thus, antenatal corticosteroids may prove valuable in the late preterm period and before elective cesarean delivery at term.

Effects of prenatal dexamethasone treatment on physical growth, pituitary-adrenal hormones, and performance of motor, motivational, and cognitive tasks in juvenile and adolescent common marmoset monkeys

Synthetic glucocorticoids such as dexamethasone (DEX) are commonly used to prevent respiratory distress syndrome in preterm infants, but there is emerging evidence of subsequent neurobehavioral abnormalities (e.g. problems with inattention/hyperactivity). In the present study, we exposed pregnant common marmosets (Callithrix jacchus, primates) to daily repeated DEX (5 mg/kg by mouth) during either early (d 42-48) or late (d 90-96) pregnancy (gestation period of 144 days). Relative to control, and with a longitudinal design, we investigated DEX effects in offspring in terms of physical growth, plasma ACTH and cortisol titers, social and maintenance behaviors, skilled motor reaching, motivation for palatable reward, and learning between infancy and adolescence. Early DEX resulted in reduced sociability in infants and increased motivation for palatable reward in adolescents. Late DEX resulted in a mild transient increase in knee-heel length in infants and enhanced reversal learning of stimulus-reward association in adolescents. There was no effect of either early or late DEX on basal plasma ACTH or cortisol titers. Both treatments resulted in impaired skilled motor reaching in juveniles, which attenuated in early DEX but persisted in late DEX across test sessions. The increased palatable-reward motivation and decreased social motivation observed in early DEX subjects provide experimental support for the clinical reports that prenatal glucocorticoid treatment impairs social development and predisposes to metabolic syndrome. These novel primate findings indicate that fetal glucocorticoid overexposure can lead to abnormal development of motor, affective, and cognitive behaviors. Importantly, the outcome is highly dependent upon the timing of glucocorticoid overexposure.

Current controversies in perinatal steroid therapy

Few therapies in perinatal medicine have created as much controversy as corticosteroids. Despite five decades of extensive research and practice, major areas of uncertainty remain. In this article, we review the most current evidence on both antenatal and postnatal therapy.

CONCLUSION

Overall, it is clear that we must continue to investigate the most appropriate doses of the ideal preparation in the most appropriate target populations before we can let the steroid issues rest.

Guideline for the use of antenatal corticosteroids for fetal maturation

The aim is to present a document, which is based on current evidence and serves as a guideline for use in clinical practice. The following questions are addressed: Is the use of antenatal corticosteroids (ACS) an effective therapy? Who are the candidates for antenatal corticosteroid therapy? Is there benefit after 34 weeks' gestation? When is the optimal time to treat? Which are the optimal steroids; what is the ideal dose and route of administration? Are there any contraindications to the administration of ACS? Are antenatal corticosteroids indicated in women with premature rupture of membranes (PROM)? Is the use of ACS recommended in pregnancies complicated by maternal diabetes mellitus? Should the treatment with corticosteroids be repeated?

Different corticosteroids and regimens for accelerating fetal lung maturation for women at risk of preterm birth

BACKGROUND

Despite the widespread use of antenatal corticosteroids to prevent respiratory distress syndrome in preterm infants, there is currently no consensus as to the type of corticosteroid to use; nor the dose, frequency or timing of use or the route of administration.

OBJECTIVES

To assess the effects of different corticosteroid regimens for women at risk of preterm birth.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of antenatal corticosteroid regimens in women at risk of preterm birth.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted the data independently.

MAIN RESULTS

Ten trials (1089 women and 1161 infants) were included. Dexamethasone decreased the incidence of intraventricular haemorrhage compared with betamethasone (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.21 to 0.92; four trials, 549 infants). No statistically significant differences were seen for other primary outcomes including respiratory distress syndrome, bronchopulmonary dysplasia, severe intraventricular haemorrhage, periventricular leukomalacia, perinatal death, or mean birthweight. Results for biophysical parameters were inconsistent, but mostly no important differences were seen for these, or any other secondary outcome except for neonatal intensive care unit (NICU) admission. In one trial of 105 infants, significantly more infants in the dexamethasone group were admitted to NICU compared with the betamethasone group (RR 3.83, 95% CI 1.24 to 11.87).Oral dexamethasone compared with intramuscular dexamethasone increased the incidence of neonatal sepsis (RR 8.48, 95% CI 1.11 to 64.93) in one trial of 183 infants. No statistically significant differences were seen for other outcomes reported.In one small trial of 69 infants comparing betamethasone acetate and phosphate with betamethasone phosphate no differences were seen for any of the outcomes reported.

AUTHORS' CONCLUSIONS

Dexamethasone may have some benefits compared with betamethasone such as less intraventricular haemorrhage, although perhaps a higher rate of NICU admission (seen in only one trial). Apart from a suggestion from another small trial that the intramuscular route may have advantages over an oral route for dexamethasone, few other conclusions about optimal antenatal corticosteroid regimens were able to be made. Trials of commonly used corticosteroids are most urgently needed, followed by trials of dosages and other variations in regimens.

Bone metabolism in pregnant women exposed to single compared with multiple courses of corticosteroids

OBJECTIVE

To compare markers of maternal bone metabolism between women who received a single compared with multiple courses of antenatal corticosteroids.

METHODS

This is an analysis of serum samples from a previously reported randomized, placebo-controlled, multicenter trial. Women at risk for preterm delivery after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone (active) or placebo. Serum levels of carboxy terminal propeptide of type I procollagen (PICP) and cross-linked carboxy terminal telopeptide of type I collagen (ICTP) were measured to assess the rate of bone formation and resorption, respectively, at three time points. The placebo group (n=93) was compared with the active group, receiving four or more courses of betamethasone (n=112).

RESULTS

There were significant (P<.001) increases in PICP and ICTP between baseline and delivery in both groups. Cross-linked carboxy terminal telopeptide of type I collagen, but not PICP, was lower with corticosteroid exposure immediately before administration of the fourth study course (P<.001). No significant differences in PICP and ICTP were seen between groups at delivery.

CONCLUSION

Increasing levels of PICP and ICTP with advancing gestation are consistent with physiologic changes in maternal bone metabolism. Multiple courses of corticosteroids for fetal maturation are not associated with persistent or cumulative effects on maternal bone metabolism as measured by PICP and ICTP.

LEVEL OF EVIDENCE

II.

Fetal mechanisms in neurodevelopmental disorders

Normal development of the central nervous system depends on complex, dynamic mechanisms with multiple spatial and temporal components during gestation. Neurodevelopmental disorders may originate during fetal life from genetic as well as intrauterine and extrauterine factors that affect the fetal-maternal environment. Fetal neurodevelopment depends on cell programs, developmental trajectories, synaptic plasticity, and oligodendrocyte maturation, which are variously modifiable by factors such as stress and endocrine disruption, exposure to pesticides such as chlorpyrifos and to drugs such as terbutaline, maternal teratogenic alleles, and premature birth. Current research illustrates how altered fetal mechanisms may affect long-term physiological and behavioral functions of the central nervous system more significantly than they affect its form, and these effects may be transgenerational. This research emphasizes the diversity of such prenatal mechanisms and the need to expand our understanding of how, when altered, they may lead to disordered development, the signs of which may not appear until long after birth.

Outcomes at 2 years of age after repeat doses of antenatal corticosteroids

BACKGROUND

We previously reported the results of a randomized, controlled trial showing that repeat doses of antenatal corticosteroids reduced the risk of respiratory distress syndrome and serious neonatal morbidity. However, data have not been available regarding longer-term effects of this treatment.

METHODS

Women who had received an initial course of corticosteroid treatment 7 or more days previously were randomly assigned to receive an intramuscular injection of corticosteroid (11.4 mg of betamethasone) or saline placebo; the dose was repeated weekly if the mother was still considered to be at risk for preterm delivery and the duration of gestation was less than 32 weeks. We assessed survival free of major neurosensory disability and body size of the children at 2 years of corrected age.

RESULTS

Of the 1085 children who were alive at 2 years of age, 1047 (96.5%) were seen for assessment (521 exposed to repeat-corticosteroid treatment and 526 exposed to placebo). The rate of survival free of major disability was similar in the repeat-corticosteroid and placebo groups (84.4% and 81.0%, respectively; adjusted relative risk, 1.04, 95% confidence interval, 0.98 to 1.10; adjusted P=0.20). There were no significant differences between the groups in body size, blood pressure, use of health services, respiratory morbidity, or child behavior scores, although children exposed to repeat doses of corticosteroids were more likely than those exposed to placebo to warrant assessment for attention problems (P=0.04).

CONCLUSIONS

Administration of repeat doses of antenatal corticosteroids reduces neonatal morbidity without changing either survival free of major neurosensory disability or body size at 2 years of age. (Current Controlled Trials number, ISRCTN48656428 [controlled-trials.com].).

Long-term outcomes after repeat doses of antenatal corticosteroids

BACKGROUND

Previous trials have shown that repeat courses of antenatal corticosteroids improve some neonatal outcomes in preterm infants but reduce birth weight and increase the risk of intrauterine growth restriction. We report long-term follow-up results of children enrolled in a randomized trial comparing single and repeat courses of antenatal corticosteroids.

METHODS

Women at 23 through 31 weeks of gestation who remained pregnant 7 days after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone, consisting of 12 mg given intramuscularly and repeated once at 24 hours, or an identical-appearing placebo. We studied the children who were born after these treatments when they were between 2 and 3 years of corrected age. Prespecified outcomes included scores on the Bayley Scales of Infant Development, anthropometric measurements, and the presence of cerebral palsy.

RESULTS

A total of 556 infants were available for follow-up; 486 children (87.4%) underwent physical examination and 465 (83.6%) underwent Bayley testing at a mean (+/-SD) corrected age of 29.3+/-4.6 months. There were no significant differences in Bayley results or anthropometric measurements. Six children (2.9% of pregnancies) in the repeat-corticosteroid group had cerebral palsy as compared with one child (0.5% of pregnancies) in the placebo group (relative risk, 5.7; 95% confidence interval, 0.7 to 46.7; P=0.12).

CONCLUSIONS

Children who had been exposed to repeat as compared with single courses of antenatal corticosteroids did not differ significantly in physical or neurocognitive measures. Although the difference was not statistically significant, the higher rate of cerebral palsy among children who had been exposed to repeat doses of corticosteroids is of concern and warrants further study. (ClinicalTrials.gov number, NCT00015002 [ClinicalTrials.gov].).

Mechanisms underlying the role of glucocorticoids in the early life programming of adult disease

Compelling epidemiological evidence suggests that exposure to an adverse intrauterine environment, manifested by low-birth weight, is associated with cardiometabolic and behavioural disorders in adulthood. These observations have led to the concept of ‘fetal programming’. The molecular mechanisms that underlie this relationship remain unclear, but are being extensively investigated using a number of experimental models. One major hypothesis for early life physiological programming implicates fetal overexposure to stress (glucocorticoid) hormones. Several animal studies have shown that prenatal glucocorticoid excess, either from endogenous overproduction with maternal stress or through exogenous administration to the mother or fetus, reduces birth weight and causes lifelong hypertension, hyperglycaemia and behavioural abnormality in the offspring. Intriguingly, these effects are transmitted across generations without further exposure to glucocorticoids, which suggests an epigenetic mechanism. These animal observations could have huge implications if extrapolated to humans, where glucocorticoids have extensive therapeutic use in obstetric and neonatal practice.

Fetal programming of hypothalamic-pituitary-adrenal (HPA) axis function and behavior by synthetic glucocorticoids

Reduced fetal growth has been closely associated with an increased risk for the development of chronic disease in later life. Accumulating evidence indicates that fetal exposure to excess glucocorticoids represents a critical mechanism underlying this association. Approximately 7% of pregnant women are at risk of preterm delivery and these women are routinely treated with synthetic glucocorticoids (sGC) between 24 and 34 of weeks gestation to improve neonatal outcome. Animal studies have demonstrated that maternally administered sGC crosses the placenta, affecting fetal hypothalamic-pituitary-adrenal (HPA) development, resulting in changes in HPA axis function that persist throughout life. These changes appear to be modulated at the level of glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) in the brain and pituitary. As the HPA axis interacts with many other physiological pathways, the changes in endocrine function are also sex-specific and age-dependent. Alterations in behavior, particularly locomotion, in animals exposed to sGC in utero have also been demonstrated. Consistent with the finding in animal models, emerging human data are indicating attention deficit-hyperactivity disorder (ADHD)-like symptoms in children exposed to repeated courses of sGC in utero. This behavioral phenotype is likely linked to alterations in dopamine (DA) signaling, suggesting that sGC are able to permanently modify or 'program' this system. Finally, it is emerging that changes in HPA axis function and behavior following antenatal exposure to sGC are transgenerational and likely involve epigenetic mechanisms. A comprehensive understanding of the acute and long-term impact of sGC exposure in utero is necessary to begin to develop recommendations and treatment options for pregnant women at risk of preterm delivery.

Repeat doses of antenatal steroids and hypothalamic-pituitary-adrenal axis (HPA) function

OBJECTIVE

This study was undertaken to compare the effects of exposure to repeated courses of antenatal steroids with those of a single course on hypothalamic-pituitary-adrenal axis function.

STUDY DESIGN

Women at risk of premature delivery were assessed for entry into a randomized controlled trial of repeated courses of corticosteroids (ACTORDS). If a woman declined the randomized trial then consent was sought for collection of observational data. Baseline bloods for cortisol and adrenocorticotropic hormone levels were collected and in a subset of infants a metyrapone test performed.

RESULTS

In the 86 studied infants, cortisol and adrenocorticotropic hormone levels did not differ between those exposed to single and repeated courses of antenatal steroids (P = .53 and P = .15, respectively). Although cortisol levels fell in response to metyrapone (P = .03) this response was not different between the single and repeated course groups (P = .46).

CONCLUSION

Repeated courses of antenatal steroids do not cause important hypothalamic-pituitary-adrenal axis suppression in the neonate.

Dexamethasone treatment differentially affects the oxidative energy metabolism of rat brain mitochondria in developing and adult animals

We studied the effect of repeated exposure to dexamethasone (Dex) treatment on rat brain mitochondrial oxidative energy metabolism in developing rats at different postnatal ages, i.e. 2-5 week and in adults. The animals were injected with a dose of 2 mg of Dex/kg body weight at around 7:00 a.m. for three alternative days prior to the day of sacrifice; the control group animals received saline vehicle. We measured rates of respiration with different substrates, viz. glutamate, pyruvate+malate, succinate and ascorbate+TMPD; the contents of individual cytochromes and the dehydrogenases and ATPase activities. Dex treatment, in general, stimulated the state 3 rates of respiration rates in young animals in age-dependent and substrate-specific manner except for the 3 week group, whereas in the adults there was substantial inhibition of the respiration. The pattern of dehydrogenases activities matched with respiration rates. Dex treatment also resulted in uncoupling of the second and third site of phosphorylation in 3-week-old animals and in the adults. The contents of cytochrome aa3, b and ATPase activities decreased significantly after Dex treatment in all the age groups. The results thus emphasize that exposure to repeated Dex treatment can significantly influence the oxidative energy metabolism of brain mitochondria in young growing animals as well as in adults.

The impact of gestational stress and prenatal growth on emotional problems in offspring: a review

OBJECTIVE

Events occurring very early in life, even prenatally, may have long-term effects on future health and behaviour. The influence of poor foetal growth and gestational stress in the mother on the risk of emotional problems in offspring was reviewed.

METHOD

A selective review of the literature was undertaken.

RESULTS

Studies of preterm infants and infants born small for gestational age have shown increased levels of emotional problems across the lifespan. In general, studies examining maternal depression/anxiety during pregnancy and other indices of gestational stress have shown significant associations with emotional problems in children. The results of several studies also point to the importance of psychosocial and genetic factors in moderating associations.

CONCLUSION

Future research that focuses on identifying the mechanisms underlying these associations is needed. The moderating role of psychosocial and genetic risk factors is an important area in which future research should be directed. These findings have clinical implications for the provision of antenatal care.

Prenatal glucocorticoid exposure alters hypothalamic-pituitary-adrenal function in juvenile guinea pigs

The neurodevelopmental consequences of prenatal glucocorticoid exposure are not well-understood, particularly in species that give birth to neuroanatomically mature offspring. In the present study, we hypothesised that repeated prenatal glucocorticoid administration would alter hypothalamo-pituitary-adrenal (HPA) function in juvenile guinea pig offspring. Pregnant guinea pigs were injected with betamethasone (1 mg/kg) or vehicle on gestational days 40, 41, 50, 51, 60 and 61 (six doses). Prenatal glucocorticoid exposure abolished the pituitary-adrenal response to maternal separation in juvenile males, but had no effect in female offspring. Indeed, female offspring (vehicle and betamethasone) did not mount a significant HPA response to separation at 10 days of age. Although there were no effects of prenatal glucocorticoid exposure on hippocampal or hypothalamic corticosteroid receptor expression or corticotrophin-releasing factor (CRF) mRNA, there were significant effects in the pituitary and adrenal; again males were more affected than females. Prenatal glucocorticoid exposure increased pituitary pro-opiomelanocortin and CRF receptor mRNA, and markedly decreased adrenocortical CYP17 mRNA. In conclusion, repeated prenatal glucocorticoid exposure has profound influences on HPA function and regulation in the juvenile guinea pig, and this involves altered regulation at the level of the pituitary and adrenal cortex. Furthermore, juvenile males appear to be more vulnerable to the effects of prenatal glucocorticoid exposure than females.

Prenatal glucocorticoid exposure affects learning and vulnerability of cholinergic neurons

Prenatal treatment with synthetic glucocorticoids is commonly used as a treatment for women at risk of preterm delivery. However, little is known about the life-long consequences of these treatments on the fetus. In the present study, we evaluated cognitive function as well as susceptibility of cholinergic neurons to (192)IgG-saporin immunolesion in adult rats after prenatal glucocorticoid treatment. Morris water maze results revealed a significant difference in learning and memory function in adult rats that were prenatally exposed to dexamethasone, and further cognitive deficits after (192)IgG-saporin exposure. Choline acetyl transferase activity was decreased in the cortex of dexamethasone-treated rats compared with controls. In addition, rats prenatally exposed to either dexa, or betamethasone revealed a dramatic decrease in choline acetyl transferase activity compared to control rats after (192)IgG-saporin lesion. We report behavioral and biochemical evidence for altered cognitive function and increased susceptibility of cholinergic neurons to (192)IgG-saporin in adult rats after prenatal glucocorticoid treatment. Taken together, these results suggest that prenatal treatment with dexamethasone could affect cognitive functions and render cholinergic neurons more vulnerable to challenges later in life.

Repeated maternal glucocorticoid treatment affects activity and hippocampal NMDA receptor expression in juvenile guinea pigs

The behavioural consequences of prenatal glucocorticoid exposure are not well understood, though emerging studies in humans indicate hyperactivity and altered cognitive development can occur. Further, recent reports indicate that N-methyl-d-aspartate receptors (NMDARs) may mediate the development of postnatal stress behaviours. We hypothesized that prenatal betamethasone (Beta) administration would alter behaviour and the expression of hippocampal NMDAR subunits NR1, NR2A and NR2B in juvenile guinea pig offspring. We found that repeated maternal Beta (1 mg kg(-1)) treatment on gestational days (gd) 40/41, 50/51 and 60/61 (term approximately 70 days) had no significant effect on birthweight or early growth. However, Beta produced sex-specific effects on open-field activity and hippocampal NMDAR subunit expression compared with controls. Female Beta offspring exhibited significantly increased locomotor activity while there was no effect in Beta males. Beta males exhibited a tendency for decreased anxiety-like behaviour. With respect to NMDAR subunit expression, Beta-exposed females exhibited significantly reduced NR1 mRNA in CA1/2 and CA3 subfields of the hippocampus; there were no effects in Beta males. In conclusion, repeated maternal treatment with Beta, in a similar regimen to that administered to pregnant women at risk of delivering preterm, has profound consequences on behaviour and development of crucial neurotransmitter systems in postnatal life.

Glucocorticoids and serotonin alter glucocorticoid receptor mRNA levels in fetal guinea-pig hippocampal neurons, in vitro

The hypothalamic-pituitary-adrenal (HPA) axis is susceptible to programming during fetal life. Such programming occurs, at least partially, at the level of the hippocampus. The hippocampus plays a central role in regulation of the HPA axis and release of endogenous glucocorticoids, via mediation of glucocorticoid negative feedback. Fetal exposure to synthetic glucocorticoids can permanently alter glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) levels within the hippocampus, and serotonin is thought to be involved in this process. In the present study, we hypothesised that dexamethasone, cortisol and serotonin exposure would modify GR mRNA expression within fetal guinea-pig hippocampal cultures. Cultures were derived from 40-day-old guinea-pig fetuses, and were exposed to 0, 1, 10 and 100 nM dexamethasone, cortisol or serotonin for 4 days. Expression of GR and MR mRNA was examined by in situ hybridisation followed by high-resolution silver emulsion autoradiography. Four-day exposure to dexamethasone (P < 0.05; 100 nM) or cortisol (P = 0.08; 100 nM) downregulated the expression of GR mRNA within neurons. There was no change in the expression of MR mRNA levels following cortisol treatment. Exposure to serotonin (100 nM) significantly increased GR mRNA levels in hippocampal neurons. We conclude that synthetic and endogenous glucocorticoids, as well as serotonin, can influence GR expression during hippocampal development and in this way may act to permanently programme HPA function.