Antenatal corticosteroids: is more better?

Prenatal corticosteroids modify glutamatergic and GABAergic synapse genomic fabric: insights from a novel animal model of infantile spasms

Prenatal exposure to corticosteroids has long-term postnatal somatic and neurodevelopmental consequences. Animal studies indicate that corticosteroid exposure-associated alterations in the nervous system include hypothalamic function. Infants with infantile spasms, a devastating epileptic syndrome of infancy with characteristic spastic seizures, chaotic irregular waves on interictal electroencephalogram (hypsarhythmia) and mental deterioration, have decreased concentrations of adrenocorticotrophic hormone (ACTH) and cortisol in cerebrospinal fluid, strongly suggesting hypothalamic dysfunction. We have exploited this feature to develop a model of human infantile spasms by using repeated prenatal exposure to betamethasone and a postnatal trigger of developmentally relevant spasms with NMDA. The spasms triggered in prenatally primed rats are more severe compared to prenatally saline-injected ones and respond to ACTH, a treatment of choice for infantile spasms in humans. Using autoradiography and immunohistochemistry, we have identified a link between the spasms in our model and the hypothalamus, especially the arcuate nucleus. Transcriptomic analysis of the arcuate nucleus after prenatal priming with betamethasone but before trigger of spasms indicates that prenatal betamethasone exposure down-regulates genes encoding several important proteins participating in glutamatergic and GABAergic transmission. Interestingly, there were significant sex-specific alterations after prenatal betamethasone in synapse-related gene expression but no such sex differences were found in prenatally saline-injected controls. A pairwise relevance analysis revealed that, although the synapse gene expression in controls was independent of sex, these genes form topologically distinct gene fabrics in males and females and these fabrics are altered by betamethasone in a sex-specific manner. These findings may explain the sex differences with respect to both normal behaviour and the occurrence and severity of infantile spasms. Changes in transcript expression and their coordination may contribute to a molecular substrate of permanent neurodevelopmental changes (including infantile spasms) found after prenatal exposure to corticosteroids.

Bone development of suckling piglets after prenatal, neonatal or perinatal treatment with dexamethasone

In mammals, the release from growth-inhibiting conditions results in catch-up growth. To investigate animal evidence for whether prenatal dexamethasone (DEX) treatment leads to the development of growth restriction especially reduced mineralization of skeleton, and release from it leads to the phenomenon of catch-up, piglets were prenatally exposed to DEX (3.0 mg/sow per day(-2)) during the last 24 days of prenatal life and tested further in two different ways: discontinued at birth and continued administration of DEX (0.5 mg/kg day(-2)) to piglets through 30 days of neonatal life. Using dual energy X-ray absorptiometry methods, bone mineral density (BMD) and bone mineral content (BMC) were measured. The three-point bending test was applied to determine the mechanical properties of the bones. Furthermore, geometric properties of the bones were assessed. Serum concentration of osteocalcin (OC) was determined. Histomorphological analysis of the ribs was also performed. The consequences of neonate DEX treatment and in utero DEX exposure were reflected in a dramatic decrease of BMD, BMC and blood serum OC concentration and geometric parameters of piglets' bones. Prenatal action of DEX during the last 24 days of pregnancy resulted in continued neonatal modification of bone tissues, thus diminishing bone quality, and negatively influenced structural development and mechanical properties, finally increasing the risk of fractures of ribs and limb bones. Prenatal DEX treatment limited to the last 24 days of foetal life did not reduce the term birth weight and the growth of suckling piglets followed up to 30 days of neonatal life, and catch-up in bone mineralization did not occur.

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.

Composite outcomes in randomized clinical trials: arguments for and against

Composite outcomes that combine a number of individual outcomes (such as types of morbidity) are frequently used as primary outcomes in obstetrical trials. The main argument for their use is to ensure that trials can answer important clinical questions in a timely fashion, without needing huge sample sizes. Arguments against their use are that composite outcomes may be difficult to use and interpret, leading to errors in sample size estimation, possible contradictory trial results, and difficulty in interpreting findings. Such problems may reduce the credibility of the research, and may impact on the implementation of findings. Composite outcomes are an attractive solution to help to overcome the problem of limited available resources for clinical trials. However, future studies should carefully consider both the advantages and disadvantages before using composite outcomes. Rigorous development and reporting of composite outcomes is essential if the research is to be useful.

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.

Neonatal respiratory distress syndrome after repeat exposure to antenatal corticosteroids: a randomised controlled trial

BACKGROUND

The efficacy and safety of repeat doses of prenatal corticosteroids remains uncertain. Our aim was to establish whether repeat prenatal corticosteroids given to women at risk of preterm birth can reduce neonatal morbidity without harm.

METHODS

In this hospital-based study, 982 women who remained at risk of preterm birth at less than 32 weeks' gestation, 7 or more days after receiving a first course of prenatal corticosteroids, were randomly assigned to receive a repeat intramuscular dose of either 11.4 mg betamethasone (as Celestone Chronodose), or saline placebo. This was repeated every week the woman remained undelivered, at less than 32 weeks' gestation, and at risk of preterm birth. Primary outcomes were occurrence and severity of neonatal respiratory distress syndrome, use and duration of oxygen and mechanical ventilation, and weight, length, and head circumference at birth and hospital discharge. Statistical analyses were on an intention to treat basis. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN48656428.

FINDINGS

Fewer babies exposed to repeat corticosteroids had respiratory distress syndrome (33%vs 41%; relative risk 0.82, 95% CI 0.71-0.95, p=0.01) and fewer had severe lung disease (12%vs 20%; relative risk 0.60, 95% CI 0.46-0.79, p=0.0003) than those in the placebo group. In keeping with these benefits, babies exposed to repeat corticosteroids needed less oxygen therapy (p=0.03), and shorter duration of mechanical ventilation (p=0.01). Mean weight, length, and head circumference at birth and hospital discharge did not differ between treatment groups. Z-scores for weight (p=0.04) and head circumference (p=0.03) at birth were lower in the babies who received repeat corticosteroids although at the time of hospital discharge Z-scores did not differ between treatment groups (p=0.29 for weight, p=0.48 for head circumference).

INTERPRETATION

Exposure to repeat doses of antenatal corticosteroids reduces neonatal morbidity. Pending long-term outcome results, the short-term benefits for the babies in our study support the use of repeat doses of corticosteroids in women who remain at risk of very preterm birth 7 or more days after an initial course.

The effects of repeated corticosteroid administration on the neurogenesis in the neonatal rat

OBJECTIVE

The purpose of this study is to clarify the effects on the brain including neurogenesis pretreated with repeated doses of dexamethasone in the neonatal rat.

STUDY DESIGN

The 4-day-old Sprague Dawley rats were pretreated with 4 different regimens, namely, single administration of dexamethasone, 2-dose administration, 3-dose administration, and saline administration as a control. Concurrently, bromodeoxyuridine (BrdU), which was incorporated into the dividing cells, was administered. We examined body weight, brain weight, and the number of BrdU-labeled cells in the subventricular zone (SVZ), the subgranular zone (SGZ), and the cortex.

RESULTS

Both the body and brain weight of the rats pretreated with dexamethasone were significantly decreased compared with those given saline. Quantitative analysis of BrdU-labeled cells revealed the significant dose-dependent decreases in the SVZ, the SGZ, and the cortex with the dexamethasone treatment.

CONCLUSION

We concluded that the decreases in neurogenesis caused by repeated antenatal corticosteroid therapy might result in the adverse effects on the size of the head at birth.

Effects into adulthood of single or repeated antenatal corticosteroids in sheep

OBJECTIVE

To determine effects of maternal or fetal injections of betamethasone on postnatal growth and arterial pressure.

STUDY DESIGN

We measured body weight, arterial pressure, and heart rate serially in sheep born after single or repeated maternal or fetal betamethasone injections. At approximately 3.5 years, organ weights were measured.

RESULTS

Repeated maternal betamethasone injections caused intrauterine growth restriction, and low body weight and blood pressure at 3 months. From 6 months to 3 years, body weight, blood pressure, and heart rate were not affected by treatment. At approximately 3.5 years, brain weight was reduced after single or repeated maternal betamethasone by 13% and 18%, respectively (P = .001). Fetal betamethasone reduced brain weight by 7% to 8% (P = .018). Weights of other organs were not affected by treatment. Brain weight was unrelated to body weight at approximately 3.5 years (P = .649) but was related to birth weight (P = .029).

CONCLUSION

Prenatal betamethasone does not have long-term effects on blood pressure but causes a persistent deficit in brain weight.

Epidemiology of preterm birth and neonatal outcome

In industrialized countries, 5-11% of infants are born preterm (<37 weeks' gestation), and the rate has been increasing since the early 1980s. Preterm births account for 70% of neonatal deaths and up to 75% of neonatal morbidity, and contribute to long-term neurocognitive deficits, pulmonary dysfunction and ophthalmologic disorders. In the past several decades, major progress has been made in improving the survival of extremely premature newborns, mostly attributable to timely access to effective interventions that ameliorate prematurity-associated mortality and morbidity such as antenatal administration of corticosteroids and exogenous surfactant therapy, rather than preventing preterm births. However, the societal and healthcare costs to care for survivors with severe morbidity and neurological handicaps remain substantial. Future research should concentrate on the ways to reduce long-term health sequelae and developmental handicaps among survivors of infants born preterm, as well as elucidating the mechanisms and aetiology of preterm births.

Fetal glucocorticoid exposure and hypothalamo-pituitary-adrenal (HPA) function after birth

The fetus may be exposed to increased endogenous glucocorticoid or synthetic glucocorticoid in late gestation. Indeed, 7-10% of pregnant women in Europe and North America are treated with synthetic glucocorticoid to promote lung maturation in fetuses at risk of preterm delivery. Such therapy is effective in reducing respiratory complications. However, very little is known about the mechanisms by which synthetic glucocorticoid or prenatal stress influence neurodevelopment in the human, or whether specific time windows of increased sensitivity exist. Glucocorticoids are essential for many aspects of normal brain development. However, there is growing evidence that exposure of the fetal brain to excess glucocorticoid can have lifelong effects on neuroendocrine function and behavior. We have shown that both endogenous glucocorticoid and synthetic glucocorticoid exposure has a number of rapid effects in the fetal brain in late gestation, including modification of neurotransmitter systems and transcriptional machinery. Such fetal exposure permanently alters hypothalamo-pituitary-adrenal (HPA) function in prepubertal, postpubertal, and aging offspring, in a sex-dependent manner. These effects are linked to changes in central glucocorticoid feedback machinery after birth. Prenatal glucocorticoid manipulation also leads to modification of HPA-associated behaviors, brain and organ morphology, as well as altered regulation of other endocrine systems. Permanent changes in endocrine function will have a long-term impact on health, since elevated cumulative exposure to endogenous glucocorticoid is linked to the premature onset of pathologies associated with aging.

Short-Term Outcomes in Low Birth Weight Infants Following Antenatal Exposure to Betamethasone Versus Dexamethasone

OBJECTIVE

To assess the incidence of short-term outcomes of low birth weight infants (</= 1,750 g) exposed prenatally to either dexamethasone or betamethasone.

METHODS

We retrospectively analyzed a cohort comprising 550 infants who were born alive at our center during the period January 1999 through December 2001, who weighed 1,750 g or less at birth, and who were exposed to prenatal steroid treatment. We compared brain ultrasound findings, such as intraventricular hemorrhage and cystic periventricular leukomalacia (PVL), as well as other clinical findings, including respiratory distress syndrome (RDS), necrotizing enterocolitis, retinopathy of prematurity, and bronchopulmonary dysplasia, for all premature infants whose mothers received either dexamethasone (from January 1, 1999 to June 30, 2000, n = 263) or betamethasone (July 1, 2000 to December 31, 2001, n = 287).

RESULTS

Patient characteristics (mothers and infants) were the same in both groups, with the exception of the number of steroid courses administered, the number of women with premature rupture of membranes (defined as > 24 hours), and the number of women who had received tocolysis. No significant difference was found between the 2 groups with respect to intraventricular hemorrhage and cystic PVL frequencies. No significant differences were found in the incidence of short-term outcomes examined, despite the fact that the dexamethasone group was exposed to a statistically significantly greater number of courses than the betamethasone group.

CONCLUSION

There seem to be no advantages to maternal antenatal treatment with betamethasone compared with dexamethasone in reducing the risk of PVL in low birth weight (</= 1,750 g) infants. Both drugs have the same effect on all short-term outcome parameters checked.

Antenatal corticosteroid therapy in premature infants

OBJECTIVE

The objective was to examine the effect of antenatal corticosteroid treatment on premature infants, with special attention to any possible adverse effects on neonatal outcome.

METHODS

A retrospective chart review of all singleton and multiple pregnancies delivered in our perinatal center between 1991 and 1999, who had a birth weight of < or =1,500 g and who were subsequently admitted to our neonatal intensive care unit. Three hundred and sixty-five infants were included in the study and divided into two groups. One group had a gestational age below 28 weeks (< or =196 days) and one group was 28 weeks (>196 days) onward.

RESULTS

Antenatal corticosteroid therapy reduced the duration of mechanical ventilation, the need for supplementary oxygen, and the need for exogenous surfactant in neonates born at >196 days's gestation (p<0.05). Corticosteroid treatment seemed to benefit the respiratory distress syndrome (RDS; p=0.051) in this group. There were less cases of necrotizing enterocolitis and neonatal death in the group with corticosteroid treatment (p<0.05). Before 28 weeks' gestation, all parameters that were examined (e.g., duration of mechanical ventilation, need for supplemental oxygen, need for exogenous surfactant, RDS) showed no significant differences between those pregnancies pre-treated with corticosteroids or those not treated with corticosteroids. There was no adverse effect of corticosteroids on chorioamnionitis and early onset sepsis in pregnancies with a premature rupture of the membranes. Repeated corticosteroid treatment had no effect on birth weight, but did not improve neonatal outcome either. The interval between last corticosteroid treatment and delivery had no influence on RDS. There was no effect of corticosteroids on periventricular leukomalacia and intraventricular hemorrhage. Regression analysis showed a higher risk of severe RDS in multiple gestations.

CONCLUSION

Antenatal betamethasone treatment reduces perinatal morbidity and mortality after 28 weeks' gestation. We found no adverse effects and also no benefit of repetitive corticosteroid treatment. The interval between last corticosteroid treatment and delivery did not influence the incidence of RDS. Dose, timing, and rate of antenatal corticosteroids should be reconsidered in multiple gestations.

Perinatal corticosteroids: A review of research. Part I: Antenatal administration

The premature infant may receive therapeutic glucocorticoid drugs while in utero or in the postnatal period. This article (part I of a two-part series) discusses the benefits and risks of in utero, or antenatal, corticosteroids (ACS) for the premature infant. Part II addresses the benefits and risks of postnatal corticosteroid (PCS) use. There are numerous clinical studies on the therapeutic use of these steroids for the prevention of respiratory distress syndrome and chronic lung disease in the premature infant, although research results on the efficacy of repeated steroid exposure among premature infants vary. Premature infants who are exposed to repeated courses of ACS and/or high-cumulative-dose PCS may show no neurologic side effects until later in life. Research in newborn animal models focused on the timing, duration, and amounts of ACS and PCS. Current clinical research includes examination of the neurodevelopment of infants who are therapeutically exposed to perinatal corticosteroids, to identify safer minimal dose protocols. Over the past 30 years, corticosteroids have been increasingly prescribed before and after birth. Understanding the potential treatment benefits and risks to human fetuses and neonates is vital to clinical practice. This review presents historic and pharmacokinetic information about prenatal use of corticosteroids. It also offers scientific evidence of the benefits and risks identified in animal models and clinical trials, to stimulate thought that gtiides neonatal clinical practice.

Prenatal glucocorticoid exposure alters hypothalamic-pituitary-adrenal function and blood pressure in mature male guinea pigs

Pregnant guinea pigs were treated with dexamethasone (1 mg kg(-1)) or vehicle on days 40-41, 50-51 and 60-61 of gestation, after which animals delivered normally. Adult male offspring were catheterized at 145 days of age and subjected to tests of hypothalamic-pituitary-adrenal (HPA) axis function in basal and activated states. Animals exposed to dexamethasone in utero (mat-dex) exhibited increased hippocampus-to-brain weight ratio, increased adrenal-to-body weight ratio and increased mean arterial pressure. There were no effects on gestation length, birth weight and postnatal growth. There were no overall differences in diurnal plasma adrenocorticotropic hormone (ACTH) and cortisol profiles, though there were subtle differences during the subjective afternoon between control and mat-dex offspring. A significant decrease in initial ACTH suppression was observed following dexamethasone injection in mat-dex offspring compared to control offspring. Molecular analysis revealed significantly increased MR mRNA expression in the limbic system and particularly in the dentate gyrus in mat-dex offspring. In the anterior pituitary, both pro-opiomelanocortin (POMC) and glucocorticoid receptor (GR) mRNA levels were significantly elevated in mat-dex offspring. In conclusion, (1) repeated prenatal treatment with synthetic glucocorticoid (sGC) permanently programmes organ growth, blood pressure and HPA regulation in mature male offspring and these changes involve modification of corticosteroid receptor expression in the brain and pituitary; (2) the effects of prenatal sGC exposure on HPA function appear to change as a function of age, indicating the importance of investigating HPA and cardiovascular outcome at multiple time points throughout life.

Developmental regulation of the 5-HT7 serotonin receptor and transcription factor NGFI-A in the fetal guinea-pig limbic system: influence of GCs

Fetal exposure to excess glucocorticoids (GCs) programs the developing hypothalamo-pituitary-adrenal (HPA) axis, and may predispose offspring to adult-onset disease. During development, serotonin (5-HT) influences transcription of hippocampal GR mRNA via the 5-HT7 receptor. The effect of 5-HT on GR involves the transcription factor NGFI-A. Given the developmental changes which we have previously reported in hippocampal GR mRNA expression, we hypothesized that (1) there are progressive developmental changes in 5-HT7 receptor and NGFI-A mRNA expression in the fetal guinea-pig limbic system, and (2) repeated exposure to synthetic GC treatment will significantly modify developmental expression of these genes. 5-HT7 receptor mRNA was highly expressed in the hippocampus and thalamus at gestational day (gd) 40 (term approximately 70 days), and significantly decreased (P < 0.05) with advancing gestation. Conversely, NGFI-A mRNA expression in the hippocampus and frontal cortex was almost undetectable at gd40, but was dramatically elevated (P < 0.05; 8-fold) near term. Changes in mRNA were refelected by NGFI-A protein levels. These changes were significantly correlated to hippocampal GR expression and fetal plasma cortisol concentrations. Synthetic GC treatment increased NGFI-A mRNA levels in CA1 and the cingulate cortex, but had no effect on 5-HT7 receptor expression. In conclusion our results suggest that (1) limbic 5-HT7 receptor expression is not directly linked to maturation of hippocampal GR in late gestation; (2) the up-regulation of NGFI-A expression near term is driven by glucocorticoid; and (3) premature exposure to synthetic glucocorticoid significantly increases NGFI-A-related transcriptional activity in the fetal limbic system.

Repeated courses of antenatal corticosteroids: is it justified?

The benefits of a single course of antenatal corticosteroids on neonatal outcomes are well established. There is, however, much controversy about how long this treatment should continue, and whether repeated courses should be administered if the women remain at risk for preterm delivery 7 days after the initial therapy. This review aims to discuss current evidence on the effectiveness and safety of repeated courses of antenatal corticosteroids.

Repeat prenatal corticosteroids: Who still recommends their use and why?

BACKGROUND

Repeat prenatal corticosteroids have been in common use worldwide, even though the National Institutes of Health recommends that 'Until data establish a favourable benefit-to-risk ratio, repeat courses of antenatal corticosteroids, including rescue therapy, should be reserved for patients enrolled in clinical trials.'

OBJECTIVES

To describe the current use/recommendations for the use of repeat prenatal corticosteroids by obstetricians and neonatologists and to examine the sources of evidence on which their practice is based.

DESIGN

Postal questionnaire.

POPULATION

All Trainees, Members and Fellows of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and neonatologists in Australia and New Zealand.

METHODS

The questionnaire was mailed to obstetricians and neonatologists in August-September 2001.

MAIN OUTCOME MEASURES

Practitioner use/recommendations for the use of repeat prenatal corticosteroids and the sources of evidence on which their practice was based.

RESULTS

Use of repeat prenatal corticosteroids was recommended by 332 (44%) obstetricians and 19 (21%) neonatologists. Obstetricians were twice as likely to recommend their use compared with neonatologists (relative risk, 2.04; 95% confidence intervals, 1.36-3.06; P < 0.001). Over half of the respondents (483, 57%) reported they had changed their use/recommendations in the previous 3 years. The sources of evidence behind these practices differed between obstetricians and neonatologists and between those practitioners who recommended the use of repeat prenatal corticosteroids and those who did not.

CONCLUSIONS

Fewer practitioners recommend repeat prenatal corticosteroids compared with previous surveys. Sources of evidence behind the practice of groups of obstetricians and neonatologists differ.

Antenatal corticosteroid therapy for fetal maturation

OBJECTIVES

To assess the benefits and risks of antenatal corticosteroid therapy for fetal maturation.

OPTIONS

To administer antenatal corticosteroids or not to women at risk of preterm birth.

OUTCOMES

Perinatal morbidity, including: respiratory distress syndrome, intraventricular hemorrhage, infection, adrenal suppression, somatic and brain growth; perinatal mortality; and maternal morbidity, including infection and adrenal suppression.

EVIDENCE

MEDLINE and PubMed searches 1996 to August 2002 for English-language articles related to antenatal corticosteroid therapy for fetal maturation, the Cochrane Library, and national statements including that of the National Institutes of Health (NIH), the American College of Obstetricians and Gynecologists, and the Royal College of Obstetricians and Gynaecologists.

VALUES

The evidence obtained was reviewed and evaluated by the Maternal-Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and recommendations were made according to guidelines developed by the Canadian Task Force on the Periodic Health Exam. BENEFITS AND HARMS: A single course of corticosteroids reduces perinatal mortality, respiratory distress syndrome, and intraventricular hemorrhage. Information regarding repeat courses of corticosteroids is limited and conflicting, with many studies being retrospective and non-randomized. Some studies suggested a reduction in respiratory distress syndrome with repeat courses, but some found increased rates of neonatal and maternal infection; fetal, neonatal, and maternal adrenal suppression; decreased fetal or neonatal somatic and brain growth; and increased perinatal mortality.

RECOMMENDATIONS

The SOGC supports the recommendations of the NIH Consensus Development Panel: 1. All pregnant women between 24 and 34 weeks' gestation who are at risk of preterm delivery within 7 days should be considered candidates for antenatal treatment with a single course of corticosteroids. (I-A) 2. Treatment should consist of two 12 mg doses of betamethasone given IM 24 hours apart, or four 6 mg doses of dexamethasone given IM 12 hours apart (I-A). There is no proof of efficacy for any other regimen. 3. Because of insufficient scientific data from randomized clinical trials regarding efficacy and safety, repeat courses of corticosteroids should not be used routinely (II-2E) but be reserved for women participating in randomized controlled trials.

VALIDATION

This Committee Opinion has been reviewed and approved by the Maternal-Fetal Medicine Committee of the SOGC and approved by SOGC Council.

Glucocorticoids, hypothalamo-pituitary-adrenal (HPA) development, and life after birth

Approximately 10% of women in North America are treated with synthetic glucocorticoid (sGC) between 24 and 32 weeks of pregnancy (term approximately 40 weeks), to promote lung maturation in fetuses at risk of preterm delivery. Such therapy is highly effective in reducing the frequency of respiratory complications, and as a result, repeated course treatment has become widespread. Nothing is known about the impact of repeated sGC treatment on neuroendocrine development in the human, or if specific time windows of increased sensitivity exist. Glucocorticoids are essential for many aspects of normal brain development. However, there is growing evidence from a number of species, that exposure of the fetal brain to excess glucocorticoid can have life-long effects on behaviour and neuroendocrine function. We have shown that exposure of fetuses to sGC in late gestation permanently alters HPA function in pre-pubertal, post-pubertal, and aging offspring, in a sex-dependent manner. These effects are linked to changes in central glucocorticoid feedback. Prenatal glucocorticoid exposure also leads to modification of HPA-associated behaviours and organ morphology, as well as altered regulation of other neuroendocrine systems. Permanent changes in HPA function will have a long-term impact on health, since elevated cumulative exposure to endogenous glucocorticoid has been linked to the premature onset of pathologies associated with aging.

Proinflammatory cytokines: a link between chorioamnionitis and fetal brain injury

OBJECTIVE

To review the etiology of impaired fetal neurodevelopment - in particular, the relationship between chorioamnionitis, cytokines, and cerebral palsy.

DATA SOURCES

A MEDLINE search was performed for all clinical and basic science studies published in the English literature from 1966 to 2002. Key words or phrases used were chorioamnionitis, cerebral palsy, fetal brain damage, fetal CNS injury, infection in pregnancy, proinflammatory cytokines in pregnancy, proinflammatory cytokines in infection, and preterm labour or birth. All relevant human and animal studies were included.

STUDY SELECTION

Fetal brain injury remains a major cause of lifelong morbidity, incurring significant societal and health care costs. It has been postulated that chorioamnionitis stimulates maternal/fetal proinflammatory cytokine release, which is damaging to the developing fetal nervous system. Elevated cytokine concentrations may interfere with glial cell development and proliferation in the late second trimester of pregnancy, when the central nervous system is most vulnerable. Increasing numbers of epidemiological and basic science studies found through MEDLINE searches support this hypothesis. Treatment options aimed at etiologic factors may lead to improved neurodevelopmental outcomes.

CONCLUSIONS

Clearly, some relationship exists between chorioamnionitis, cytokines, and the development of cerebral palsy, but the severity and duration of exposure required to produce fetal damage remains unknown. Future research addressing these issues may aid in clinical decision-making. As well, the elucidation of mechanisms of cytokine action may aid in early treatment options to prevent or limit development of fetal brain injury.

Comparison of single and repeated antenatal corticosteroid therapy to prevent neonatal death and morbidity in the preterm infant

INTRODUCTION

In the case of threatened preterm delivery, repeat administration of antenatal corticosteroids is a common practice in women who have not delivered 7-14 days after the first course of corticosteroids. However, the benefits of this policy as compared to single-course administration have not been proven.

AIM

Our purpose was to compare neonatal death and morbidity after repeat antenatal courses of corticosteroids with neonatal death and morbidity after a single course.

METHODS

We performed a cohort study with matched controls. Neonates treated with repeat antenatal courses of corticosteroids were matched with neonates treated with a single course. Matching criteria were sex, single or multiple gestation, route of delivery, gestational age at delivery and year of birth. Intrauterine growth-restricted infants were matched separately. We excluded neonates with congenital malformation and neonates with an unknown number of antenatal corticosteriod courses. Outcome measures were the incidences of neonatal death, respiratory distress syndrome, intraventricular haemorrhage and necrotizing enterocolitis.

RESULTS

From the neonates treated with two or three courses of antenatal corticosteroids, 56 appropriate grown neonates and 24 intrauterine growth-restricted neonates could be matched. The incidences of neonatal death, respiratory distress syndrome, intraventricular haemorrhage and necrotizing enterocolitis did not show statistically significant differences after single and repeat courses of corticosteroids. Appropriate grown and intrauterine growth-restricted neonates showed the same results.

CONCLUSION

From our study, it can be concluded that in preterm neonates, repetition of antenatal corticosteroids seems not to improve neonatal outcome.

Programming effects in sheep of prenatal growth restriction and glucocorticoid exposure

Our aim was to determine the postnatal effects of single and repeated glucocorticoid injections during late gestation. Repeated (104, 111, 118, 125 days) or single (104 days) injections of betamethasone or saline were given to the ewe or by ultrasound guided injection to the fetus (term 150 days). Lambs were born spontaneously and studied at 3 and 6 mo and 1 yr of age. Arterial pressure was measured at each age, and we performed intravenous glucose tolerance tests at 6 mo and 1 yr. Repeated maternal, but not single maternal or fetal, betamethasone injections prolonged gestation, reduced weight at birth and 3 mo, and was associated with low arterial pressure at 3 mo but not at 6 mo and 1 yr. Glucose metabolism was altered in all betamethasone treatment groups, regardless of the number or route of injections. Our data demonstrate that glucocorticoid-induced fetal growth restriction is associated with a transient reduction in postnatal arterial pressure, but glucocorticoid exposure with or without growth restriction alters glucose metabolism.

Repeated antenatal glucocorticoid treatment decreases hypothalamic corticotropin releasing hormone mRNA but not corticosteroid receptor mRNA expression in the fetal guinea-pig brain

Approximately 10% of pregnant women are treated with synthetic glucocorticoids in late gestation, to promote fetal lung maturation. The effectiveness of this treatment has led to the use of repeated dose regimens, with little knowledge of the impact on neuroendocrine development. Animal studies have recently shown that repeated fetal glucocorticoid exposure can lead to permanent changes in hypothalamic-pituitary-adrenal (HPA) function in offspring. In this study, we hypothesized that such treatment modifies corticotropin releasing hormone (CRH), glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) systems in the developing limbic system and hypothalamus. Pregnant guinea-pigs were treated with dexamethasone, betamethasone or vehicle on days 40,41,50,51,60 and 61 of gestation (birth = 68 days). On day 62, guinea-pigs were killed and the fetuses rapidly removed. Glucocorticoid treatment resulted in a dose-dependent reduction in plasma cortisol concentrations in both male and female fetuses. There was also a significant reduction in CRH mRNA expression in the hypothalamic paraventricular nucleus. In contrast, exposure to glucocorticoid increased MR mRNA expression in the hippocampus (CA1/2 and CA3) and dentate gyrus of female fetuses. There was a small but significant increase in GR mRNA expression in limbic structures in male fetuses following treatment with 1 mg/kg dexamethasone. However, there was no significant effect of glucocorticoid exposure on hippocampal GR mRNA expression in female fetuses, or hypothalamic GR mRNA in either males or females. In conclusion, repeated maternal glucocorticoid treatment inhibits fetal HPA function. The fact that CRH mRNA levels were reduced indicates that synthetic glucocorticoids enter the fetal brain. By contrast, fetal glucocorticoid exposure does not downregulate GR mRNA, and increases MR mRNA expression. The latter likely reflects removal of circulating endogenous ligand (cortisol). These alterations may form the basis for permanently modified HPA activity in later life.

Maternal glucocorticoid treatment programs HPA regulation in adult offspring: sex-specific effects

Pregnant guinea pigs were treated with dexamethasone (1 mg/kg) or vehicle on days 40--41, days 50--51, and days 60--61 of gestation. Adult offspring were split into two groups. Group 1 guinea pigs were catheterized, and the hypothalamo-pituitary-adrenal (HPA) axis was tested in basal and activated states. Group 2 guinea pigs were euthanized with no further manipulation. In male offspring, prenatal dexamethasone exposure resulted in a significant reduction in brain-to-body weight ratio. Dexamethasone-exposed male offspring exhibited reduced basal and activated plasma cortisol levels, which was associated with elevated hippocampal mineralocorticoid receptor (MR) mRNA and increased plasma testosterone. In females exposed to glucocorticoids in utero, basal and stimulated plasma cortisol levels were higher in the follicular and early luteal phases of the cycle, but this effect was reversed in the late luteal phase, indicating a significant interaction of sex steroids. In female offspring (at estrus), glucocorticoid receptor mRNA levels were lower in the paraventricular nucleus and pars distalis but higher in the hippocampus in animals exposed to dexamethasone in utero. Hippocampal MR mRNA levels were significantly lower (approximately 50%) than in controls. In conclusion, repeated antenatal glucocorticoid treatment programs HPA function in a sex-specific manner, and these changes are associated with modification of corticosteroid receptor expression in the adult brain and pituitary.

Antenatal therapies and the developing brain

This chapter presents a review of basic science and human studies of two commonly used pharmacologic agents (antenatal steroids and magnesium sulfate), in pregnancies at risk of preterm delivery, and examines the effects of these therapies on the developing brain. Very low birthweight (VLBW) infants are known to be at risk of both short-term and long-term neurodevelopmental sequelae; therefore, an understanding of the mechanisms contributing to both neuroprotective and neurotoxic effects of antenatal therapies on the immature brain and potential effects on long-term outcome are critical. Although the short-term beneficial effects of a single course of antenatal steroids are well documented, the experimental animal literature suggests detrimental effects on neurodevelopment of multiple doses. In addition, clinical studies of repeat doses suggest a negative impact on head and brain growth. The animal and human data on the effects of MgSO(4)are also mixed with both beneficial effects or no effects on neurodevelopment. This review will discuss the potential impact of single versus multiple doses and timing of doses on the brain.

[Jargon of the neonatal intensive care unit]

Jargon, the specialized vocabulary and idioms, is frequently used by people of the same work or profession. The neonatal intensive care unit (NICU) makes no exception to this. As a matter of fact, NICU is one place where jargon is constantly developing in parallel with the evolution of techniques and treatments. The use of jargon within the NICU is very practical for those who work in these units. However, this jargon is frequently used by neonatologists in medical reports or other kinds of communication with unspecialized physicians. Even if part of the specialized vocabulary can be decoded by physicians not working in the NICU, they do not always know the exact place that these techniques or treatments have in the management of their patients. The aim of this article is to describe the most frequent jargon terms used in the French NICU and to give up-to-date information on the importance of the techniques or treatments that they describe.

Randomised, double-blind, placebo-controlled trial of corticosteroids for the treatment of hyperemesis gravidarum

OBJECTIVE

To assess the efficacy of corticosteroids in the treatment of severe hyperemesis gravidarum refractory to conventional management.

DESIGN

Multicentre, double-blind, randomised, placebo-controlled trial.

SETTING

Inpatient gynaecology wards in eight collaborating centres.

POPULATION

Twenty-five women with severe hyperemesis of which 24 completed the one- week study period.

METHODS

Twenty-five women were randomised to receive either 40 mg prednisolone daily in two divided oral doses, or equivalent placebo tablets. If, after three days, a woman was still vomiting, medication was changed to the equivalent intravenous alternative (hydrocortisone 100 mg twice daily or normal saline injections)

MAIN OUTCOME MEASURES

Frequency of vomiting and the dependence on intravenous fluid replacement therapy after one week of treatment.

RESULTS

There was a non-significant trend towards improved nausea and vomiting and reduced dependence on intravenous fluids. However, steroid therapy led to an improved sense of wellbeing (P = 0.021), improved appetite (P = 0.039) and increased weight gain (P = 0.025) compared with placebo. There was no difference in pregnancy outcome between the treatment and placebo groups.

CONCLUSIONS

This study supports a beneficial role for steroids in severe hyperemesis, but did not validate the hypothesis that they lead to rapid and complete remission of symptoms. The study was not large enough to demonstrate a significant improvement in the primary outcome measures.

Hormonal modulation of fetal pulmonary development: relevance for the fetus with diaphragmatic hernia

Antenatal hormonal modulation of pulmonary growth has been successfully introduced in clinical practice to reduce the incidence of respiratory distress syndrome (RDS) of preterm born infants. However, a certain amount of reserve to repeat courses should be taken into account because of possible adverse effects of antenatal administration of glucocorticoids. Although in experimental animals thyroid hormones given alone were not shown to have stimulatory effects on pulmonary development, there was an apparent synergistic effect with corticosteroids. Yet, such effects have not been substantiated in clinical trials. Whereas in cases of congenital diaphragmatic hernia (CDH) in utero tracheal occlusion could stimulate fetal lung growth and modulation, the enhancement of type II cell differentiation is more likely to be achieved with antenatal exposure to hormonal therapies. However, there is still no firm scientific basis for either of these two treatment modalities in CDH. Yet, antenatal hormonal modulation is now soon to be tested in an extensive multi-center clinical trial. In this review, the current status of antenatal hormonal modulation of pulmonary growth will be described and its potential role in the treatment of CDH will be discussed.