Repeated doses of antenatal corticosteroids in animals: a systematic review

The Impact of Infant Sex on Multiple Courses versus a Single Course of Antenatal Corticosteroids: A Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE

 Animal literature has suggested that the impact of antenatal corticosteroids (ACS) may vary by infant sex. Our objective was to assess the impact of infant sex on the use of multiple courses versus a single course of ACS and perinatal outcomes.

STUDY DESIGN

 We conducted a secondary analysis of the Multiple Courses of Antenatal Corticosteroids for Preterm Birth trial, which randomly allocated pregnant people to multiple courses versus a single course of ACS. Our primary outcome was a composite of perinatal mortality or clinically significant neonatal morbidity (including neonatal death, stillbirth, severe respiratory distress syndrome, intraventricular hemorrhage [grade III or IV], cystic periventricular leukomalacia, and necrotizing enterocolitis [stage II or III]). Secondary outcomes included individual components of the primary outcome as well as anthropometric measures. Baseline characteristics were compared between participants who received multiple courses versus a single course of ACS. An interaction between exposure to ACS and infant sex was assessed for significance and multivariable regression analyses were conducted with adjustment for predefined covariates, when feasible.

RESULTS

 Data on 2,300 infants were analyzed. The interaction term between treatment status (multiple courses vs. a single course of ACS) and infant sex was not significant for the primary outcome (p = 0.86), nor for any of the secondary outcomes (p > 0.05).

CONCLUSION

 Infant sex did not modify the association between exposure to ACS and perinatal outcomes including perinatal mortality or neonatal morbidity or anthropometric outcomes. However, animal literature indicates that sex-specific differences after exposure to ACS may emerge over time and thus investigating long-term sex-specific outcomes warrants further attention.

KEY POINTS

· We explored the impact of infant sex on perinatal outcomes after multiple versus a single course of ACS.. · Infant sex was not a significant effect modifier of ACS exposure and perinatal outcomes.. · Animal literature indicates that sex-specific differences after ACS exposure may emerge over time.. · Further investigation of long-term sex-specific outcomes is warranted..

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

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

CONCLUSIONS

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

Administration of antenatal corticosteroid is associated with reduced fetal growth velocity: a longitudinal study

OBJECTIVE

To elucidate whether antenatal administration of corticosteroids in pregnancies with threatened preterm labor affects growth velocity.

METHODS

A cohort of 262 pregnancies exposed to antenatal corticosteroids longitudinally studied and delivered from 36 weeks (cases) were compared to an unexposed group of 270 women (controls).

METHODS

Fetal growth was assessed analyzing the growth velocity of head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). Growth velocity (GV) was calculated as the difference in the Z-score between the biometric measurements recorded at the time of steroids administration and at 36 week of gestation, divided by the time interval (expressed in days) between the two scans and multiplied by 100. Similarly, changes in the Pulsatility Index (PI) of uterine, umbilical (UA), middle cerebral (MCA) arteries and cerebroplacental ratio (CPR) during the same time interval were also computed.

RESULTS

Median gestational age at steroid administration (30.2 weeks vs 30.4) and follow-up ultrasound (36.4 weeks vs 36.4) were similar between cases and controls. In pregnancies exposed to antenatal corticosteroids, growth velocity in the HC (-0.61 vs. 0.12; p ≤ 0.001), AC (-0.55 vs. -0.04; p ≤ 0.001) and EFW (-0.89 vs. 0.06; p ≤ 0.001) were lower when compared to pregnancies not exposed to steroid therapy, while there was no difference in the growth velocity of FL (-0.05 vs 0.19; p = .06) or in any of the Doppler parameters explored.

CONCLUSION

In pregnancies exposed to antenatal steroid therapy, there is a significant reduction in fetal growth velocity not otherwise associated with changes in cerebroplacental Dopplers.

Developmental plasticity of mitochondrial aerobic metabolism, growth and survival by prenatal glucocorticoids and thyroid hormones: an experimental test in wild great tits

Developmental plasticity is partly mediated by transgenerational effects, including those mediated by the maternal endocrine system. Glucocorticoid and thyroid hormones may play central roles in developmental programming through their action on metabolism and growth. However, the mechanisms by which they affect growth and development remain understudied. One hypothesis is that maternal hormones directly affect the production and availability of energy-carrying molecules (e.g. ATP) by their action on mitochondrial function. To test this hypothesis, we experimentally increased glucocorticoid and thyroid hormones in wild great tit eggs (Parus major) to investigate their impact on offspring mitochondrial aerobic metabolism (measured in blood cells), and subsequent growth and survival. We show that prenatal glucocorticoid supplementation affected offspring cellular aerobic metabolism by decreasing mitochondrial density, maximal mitochondrial respiration and oxidative phosphorylation, while increasing the proportion of the maximum capacity being used under endogenous conditions. Prenatal glucocorticoid supplementation only had mild effects on offspring body mass, size and condition during the rearing period, but led to a sex-specific (females only) decrease in body mass a few months after fledging. Contrary to our expectations, thyroid hormones supplementation did not affect offspring growth or mitochondrial metabolism. Recapture probabilities as juveniles or adults were not significantly affected by prenatal hormonal treatments. Our results demonstrate that prenatal glucocorticoids can affect post-natal mitochondrial density and aerobic metabolism. The weak effects on growth and apparent survival suggest that nestlings were mostly able to compensate for the transient decrease in mitochondrial aerobic metabolism induced by prenatal glucocorticoids.

Maternal Undernutrition Modulates Neonatal Rat Cerebrovascular Structure, Function, and Vulnerability to Mild Hypoxic-Ischemic Injury via Corticosteroid-Dependent and -Independent Mechanisms

The present study explored the hypothesis that an adverse intrauterine environment caused by maternal undernutrition (MUN) acted through corticosteroid-dependent and -independent mechanisms to program lasting functional changes in the neonatal cerebrovasculature and vulnerability to mild hypoxic-ischemic (HI) injury. From day 10 of gestation until term, MUN and MUN-metyrapone (MUN-MET) group rats consumed a diet restricted to 50% of calories consumed by a pair-fed control; and on gestational day 11 through term, MUN-MET groups received drinking water containing MET (0.5 mg/mL), a corticosteroid synthesis inhibitor. P9/P10 pups underwent unilateral carotid ligation followed 24 h later by 1.5 h exposure to 8% oxygen (HI treatment). An ELISA quantified MUN-, MET-, and HI-induced changes in circulating levels of corticosterone. In P11/P12 pups, MUN programming promoted contractile differentiation in cerebrovascular smooth muscle as determined by confocal microscopy, modulated calcium-dependent contractility as revealed by cerebral artery myography, enhanced vasogenic edema formation as indicated by T2 MRI, and worsened neurobehavior MUN unmasked HI-induced improvements in open-field locomotion and in edema resolution, alterations in calcium-dependent contractility and promotion of contractile differentiation. Overall, MUN imposed multiple interdependent effects on cerebrovascular smooth muscle differentiation, contractility, edema formation, flow-metabolism coupling and neurobehavior through pathways that both required, and were independent of, gestational corticosteroids. In light of growing global patterns of food insecurity, the present study emphasizes that infants born from undernourished mothers may experience greater risk for developing neonatal cerebral edema and sensorimotor impairments possibly through programmed changes in neonatal cerebrovascular function.

Single-course antenatal corticosteroids is related to faster growth in very-low-birth-weight infant

Background

Antenatal corticosteroids (ACS) treatment is critical to support survival and lung maturation in preterm infants, however, its effect on feeding and growth is unclear. Prior preterm delivery, it remains uncertain whether ACS treatment should be continued if possible (repeated course ACS), until a certain gestational age is reached. We hypothesized that the association of single-course ACS with feeding competence and postnatal growth outcomes might be different from that of repeated course ACS in very-low-birth-weight preterm infants.

Methods

A multicenter retrospective cohort study was conducted in very-low-birth-weight preterm infants born at 23–37 weeks’ gestation in South China from 2011 to 2014. Data on growth, nutritional and clinical outcomes were collected. Repeated course ACS was defined in this study as two or more courses ACS (more than single-course). Infants were stratified by gestational age (GA), including GA < 28 weeks, 28 weeks ≤ GA < 32 weeks and 32 weeks ≤ GA < 37 weeks. Multiple linear regression and multilevel model were applied to analyze the association of ACS with feeding and growth outcomes.

Results

A total of 841 infants were recruited. The results, just in very-low-birth-weight preterm infants born at 28–32 weeks’ gestation, showed both single and repeated course of ACS regimens had shorter intubated ventilation time compared to non-ACS regimen. Single-course ACS promoted the earlier application of amino acid and enteral nutrition, and higher rate of weight increase (15.71; 95%CI 5.54–25.88) than non-ACS after adjusting for potential confounding factors. No associations of repeated course ACS with feeding, mean weight and weight increase rate were observed.

Conclusions

Single-course ACS was positively related to feeding and growth outcomes in very-low-birth-weight preterm infants born at 28–32 weeks’ gestation. However, the similar phenomenon was not observed in the repeated course of ACS regimen.

Long-term neuropathological and/or neurobehavioral effects of antenatal corticosteroid therapy in animal models: a systematic review

BACKGROUND

Antenatal corticosteroids (ACSs) are recommended to all women at risk for preterm delivery; currently, there is controversy about the subsequent long-term neurocognitive sequelae. This systematic review summarizes the long-term neurodevelopmental outcomes after ACS therapy in animal models.

METHODS

An electronic search strategy incorporating MeSH and keywords was performed using all known literature databases and in accordance with PRISMA guidance (PROSPERO CRD42019119663).

RESULTS

Of the 669 studies identified, eventually 64 were included. The majority of studies utilized dexamethasone at relative high dosages and primarily involved rodents. There was a high risk of bias, mostly due to lack of randomization, allocation concealment, and blinding. The main outcomes reported on was neuropathological, particularly glucocorticoid receptor expression and neuron densities, and neurobehavior. Overall there was an upregulation of glucocorticoid receptors with lower neuron densities and a dysregulation of the dopaminergic and serotonergic systems. This coincided with various adverse neurobehavioral outcomes.

CONCLUSIONS

In animal models, ACSs consistently lead to deleterious long-term neurocognitive effects. This may be due to the specific agents, i.e., dexamethasone, or the repetitive/higher total dosing used. ACS administration varied significantly between studies and there was a high risk of bias. Future research should be standardized in well-characterized models.

Prenatal stress and later metabolic consequences: Systematic review and meta-analysis in rodents

BACKGROUND

Numerous rodent studies have evaluated the effects of maternal stress (MS) on later in life susceptibility to Metabolic Syndrome (MetS) intermediate phenotypes with varying results. The aim of this study was to quantitatively synthesize the available data on the effects of MS on offspring obesity, estimated indirectly by body mass (BM), body fat (BF) and plasma leptin; systolic blood pressure (SBP); plasma glucose (and insulin) and blood lipid concentrations.

METHODS

Literature was screened and summary estimates of the effect of MS outcomes were calculated by using random-effects models. Data on the effects of exogenous corticosteroid administration (or inhibition of 11β-HSD2) during pregnancy in rodents was analysed separately to characterize the direct phenotypic effects of prenatal corticosteroid excess (PCE).

RESULTS

We conducted 14 separate meta-analyses and synthesized relevant data on outcomes scarcely reported in literature. Both MS and PCE were associated with low birth weight without rapid catch-up growth resulting in decreased body mass later in life. Our analysis also revealed significant and contradictory effects on offspring adiposity. Little evidence was found for effects on glucose metabolism and blood lipids. We identified increased SBP in offspring exposed to PCE; however, there is not enough data to draw any conclusion about effects of MS on SBP.

CONCLUSIONS

Neonatal weight proved to be decreased in offspring prenatally exposed to stress or corticosteroids, but laboratory rodents in the absence of a challenging environment did not show catch-up growth. The available evidence is inconclusive regarding the effect on adiposity revealing clear methodological and knowledge gaps. This meta-analysis also confirmed a significant positive association between PCE and SBP. Nevertheless, additional studies should address the association with MS.

Antenatal corticosteroid administration is associated with decreased growth of the fetal thymus: a prospective cohort study

OBJECTIVE

To examine the effect of antenatal corticosteroid administration (ACS) on fetal thymus growth in women who received ACS compared with gestational-age-matched controls.

STUDY DESIGN

Fetal thymus size and growth were measured in women at risk for preterm delivery who received ACS and compared with a matched cohort of women who were at low risk for preterm delivery and did not receive ACS. Fetal thymus perimeter and diameter were measured by 2-D ultrasound at baseline and every 2 weeks until delivery.

RESULTS

After adjusting for confounders, ACS exposure was associated with a significant reduction in thymus perimeter size (-0.70; 95% CI: -1.33, -0.07; P = 0.03). For every additional week of exposure, thymus growth trajectory was significantly decreased in ACS-exposed fetuses (P = 0.04).

CONCLUSION

The association between ACS and reduced fetal thymus growth should be further examined to establish the impact of ACS on childhood thymus development and immune programming.

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

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

Development of somatosensory-evoked potentials in foetal sheep: effects of betamethasone

AIM

Antenatal glucocorticoids are used to accelerate foetal lung maturation in babies threatened with premature labour. We examined the influence of glucocorticoids on functional and structural maturation of the central somatosensory pathway in foetal sheep. Somatosensory-evoked potentials (SEP) reflect processing of somatosensory stimuli. SEP latencies are determined by afferent stimuli transmission while SEP amplitudes reveal cerebral processing.

METHODS

After chronic instrumentation of foetal sheep, mothers received saline (n = 9) or three courses of betamethasone (human equivalent dose of 2 × 110 μg kg^-1 betamethasone i.m. 24 h apart, n = 12) at 0.7, 0.75 and 0.8 of gestational age. Trigeminal SEP were evoked prior to, 4 and 24 h after each injection and at 0.8 of gestational age before brains were histologically processed.

RESULTS

Somatosensory-evoked potentials were already detectable at 0.7 of gestation age. The early and late responses N20 and N200 were the only reproducible peaks over the entire study period. With advancing gestational age, SEP latencies decreased but amplitudes remained unchanged. Acutely, betamethasone did not affect SEP latencies and amplitudes 4 and 24 h following administration. Chronically, betamethasone delayed developmental decrease in the N200 but not N20 latency by 2 weeks without affecting amplitudes. In parallel, betamethasone decreased subcortical white matter myelination but did not affect network formation and synaptic density in the somatosensory cortex.

CONCLUSION

Somatosensory stimuli are already processed by the foetal cerebral cortex at the beginning of the third trimester. Subsequent developmental decrease in SEP latencies suggests ongoing maturation of afferent sensory transmission. Antenatal glucocorticoids affect structural and functional development of the somatosensory system with specific effects at subcortical level.

Threatened preterm labor is a risk factor for impaired cognitive development in early childhood

BACKGROUND

Threatened preterm labor is a leading cause of hospital admission during pregnancy. Patients with an episode of threatened preterm labor who deliver at term are considered to have false preterm labor. However, threatened preterm labor has been proposed as a pathologic insult that is not always sufficient to induce irreversible spontaneous preterm birth but that could alter the normal course of pregnancy.

OBJECTIVE

The aim of this study was to evaluate threatened preterm labor during pregnancy as a risk factor of neurodevelopmental deficits of children at 2 years of age.

STUDY DESIGN

Two-year-old children who were born late preterm (n=22) or at term after threatened preterm labor (n=23) were compared with at-term control children (n=42). Neurodevelopment was evaluated at a corrected age of 24-29 months with the use of the Merrill-Palmer-Revised Scales of Development.

RESULTS

Children who were born at term after threatened preterm labor had lower scores than control children on global cognitive index (95.4 vs 104.2; P=.011), cognition (95.1 vs 103.1; P=.021), fine motor (95.2 vs 103.4; P=.003), gross motor (84.7 vs 99.8; P=.001), memory (92.9 vs 100.4; P=.015), receptive language (93.9 vs 102.9; P=.03), speed of processing (105.7 vs 113.3; P=.011), and visual motor coordination (98.8 vs 106.7; P=.003) subtests. Children born at term after threatened preterm labor had an increased risk of mild neurodevelopmental delay compared with control children (odds ratio for global cognitive index, 2.06; 95% confidence interval, 1.09-3.88; P=.033). There were no significant differences in any cognitive domain between children who were born late preterm and children who were born at term after threatened preterm labor.

CONCLUSIONS

Threatened preterm labor is a risk factor for impaired cognitive development at 2 years of age, even if birth occurred at term.

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.

Multiple Antenatal Dexamethasone Treatment Alters Brain Vessel Differentiation in Newborn Mouse Pups

Antenatal steroid treatment decreases morbidity and mortality in premature infants through the maturation of lung tissue, which enables sufficient breathing performance. However, clinical and animal studies have shown that repeated doses of glucocorticoids such as dexamethasone and betamethasone lead to long-term adverse effects on brain development. Therefore, we established a mouse model for antenatal dexamethasone treatment to investigate the effects of dexamethasone on brain vessel differentiation towards the blood-brain barrier (BBB) phenotype, focusing on molecular marker analysis. The major findings were that in total brains on postnatal day (PN) 4 triple antenatal dexamethasone treatment significantly downregulated the tight junction protein claudin-5, the endothelial marker Pecam-1/CD31, the glucocorticoid receptor, the NR1 subunit of the N-methyl-D-aspartate receptor, and Abc transporters (Abcb1a, Abcg2 Abcc4). Less pronounced effects were found after single antenatal dexamethasone treatment and in PN10 samples. Comparisons of total brain samples with isolated brain endothelial cells together with the stainings for Pecam-1/CD31 and claudin-5 led to the assumption that the morphology of brain vessels is affected by antenatal dexamethasone treatment at PN4. On the mRNA level markers for angiogenesis, the sonic hedgehog and the Wnt pathway were downregulated in PN4 samples, suggesting fundamental changes in brain vascularization and/or differentiation. In conclusion, we provided a first comprehensive molecular basis for the adverse effects of multiple antenatal dexamethasone treatment on brain vessel differentiation.

Applying developmental programming to clinical obstetrics: my ward round

The theory of developmental programming is supported by accumulating evidence, both observational and experimental. The direct application of the principles of developmental programming by clinicians to benefit pregnant women remains an area of limited attention. Examining a selection of inpatients at an obstetric referral center, I searched for situations in which clinical decision making could be driven by the principles of developmental programming. I also looked for situations in which the clinical research agenda could be dictated by these concepts. In the decision to undertake preventive measures to avoid preeclampsia, the offspring’s perspective may support more liberal application of calcium and aspirin. Consideration of the long-term health perspective of the offspring could drive choices in the management of obesity and diabetes in pregnancy. The administration of corticosteroids in women delivering by elective cesarean at term may have modest short-term benefits, but additional trials are necessary to investigate long-term offspring health. The offspring of women suffering hyperemesis gravidarum may benefit from nutritional therapy. The long-term health of the offspring could affect couples’ choice for IVF or expectant management. Applying the principles of developmental programming to the management of pregnant women could drive clinical decision making and is driving the clinical research agenda. Increasingly, developmental programming concepts are becoming an integral part of clinical practice, as well as determining the choice of outcomes in trials in obstetrics and fertility medicine. The presented cases underscore the need for more research to guide clinical practice.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Effect of corticosteroids and lung ventilation in the VEGF and NO pathways in congenital diaphragmatic hernia in rats

PURPOSE

The use of dexamethasone (Dx) stimulates growth, fetal lung maturation and can improve pulmonary hypertension in congenital diaphragmatic hernia (CDH). Our aim was to evaluate the effect of Dx on the lung after fetal pulmonary ventilation in the CDH rat model.

METHODS

Some groups underwent prenatal treatment with dexamethasone (0.4 mg/kg) that was given at 18.5 gestational day (GD). Sprague-Dawley rat fetuses were divided into groups: control (C); ventilated control (CV); control exposed to dexamethasone (CDx); ventilated control exposed to dexamethasone (CVDx); congenital diaphragmatic hernia (CDH), ventilated CDH (CDHV), CDH exposed to dexamethasone (CDHDx) and ventilated CDH exposed to dexamethasone (CDHVDx). At 21.5 GD fetuses were delivered by C-section, weighed and ventilated for 30 min. We analyzed the lung morphometry by Masson's Trichrome stain, and VEGF, VEGFR1, VEGFR2 and NOS3 expression by immunohistochemistry.

RESULTS

All fetuses with CDH, with or without prenatal dexamethasone showed lung and body weight lower than control fetuses (p < 0.05). All groups that received dexamethasone showed a decrease in the medial muscular layer of arterioles, the internal diameter of the air spaces (Lma) and length of parenchymal transection/airspace ratio (p < 0.05). In the immunohistochemistry, VEGF decreased more in CDHDV group (p < 0.05). VEGFR1 showed no difference, whereas VEGFR2 decreased significantly in the CDHDV group (p < 0.05). NOS3 increased in the group CDHDV (p < 0.05).

CONCLUSION

The use of prenatal dexamethasone added to ventilation alters the VEGF and NO pathways.

Glucocorticoid exposure altered angiogenic factor expression via Akt/mTOR pathway in rat placenta

During pregnancy, glucocorticoids (GCs) are used for fetal lung maturation in women at risk of preterm labor. Exogenous GCs do not have exclusively beneficial effects and repeated use of GCs remains controversial. It has been observed that GC exposed rats have smaller placentas and intrauterine growth retarded fetuses. In this study, we questioned whether or not glucocorticoids effect placental angiogenesis mechanisms. One of the most important signaling pathways among several downstream of VEGFR-2 is PI3K/Akt which subsequently activates the mammalian target of rapamycin. Therefore, we hypothesized that overexposure to GCs may adversely affect placental angiogenesis mechanisms by regulating pro-angiogenic factors and their receptors via Akt/mTOR pathway. According to our results Dexamethasone, a synthetic glucocorticoid, administration led to a decrease in VEGF, PIGF expression during pregnancy. VEGFR2 expression was first decreased at gestational day 14 and afterwards increased at gestational days 16, 18 and 20 in rat placentas. These results are in accordance with the reduced phosphorylation of Akt, 4EBP1 and p70S6K. Dexamethasone injection also resulted in a reduction of VEGF, VEGFR1, and VEGFR2 mRNA expression at gestational days 14 and 20, but PIGF mRNA expression was not altered. Growth retarded fetuses seen in Dexamethasone treated pregnancies, may be a result of altered angiogenic factor expression of the placenta mediated via altered mTOR pathway signaling.

Breast-feeding after transplantation

Transplantation affords recipients the potential for a full life and, for some, parenthood. Female transplant recipients must continue to take immunosuppression during pregnancy and breast-feeding. This article reviews case and series reports regarding breast-feeding in those taking transplant medications. Avoidance of breast-feeding has been the customary advice because of the potential adverse effects of immunosuppressive exposure on the infant. Subsequent studies have demonstrated that not all medication exposure translates to risk for the infant, that the exposure in utero is greater than via breast milk and that no lingering effects due to breast-feeding have been found to date in infants who were breast-fed while their mothers were taking prednisone, azathioprine, cyclosporine, and/or tacrolimus. Thus, except for those medications where clinical information is inadequate (mycophenolic acid products, sirolimus, everolimus, and belatacept), the recommendation for transplant recipients regarding breast-feeding has evolved into one that is cautiously optimistic.

The protective effect of glibenclamide in a model of hemorrhagic encephalopathy of prematurity

We studied a model of hemorrhagic encephalopathy of prematurity (EP) that closely recapitulates findings in humans with hemorrhagic EP. This model involves tandem insults of 20 min intrauterine ischemia (IUI) plus an episode of elevated venous pressure induced by intraperitoneal glycerol on post-natal day (P) 0. We examined Sur1 expression, which is upregulated after focal ischemia but has not been studied after brief global ischemia including IUI. We found that 20 min IUI resulted in robust upregulation of Sur1 in periventricular microvessels and tissues. We studied tandem insult pups from untreated or vehicle-treated dams (TI-CTR), and tandem insult pups from dams administered a low-dose, non-hypoglycemogenic infusion of the Sur1 blocker, glibenclamide, for 1 week after IUI (TI-GLIB). Compared to pups from the TI-CTR group, pups from the TI-GLIB group had significantly fewer and less severe hemorrhages on P1, performed significantly better on the beam walk and accelerating Rotarod on P35 and in tests of thigmotaxis and rapid learning on P35–49, and had significantly greater body and brain weights at P52. We conclude that low-dose glibenclamide administered to the mother at the end of pregnancy protects pups subjected to IUI from post-natal events of elevated venous pressure and its consequences.

Long-term effects of prenatal stress and glucocorticoid exposure

There is a growing body of evidence suggesting that events during prenatal life can have long-lasting effects on development and adult health. Stress during pregnancy is common and has been linked to increased incidence of a range of affective and behavioral outcomes in the offspring in later life and also some somatic outcomes. Glucocorticoids, and their actions on the fetus, which are regulated by placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), are hypothesized to mediate these effects. Animal studies have demonstrated long-term effects of stress and glucocorticoid administration on behavioral outcomes, as well as increased blood pressure, altered hypothalamic pituitary adrenal axis (HPA) function, and decreased glucose tolerance and brain size. In humans, licorice, which inhibits placental 11β-HSD2 when consumed during pregnancy, has been shown to increase the risk of behavioral problems linked to altered HPA activity. Synthetic glucocorticoids administered during pregnancy to improve fetal lung maturity in threatened preterm birth have been shown to reduce birth weight and head circumference, but have not been linked to gross changes in long-term health to date. It is important to consider the long-term consequences of stress, and medication that mimics stress, during pregnancy.

Prenatal stress and subsequent exposure to chronic mild stress in rats; interdependent effects on emotional behavior and the serotonergic system

Exposure to prenatal stress (PS) can predispose individuals to the development of psychopathology later in life. We examined the effects of unpredictable chronic mild stress (CMS) exposure during adolescence on a background of PS in male and female Sprague-Dawley rats. PS induced more anxiety-like behavior in the elevated zero maze in both sexes, an effect that was normalized by subsequent exposure to CMS. Moreover, PS was associated with increased depression-like behavior in the forced swim test in males only. Conversely, sucrose intake was increased in PS males, whilst being decreased in females when consecutively exposed to PS and CMS. Hypothalamo-pituitary-adrenal (HPA) axis reactivity was affected in males only, with higher stress-induced plasma corticosterone levels after PS. Markedly, CMS normalized the effects of PS on elevated zero maze behavior as well as basal and stress-induced plasma corticosterone secretion. At the neurochemical level, both PS and CMS induced various sex-specific alterations in serotonin (5-HT) and tryptophan hydroxylase 2 (TPH2) immunoreactivity in the dorsal raphe nucleus, hippocampus and prefrontal cortex with, in line with the behavioral observations, more profound effects in male offspring. In conclusion, these findings show that prenatal maternal stress in Sprague-Dawley rats induces various anxiety- and depression-related behavioral and neuroendocrine changes, as well as alterations in central 5-HT and TPH2 function, predominantly in male offspring. Moreover, CMS exposure partially normalized the effects of previous PS experience, suggesting that the outcome of developmental stress exposure largely depends on the environmental conditions later in life and vice versa.

Antenatal corticosteroids for periviable birth

Antenatal corticosteroids have been proven to accelerate fetal lung development and reduce neonatal morbidity and mortality when given between 28 and 34 weeks of gestation. However, there is only limited research to guide their use in the periviable period (22-26 weeks). Laboratory studies suggest that it is biologically plausible for antenatal steroids to be effective in this gestational period. In addition, cohort studies have demonstrated the efficacy of antenatal corticosteroids in reducing neonatal mortality and IVH. Follow-up studies performed between 18 and 22 months of age also suggest a long-term benefit to antenatal use in this period. Based on this information, antenatal corticosteroids should be used in appropriate patients at high risk for preterm birth at 23-26 weeks of gestation. An advantageous outcome to treatment at 22 weeks is less certain.

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.

Are antenatal steroids beneficial to severely growth restricted fetuses?

Antenatal steroids (AS) have been shown to enhance fetal maturation in preterms and to improve outcome. The aim of this study was to evaluate the efficacy of AS in premature severely intrauterine growth restricted infants. The electronic data of 149 inborn, single infants born 24 to 31 6/7 weeks of GA and with a BW ≤ 3rd percentile were reviewed. Infants with congenital anomalies and syndromes were excluded. We compared the outcome of those who received 2 doses of AS (group A, 87 infants) with those who did not receive AS (group B, 62 infants). Sixty-eight infants in group A and 53 in group B were discharged home alive. AS did not improve the neonatal outcome, with the exception of a better cord pH and 5-min Apgar and we did not observe a significant difference in the Griffith's test at 2 years of corrected age, although there was a trend to a higher incidence of severe global delay in the steroid group. In view of the potential cerebral and CVS risks associated with high circulating steroids, the indications for AS in such a population need to be re-evaluated.

The interplay of variants near LEKR and CCNL1 and social stress in relation to birth size

BACKGROUND

We previously identified via a genome wide association study variants near LEKR and CCNL1 and in the ADCY5 genes lead to lower birthweight. Here, we study the impact of these variants and social stress during pregnancy, defined as social adversity and neighborhood disparity, on infant birth size. We aimed to determine whether the addition of genetic variance magnified the observed associations.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed data from the Northern Finland Birth Cohort 1986 (n=5369). Social adversity was defined by young maternal age (<20 years), low maternal education (<11 years), and/or single marital status. Neighborhood social disparity was assessed by discrepancy between neighborhoods relative to personal socio-economic status. These variables are indicative of social and socioeconomic stress, but also of biological risk. The adjusted multiple regression analysis showed smaller birth size in both infants of mothers who experienced social adversity (birthweight by -40.4 g, 95%CI -61.4, -19.5; birth length -0.14 cm, 95%CI -0.23, -0.05; head circumference -0.09 cm 95%CI -0.15, -0.02) and neighborhood disparity (birthweight -28.8 g, 95%CI -47.7, -10.0; birth length -0.12 cm, 95%CI -0.20, -0.05). The birthweight-lowering risk allele (SNP rs900400 near LEKR and CCNL1) magnified this association in an additive manner. However, likely due to sample size restriction, this association was not significant for the SNP rs9883204 in ADCY5. Birth size difference due to social stress was greater in the presence of birthweight-lowering alleles.

CONCLUSIONS/SIGNIFICANCE

Social adversity, neighborhood disparity, and genetic variants have independent associations with infant birth size in the mutually adjusted analyses. If the newborn carried a risk allele rs900400 near LEKR/CCNL1, the impact of stress on birth size was stronger. These observations give support to the hypothesis that individuals with genetic or other biological risk are more vulnerable to environmental influences. Our study indicates the need for further research to understand the mechanisms by which genes impact individual vulnerability to environmental insults.

Effect of antenatal corticosteroids on fetal growth and gestational age at birth

OBJECTIVE

To estimate the effect of multiple courses of antenatal corticosteroids on neonatal size, controlling for gestational age at birth and other confounders, and to determine whether there was a dose-response relationship between number of courses of antenatal corticosteroids and neonatal size.

METHODS

This is a secondary analysis of the Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study, a double-blind randomized controlled trial of single compared with multiple courses of antenatal corticosteroids in women at risk for preterm birth and in which fetuses administered multiple courses of antenatal corticosteroids weighed less, were shorter, and had smaller head circumferences at birth. All women (n=1,858) and children (n=2,304) enrolled in the Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study were included in the current analysis. Multiple linear regression analyses were undertaken.

RESULTS

Compared with placebo, neonates in the antenatal corticosteroids group were born earlier (estimated difference and confidence interval [CI]: -0.428 weeks, CI -0.10264 to -0.75336; P=.01). Controlling for gestational age at birth and confounding factors, multiple courses of antenatal corticosteroids were associated with a decrease in birth weight (-33.50 g, CI -66.27120 to -0.72880; P=.045), length (-0.339 cm, CI -0.6212 to -0.05676]; P=.019), and head circumference (-0.296 cm, -0.45672 to -0.13528; P<.001). For each additional course of antenatal corticosteroids, there was a trend toward an incremental decrease in birth weight, length, and head circumference.

CONCLUSION

Fetuses exposed to multiple courses of antenatal corticosteroids were smaller at birth. The reduction in size was partially attributed to being born at an earlier gestational age but also was attributed to decreased fetal growth. Finally, a dose-response relationship exists between the number of corticosteroid courses and a decrease in fetal growth. The long-term effect of these findings is unknown.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00187382.

LEVEL OF EVIDENCE

II.

Repeat antenatal glucocorticoids for women at risk of preterm birth: a Cochrane Systematic Review

Administration of antenatal glucocorticoids to women at risk of preterm birth has major benefits for infants but the use of repeat dose(s) is controversial. We performed a systematic review of randomized trials, using standard Cochrane methodology, to assess the effectiveness and safety of 1 or more repeat doses given to women at risk of preterm birth 7 or more days after an initial course. Ten trials were included involving over 4730 women and 5700 infants. Treatment with repeat dose(s) compared with no repeat treatment reduced the risk of respiratory distress syndrome (risk ratio, 0.83; 95% confidence interval, 0.75-0.91) and serious neonatal morbidity (risk ratio, 0.84; 95% confidence interval, 0.75-0.94). At 2- to 3-year follow-up (4 trials, 4170 children), there was no evidence of either significant benefit or harm. Repeat doses of glucocorticoids should be considered in women at risk of preterm birth 7 or more days after an initial course, in view of the neonatal benefits.

Natural variation in gestational cortisol is associated with patterns of growth in marmoset monkeys (Callithrix geoffroyi)

High levels of prenatal cortisol have been previously reported to retard fetal growth. Although cortisol plays a pivotal role in prenatal maturation, heightened exposure to cortisol can result in lower body weights at birth, which have been shown to be associated with adult diseases like hypertension and cardiovascular disease. This study examines the relationship between natural variation in gestational cortisol and fetal and postnatal growth in marmoset monkeys. Urinary samples obtained during the mother's gestation were analyzed for cortisol. Marmoset body mass index (BMI) was measured from birth through 540 days in 30- or 60-day intervals. Multi-level modeling was used to test if marmoset growth over time was predicted by changes in gestational cortisol controlling for time, sex, litter, and litter size. The results show that offspring exposed to intra-uterine environments with elevated levels of cortisol had lower linear BMI rates of change shortly after birth than did offspring exposed to lower levels of cortisol, but exhibited a higher curvilinear growth rate during adolescence. Average daily change in gestational cortisol during the first trimester had a stronger relationship with postnatal growth than change during the third trimester. Higher exposure to cortisol during gestation does alter developmental trajectories, however there appears to be a catch-up period during later post-natal growth. These observations contribute to a larger discussion about the relationship of maternal glucocorticoids on offspring development and the possibility of an earlier vulnerable developmental window.

Prenatal corticosteroid exposure alters early developmental seizures and behavior

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

Does in utero exposure to synthetic glucocorticoids influence birthweight, head circumference and birth length? A systematic review of current evidence in humans

Synthetic glucocorticoids are the mainstay treatment for stimulating lung maturation in threatened preterm delivery. Animal studies suggest that in utero exposure to glucocorticoids leads to a reduction in birth size. Smaller birthweight has been associated with higher risk of many chronic diseases. Therefore, the authors undertook a systematic review of human studies examining the association between synthetic glucocorticoid treatment and birth size. Medline, EMBASE, PubMed, Cochrane, Google scholar and Institute of Life Science databases were searched for studies published between 1978 and 2009 investigating the association between synthetic glucocorticoids and birthweight, head circumference, birth length and ponderal index. All studies controlling for gestational age were examined. Seventeen studies were included in the analysis. Nine out of 17 studies reported a reduction in birthweight (range 12-332 g), five of nine a reduction of head circumference (range 0.31-1.02 cm) and two of four a reduction of 0.8 cm in birth length. Despite methodological inconsistencies and limitations that impede clear conclusions, the evidence suggests an association between in utero exposure to synthetic glucocorticoids and reduced birth size.

Effect of prenatal glucocorticoids on cerebral vasculature of the developing brain

BACKGROUND AND PURPOSE

Prenatal glucocorticoids prevent germinal matrix hemorrhage in premature infants. The underlying mechanism, however, is elusive. Germinal matrix is enriched with angiogenic vessels exhibiting paucity of pericytes and glial fibrillary acidic protein-positive astrocyte end feet. Therefore, we asked whether glucocorticoid treatment would suppress angiogenesis and enhance periendothelial coverage by pericytes and glial fibrillary acidic protein-positive end feet in the germinal matrix microvasculature.

METHODS

We treated pregnant rabbits with intramuscular betamethasone and delivered pups prematurely by cesarean section at E29 (term=32 days). Endothelial turnover, vascular density, pericyte coverage, glial fibrillary acidic protein-positive end feet, cell death, and growth factors orchestrating angiogenesis, including vascular endothelial growth factor, angiopoietins, transforming growth factor-beta, and platelet-derived growth factor-B, were compared between betamethasone-treated and untreated pups. Similar comparisons were done between autopsy materials from premature infants exposed and unexposed to prenatal glucocorticoids.

RESULTS

Antenatal glucocorticoid treatment reduced endothelial proliferation, vascular density, and vascular endothelial growth factor expression in the germinal matrix of both rabbits and humans. The pericyte coverage was greater in glucocorticoid-treated rabbit pups and human infants than in controls, but not the glial fibrillary acidic protein-positive end feet coverage. Transforming growth factor-beta, but not angiopoietins and platelet-derived growth factor-B, were elevated in glucocorticoid-treated rabbit pups compared with controls. Betamethasone treatment induced apoptosis, neuronal degeneration, and gliosis in rabbit pups. However, there was no evidence of increased cell death in glucocorticoid-exposed human infants.

CONCLUSIONS

Prenatal glucocorticoid suppresses vascular endothelial growth factor and elevates transforming growth factor-beta levels, which results in angiogenic inhibition, trimming of neovasculature, and enhanced pericyte coverage. These changes contribute to stabilizing the germinal matrix vasculature, thereby reducing its propensity to hemorrhage. Prenatal glucocorticoid exposure does not induce neural cell death in humans, unlike rabbits.

Effects of birth advancement in Chiari malformation in a surgical myelomeningocele model in rabbits

BACKGROUND/PURPOSE

In myelomeningocele (MMC), Chiari II malformation progresses during gestation because of the continuous loss of cerebrospinal fluid at the site of the defect. Our purpose was to assess the impact of birth advancement (BA) and prenatal corticosteroid treatment (PCT) on Chiari malformation in a surgical MMC model in rabbits.

METHODS

A surgical MMC-like defect was created in 75 fetal rabbits. Animals were distributed into 4 groups depending on the treatment received: not treated and those undergoing BA + PCT, BA, or PCT. The degree of Chiari malformation in newborn rabbits was defined as the percentage of downward protrusion of the hindbrain between the end of the occipital bone and the beginning of the first vertebral arch.

RESULTS

The degree of hindbrain herniation was 80% (8.15) in the not treated group, 36.8% (10.57) in BA + PCT, 41.8% (8.27) in BA, and 44.4% (8.32) in PCT. The BA + PCT, BA, and PCT groups showed less severe hindbrain herniation than not treated animals (mean decrease, 39.86%; SD, 10.57; P = .000). There were no significant differences between the BA + PCT, BA, and PCT groups (P = .311).

CONCLUSIONS

Birth advancement and prenatal administration of corticosteroids decrease the severity of the hindbrain herniation component of Chiari II malformation in surgical MMC in fetal rabbits.

The links between prenatal stress and offspring development and psychopathology: disentangling environmental and inherited influences

BACKGROUND

Exposure to prenatal stress is associated with later adverse health and adjustment outcomes. This is generally presumed to arise through early environmentally mediated programming effects on the foetus. However, associations could arise through factors that influence mothers' characteristics and behaviour during pregnancy which are inherited by offspring.

METHOD

A 'prenatal cross-fostering' design where pregnant mothers are related or unrelated to their child as a result of in vitro fertilization (IVF) was used to disentangle maternally inherited and environmental influences. If links between prenatal stress and offspring outcome are environmental, association should be observed in unrelated as well as related mother-child pairs. Offspring birth weight and gestational age as well as mental health were the outcomes assessed.

RESULTS

Associations between prenatal stress and offspring birth weight, gestational age and antisocial behaviour were seen in both related and unrelated mother-offspring pairs, consistent with there being environmental links. The association between prenatal stress and offspring anxiety in related and unrelated groups appeared to be due to current maternal anxiety/depression rather than prenatal stress. In contrast, the link between prenatal stress and offspring attention deficit hyperactivity disorder was only present in related mother-offspring pairs and therefore was attributable to inherited factors.

CONCLUSIONS

Genetically informative designs can be helpful in testing whether inherited factors contribute to the association between environmental risk factors and health outcomes. These results suggest that associations between prenatal stress and offspring outcomes could arise from inherited factors and post-natal environmental factors in addition to causal prenatal risk effects.

[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.

No short-term benefits of antenatal corticosteroid treatment in severely preterm growth restricted fetuses: a case-control study

BACKGROUND

Antenatal corticosteroid administration to premature, growth restricted fetuses may not be beneficial and even have adverse effects on neonatal outcome.

AIMS

To determine if preterm growth restricted fetuses benefit from antenatal corticosteroids.

STUDY DESIGN

Retrospective cohort study.

METHODS

All singleton pregnancies with growth restricted fetuses delivered at our department before 34 weeks' gestation or weighing less than 1500 g, between January 2001 and December 2005, were retrospectively reviewed. Neonatal outcome was compared between growth restricted fetuses (defined as abnormal flow patterns in umbilical and middle cerebral arteries) that received antenatal CST (CST group) and those who did not receive antenatal CST (no CST group). The administration of CST appeared to be quasi randomized.

RESULTS

A total of 88 pregnancies fulfilled the inclusion criteria (CST group, n=54; no CST group, n=34). The incidence of neonatal respiratory distress syndrome in the CST and no CST group was 42% (22/54) and 50% (17/34), respectively (p=0.44). Neonatal mortality in the CST and no CST group was 9% (5/54) and 12% (4/34), respectively (p=0.73). The prevalence of adverse neonatal outcome (neonatal mortality, major neonatal morbidity or severe cerebral lesions) in the CST and no CST group was 28% (15/54) versus 24% (8/34), (p=0.62).

CONCLUSIONS

Administration of CST to growth restricted preterm fetuses does not appear to be beneficial with respect to short term neonatal outcome.

Multiple courses of antenatal corticosteroids for preterm birth (MACS): a randomised controlled trial

BACKGROUND

One course of antenatal corticosteroids reduces the risk of respiratory distress syndrome and neonatal death. Weekly doses given to women who remain undelivered after a single course may have benefits (less respiratory morbidity) or cause harm (reduced growth in utero). We aimed to find out whether multiple courses of antenatal corticosteroids would reduce neonatal morbidity and mortality without adversely affecting fetal growth.

METHODS

1858 women at 25-32 weeks' gestation who remained undelivered 14-21 days after an initial course of antenatal corticosteroids and continued to be at high risk of preterm birth were randomly assigned to multiple courses of antenatal corticosteroids (n=937) or placebo (n=921), every 14 days until week 33 or delivery, whichever came first. The primary outcome was a composite of perinatal or neonatal mortality, severe respiratory distress syndrome, intraventricular haemorrhage (grade III or IV), periventricular leucomalacia, bronchopulmonary dysplasia, or necrotising enterocolitis. Analysis was by intention to treat. All patients and caregivers were unaware of the treatment given. This trial is registered as number ISRCTN2654148.

FINDINGS

Infants exposed to multiple courses of antenatal corticosteroids had similar morbidity and mortality to those exposed to placebo (150 [12.9%] vs 143 [12.5%]). Those receiving multiple doses of corticosteroids also weighed less at birth than those exposed to placebo (2216 g vs 2330 g, p=0.0026), were shorter (44.5 cm vs 45.4 cm, p<0.001), and had a smaller head circumference (31.1 cm vs 31.7 cm, p<0.001).

INTERPRETATION

Multiple courses of antenatal corticosteroids, every 14 days, do not improve preterm-birth outcomes, and are associated with a decreased weight, length, and head circumference at birth. Therefore, this treatment schedule is not recommended.

FUNDING

Canadian Institutes of Health Research.

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?

Prenatal stress and risk for autism

This paper reviews several converging lines of research that suggest that prenatal exposure to environmental stress may increase risk for Autistic Disorder (AD). We first discuss studies finding that prenatal exposure to stressful life events is associated with significantly increased risk of AD, as well as other disorders, such as schizophrenia and depression. We then review evidence from animal and human studies that prenatal stress can produce both (a) abnormal postnatal behaviors that resemble the defining symptoms of AD, and (b) other abnormalities that have elevated rates in AD, such as learning deficits, seizure disorders, perinatal complications, immunologic and neuroinflammatory anomalies, and low postnatal tolerance for stress. We explain why an etiologic role for prenatal stress is compatible with genetic factors in AD, and describe how stress can disrupt fetal brain development. Finally, we discuss implications for understanding underlying processes in AD, including potential gene-environment interactions, and developing new therapies and early prevention programs.

Sex-related variation in compact bone microstructure of the femoral diaphysis in juvenile rabbits

Background

While gross morphological changes in the skeleton between males and females are well know, differences between sexes in the histomorphology are less known. It is important to have knowledge on the bone structure of rabbits, as this is a widely used species in biomedical research. A study was performed to evaluate the association between sex and the compact bone morphology of the femoral diaphysis in juvenile rabbits.

Methods

Seventeen clinically healthy 2–3 month-old rabbits (9 females, 8 males) were included in the study. The rabbits were euthanized and the right femur was sampled for analysis. 70–80 microns thick bone sections of the femoral diaphysis were prepared using standard histological equipment. The qualitative histological characteristics were determined according to internationally accepted classification systems while the quantitative parameters were assessed using the software Scion Image. Areas, perimeters, minimum and maximum diameters of primary osteons' vascular canals, Haversian canals and secondary osteons were measured. Additionally, blood plasma concentrations of progesterone, corticosterone, IGF-I, testosterone and estradiol were analyzed.

Results

Qualitative histological characteristics were similar for both sexes. However, variations of certain quantitative histological characteristics were identified. Measured parameters of the primary osteons' vascular canals were higher in males than for females. On the other hand, females had significant higher values of secondary osteons parameters. Differences in Haversian canals parameters were only significant for minimum diameter.

Conclusion

The study demonstrated that quantitative histological characteristics of compact bone tissue of the femoral diaphysis in juvenile rabbits were sex dependent. The variations may be associated with different growth and modeling of the femur through influence by sex-specific steroids, mechanical loads, genetic factors and a multitude of other sources. The results can be applied in experimental studies focusing on comparison of the skeletal biology of the sexes.

Antenatal administration of granulocyte–macrophage colony-stimulating factor increases fetal lung maturation and endothelial nitric oxide synthase expression in the fetal rat lung

OBJECTIVES

We investigated how maternal administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) induced fetal lung maturation compared with dexamethasone and whether maternal administration of GM-CSF and dexamethasone influenced the fetal lung eNOS expression.

STUDY DESIGN

Thirty pregnant rats were divided into three groups of 10 rats each to receive GM-CSF, dexamethasone or saline solution at 16 days of gestation. Lung maturation using bronchial area and immunohistochemical lung airway epithelium and the vascular endothelial eNOS expression, using H Scores, were evaluated at 18 and 20 days of gestation. The statistical analysis was done with the Kruskal-Wallis test for comparisons of more than two groups and the Mann-Whitney U-test as a post hoc test using SPSS for windows release 10.0. Values of p>0, 0.05 were considered significant.

RESULTS

On the 20th day of gestation both GM-CSF and dexamethasone injections caused a significant increase in fetal lung bronchial area, as compared with the controls (24.9%, 36.8%, 13.4%, respectively, p=0.001). eNOS immunoreactivity was observed in the endothelium of large pulmonary vessels and large and small airway epithelium on the 18th and 20th day of gestation. Maternal GM-CSF and dexamethasone increased lung eNOS expression in the airway epithelium when compared to controls.

CONCLUSION

Maternal administration of GM-CSF induced fetal lung maturation and this effect may be mediated, at least partly, by an increase in the eNOS expression.

Prenatal maternal paroxetine treatment and neonatal mortality in the rat: a preliminary study

Recent evidence has shown that prenatal maternal stress has negative consequences for the mental health of the adult organism. Our aim was to examine the efficacy of using the selective serotonin reuptake inhibitor, paroxetine, to alleviate the symptoms of prenatal maternal stress in Fisher 344 rats. Pregnant rats were subjected to daily restraint stress and concurrent paroxetine treatment (10 mg/kg p.o.) during the last week of gestation. Maternal paroxetine treatment led to a shortened gestational length, reduced birth weight and a 10-fold rise in neonatal mortality in both stressed and non-stressed litters. These results reiterate the need for further research on the effects of paroxetine treatment during gestation.

The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network Beneficial Effects of Antenatal Repeated Steroids study: impact of repeated doses of antenatal corticosteroids on placental growth and histologic findings

OBJECTIVE

In utero exposure to repeated doses of antenatal corticosteroids (ACSs) has been shown to reduce fetal growth. Our goal was to evaluate whether weekly betamethasone (R-ACS) alters placental growth and histologic findings.

STUDY DESIGN

In a multicenter randomized controlled trial of R-ACS vs a single course of ACS followed by weekly placebo (S-ACS), placentas were weighed after removal of the membranes and umbilical cord. A single pathologist who was masked to study group and pregnancy outcomes performed histologic evaluation for placental calcifications, infarction, fibrin deposition, and hemorrhage or thrombus formation, acute and chronic chorioamnionitis, fibromuscular vascular hyperplasia, nucleated red blood cells, and villous crowding, edema, fibrosis, or fibrinoid necrosis. Findings were compared between study groups and according to the number of courses of ACS.

RESULTS

One hundred ninety-four placentas were available for evaluation. Univariable analyses revealed no differences between study groups in any of the 19 evaluated histologic parameters between R-ACS and S-ACS groups overall or in analyses that were restricted to deliveries at < 32 or > or = 32 weeks of gestation. Calcifications were more common (P = .045) in the R-ACS group after controlling for other factors. Multivariable analysis revealed increasing gestational age at delivery, but not increasing ACS courses, to be associated with decreasing chorionic inflammation, villous edema, and fibrosis and with increasing villus crowding, fibrin deposition, and calcifications. Ninety-three placentas were weighed before formalin fixation. After controlling for delivery gestation and infant gender, placental weight was significantly lower in the R-ACS group (P = .017) and was related inversely to the number of ACS courses (P = .037). This finding was confirmed only for deliveries at > or = 32 weeks of gestation (525 vs 441 g for R-ACS and S-ACS group, respectively; P = .036).

CONCLUSION

Repeated antenatal corticosteroid treatments in pregnancy are associated with decreased placental growth in a dose-dependent fashion, but not with evident differences in histologic markers of placental inflammation, ischemia, or infarction. Histologic placental abnormalities should not be attributed to repeated courses of corticosteroids.