Relationship between antenatal steroid administration and grades III and IV intracranial hemorrhage in low birth weight infants. The NICHD Neonatal Research Network

The need for assisted ventilation corroborates the effectiveness of antenatal corticosteroid therapy in preventing premature lamb mortality

In premature births, deficiency and/or inactivation of surfactant and incomplete development of lung occur, leading to pulmonary complications and greater need for ventilatory interventions. Prenatal corticosteroid therapy is used to improve neonatal lung function and, thus, may reduce mortality and lower incidence and severity of lung injury. Therefore, this study aimed to assess the need for ventilatory support in preterm lambs subjected or not to prenatal betamethasone treatment, and to evaluate the effectiveness on neonatal survival. Lambing was induced and 13 premature lambs were assigned to Corticosteroid Group (n = 8; lambs from ewes subjected previously to 0.5 mg/kg betamethasone, IM, at 133 days of pregnancy) and Control Group (n = 5; non-treated lambs). Lambs were evaluated for vitality, neurologic reflexes, vital functions and birth weight. Three ventilatory modalities were preconized for critical lambs, according to specific criteria: mask oxygen therapy, self-inflating bag with tracheal tube and mechanical ventilation. Non-treated lambs had lower vitality score, muscle tonus and respiratory rate compared to Corticosteroid Group. Ventilatory support was needed for 3 Control lambs and only 1 Corticosteroid neonate. Corticosteroid lamb required significant less time-frame between birth and onset of ventilatory assistance and remained under ventilation for a shorter time. Percentage of ventilated non-treated lambs correlated negatively with birth weight, muscle tone, heart and respiratory rate. In conclusion, antenatal betamethasone treatment reduces the need for ventilatory assistance in premature lambs. Additionally, mortality is low when a protocol for inducing pulmonary maturity (maternal corticosteroid therapy) and/or ventilatory interventions are employed, ensuring the survival of premature lambs.

Does Antenatal Progesterone Administration Modify the Risk of Neonatal Intraventricular Hemorrhage?

OBJECTIVE

Progesterone administration has been associated with improved neurological outcomes following traumatic brain injury in adults. However, studies examining the effect of progesterone on the risk of neonatal intraventricular hemorrhage (IVH) are inconsistent. We sought to determine if maternal administration of intramuscular 17-α-hydroxyprogesterone caproate (17-OHPC) is associated with decreased rates of IVH in infants born before 32-weeks gestation.

STUDY DESIGN

This is a retrospective study of liveborn singleton deliveries between 20- and 32-weeks gestation at two large academic medical centers from January 1, 2012 to August 30, 2020. Data were extracted from hospital electronic medical record data warehouses using standardized definitions and billing and diagnosis codes. We evaluated receipt of 17-OHPC in the antepartum period and diagnosis of IVH (grade I-IV, per Volpe classification) during the neonatal delivery hospitalization encounter. Bivariate and multivariate analyses were performed to examine the association between 17-OHPC and neonatal IVH adjusting for potential confounders. Odds ratio (ORs) and 95% confidence intervals (CIs) were presented.

RESULTS

Among 749 neonates born between 20- and 32-week gestation, 140 (18.7%) of their mothers had received antenatal 17-OHPC and 148 (19.8%) were diagnosed with IVH after birth. No significant association was observed between maternal 17-OHPC and neonatal IVH in unadjusted (OR 1.14, 95% CI 0.72-1.78) or adjusted analyses (adjusted odds ratio 1.14, 95% CI 0.71-1.84). Independent of exposure to 17-OHPC, as expected, infants born <28-weeks gestation or those with very low birthweight (<1,500 g) were at an increased risk of IVH (OR 2.32, 95% CI 1.55-3.48 and OR 2.19, 95% CI 1.09-4.38, respectively).

CONCLUSION

Antenatal maternal 17-OHPC administration was not associated with the risk of neonatal IVH. Further research may be warranted to determine whether timing, route of delivery, and duration of progesterone therapy impact rates of neonatal IVH.

KEY POINTS

· This study aimed to compare the frequency of intraventricular hemorrhage in preterm neonates exposed to antenatal 17-α-hydroxyprogesterone caproate to those not exposed.. · In neonates born at <32-weeks gestation, maternal use of progesterone is not associated with the risk of intraventricular hemorrhage.. · In contrast to preclinical and adult data, this study suggests that progesterone exposure is not associated with the prevention of neonatal brain injury..

Clinical Variables Associated With Grade III and IV Intraventricular Hemorrhage (IVH) in Preterm Infants Weighing Less Than 750 Grams

BACKGROUND

Despite innovative advances in neonatal medicine, intraventricular hemorrhage (IVH) continues to be a significant complication in neonatal intensive care units globally.

OBJECTIVE

The study aimed to discern the variables heightening the risk of severe IVH (Grade III and IV) in extremely premature infants weighing less than 750 grams. We postulated that a descending hematocrit (Hct) trend during the first week of life could serve as a predictive marker for the development of severe IVH in this vulnerable population.

METHODS

This retrospective case-control study encompassed infants weighing less than 750 grams at birth, diagnosed with Grade III and/or IV IVH, and born in a tertiary center from 2009 to 2014. A group of 17 infants with severe IVH was compared with 14 gestational age-matched controls. Acid-base status, glucose, fluid goal, urine output, and nutrient (caloric and protein) intake during the first four days of life were meticulously evaluated. Statistically significant variables from baseline data were further analyzed via univariable and multivariable logistic regression analyses, ensuring control for potential confounding variables.

RESULTS

The univariate logistic regression model delineated odds ratios (ORs) of 0.842 for day 2 average Hct (confidence interval [CI], 0.718-0.987) and 0.16 for urine output on day 3 (CI, 0.024-1.056), with the remaining six variables demonstrating no significant association. In the post-multivariable regression analysis, day 2 Hct was the only significant variable (OR, 0.731; 95% CI, 0.537-0.995; P=0.04). The receiver operating characteristic (ROC) curve analysis portrayed an area under the curve of 71% for the day 2 Hct variable.

CONCLUSION

The study revealed that a dip in Hct on day 2 of life augments the likelihood of Grade III and IV IVH among extremely premature infants with a birth weight of less than 750 grams. This insight amplifies our understanding of risk factors associated with severe IVH development in extremely preterm infants, potentially aiding in refining preventive strategies and optimizing clinical management and treatment of these affected infants.

Impact of a “Brain Protection Bundle” in Reducing Severe Intraventricular Hemorrhage in Preterm Infants <30 Weeks GA: A Retrospective Single Centre Study

Background: despite advances in perinatal care, periventricular/intraventricular hemorrhage (IVH) continues to remain high in neonatal intensive care units (NICUs) worldwide. Studies have demonstrated the benefits of implementing interventions during the antenatal period, stabilization after birth (golden hour management) and postnatally in the first 72 h to reduce the incidence of IVH. Objective: to compare the incidence of severe intraventricular hemorrhage (IVH ≥ Grade III) before and after implementation of a “brain protection bundle” in preterm infants <30 weeks GA. Study design: a pre- and post-implementation retrospective cohort study to compare the incidence of severe IVH following execution of a “brain protection bundle for the first 72 h from 2015 to 2018. Demographics, management practices at birth and in the NICU, cranial ultrasound results and short-term morbidities were compared. Results: a total of 189 and 215 infants were included in the pre- and post-implementation phase, respectively. No difference in the incidence of severe IVH (6.9% vs. 9.8%, p = 0.37) was observed on the first cranial scan performed after 72 h of age. Conclusion: the implementation of a “brain protection bundle” was not effective in reducing the incidence of severe IVH within the first 72 h of life in our centre.

Reduction of severe intraventricular hemorrhage, a tertiary single-center experience: incidence trends, associated risk factors, and hospital policy

OBJECTIVES

To determine the incidence, trends, maternal and neonatal risk factors of severe intraventricular hemorrhage (IVH) among infants born 24-32 weeks and/or < 1500 g, and to evaluate the impact of changing of hospital policies and unit clinical practice on the IVH incidence.

STUDY DESIGN

Retrospective chart review of preterm infants with a gestational age (GA) of 24-32⁶ weeks and/or weight of < 1500 g born at King Abdulaziz Medical City-Riyadh (KAMC-R), Saudi Arabia, from 2016 to 2018. Multivariate logistic regression model was constructed to determine the probability of developing severe IVH and identify associations with maternal and neonatal risk factors.

RESULTS

Among 640 infants, the overall incidence of severe IVH was 6.4% (41 infants), and its rate decreased significantly, from 9.4% in 2016 to 4.5% and 5% in 2017 and 2018 (p = 0.044). Multivariate analysis revealed that caesarian section delivery decreased the risk of severe IVH in GA group 24-27 weeks (p = 0.045). Furthermore use of inotropes (p = 0.0004) and surfactant (p = 0.0003) increased the risk of severe IVH. Despite increasing use of inotropes (p = 0.024), surfactant therapy (p = 0.034), and need for delivery room intubation (p = 0.015), there was a significant reduction in the incidence of severe IVH following the change in unit clinical practice and hospital policy (p = 0.007).

CONCLUSION

Cesarean section was associated with decreased all grades of IVH and severe IVH, while use of inotropes was associated with increased severe IVH. The changes in hospital and unit policy were correlated with decreased IVH during the study period.

A preliminary evaluation of glial cell line-derived neurotrophic factor (GDNF) levels in cerebrospinal fluid across various gestational ages and clinical conditions of the neonate

BACKGROUND

This study aims to investigate glial cell derived neurotrophic factor (GDNF) levels in newborns' umbilical cord blood and cerebrospinal fluid across various perinatal growth parameters and clinical conditions.

METHODS

Cord blood from 20 newborns and 58 residual CSF samples (stored after completion of clinical testing) were collected. GDNF levels were determined using GDNF ELISA kits from R&D Systems in triplicates with appropriate controls to eliminate background.

RESULTS

Cord blood GDNF levels were significantly higher (p=0.004) in preterm newborns (n=6) (115.05±57.17,pg/ml) when compared to term newborns (n=14) (19.67±10.67,pg/ml). GDNF levels in CSF trended (p=0.07) higher in term newborns (n=10) (19.56±9.11,pg/ml) when compared to preterm newborns at term or post term corrected gestational ages (n=5) (14.49±3.53,pg/ml).

CONCLUSIONS

GDNF levels in preterm newborns were higher in cord blood and lower in CSF as compared to term newborns. It is important to further study circulating and CSF-GDNF levels in newborns at different gestational ages and clinical conditions.

Hypertensive disorders of pregnancy and outcomes of preterm infants of 24 to 28 weeks' gestation

OBJECTIVE

To examine the relationship between hypertensive disorders of pregnancy (HDPs) and mortality and major morbidities in preterm neonates born at 24 to 28 weeks of gestation.

STUDY DESIGN

Using an international cohort, we retrospectively studied 27 846 preterm neonates born at 24⁰ to 28⁶ weeks of gestation during 2007 to 2010 from 6 national neonatal databases. The incidence of HDP was compared across countries, and multivariable logistic regression analyses were conducted to examine the association of HDP and neonatal outcomes including mortality to discharge, bronchopulmonary dysplasia, severe brain injury, necrotizing enterocolitis and treated retinopathy of prematurity.

RESULTS

The incidence of HDP in the entire cohort was 13% (range 11 to 16% across countries). HDP was associated with reduced odds of mortality (adjusted odds ratio (aOR) 0.77; 95% confidence interval (CI) 0.67 to 0.88), severe brain injury (aOR 0.74; 95% CI 0.62 to 0.89) and treated retinopathy (aOR 0.82; 95% CI 0.70 to 0.96), but increased odds of bronchopulmonary dysplasia (aOR 1.16; 95% CI 1.05 to 1.27).

CONCLUSIONS

In comparison with neonates born to mothers without HDP, neonates of HDP mothers had lower odds of mortality, severe brain injury and treated retinopathy, but higher odds of bronchopulmonary dysplasia. The impact of maternal HDP on newborn outcomes was inconsistent across outcomes and among countries; therefore, further international collaboration to standardize terminology, case definition and data capture is warranted.

Perinatal management: What has been learned through the network?

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) has examined the effects of various obstetrical perinatal interventions and neonatal delivery room practices on the newborn with particular focus on those born preterm. Studies exploring the effects and safety of various antepartum maternal medications and the effects of the route and timing of delivery are examined. The NRN has contributed key studies to the evidence base for the International Liaison Committee on Resuscitation neonatal resuscitation guidelines. These studies are reviewed including research on timing of cord clamping, the importance of maintaining euthermia immediately after birth, delivery room ventilation strategies, outcomes following delivery room cardiopulmonary resuscitation, and the effects of prolonged resuscitation efforts. In addition, the NRN's detailed outcome data at the lowest gestational ages have greatly influenced on how providers counsel families regarding the appropriateness of resuscitation efforts at the lowest gestational ages.

Impact of antenatal steroids on intraventricular hemorrhage in very-low-birth weight infants

OBJECTIVE

To determine the association between antenatal steroids administration and intraventricular hemorrhage rates.

METHODS

We used cross-sectional data from the California Perinatal Quality Care Collaborative during 2007 to 2013 for infants ⩽32 weeks gestational age. Using multivariable logistic regression, we evaluated the effect of antenatal steroids on intraventricular hemorrhage, stratified by gestational age.

RESULTS

In 25 979 very-low-birth weight infants, antenatal steroid use was associated with a reduction in incidence of any grade of intraventricular hemorrhage (odds ratio=0.68, 95% confidence interval: 0.62, 0.75) and a reduction in incidence of severe intraventricular hemorrhage (odds ratio=0.51, 95% confidence interval: 0.45, 0.58). This association was seen across gestational ages ranging from 22 to 29 weeks.

CONCLUSIONS

Although current guidelines recommend coverage for preterm birth at 24 to 34 weeks gestation, our results suggest that treatment with antenatal steroids may be beneficial even before 24 weeks of gestational age.

PPARγ-induced upregulation of CD36 enhances hematoma resolution and attenuates long-term neurological deficits after germinal matrix hemorrhage in neonatal rats

Germinal matrix hemorrhage remains the leading cause of morbidity and mortality in preterm infants in the United States with little progress made in its clinical management. Survivors are often afflicted with long-term neurological sequelae, including cerebral palsy, mental retardation, hydrocephalus, and psychiatric disorders. Blood clots disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage are thought to be important contributors towards post-hemorrhagic hydrocephalus development. We evaluated if upregulating CD36 scavenger receptor expression in microglia and macrophages through PPARγ stimulation, which was effective in experimental adult cerebral hemorrhage models and is being evaluated clinically, will enhance hematoma resolution and ameliorate long-term brain sequelae using a neonatal rat germinal matrix hemorrhage model. PPARγ stimulation (15d-PGJ2) increased short-term PPARγ and CD36 expression levels as well as enhanced hematoma resolution, which was reversed by a PPARγ antagonist (GW9662) and CD36 siRNA. PPARγ stimulation (15d-PGJ2) also reduced long-term white matter loss and post-hemorrhagic ventricular dilation as well as improved neurofunctional outcomes, which were reversed by a PPARγ antagonist (GW9662). PPARγ-induced upregulation of CD36 in macrophages and microglia is, therefore, critical for enhancing hematoma resolution and ameliorating long-term brain sequelae.

Pathogenesis and prevention of intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is a major neurologic complication of prematurity. Pathogenesis of IVH is attributed to intrinsic fragility of germinal matrix vasculature and to the fluctuation in the cerebral blood flow. Germinal matrix exhibits rapid angiogenesis orchestrating formation of immature vessels. Prenatal glucocorticoid exposure remains the most effective means of preventing IVH. Therapies targeted to enhance the stability of the germinal matrix vasculature and minimize fluctuation in the cerebral blood flow might lead to more effective strategies in preventing IVH.

Vulnerability of the developing brain to hypoxic-ischemic damage: contribution of the cerebral vasculature to injury and repair?

As clinicians attempt to understand the underlying reasons for the vulnerability of different regions of the developing brain to injury, it is apparent that little is known as to how hypoxia-ischemia may affect the cerebrovasculature in the developing infant. Most of the research investigating the pathogenesis of perinatal brain injury following hypoxia-ischemia has focused on excitotoxicity, oxidative stress and an inflammatory response, with the response of the developing cerebrovasculature receiving less attention. This is surprising as the presentation of devastating and permanent injury such as germinal matrix-intraventricular haemorrhage (GM-IVH) and perinatal stroke are of vascular origin, and the origin of periventricular leukomalacia (PVL) may also arise from poor perfusion of the white matter. This highlights that cerebrovasculature injury following hypoxia could primarily be responsible for the injury seen in the brain of many infants diagnosed with hypoxic-ischemic encephalopathy (HIE). Interestingly the highly dynamic nature of the cerebral blood vessels in the fetus, and the fluctuations of cerebral blood flow and metabolic demand that occur following hypoxia suggest that the response of blood vessels could explain both regional protection and vulnerability in the developing brain. However, research into how blood vessels respond following hypoxia-ischemia have mostly been conducted in adult models of ischemia or stroke, further highlighting the need to investigate how the developing cerebrovasculature responds and the possible contribution to perinatal brain injury following hypoxia. This review discusses the current concepts on the pathogenesis of perinatal brain injury, the development of the fetal cerebrovasculature and the blood brain barrier (BBB), and key mediators involved with the response of cerebral blood vessels to hypoxia.

Antepartum eclampsia <34 weeks case series: advisable to postpone delivery to administer corticosteroids for fetal pulmonary benefit?

OBJECTIVE

To determine if postponement of delivery to administer fetal lung maturation corticosteroids (PDACs) in mothers with antepartum eclampsia <34 weeks gestation benefits the fetus without compromising the mother.

STUDY DESIGN

A case series of 37 maternal-perinatal pairs over a 9-year period with antepartum eclampsia between 24 and 34 weeks gestation from a single tertiary center were reviewed retrospectively. Duration of PDAC, clinical course and maternal-fetal outcomes, including impact of duration of PDAC on neonatal pulmonary function, were recorded for each case. Group assignment was based on length of corticosteroid treatment course before delivery: Group A, 0 to ≤ 24 h, n=28; B, 24 to <48 h, n=5; C, ≥ 48 h, n=4. Data were collected and analyzed by one-way analysis of variance (ANOVA), ANOVA on ranks, χ(2)-test and Fisher's exact tests where appropriate; statistical significance was determined by a P-value <0.05.

RESULT

Overall, 37 of 68 eclampsia patients in 1999 to 2007 met inclusion criteria. No adverse maternal or fetal event occurred while delivery was postponed. Immediate neonatal intubation or continuous positive airway pressure was required for 23/28 in A, 4/5 in B and 2/4 in C; room air was sufficient at birth for 5/28 in A, 1/5 in B and 2/4 in C. No newborn >33 weeks gestation required INI. Prolonged (that is, >1 day) mechanical ventilation was not required for any infant with a gestational age ≥ 32 weeks or PDAC ≥ 48 h. Two of three neonatal deaths in group A were attributed to pulmonary insufficiency.

CONCLUSION

PDAC for antepartum preterm eclampsia, especially ≤ 32 weeks gestation, appears to offer notable fetal pulmonary benefit without significantly increasing maternal or fetal risk.

Uso antenatal do corticosteroide e hemorragia peri-intraventricular

OBJETIVO: Realizar uma revisão bibliográfica sobre o uso antenatal do corticosteroide na prevenção da hemorragia peri-intraventricular. FONTES DE DADOS: Levantamento bibliográfico por meio do Pubmed e SciELO abrangendo os últimos 20 anos. Foram utilizadas as palavras chaves no idioma inglês: "cerebral hemorrhage", "steroids" e "newborn, infant". SÍNTESES DE DADOS: A hemorragia peri-intraventricular é uma importante patologia nos prematuros, sobretudo nos menores de 34 semanas, devido a suas graves sequelas neurológicas. Uma vez ocorrido o sangramento, não há tratamento específico. Desta forma, a prevenção torna-se o maior objetivo das pesquisas. O resultado da meta-análise de estudos randomizados demonstrou que o corticosteroide antenatal reduz a mortalidade e a incidência da doença de membrana hialina e da hemorragia peri-intraventricular. O efeito protetor na redução do risco da hemorragia peri-intraventricular não está completamente esclarecido. Além de acelerar a maturidade pulmonar, o corticosteroide antenatal estimula a maturação da microvasculatura da matriz germinativa, promove o espessamento da membrana basal, acelera a formação proteica nas junções firmes e estabiliza o fluxo sanguíneo cerebral. Também melhora as condições de nascimento dos fetos pré-termo. CONCLUSÕES: O uso antenatal do corticosteroide associado à implementação de melhores práticas de atendimento ao prematuro tem sido responsável pela evidente redução dos índices dessa doença. Apesar de comprovada eficácia e segurança, não é amplamente utilizado. Medidas devem ser tomadas para estimular seu uso como prática rotineira no atendimento de gestantes com risco de parto prematuro.

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.

Neurodevelopmental outcomes of extremely low birth weight infants exposed prenatally to dexamethasone versus betamethasone

OBJECTIVE

We compared the development of adverse neurodevelopmental outcomes at corrected ages of 18 to 22 months for extremely low birth weight infants exposed prenatally to dexamethasone, betamethasone, or no steroid.

METHODS

Study infants were extremely low birth weight (401-1000 g) infants who were in the care of National Institute of Child Health and Human Development Neonatal Research Network centers between January 1, 2002, and April 30, 2003; they were assessed neurodevelopmentally at corrected ages of 18 to 22 months. Outcomes were defined as Bayley Scales of Infant Development-II Mental Development Index of < 70, Bayley Scales of Infant Development-II Psychomotor Development Index of < 70, bilateral blindness, bilateral hearing aid use, cerebral palsy, and neurodevelopmental impairment. Neurodevelopmental impairment was defined as > or = 1 of the aforementioned outcomes.

RESULTS

A total of 1124 infants met entry criteria. There were no statistically significant associations between prenatal dexamethasone exposure and any follow-up outcome, compared with no prenatal steroid exposure. Prenatal betamethasone exposure was associated with reduced risks of hearing impairment and neurodevelopmental impairment and with increased likelihood of unimpaired status, compared with no prenatal steroid exposure. Compared with betamethasone, dexamethasone was associated with a trend for increased risk of Psychomotor Development Index of < 70, increased risk of hearing impairment, and decreased likelihood of unimpaired status.

CONCLUSIONS

Prenatal betamethasone exposure was associated with increased likelihood of unimpaired neurodevelopmental status and reduced risk of hearing impairment at corrected ages of 18 to 22 months among extremely low birth weight infants, compared with prenatal dexamethasone exposure or no prenatal steroid exposure. Pending a randomized, clinical trial, it may be in the best interests of infants to receive betamethasone, rather than dexamethasone, when possible.

Corticosteroids in perinatal medicine: how to improve outcomes without affecting the developing brain?

Antenatal glucocorticoid therapy remains one of the most striking successes in the perinatal management of complicated pregnancies that result in premature birth. The anti-inflammatory and maturative properties of fluorocorticoids are such that all women at risk of preterm delivery before 34weeks gestation should be treated. Betamethasone is preferred to dexamethasone and no more than two courses, 2weeks apart, should be given until the evidence from further controlled trials on repeated doses becomes available. In particular, the early use of postnatal dexamethasone should be avoided in preterm infants because of the deleterious effects on neurological development, including not only cerebral palsy but also cognitive function and psychiatric-related behavior. Treatment with other steroids should be restricted to the context of randomized controlled trials.

Adverse neonatal outcomes associated with antenatal dexamethasone versus antenatal betamethasone

OBJECTIVE

Antenatal dexamethasone and betamethasone may not be equally efficacious in the prevention of adverse neonatal outcomes. We compared the risks of periventricular leukomalacia (PVL), intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP), and neonatal death among very low birth weight infants who were exposed to dexamethasone, betamethasone, or neither steroid.

METHODS

Infants (401-1500 g) in the National Institute of Child Health and Human Development Neonatal Research Network were studied. Multivariate logistic regression analyses compared the 3 groups with regard to PVL, IVH, ROP, and neonatal death, adjusting for network center and selected covariates.

RESULTS

A total of 3600 infants met entry criteria. Compared with no antenatal steroids, there were trends for a reduced risk for PVL associated with dexamethasone and betamethasone but no difference in risk between dexamethasone and betamethasone. Dexamethasone reduced the risk for IVH and severe IVH, compared with no antenatal steroid exposure. Betamethasone reduced the risk for IVH, severe IVH, and neonatal death, compared with no antenatal steroids. Compared with betamethasone, dexamethasone had a statistically significant increased risk for neonatal death. There were trends for greater risks associated with dexamethasone compared with betamethasone for IVH and severe ROP.

CONCLUSIONS

Betamethasone was associated with a reduced risk for neonatal death, with trends of decreased risk for other adverse neonatal outcomes, compared with dexamethasone. It may be in the best interest of neonates to receive betamethasone rather than dexamethasone when available.

Cardiac effects of a single course of antenatal betamethasone in preterm infants

AIM

To show the effects of a single course of antenatal betamethasone on cardiac measurements and systolic functions in premature newborn infants.

METHODS

Seventy six newborn infants with a gestational age of 25-33 weeks were included in the study. They were first classified according to their gestational age: 25-29 weeks (n = 28) and 30-33 weeks (n = 48). They were then reclassified as betamethasone positive (mother received one course of betamethasone) or betamethasone negative (mother did not receive any antenatal glucocorticoid treatment). Cross sectional M mode echocardiographic scans were performed during the first three postnatal days and at the end of the first and third weeks. Left interventricular septum (IVS), left ventricular posterior wall (LVPW), left ventricular end diastolic (LVED), and left ventricular end systolic (LVES) dimensions, aortic root (AO), and left atrial diameters (LAs) were measured. The IVS to LVPW ratio was calculated to identify asymmetrical septal hypertrophy.

RESULTS

In neither group was any statistically significant difference noted in IVS, LVED, LVES, LVPW, LA, and AO measurements during the three cardiac ultrasonography scans. Systolic function, as assessed by fractional shortening, was not significantly different in infants who received betamethasone antenatally, in either age group. There was no difference in the IVS/LVPW ratios between those who received antenatal steroid and those who did not for the 25-29 week and 30-33 week groups during these three consecutive scans.

CONCLUSION

One course of antenatal betamethasone did not affect the cardiac wall thicknesses and systolic function in premature infants.

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.

Umbilical vein interleukin-6 levels in very low birth weight infants developing intraventricular hemorrhage

To assess the relationship between perinatal infection/inflammation as reflected by umbilical vein interleukin-6 (IL-6) levels and the development of periventricular-intraventricular hemorrhage (IVH) in very low birth weight (VLBW) infants, we tested the hypothesis that VLBW infants who develop IVH have higher concentrations of IL-6 in an umbilical vein sample compared to infants without IVH. An inception cohort of 69 VLBW infants was followed from birth until discharge or death to determine the development of IVH by serial neuroultrasounds. Umbilical vein IL-6 levels were measured using commercially available ELISA kit (Endogen Laboratories, Woburn, MA) and compared in IVH and control cohorts. Twenty-two (32%) infants developed IVH, including 18 (82%) with grade I or II and 4 (18%) with grade III or IV. One of these infants also developed periventricular leukomalacia. The umbilical vein IL-6 levels were significantly elevated in infants with IVH with median value of 87 pg/ml (25th percentile value 30 pg/ml and 75th percentile value 310 pg/ml) compared with infants without IVH, with a median value of 0 pg/ml (25th percentile value 0 pm/ml and 75th percentile value 4 pg/ml) (P = 0.007). Umbilical vein IL-6 levels are elevated in neonates who subsequently develop IVH.

Changes in neonatology: comparison of two cohorts of very preterm infants (gestational age <32 weeks): the Project On Preterm and Small for Gestational Age Infants 1983 and the Leiden Follow-Up Project on Prematurity 1996-1997

OBJECTIVE

To determine changes in peri- and neonatal care concerning neonatal mortality and morbidity by comparing 2 cohorts of very prematurely born infants (gestational age [GA] <32 weeks), 1 from the 1980s and 1 from the 1990s.

METHODS

The Leiden Follow-Up Project on Prematurity (LFUPP-1996/97), a regional, prospective study, includes all infants who were born alive after a GA <32 weeks in 1996 and 1997 in the Dutch health regions Leiden, The Hague, and Delft. The Project On Preterm and Small for Gestational Age Infants (POPS-1983), a national, prospective study from the presurfactant era, includes all liveborn infants <32 weeks' GA and/or <1500 g from 1983 (n = 1338). For comparison, infants from the POPS-1983 cohort with a GA <32 weeks from the same Dutch health regions were selected (n = 102).

RESULTS

The absolute number of preterm births in the study region increased by 30%: 102 in 1983 to on average of 133 in 1996-1997. Centralization of perinatal care improved: the percentage of extrauterinely transported infants decreased from 61% in 1983 to 35% in 1996-1997. A total of 182 (73%) of the LFUPP-1996/97 infants were treated antenatally with glucocorticosteroids compared with 6 (6%) of the POPS-1983 infants. A total of 112 (42%) of the LFUPP-1996/97 infants received surfactant. In-hospital mortality decreased from 30% in the 1980s to 11% in the 1990s. Mortality of the extremely preterm infants (<27 weeks) decreased from 76% to 33%. The incidence of respiratory distress syndrome remained the same: approximately 60% in both groups. Mortality from respiratory distress syndrome, however, decreased from 29% to 8%. The incidence of bronchopulmonary dysplasia increased from 6% to 19%. For the surviving infants, the average length of stay in the hospital and the mean number of NICU days stayed approximately the same ( approximately 67 days total admission time and 44 NICU days in both groups); including the infants who died, the mean NICU admission time increased from 27 days in the 1980s to 41 days in the 1990s. Equal percentages of adverse outcome (dead or an abnormal general condition) at the moment of discharge from hospital were found (+/-40% in both groups).

CONCLUSIONS

An increase in the absolute number of very preterm births in this study region was found, leading to a greater burden on the regional NICUs. Improvements in peri- and neonatal care have led to an increased survival of especially extremely preterm infants. However, increased survival has resulted in more morbidity, mainly bronchopulmonary dysplasia, at the moment of discharge from the hospital.

Prenatal and postnatal steroid therapy and child neurodevelopment

In recent years, scientific evidence has accumulated on the potential neuro-toxic effects of perinatal steroid therapy on the incompletely developed brain; therefore, much effort has been directed toward finding the optimal regimen that may reduce lung disease without incurring significant brain injury in fetuses and preterm infants. Current recommendations of the NIH endorse a single course of prenatal steroids in cases of imminent preterm delivery. Postnatal steroid therapy should be limited, according to the American Association of Pediatrics Guide-lines, to selected clinical cases after the first week of life. These cautions aim to decrease possible harmful effects that could affect short- and long-term neuro-developmental outcome in this high-risk population.

Decreasing incidence of chronic lung disease despite the gradual reduction of postnatal dexamethasone use in very low birth weight infants

Dexamethasone has been widely used in very low birth weight infants (VLBWI) weighing less than 1,500 g at birth for the prevention or treatment of chronic lung disease (CLD). Recently, however the use of dexamethasone is being reduced, as its association with abnormal neurodevelopmental outcome is known. On the other hand, there have been persistent concerns about the increased risk of CLD according to the reduction of postnatal dexamethasone use. Hence, we did a retrospective cohort study to delineate the change in the incidence of CLD according to the reduction of dexamethasone use in VLBWI. The medical records of 559 VLBWI admitted to neonatal intensive care unit at Samsung Medical Center between November 1994 and December 2002 were reviewed with a focus on the use of postnatal dexamethasone and the incidence of CLD. The use of postnatal dexamethasone has significantly decreased over the study period. Especially, the use of high-dose regimen has markedly decreased. The day when postnatal dexamethasone therapy was begun has also been significantly delayed. The incidence of CLD has significantly decreased over the same period. In conclusion, the incidence of CLD has not increased despite the decreased use of postnatal dexamethasone.

Antenatal corticosteroid therapy: benefits and risks

Antenatal glucocorticoid therapy remains one the most striking successes in perinatal management of complicated pregnancies leading to premature birth. All women at risk of preterm delivery before 34 weeks gestation should be treated, given the anti-inflammatory and maturative properties of fluorocorticoids. Betamethasone is preferred to dexamethasone and no more than two courses, two weeks apart, should be given, until the evidence from further controlled trials on repeated doses becomes available.

Partial or complete antenatal steroids treatment and neonatal outcome in extremely low birth weight infants < or =1000 g: is there a dose-dependent effect?

OBJECTIVES

To assess the outcome of extremely low birth weight (ELBW) infants < or =1000 g as it relates to antenatal steroids (ANS) therapy.

STUDY DESIGN

A retrospective analysis of 124 infants born between January 1995 and December 1997. Infants born to mothers with pregnancy-induced hypertension, diabetes, and severe growth restriction were excluded. In all, 77 (62%) infants were exposed to ANS, of whom 31 (25%) received one to two doses (partial course), and 46 (37%) received three to four doses (complete course). A total of 47 infants (38%) were not exposed to ANS.

RESULTS

Infants not exposed to ANS, who exhibited more HMD, PDA, and IVH, were administered more surfactants, and were more likely to die versus infants with complete ANS dosing. Regression models revealed a dose-dependent effect of ANS on HMD, surfactant use, IVH, and CLD or death, with a significant decrease in HMD with > or =2 ANS doses.

CONCLUSIONS

ANS, in a dose-dependent way, are associated with improved outcome in ELBW infants < or =1000 g, with the best outcome seen after a complete course.

Antenatal treatment with corticosteroids for preterm neonates: impact on the incidence of respiratory distress syndrome and intra-hospital mortality

CONTEXT

Although the benefits of antenatal corticosteroids have been widely demonstrated in other countries, there are few studies among Brazilian newborn infants.

OBJECTIVE

To evaluate the effectiveness of antenatal corticosteroids on the incidence of respiratory distress syndrome and intra-hospital mortality among neonates with a gestational age of less than 34 weeks.

TYPE OF STUDY

Cross-sectional.

SETTING

A tertiary-care hospital.

PARTICIPANTS

Neonates exposed to any dose of antenatal corticosteroids for fetal maturation up to 7 days before delivery, and newborns paired by sex, birth weight, gestational age and time of birth that were not exposed to antenatal corticosteroids. The sample obtained consisted of 205 exposed newborns, 205 non-exposed and 39 newborns exposed to antenatal corticosteroids for whom it was not possible to find an unexposed pair.

PROCEDURES

Analysis of maternal and newborn records.

MAIN MEASUREMENTS

The primary clinical outcomes for the two groups were compared: the incidence of respiratory distress syndrome and intra-hospital mortality; as well as secondary outcomes related to neonatal morbidity.

RESULTS

Antenatal corticosteroids reduced the occurrence of respiratory distress syndrome (OR: 0.33; 95% CI: 0.21-0.51) and the protective effect persisted when adjusted for weight, gestational age and the presence of asphyxia (adjusted OR: 0.27; 95% CI: 0.17-0.43). The protective effect could also be detected through the reduction in the need for and number of doses of exogenous surfactant utilized and the number of days of mechanical ventilation needed for the newborns exposed to antenatal corticosteroids. Their use also reduced the occurrence of intra-hospital deaths (OR: 0.51: 95% CI: 0.38-0.82). However, when adjusted for weight, gestational age, presence of prenatal asphyxia, respiratory distress syndrome, necrotizing enterocolitis and use of mechanical ventilation, the antenatal corticosteroids did not maintain the protective effect in relation to death. With regard to other outcomes, antenatal corticosteroids reduced the incidence of intraventricular hemorrhage grades III and IV (OR: 0.28; 95% CI: 0.10-0.77).

CONCLUSIONS

Antenatal corticosteroids were effective in the reduction of morbidity and mortality among premature newborns in the population studied, and therefore their use should be stimulated within our environment.

Association of antenatal and postnatal dexamethasone exposure with outcomes in extremely low birth weight neonates

BACKGROUND

Recent studies of preterm neonates have indicated that antenatal dexamethasone (ADX) may have adverse effects on cranial ultrasound findings at the time of hospital discharge, including periventricular leukomalacia. Furthermore, both ADX and postnatal dexamethasone (PDX) may have adverse effects on subsequent neurodevelopmental outcome.

OBJECTIVES

1) To assess the effects of ADX exposure on cranial ultrasound findings at the time of hospital discharge and 2) to evaluate the individual effects of ADX and/or PDX exposure on subsequent neurodevelopmental outcome in extremely low birth weight (ELBW) neonates in whom confounding risk factors known to influence outcome were controlled.

METHODS

One hundred seventy-three ELBW (< or =1000 g) neonates were studied using a prospectively collected database and hospital and clinic records. Study patients were assigned to 1 of 4 groups according to dexamethasone exposure: group I, no dexamethasone exposure; group II, ADX exposure to hasten fetal lung maturity; group III, PDX exposure for chronic lung disease; group IV, both ADX and PDX exposure. The 4 groups were compared using multinomial logistic regression or analysis of covariance to control for confounding variables. Primary outcome variables were cranial ultrasound findings at hospital discharge and results of developmental testing at 18 to 22 months' corrected age (Bayley Scales of Infant Development).

RESULTS

Cranial ultrasound results as well as Bayley Scales of Infant Development scores were similar in groups I and II and in groups III and IV. The likelihood of abnormal cranial ultrasound studies and lower scores on neurodevelopmental testing was greater in groups III and IV versus groups I and II. In this study, ADX did not seem to increase the risk of periventricular leukomalacia.

CONCLUSIONS

ADX exposure is not associated with an increase in abnormal cranial ultrasound findings in ELBW neonates. PDX exposure, but not ADX exposure, is associated with worse neurodevelopmental outcome in this population. These results are supportive of the recent statement by the American Academy of Pediatrics (Committee on Fetus and Newborn) and the Canadian Paediatric Society (Fetus and Newborn Committee) and emphasize that PDX should be used with caution in ELBW neonates.

Do we use too much antenatal betamethasone?

OBJECTIVE

To review and rationalize the liberal use of antenatal betamethasone in the setting of threatened preterm birth.

STUDY DESIGN

A retrospective review was performed using the charts of all patients at Ste-Justine Hospital, Montreal QC, who received antenatal betamethasone between 01 April 1997 and 31 March 1998. Initial treatment consisted of 2 doses of 12 mg IM given 24 hours apart. Repeat doses of 12 mg weekly were administered at the discretion of the treating physician. Optimal antenatal betamethasone therapy was defined as delivery within 1 week of initial treatment, prior to 34 weeks. Aside from number and timing of doses, other factors analyzed included: gestational age at admission and delivery, diagnosis associated with threatened preterm birth (PTB), number of hospital admissions, and delay between re-admission and delivery.

RESULTS

Of the 334 patients identified, 82 (25%) received optimal treatment. Of the remaining 252 patients, 204 (81%) received repeat doses. In the repeat dose group, 112 (55%) women delivered after 34 weeks, while 70 of the 92 remaining patients were hospitalized until delivery. The other 22 patients who received serial doses were discharged at least once prior to delivery; of these patients, 8 were re-admitted more than 24 hours pre-delivery (i.e., adequate time for re-treatment), while 14 were not, but only 6 of these were delivered urgently. Thus, a maximum of 60 patients (25% of repeat doses) could potentially have benefited from this approach. Of the 48 patients not receiving repeat doses, 37 (77%) delivered after 34 weeks. Five remained hospitalized, and 6 were discharged prior to delivery and re-admitted (2 patients > 24 hr and 4 patients < 24 hr from delivery). This represented a potential underutilization of betamethasone by 3% (11/334) of the patients, but only 1.8% (6/334) were of less than 32 weeks' gestation.

CONCLUSION

This study demonstrated the difficulty in predicting which of the patients presenting with threatened preterm birth would actually go on to deliver during the window of benefit of antenatal betamethasone therapy. Our desire to permit all premature fetuses to profit from the positive effects of this therapy must be balanced by a reserve in exposing too many to too much. Use of antenatal betamethasone in our unit has significantly decreased since this review.

Neurobehavioral deficits in premature graduates of intensive care--potential medical and neonatal environmental risk factors

There is growing evidence that a large number of very low birth weight infants are exhibiting neurobehavioral problems in the absence of cerebral palsy at follow-up that has extended into school age and adolescence. Many clinical factors (ie, chronic lung disease, recurrent apnea and bradycardia, transient hypothyroxemia of prematurity, hyperbilirubinemia, nutritional deficiencies, glucocorticoid exposure), as well as stressful environmental conditions, including infant-provider interaction, constant noise, and bright light, may act in combination to impact on the developing brain, even in the absence of overt hemorrhage and/or ischemia. Any potential intervention strategy designed to prevent cognitive and behavioral problems has to account for the numerous biological and clinical conditions and/or interventions, as well as postdischarge social and environmental influences.

Perinatal factors associated with severe intracranial hemorrhage

OBJECTIVE

The purpose of this study was to assess the incidence of perinatal factors that are associated with severe intracranial hemorrhage in a large and recent multicenter experience.

STUDY DESIGN

Retrospective analyses of nonanomalous newborns who were admitted to 100 neonatal intensive care units from 23 to 34 6/7 weeks' gestation were analyzed by multiple regression.

RESULTS

There were 12,578 premature newborns with a mean (+/- SD) gestational age of 31.3 +/- 2.9 weeks and a birth weight of 1685 +/- 571 g, respectively. The overall incidence of severe intracranial hemorrhage was 2.9%; in 4575 newborns who weighed < or = 1500 g the incidences of intracranial hemorrhage was 7.1%. Factors with positive and negative associations with severe intracranial hemorrhage are listed in order of decreasing statistical significance: gestational age (negative), surfactant (positive), antenatal indomethacin (positive), neonatal transport (positive), cesarean birth (negative), poor prenatal care (positive), 5-minute Apgar score of < 7 (positive), chorioamnionitis (positive), antenatal terbutaline (negative), preterm premature rupture of fetal membranes (negative), and abruption (positive).

CONCLUSION

The incidence of severe intracranial hemorrhage has dramatically declined over the past 2 decades. Antenatal steroids were not associated with reductions in severe intracranial hemorrhage.

Perinatal glucocorticoid therapy and neurodevelopmental outcome: an epidemiologic perspective

A relatively brief course of antenatal glucocorticoids (ACS), given to reduce the severity of respiratory distress syndrome in preterm infants, improves survival and appears to protect against brain damage. In clinical trials as well as observational studies, ACS have been associated with a decreased risk of intraventricular haemorrhage and cerebral palsy. In observational studies a decreased risk of white-matter damage, identified with cranial ultrasound, has been observed. There is some evidence, from observational studies, that repeated courses of ACS (typically given at weekly intervals) can reduce the rate of fetal head growth, and experiments in animals provide further support for this possibility. In contrast to the effects of a brief course of ACS, postnatal glucocorticoids (PCS), given to preterm infants to reduce the severity of chronic lung disease have been associated with an increased risk of neurologic impairment. Available evidence suggests that PCS does not improve survival. Further study is needed of the neurodevelopmental consequences of both multiple courses of ACS, as well as PCS.

Exogenous and endogenous corticosteroids modulate blood-brain barrier development in the ovine fetus

We previously reported decreases in blood-brain barrier permeability in the ovine fetus at 80% of gestation after antenatal corticosteroids and shown that permeability is not reduced in newborn lambs after postnatal corticosteroids. We now test the hypotheses that exogenous antenatal corticosteroids decrease blood-brain barrier permeability at 60% but not 90% of gestation in ovine fetuses and that endogenous increases in plasma cortisol concentrations are associated with ontogenic decreases in barrier permeability during gestation. Chronically instrumented ovine fetuses were studied 12 h after the last of four 6-mg dexamethasone or placebo injections were given 12 h apart over 48 h to ewes. Fetuses at 80% of gestation from placebo-treated ewes studied under the same protocol were also included. Blood-brain barrier function was quantified with the blood-to-brain transfer constant (K(i)) to alpha-aminoisobutyric acid. K(i) values were lower in cerebral cortex, caudate nucleus, hippocampus, superior colliculus, thalamus, medulla, and cervical spinal cord in fetuses of dexamethasone- than placebo-treated ewes at 60% but not 90% of gestation. Regional brain K(i) values demonstrated inverse correlations with increases in gestation and plasma cortisol concentrations in most brain regions. We conclude that maternal treatment with exogenous corticosteroids was associated with decreases in blood-brain barrier permeability at 60% but not 90% of gestation and that increases in gestation and endogenous cortisol concentrations were associated with ontogenic decreases in barrier permeability during fetal development.

Antenatal corticosteroids and cranial ultrasonographic abnormalities

OBJECTIVE

This study was undertaken to determine whether very-low-birth-weight infants whose mothers received a course of antenatal corticosteroids were at decreased risk for 3 cranial ultrasonographic entities that predict neurodevelopmental dysfunction.

STUDY DESIGN

This retrospective cohort study evaluated 1604 infants weighing 500 to 1500 g who underwent >/=1 of 3 cranial ultrasonographic scans required by design at specified postnatal intervals and whose own and mother's hospital charts were reviewed. Infants were classified according to mother's course of antenatal corticosteroids (none, partial, or complete).

RESULTS

In the total sample the risks of intraventricular hemorrhage and of an echolucent image in the cerebral white matter were only modestly (and not statistically significantly) reduced after a full course of antenatal corticosteroids, whereas antenatal corticosteroids appeared to significantly reduce the risk of ventriculomegaly after even a partial course. Antenatal corticosteroids appeared to halve the risk of ventriculomegaly and echolucent image among the gestationally youngest infants and those with intraventricular hemorrhage, hypothyroxinemia, or vasculitis of the umbilical cord or chorionic plate of the placenta.

CONCLUSION

These observations are consistent with the hypothesis that antenatal corticosteroids protect very-low-birth-weight infants, especially those who are most vulnerable, against the risk of cranial ultrasonographic abnormalities.

Postnatal hemodynamic changes in very-low-birthweight infants

The purpose of this study was to characterize postnatal changes in regional Doppler blood flow velocity (BFV) and cardiac function of very-low-birthweight infants and to examine factors that might influence these hemodynamic changes. Mean and end-diastolic BFV of the middle cerebral and superior mesenteric arteries, cardiac output, stroke volume, and fractional shortening were measured in 20 infants birthweight 1,002 +/- 173 g, gestational age 28 +/- 2 wk) at 6, 30, and 54 h after birth and before and after feedings on days 7 and 14. Postnatal increases in cerebral BFV, mesenteric BFV, and cardiac output were observed that were not associated with changes in blood pressure, hematocrit, pH, arterial PCO(2), or oxygen saturation. The postnatal pattern of relative vascular resistance (RVR) differed between the cerebral and mesenteric vasculatures. RVR decreased in the middle cerebral but not the superior mesenteric artery. Physiological patency of the ductus arteriosus did not alter postnatal hemodynamic changes. In response to feeding, mesenteric BFV and stroke volume increased, and mesenteric RVR and heart rate decreased. Postprandial responses were not affected by postnatal age or the age at which feeding was initiated. However, the initiation of enteral nutrition before 3 days of life was associated with higher preprandial mesenteric BFV and lower mesenteric RVR than was later initiation of feeding. We conclude that in very-low-birthweight infants over the first week of life 1) systemic, cerebral, and mesenteric hemodynamics exhibit region-specific changes; 2) asymptomatic ductus arteriosus patency and early feedings do not significantly influence these postnatal hemodynamic changes; and 3) cardiac function adapts to increase local mesenteric BFV in response to feedings.

Antenatal steroids decrease blood-brain barrier permeability in the ovine fetus

Antenatal corticosteroid therapy reduces the incidence of intraventricular hemorrhage in premature infants. Enhanced microvascular integrity might provide protection against intraventricular hemorrhage. In the adult, there is evidence to suggest that the blood-brain barrier may be under hormonal control. We hypothesized that antenatal corticosteroids decrease blood-brain barrier permeability in the preterm ovine fetus. Chronically instrumented 120-day-gestation fetuses were studied 12 h after the last of four 6-mg dexamethasone (n = 5) or placebo (n = 6) injections had been given over 48 h to the ewes. Blood-brain barrier function was quantified with the blood-to-brain transfer constant (Ki) for alpha-aminoisobutyric acid (AIB). Ki was significantly lower across brain regions in the fetuses of ewes that received antenatal dexamethasone compared with placebo (ANOVA; interaction, F = 2.54, P < 0.004). In fetuses of dexamethasone- and placebo-treated ewes, Ki (microliter . g brain wt-1. min-1, mean +/- SD) was, respectively, 2.43 +/- 0.27 vs. 3.41 +/- 0.74 in the cortex, 4.46 +/- 0.49 vs. 5.29 +/- 0.85 in the cerebellum, and 3.70 +/- 0.49 vs. 5.11 +/- 0.70 in the medulla. We conclude that antenatal treatment with corticosteroids reduces blood-brain permeability in the ovine fetus.

Repeated antenatal corticosteroids: size at birth and subsequent development

OBJECTIVE

The objective was to study the effects of repeated antenatal corticosteroids on birth size, growth, and development in preterm infants.

STUDY DESIGN

This observational study followed up for 3 years a prospective geographic cohort in the state of Western Australia of 477 singleton infants born at <33 weeks' gestation.

RESULTS

Birth weight ratio decreased with increasing number of corticosteroid courses (P =.001), and multivariate analyses confirmed a reduction in birth weight of as much as 9% (P =.014) and a reduction in head circumference of as much as 4% (P =.0024). There were no additional benefits in mortality or respiratory outcomes, and there was a trend toward more severe chronic lung disease. At age 3 years growth and severe disability outcomes did not appear to be related to increasing number of corticosteroid courses.

CONCLUSIONS

In this cohort study repeated corticosteroid courses were associated with adverse effects on size at birth without apparent benefits. These changes have the potential to affect later development.

Antenatal corticosteroids in preterm premature rupture of membranes

It is clear that there is no unequivocal indication for the use of antenatal corticosteroids in the preterm gestation with PROM. Extrapolating the effects seen in gestations with intact membranes, however, there are potential benefits in reduction of neonatal respiratory disease and intracranial hemorrhage at the expense of increased risks of maternal postpartum infection. Because the lifetime harm from the neonatal grave and the sequelae of infection in the mother are usually mild, we recommend that antenatal corticosteroids be administered to patients with PPROM between the gestational ages of 24-33 weeks in the absence of frank maternal or fetal infection or fetal compromise. With the increasing acceptance of antenatal corticosteroid therapy, it is unlikely that any further prospective randomized trials will be possible because withholding corticosteroids may expose patients to unacceptable potential harm. Therefore, clinical judgments may have to made based solely on the limited data presently available. Hopefully, future clinical investigations will provide useful information about the relation between antenatal corticosteroids and perinatal infections of the mother and infant in the setting of prophylactic antibiotic exposure. Additionally, there is also a need for information establishing a clinical profile for the patient with PPROM that accurately predicts when she is likely to enter spontaneous labor, thus allowing clinicians to increase the likelihood of appropriately administering corticosteroids within 1 week of delivery to maximize potential neonatal benefit.

Posthemorrhagic hydrocephalus and brain injury in the preterm infant: dilemmas in diagnosis and management

Advances in neonatal critical care have reduced the incidence of intraventricular hemorrhage (IVH) in the newborn. Paradoxically, however, the prevalence of the complications of IVH including posthemorrhagic hydrocephalus (PHHC) has increased. By virtue of its association with long-term neurodevelopmental disability, posthemorrhagic hydrocephalus is an ominous diagnosis in the premature infant. Animal models have demonstrated that ventricular distention may cause direct cerebral parenchymal injury. Evidence for secondary parenchymal injury in the premature infant with PHHC is by necessity indirect. The precise impact of secondary parenchymal injury on the overall neurological outcome of premature infants with PHHC remains unclear in large part because of the vulnerability of the immature brain to other forms of injury (e.g., periventricular leukomalacia) that may be difficult to distinguish from injury due to distention. Furthermore, parenchymal injury due to PVL may cause ventricular enlargement that does not benefit from CSF diversion. Because these primary and secondary mechanisms of injury may operate concurrently, the precise or dominant cause of ventricular enlargement is often difficult to establish with certainty in the neonatal period. These diagnostic dilemmas have in turn impeded the development and evaluation of therapies specifically aimed at reversing ventricular distention and preventing secondary parenchymal injury. This article focuses on the current dilemmas in diagnosis and management of this potentially reversible form of injury as well as on potential future strategies for its prevention.

Antenatal glucocorticoid, magnesium exposure, and the prevention of brain injury of prematurity

Prevention of perinatal white matter injury with or without severe intraventricular hemorrhage (IVH) is critical to reduce cerebral palsy (CP) in premature infants. Antenatal therapies that may afford neuroprotection include glucocorticoids, which are associated with a significant reduction in severe IVH, and magnesium, which is associated with reduced CP. Potential protective mechanisms of glucocorticoids include a direct effect on brain, improved respiratory function, and more stable blood pressure hemodynamics. Because magnesium is often administered to mothers with pregnancy-induced hypertension, a condition associated with reduction in severe IVH, the independent neuroprotective role of magnesium remains unclear and warrants additional studies.

Trends in incidence and severity of intraventricular hemorrhage

The incidence of germinal matrix-intraventricular hemorrhages declined from 50% in 1977 to 24% in 1985. Over the last decade intraventricular hemorrhage rates ranging from 8% to 56% were reported, leaving uncertainty as to the direction of recent intraventricular hemorrhage trends. Records of all 1950 neonates weighing 2250 g or less at birth (867 weighing 1500 g or less and 1083 weighing 1501-2250 g) at a university neonatal intensive care unit between 1986 and 1995 were studied. Intraventricular hemorrhage rate declined by 53%, from 11.5% in 1986 to 5.5% in 1995 (P < .01), and was consistent across all birthweight groups: 750 g or less from 36% to 24%, 751-1000 g from 38% to 22%, 1001-1250 g from 19% to 13%, 1251-1500 g from 12% to 2% and 1551-2250 g from 3% to 0.2% (P < .05). Proportionately, severe intraventricular hemorrhage (grades 3 +/- intraparenchymal hemorrhage) declined from 70% of all intraventricular hemorrhages in 1986 to 23% in 1995 (P < .005). Overall mortality declined by 65% between 1986 and 1995 (P < .001), whereas mortality associated with intraventricular hemorrhage declined by 30% (P = .34). Despite dramatic declines in intraventricular hemorrhage rates, 21% of infants weighing less than 1000 g and 12% of those weighing less than 1500 g at birth were affected in 1995.

Health and developmental outcomes at 18 months in very preterm infants with bronchopulmonary dysplasia

OBJECTIVE

To determine whether very preterm infants who are oxygen-dependent at 28 days of life but not at 36 weeks' gestational age are at high risk of morbidities at 18 months.

POPULATION

A total of 217 infants born in a tertiary care center at 24 to 28 weeks' gestation in 1987 to 1992, classified into three groups: neonatal comparison group, O2 <28 days of life (n = 76); bronchopulmonary dysplasia (BPD)-1, O2 >/=28 days but not at 36 weeks' gestational age (n = 48); and BPD-2, O2 >/=36 weeks (n = 93).

OUTCOME MEASURES

Growth, persistent respiratory problems (asthma, tracheostomy, home oxygen therapy), surgery, hospitalizations, and neurodevelopmental impairments.

RESULTS

Among the three groups, no differences were found in weight, height, head circumference, or total number of days of rehospitalizations for any causes, or in rate of rehospitalizations to the intensive care unit, persistent respiratory problems, cerebral palsy, or sensory impairment. Children with BPD-2 needed more hernia repairs compared with the other two groups (comparison group: 12% vs BPD-1: 10% vs BPD-2: 30%), had more days of readmissions for respiratory problems (comparison group: 2.0 vs BPD-1: 2.0 vs BPD-2 6.3 [BPD-1 vs BPD-2]), had a lower mean developmental quotient (comparison group: 97.4 +/- 15.0 vs BPD-1: 97.9 +/- 11.6 vs BPD-2: 90.7 +/- 19.3). Intraparenchymal cerebral lesions, high family adversity, and prolonged ventilation were the most important factors influencing the developmental outcome.

CONCLUSION

Children with BPD-1 are similar in all respect at 18 months to children in the comparison group. Children with BPD-2 are similar to the other groups at 18 months in growth, general health, and neurologic outcome but differ in having a higher number of days of rehospitalizations for respiratory causes, more hernia repairs, and more developmental delays.

[Prenatal corticotherapy and acceleration of fetal maturation. II. Results of clinical applications]

Numerous subsequent controlled trials and recent meta-analysis have confirmed the efficiency of antenatal glucocorticoid therapy in reducing both the incidence of respiratory distress syndrome (RDS) and perinatal mortality. Moreover, antenatal glucocorticoid administration reduces the odds of several severe complications relating to immaturity: intraventricular hemorrhage (IVH), ductus arteriosus patency, necrotising enterocolitis, and hemodynamic failure. Exogenous surfactant therapy has not ruled out the benefits of corticosteroids: on the contrary, a synergic effect is obtained when both antenatal and postnatal therapeutic approaches are combined. Very premature infants may also take advantage of the hormonal treatment: in this population, RDS occurrence, IVH incidence and perinatal mortality are also reduced. Unfortunately, despite convincing evidence, the incidence of antenatal steroids therapy has not yet achieved the optimal and desirable level. Obstetricians and pediatricians must be encouraged to ensure high maternal exposure to steroids when preterm delivery is likely to occur.

Antenatal steroids: miracle drug for preemies

Antenatal corticosteroid administration has been unequivocally demonstrated to reduce neonatal morbidity and mortality. In addition to its well-documented role in reducing respiratory distress syndrome, evidence is accumulating indicating the global maturational effect of this therapy in the growing fetus. New data demonstrates, the hitherto relatively not well known, beneficial effects of this mode of therapy on renal, cardiovascular, gastrointestinal, endocrinal and cerebral maturation. Despite its well proven efficacy and safety, this therapy is used only in a small fraction of eligible mothers. In this article, biological basis of antenatal steroids use, clinical benefits including those to extremely premature infants, indications for their administration, treatment regimens, practice variations in their administration, cost analysis, and some directions for future research are reviewed. It is hoped that given the evidence reviewed in this article, the use of antenatal steroids administration in proper clinical settings will increase with a significant impact in reducing the neonatal morbidity and mortality.