Antenatal corticosteroids and cranial ultrasonographic abnormalities

Antenatal corticosteroids for threatened labour facilitate thyroid maturation among preterm neonates

OBJECTIVE

To examine the effect of antenatal corticosteroids (ANS) on the maturation of thyroid function in the preterm infants.

CONTEXT

ANS reduce mortality and morbidities in preterm neonates. Organ maturation by the glucocorticoids is the key, at least in part. However, the effect of ANS on thyroid is controversial.

PATIENTS

A study group of 99 very low birthweight neonates (<34 weeks' gestational age) with the exception of those born more than 7 days after ANS administration were divided into a complete group (n = 49) whose mothers completed two doses of betamethasone and who were born more than 24 hours after the completion of ANS administration, and an incomplete group (n = 50) who were not exposed to any ANS or were born within 24 hours after the completion of ANS administration. Serum-free thyroxine and thyroid-stimulating hormone (TSH) levels were measured, and thyrotropin-releasing hormone (TRH) stimulation tests were performed at about 2 weeks of age.

RESULTS

The incidence of hyperthyrotropinaemia (TSH > 15 mIU/L) in the complete group was significantly lower than in the incomplete group (6% vs 22%, P = .023). Exaggerated responses to TRH tests were more frequent in the incomplete group (17% vs 44%; P = .053). TSH₃₀ was significantly lower in the complete group, (P = .046). Multivariate logistic regression analysis showed that the incidence of hyperthyrotropinaemia was associated with complete ANS administration (adjusted odds ratios 0.39).

CONCLUSIONS

ANS administration might facilitate thyroid maturation in preterm neonates.

Do Prenatal Corticosteroids Affect Brain Maturation of the Premature Infant? An Electroencephalography Study

OBJECTIVE

To assess whether prenatal treatment with betamethasone has a significant influence on cerebral maturation indices as measured by electroencephalographic (EEG) indices.

STUDY DESIGN

Infants born less than 35 weeks postmenstrual age (PMA) were prospectively enrolled if their mother received a full course of bethametasone prior to delivery (study group) or not (control group); infants with major intracranial abnormalities were excluded as well as those who were sedated or needed assisted ventilation. EEG was recorded during the first 10 days of life. Interburst intervals and maximal amplitudes of theta and delta bandwidths were calculated by a signal processing software. A multivariate general linear model was used to analyze the relationship between the 2 groups and the different electrophysiologic parameters, adjusting for PMA and mode of delivery.

RESULTS

Thirty-eight infants were included in the study group and 36 in the control group. Univariate analysis demonstrated a negative correlation between PMA at test and EEG indices (interburst interval and delta and theta frequencies). Multivariate analysis demonstrated a less robust correlation of PMA and EEG indices and a positive correlation of prenatal betamethasone treatment with Theta frequencies. Repeating the data analysis separately for each study group, the above results remained significant mainly in the study group.

CONCLUSIONS

Our findings suggest a possible stabilization effect of corticosteroids on the central nervous system and a possible delay of the maturation of cerebral activity related to prenatal corticosteroids use. These findings may relate to a better neurodevelopmental outcome of infants treated prenatally with corticosteroids.

Extremely low gestational age and very low birthweight for gestational age are risk factors for autism spectrum disorder in a large cohort study of 10-year-old children born at 23-27 weeks' gestation

BACKGROUND

No prospective cohort study of high-risk children has used rigorous exposure assessment and optimal diagnostic procedures to examine the perinatal antecedents of autism spectrum disorder separately among those with and without cognitive impairment.

OBJECTIVE

We sought to identify perinatal factors associated with increased risk for autism spectrum disorder with and without intellectual disability (intelligence quotient <70) in children born extremely preterm.

STUDY DESIGN

This prospective multicenter (14 institutions in 5 states) birth cohort study included children born at 23-27 weeks' gestation in 2002 through 2004 who were evaluated for autism spectrum disorder and intellectual disability at age 10 years. Pregnancy information was obtained from medical records and by structured maternal interview. Cervical-vaginal "infection" refers to maternal report of bacterial infection (n = 4), bacterial vaginosis (n = 30), yeast infection (n = 62), mixed infection (n = 4), or other/unspecified infection (n = 43; eg, chlamydia, trichomonas, or herpes). We do not know the extent to which infection per se was confirmed by microbial colonization. We use the terms "fetal growth restriction" and "small for gestational age" interchangeably in light of the ongoing challenge to discern pathologically from constitutionally small newborns. Severe fetal growth restriction was defined as a birthweight Z-score for gestational age at delivery <-2 (ie, ≥2 SD below the median birthweight in a referent sample that excluded pregnancies delivered for preeclampsia or fetal indications). Participants were classified into 4 groups based on whether or not they met rigorous diagnostic criteria for autism spectrum disorder and intellectual disability (autism spectrum disorder+/intellectual disability-, autism spectrum disorder+/intellectual disability+, autism spectrum disorder-/intellectual disability+, and autism spectrum disorder-/intellectual disability-). Temporally ordered multinomial logistic regression models were used to examine the information conveyed by perinatal factors about increased risk for autism spectrum disorder and/or intellectual disability (autism spectrum disorder+/intellectual disability-, autism spectrum disorder+/intellectual disability+, and autism spectrum disorder-/intellectual disability+).

RESULTS

In all, 889 of 966 (92%) children recruited were assessed at age 10 years, of whom 857 (96%) were assessed for autism spectrum disorder; of these, 840 (98%) children were assessed for intellectual disability. Autism spectrum disorder+/intellectual disability- was diagnosed in 3.2% (27/840), autism spectrum disorder+/intellectual disability+ in 3.8% (32/840), and autism spectrum disorder-/intellectual disability+ in 8.5% (71/840). Maternal report of presumed cervical-vaginal infection during pregnancy was associated with increased risk of autism spectrum disorder+/intellectual disability+ (odds ratio, 2.7; 95% confidence interval, 1.2-6.4). The lowest gestational age category (23-24 weeks) was associated with increased risk of autism spectrum disorder+/intellectual disability+ (odds ratio, 2.9; 95% confidence interval, 1.3-6.6) and autism spectrum disorder+/intellectual disability- (odds ratio, 4.4; 95% confidence interval, 1.7-11). Severe fetal growth restriction was strongly associated with increased risk for autism spectrum disorder+/intellectual disability- (odds ratio, 9.9; 95% confidence interval, 3.3-30), whereas peripartum maternal fever was uniquely associated with increased risk of autism spectrum disorder-/intellectual disability+ (odds ratio, 2.9; 95% confidence interval, 1.2-6.7).

CONCLUSION

Our study confirms that low gestational age is associated with increased risk for autism spectrum disorder irrespective of intellectual ability, whereas severe fetal growth restriction is strongly associated with autism spectrum disorder without intellectual disability. Maternal report of cervical-vaginal infection is associated with increased risk of autism spectrum disorder with intellectual disability, and peripartum maternal fever is associated with increased risk for intellectual disability without autism spectrum disorder.

Antenatal Corticosteroid Therapy Before 24 Weeks of Gestation: A Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the effectiveness of antenatal corticosteroids compared with placebo or no treatment in neonates born before 24 weeks of gestation.

DATA SOURCES

We searched MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Cochrane Central Register of Controlled Trials databases from 1990 to March 13, 2015, and ClinicalTrials.gov.

METHODS OF STUDY SELECTION

Studies considered were published randomized or quasirandomized controlled trials and observational studies that compared outcomes between neonates who received or did not receive antenatal corticosteroids born before 24 weeks of gestation.

TABULATION, INTEGRATION, AND RESULTS

We performed duplicate independent assessment of the title and abstracts, full-text screening, inclusion of articles, and data abstraction. We performed meta-analyses using random-effects models and quality assessment with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. There were 17 observational studies, and our primary outcome, mortality to discharge in neonates receiving active intensive treatment, had a total of 3,626 neonates. The adjusted odds of mortality to discharge were reduced by 52% in the antenatal corticosteroid group compared with the control group (crude adjusted odds ratio [OR] 0.45, 95% confidence interval [CI] 0.36-0.56; adjusted OR 0.48, 95% CI 0.38-0.61; mortality to discharge 58.1% [intervention] compared with 71.8% [control]) with a "moderate" quality of evidence based on the GRADE system. There were no significant differences between the groups for severe morbidity.

CONCLUSION

The available data, all observational, show reduced odds of mortality to discharge in neonates born before 24 weeks of gestation who received antenatal corticosteroids and active intensive treatment. Antenatal corticosteroids should be considered for women at risk of imminent birth before 24 weeks of gestation who choose active postnatal resuscitation.

Systemic inflammation on postnatal days 21 and 28 and indicators of brain dysfunction 2years later among children born before the 28th week of gestation

BACKGROUND

Systemic inflammation during the first two postnatal weeks in extremely preterm newborns (<28weeks gestation) has been associated with an increased risk of neurodevelopmental dysfunctions. Little is known, however, about the relationship between systemic inflammation during the third and fourth postnatal weeks and subsequent development.

METHODS

We measured the concentrations of 16 inflammation-related proteins in blood spots collected on postnatal days 21 (N=749) and 28 (N=697) from infants born before the 28th week of gestation and assessed at age 2years. We then sought the developmental correlates of top quartile concentrations for gestational age and day the specimen was collected. Odds ratios and 95% confidence intervals were calculated from regular or multinomial logistic regression models (as appropriate).

RESULTS

Top quartile concentrations of CRP, IL-1β, IL-6, IL-6R, TNF-R2, IL-8, ICAM-1, and TSH on both days 21 and 28 were associated with ventriculomegaly (when in the NICU) and microcephaly at age 2years. Top quartile concentrations of CRP, SAA, IL-6, TNF-R2, IL-8, and ICAM-1 were associated with mental development index (MDI) of the Bayley-II<55, while top quartile concentrations of CRP, TNF-α (inversely), IL-8, and ICAM-1 were associated with psychomotor development index (PDI)<55 CONCLUSION: Extremely preterm newborns who had systemic inflammation during the third and fourth postnatal weeks were at increased risk of ventriculomegaly during the months after birth, and of microcephaly, and low Bayley Scale scores at 2years old.

Brain MRI measurements at a term-equivalent age and their relationship to neurodevelopmental outcomes

BACKGROUND AND PURPOSE

An increased prevalence of disabilities is being observed as more preterm infants survive. This study was conducted to evaluate correlations between brain MR imaging measurements taken at a term-equivalent age and neurodevelopmental outcome at 2 years' corrected age among very low-birth-weight infants.

MATERIALS AND METHODS

Of the various brain MR imaging measurements obtained at term-equivalent ages, reproducible measurements of the transcerebellar diameter and anteroposterior length of the corpus callosum on sagittal images were compared with neurodevelopmental outcomes evaluated by the Bayley Scales of Infant Development (II) at 2 years' corrected age (mean ± standard deviation, 16.1 ± 6.4 months of age).

RESULTS

Ninety infants were enrolled. The mean gestational age at birth was 27 weeks and the mean birth weight was 805.5 g. A short corpus callosal length was associated with a Mental Developmental Index <70 (P = .047) and high-risk or diagnosed cerebral palsy (P = .049). A small transcerebellar diameter was associated with a Psychomotor Developmental Index <70 (P = .003), Mental Developmental Index <70 (P = .004), and major neurologic disability (P = .006).

CONCLUSIONS

A small transcerebellar diameter and short corpus callosal length on brain MR imaging at a term-equivalent age are related to adverse neurodevelopmental outcomes at a corrected age of 2 years and could be a useful adjunctive tool for counseling parents about future developmental outcomes.

Antecedents of perinatal cerebral white matter damage with and without intraventricular hemorrhage in very preterm newborns

BACKGROUND

Isolated periventricular leukomalacia, defined as periventricular leukomalacia unaccompanied by intraventricular hemorrhage, is reportedly increased in newborns with systemic hypotension and in infants who received treatment for systemic hypotension or a patent ductus arteriosus.

METHODS

This study sought to determine if the risk profile of one or more hypoechoic lesions unaccompanied by intraventricular hemorrhage, our surrogate for isolated periventricular leukomalacia, differs from that of one or more hypoechoic lesions preceded or accompanied by intraventricular hemorrhage. We compared extremely preterm infants (i.e., gestation 23-27 weeks) with each of these entities to 885 extremely preterm infants who had neither an isolated hypoechoic lesion nor a hypoechoic lesion preceded or accompanied by intraventricular hemorrhage.

RESULTS

The risk of a hypoechoic lesion with intraventricular hemorrhage (N = 61) was associated with gestation <25 weeks, high Score for Acute Neonatal Physiology, early recurrent or prolonged acidemia, analgesic exposure, and mechanical ventilation 1 week after birth.

CONCLUSIONS

In this large, multicenter sample of extremely low gestational age newborns, the risk profile of a hypoechoic lesion unaccompanied by intraventricular hemorrhage differed from that of a hypoechoic lesion with intraventricular hemorrhage. This suggests that hypoechoic lesions accompanied or preceded by intraventricular hemorrhage (our surrogate for periventricular hemorrhagic infarction) may have a different causal pathway than hypoechoic lesions without intraventricular hemorrhage, our surrogate for periventricular leukomalacia.

Mortality, neonatal morbidity and two year follow-up of extremely preterm infants born in The Netherlands in 2007

BACKGROUND

Extremely preterm infants are at high risk of neonatal mortality and adverse outcome. Survival rates are slowly improving, but increased survival may come at the expense of more handicaps.

METHODOLOGY/PRINCIPAL FINDINGS

Prospective population-based cohort study of all infants born at 23 to 27 weeks of gestation in The Netherlands in 2007. 276 of 345 (80%) infants were born alive. Early neonatal death occurred in 96 (34.8%) live born infants, including 61 cases of delivery room death. 29 (10.5%) infants died during the late neonatal period. Survival rates for live born infants at 23, 24, 25 and 26 weeks of gestation were 0%, 6.7%, 57.9% and 71% respectively. 43.1% of 144 surviving infants developed severe neonatal morbidity (retinopathy of prematurity grade ≥3, bronchopulmonary dysplasia and/or severe brain injury). At two years of age 70.6% of the children had no disability, 17.6% was mild disabled and 11.8% had a moderate-to-severe disability. Severe brain injury (p = 0.028), retinopathy of prematurity grade ≥3 (p = 0.024), low gestational age (p = 0.019) and non-Dutch nationality of the mother (p = 0.004) increased the risk of disability.

CONCLUSIONS/SIGNIFICANCE

52% of extremely preterm infants born in The Netherlands in 2007 survived. Surviving infants had less severe neonatal morbidity compared to previous studies. At two years of age less than 30% of the infants were disabled. Disability was associated with gestational age and neonatal morbidity.

Renal function, renal volume, and blood pressure in infants with antecedent of antenatal steroids

Steroids have been used for more than 20 years in preterm infants to induce pulmonary maturity; however, some long-term effects have been reported, such as insulin resistance and elevation of blood pressure. The aim of our study was to compare renal volume, renal function, and blood pressure in infants between 12-36 months of age with and without antecedent of antenatal steroid treatment. This was a cross-sectional study comprised of three groups of infants (n = 30, respectively): preterm infants with and without antecedent of receiving antenatal steroids, respectively, and full-term infants. Blood pressure, renal volume, glomerular filtration rate, and tubular function were measured. Blood pressure and cystatin C levels and glomerular filtration rate were higher in both groups of preterm infants than in the control group (p < 0.01). However, no difference in any of the tested variables between the steroid and non-steroid group of preterm infants. Renal volume was similar in preterm and control infants. Based on these results, we conclude that prematurity independent of antenatal steroid use is associated with higher cystatin C and blood pressure levels and a higher glomerular filtration rate in infants between 12-36 months of age.

Patterns of blood protein concentrations of ELGANs classified by three patterns of respiratory disease in the first 2 postnatal weeks

We examined the association between elevated concentrations of 25 blood proteins in blood spots collected on postnatal d 1, 7, and 14 from infants <28 wk gestation who survived to 24 mo and the risk of two patterns of early lung disease i.e. early and persistent pulmonary dysfunction (EPPD) and normal early pulmonary function followed by pulmonary deterioration (PD). Thirty-eight percent (n = 347) of our cohort had PD, and 43% (n = 383) had EPPD. On postnatal d 14, elevated concentrations of two proteins (RANTES and VEGF) were associated with reduced risk of PD. Similarly, the risk of EPPD was also reduced if three proteins had elevated concentrations on postnatal d 14 (RANTES, MMP-1, and VEGF). In contrast, the risk of EPPD was increased if on d 14 two proteins had elevated concentrations (IL-8 and ICAM-1). Inflammation might influence the risk of EPPD and PD or be a consequence of lung damage or therapies to minimize lung dysfunction.

The relationship between early concentrations of 25 blood proteins and cerebral white matter injury in preterm newborns: the ELGAN study

OBJECTIVE

To evaluate whether concentrations of inflammation-related proteins are elevated in the blood of preterm newborns who develop cerebral white matter damage.

STUDY DESIGN

We measured 25 proteins in blood collected on days 1, 7, and 14 from 939 infants born before the 28th week of gestation. Brain ultrasound scans were read by at least two sonologists, who agreed on the presence or absence of lesions. A protein concentration was considered elevated if it was in the highest quartile for gestational age and the day on which the specimen was collected.

RESULTS

In time-oriented models, elevated concentrations of vascular endothelial growth factor receptor 1, serum amyloid A, and macrophage inflammatory protein 1β on day 1 and interleukin-8 on day 7 were associated with increased risk of ventriculomegaly. Elevated concentrations of macrophage inflammatory protein 1β on day 1 and intercellular adhesion molecule 1 on day 7 were associated with increased risk of an echolucent lesion. Infants with elevated concentrations of inflammation-related proteins on two separate days were at significantly increased risk for ventriculomegaly, but at only modestly increased risk for an echolucent lesion.

CONCLUSIONS

Concentrations of inflammation-related proteins in the circulation in the first days after preterm birth provide information about the risk of sonographic white matter damage. The inflammatory process might begin in utero.

Antecedents of chronic lung disease following three patterns of early respiratory disease in preterm infants

INTRODUCTION

The incidence of chronic lung disease (CLD) varies among groups defined by their early pattern of respiratory disease.

METHODS

The study examined data collected prospectively on 1204 of the 1506 infants born in 2002-2004 at 23-27 weeks gestation who survived to 36 weeks post-menstrual age. Based on their initial respiratory presentation and need for supplemental oxygen during the first 2 weeks, infants were classified as having early and persistent pulmonary dysfunction (EPPD), early recovery of pulmonary function followed by deterioration (PD) or consistently good pulmonary function characterised by low FiO(2) (Low FiO(2)).

RESULTS

CLD was diagnosed in 69% of infants with EPPD, 52% with PD, and 17% in the Low FiO(2) group. Birth weight z score <-1 conveyed information about CLD risk in all three groups and was the major risk factor for infants in the Low FiO(2) group (OR 27; 95% CI 7 to 95). Mechanical ventilation at 7 days was associated with increased risk in the PD (OR 4.2, 95% CI 2.5 to 6.9) and EPPD groups (OR 2.7, 95% CI 1.5 to 4.7), but not the Low FiO(2) group (OR 1.5, 95% CI 0.5 to 3.9).

CONCLUSION

The likelihood of a very preterm infant developing CLD and the profile of risk factors linked with CLD are related to the infant's pattern of respiratory disease during the first 2 postnatal weeks. Among infants with little exposure to oxygen during this period, fetal growth restriction, not mechanical ventilation, is the factor with the strongest association with CLD.

Intracranial haemorrhage after transport of premature newborns

Intracranial hemorrhage remains an important factor of premature newborns? morbidity. Its incidence is significantly influenced by adequate perinatal care and safe neonatal transport. Risk factors for the development of intracranial hemorrhage in premature newborns after neonatal transport were analyzed in the retrospective transversal clinical study. Out of 150 study subjects, 60% (n=90/150) had intracranial hemorrhage with a statistically significant difference in relation to Apgar score, gestational age, birth weight, age at the moment of transport and the prophylactic use of surfactant. In this group, grades I/II intracranial hemorrhage were detected in 77% (n=69/90), while grades III/IV intracranial hemorrhage were diagnosed in 23% (n=21/90). A statistically significant difference was observed in relation to gestational age, birth weight, antenatal use of tocolytics and steroids, delivery mode and age in the time of transport between these groups. All patients were transferred to Intensive Care Unit, the duration of transport was less than 5 minutes in 71% 9n=107/150), whereas longer transport was recorded in 29% (n=43/150). In the group of longer transport, prophylactic surfactant was less frequently used with a higher incidence of grades III/IV intracranial hemorrhage. In order to prevent the development of intracranial hemorrhage in premature newborns, the most important measures are the antenatal use of steroids and postnatal prophylactic use of surfactant.

The relationship between systemic hemodynamic perturbations and periventricular-intraventricular hemorrhage--a historical perspective

Periventricular-intraventricular hemorrhage (PV-IVH) remains the major cause of injury to the developing brain. Predisposing factors include a germinal matrix with an immature vasculature, a pressure passive cerebral circulation, and hemodynamic perturbations in sick premature infants. Intact cerebral autoregulation has been documented in stable premature infants; however, it functions within a limited blood pressure range and is likely to be absent in the sick hypotensive infant, which increases the risk for PV-IVH with perturbations in blood pressure. The risk for PV-IVH is markedly increased in the absence of antenatal glucocorticoid exposure in the intubated low birthweight infant <1000 g with respiratory distress syndrome; +/- other complications. Although surfactant administration reduces the severity of respiratory distress syndrome, it has not led to a reduction in PV-IVH. Early postnatal administration of indomethacin has been associated with a reduction in PV-IVH, although this has not translated into long-term neurocognitive benefits.

The ELGAN study of the brain and related disorders in extremely low gestational age newborns

BACKGROUND

Extremely low gestational age newborns (ELGANs) are at increased risk for structural and functional brain abnormalities.

AIM

To identify factors that contribute to brain damage in ELGANs.

STUDY DESIGN

Multi-center cohort study.

SUBJECTS

We enrolled 1506 ELGANs born before 28 weeks gestation at 14 sites; 1201 (80%) survived to 2 years corrected age. Information about exposures and characteristics was collected by maternal interview, from chart review, microbiologic and histological examination of placentas, and measurement of proteins in umbilical cord and early postnatal blood spots.

OUTCOME MEASURES

Indicators of white matter damage, i.e. ventriculomegaly and echolucent lesions, on protocol cranial ultrasound scans; head circumference and developmental outcomes at 24 months adjusted age, i.e., cerebral palsy, mental and motor scales of the Bayley Scales of Infant Development, and a screen for autism spectrum disorders.

RESULTS

ELGAN Study publications thus far provide evidence that the following are associated with ultrasongraphically detected white matter damage, cerebral palsy, or both: preterm delivery attributed to preterm labor, prelabor premature rupture of membranes, or cervical insufficiency; recovery of microorganisms in the placenta parenchyma, including species categorized as human skin microflora; histological evidence of placental inflammation; lower gestational age at delivery; greater neonatal illness severity; severe chronic lung disease; neonatal bacteremia; and necrotizing enterocolitis.

CONCLUSIONS

In addition to supporting a potential role for many previously identified antecedents of brain damage in ELGANs, our study is the first to provide strong evidence that brain damage in extremely preterm infants is associated with microorganisms in placenta parenchyma.

Gestational age at glucocorticoids administration after premature rupture of membranes and cerebral white matter damage

OBJECTIVE

We investigated whether gestational age at glucocorticoids administration in very preterm premature rupture of membranes (PROM) affects the occurrence of neonatal cerebral white matter damage (WMD).

METHODS

In a cohort of singleton neonates born at 24.0-33.6 weeks after PROM who underwent at least one full course of glucocorticoids (n = 130), we compared the gestational age at first and last course of glucocorticoids between those who developed WMD (n = 8) and those who did not (n = 122) after adjusting for gestational age at PROM using logistic regression with P < 0.05 considered significant.

RESULTS

Gestational age at first course of glucocorticoids (P = 0.2), at last course of glucocorticoids (P = 0.2) and at delivery (P = 0.2), were not significantly different between those who developed WMD and those who did not. Although latency between PROM and first course of glucocorticoids was protective against WMD (P = 0.02), the significance was lost after controlling for gestational age at PROM, which was significantly lower in cases that developed WMD (P < 0.01).

CONCLUSIONS

In very preterm PROM, the beneficial effect of glucocorticoids on occurrence of WMD is not related to gestational age at steroid administration.

Chronic lung disease and developmental delay at 2 years of age in children born before 28 weeks' gestation

INTRODUCTION

Extremely low gestational age newborns (ELGANs) are at increased risk of chronic lung disease (CLD) and of developmental delay. Some studies have suggested that CLD contributes to developmental delay.

PATIENTS AND METHODS

We examined data collected prospectively on 915 infants born before the 28th week of gestation in 2002-2004 who were assessed at 24 months of age with the Bayley Scales of Infant Development-2nd Edition or the Vineland Adaptive Behavior Scales. We excluded infants who were not able to walk independently (Gross Motor Function Classification System score < 1) and, therefore, more likely to have functionally important fine motor impairments. We defined CLD as receipt of oxygen at 36 weeks' postmenstrual age and classified infants as either not receiving mechanical ventilation (MV) (CLD without MV) or receiving MV (CLD with MV).

RESULTS

Forty-nine percent of ELGANs had CLD; of these, 14% were receiving MV at 36 weeks' postmenstrual age. ELGANs without CLD had the lowest risk of a Mental Developmental Index (MDI) or a Psychomotor Developmental Index (PDI) of <55, followed by ELGANs with CLD not receiving MV, and ELGANs with CLD receiving MV (9%, 12%, and 18% for the MDI and 7%, 10%, and 20% for the PDI, respectively). In time-oriented multivariate models, the risk of an MDI of <55 was associated with the following variables: gestational age of <25 weeks; single mother; late bacteremia; pneumothorax; and necrotizing enterocolitis. The risk of a PDI of <55 was associated with variables such as single mother, a complete course of antenatal corticosteroids, early and persistent pulmonary dysfunction, pulmonary deterioration during the second postnatal week, pneumothorax, and pulmonary interstitial emphysema. CLD, without or with MV, was not associated with the risk of either a low MDI or a low PDI. However, CLD with MV approached, but did not achieve, nominal statistical significance (odds ratio: 1.9 [95% confidence interval: 0.97-3.9]) for the association with a PDI of <55.

CONCLUSIONS

Among children without severe gross motor delays, risk factors for CLD account for the association between CLD and developmental delay. Once those factors are considered in time-oriented risk models, CLD does not seem to increase the risk of either a low MDI or a low PDI. However, severe CLD might increase the risk of a low PDI.

Trends in the rates of cerebral palsy associated with neonatal intensive care of preterm children

Progressive changes in perinatal and neonatal intensive care of preterm infants since the late 1960s have led to an increase in survival and had an effect on the rates of neonatal morbidity, including brain injury, chronic lung disease, and sepsis. These have influenced the rates of neurodevelopmental impairment, including cerebral palsy. There was initially an increase in neonatal morbidity and rates of cerebral palsy associated with the increased survival of extremely low birth weight and low gestation infants. However, since the late 1990s and especially since the year 2000, the rates of neonatal morbidity have decreased with evidence of a decrease in the rates of cerebral palsy. Efforts to further decrease neonatal morbidity should continue to improve the outcomes of preterm children.

Impact of the use of antenatal corticosteroids on mortality, cerebral lesions and 5-year neurodevelopmental outcomes of very preterm infants: the EPIPAGE cohort study

OBJECTIVE

To assess the impact of antenatal corticosteroids (ACS) on neonatal mortality, cerebral lesions and 5-year neurodevelopmental outcome of infants born at 24-27 and 28-32 weeks of gestational age (GA).

DESIGN

Observational population-based study including all births at GAs between 22 and 32 weeks in 1997 in nine regions of France. Survivors were assessed at the age of 5 years.

SAMPLE AND METHODS

The population enrolled in the follow up comprised 2323 infants; there were 23 deaths before age 5 years and outcome at 5 years was available for up to 1781 subjects. Two GA subgroups (24-27 and 28-32 weeks of GA) were analysed separately. Propensity scores were used to reduce bias in the estimation of the association between ACS treatment and outcomes.

MAIN OUTCOME MEASURES

Neonatal death, neonatal white matter injury, cerebral palsy, mental processing composite (MPC) of the Kaufman Assessment Battery for Children test and behavioural difficulties at 5 years.

RESULTS

In the 28- to 32-week GA subgroup, there was a significant association between ACS and a decreased risk of both neonatal death (OR = 0.61 [0.41-0.91]) and white matter injury (OR = 0.60 [0.46-0.79]) but only a nonsignificant trend for improved 5-year outcome (cerebral palsy, MPC < 70). In the 24- to 27-week GA subgroup, ACS was associated with a significant decrease risk of neonatal death (OR = 0.43 [0.27-0.68]) but there was only a trend for a lower risk of white matter injury and no beneficial impact on outcome at 5 years. Limiting the analysis to only those who received complete courses of ACS did not modify the results.

CONCLUSION

The study shows that ACS therapy greatly increases the survival of very preterm infants, including the most immature, but there is little evidence that ACS affects long-term neurodevelopmental and behavioural outcome in 28- to 32-week survivors, and none in <28-week survivors.

Neuregulin-1: a potential endogenous protector in perinatal brain white matter damage

Brain white matter damage, an important antecedent of long-term disabilities among preterm infants, has both endogenous and exogenous components. One of the endogenous components is the paucity of developmentally regulated protectors. Here we expand on this component, discussing the potential roles of one putative protector, neuregulin (NRG)-1, in brain development and damage. We outline how NRG-1 might be involved in perinatal brain damage pathomechanisms and suggest that NRG-1 might be one target for intervention.

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.

Racial differences in prenatal care of mothers delivering very low birth weight infants

OBJECTIVES

To determine whether there are any racial differences in the prenatal care of mothers delivering very low birth weight infants (VLBW).

STUDY DESIGN

Retrospective cohort study of infants cared for at a single regional level III neonatal intensive care unit over a 9-year period, July 1993-June 2002, N = 1234. The main outcome variables investigated included antenatal administration of steroids, delivery by cesarean section, and use of tocolytic medications. Both univariate and multivariate analyses were performed.

RESULTS

After controlling for potential confounding variables, white mothers delivering VLBWs had an increased odds of cesarean delivery (odds ratio 1.5, 95% confidence intervals (CI) 1.1-2.0), receiving antenatal steroids (1.3, CI 1.01-1.8), and tocolysis (1.4, CI 1.1-2.0) compared to black mothers. The models controlled for gestational age, multiple gestation, premature labor, clinical chorioamnionitis, maternal age, income, year of birth, and presentation.

CONCLUSIONS

In our population of VLBWs, white mothers are more likely to receive antenatal steroids, tocolytic medications, and deliver by cesarean section when compared to black mothers. From our data we cannot determine the reasons behind these racial differences in care of mothers delivering VLBWs.

Gestational age at preterm premature rupture of membranes: a risk factor for neonatal white matter damage

OBJECTIVE

Gestational age at delivery and spontaneous prematurity are independent risk factors for white matter damage (WMD). However, among infants delivered spontaneously after preterm premature rupture of membranes (PPROM), latency of PPROM has been inconsistently correlated with risk of WMD. We have explored whether gestational age at membrane rupture is independently associated with WMD.

STUDY DESIGN

Using a cohort of 196 liveborn singleton nonanomalous neonates born at 24.0 to 33.6 weeks from January 1993 to December 2002 after pPROM and who survived 7 days, we compared the characteristics of those who developed WMD (n = 15) with those who did not (n = 181) using Fisher exact test, Student t test, and logistic regression analysis, with a 2-tailed P < .05 or odds ratio (OR) with 95% CI not inclusive of the unity considered significant.

RESULTS

Stepwise logistic regression analysis demonstrated that gestational age at PPROM (P < .001, OR 0.79) was significantly associated with WMD. The association was independent of corticosteroid administration (P = .016), latency interval (P = .69), gestational age at delivery (P = .99), and birth weight (P = .62).

CONCLUSION

Among premature infants born at <34 weeks after pPROM, gestational age at diagnosis is independently associated with WMD.

Are maternal hypertension and small-for-gestational age risk factors for severe intraventricular hemorrhage and cystic periventricular leukomalacia? Results of the EPIPAGE cohort study

OBJECTIVE

The purpose of this study was to examine the relationships between different causes of preterm delivery (eg, maternal hypertension, small-for-gestational age [SGA], other) and cerebral damage (eg, cystic periventricular leukomalacia [c-PVL], grade III intraventricular hemorrhage [IVH], and intra-parenchymal hemorrhage [IPH]).

STUDY DESIGN

This study included 1902 very preterm singletons who were transferred to neonatal intensive care units in 9 French regions. We used logistic regression models to compare the risk of cerebral injury associated with maternal hypertension, SGA, and all other causes of preterm delivery.

RESULTS

We found that the risk of c-PVL and grade III IVH was higher in infants born after preterm premature rupture of membranes (PPROM) with short latency or idiopathic preterm labor than in infants born to hypertensive mothers. We show that SGA and antepartum maternal hemorrhage significantly increase the risk of IPH.

CONCLUSION

Our results show that infants born to hypertensive mothers have a lower risk of cerebral injuries than infants born following idiopathic preterm labor and PPROM because they are less exposed to prenatal infection.

Identification of kynurenine pathway enzyme mRNAs and metabolites in human placenta: up-regulation by inflammatory stimuli and with clinical infection

OBJECTIVE

The purpose of this study was to determine whether placental-derived kynurenines (neuroactive metabolites that are derived from tryptophan) contributes to infection-mediated fetal cerebral injury.

STUDY DESIGN

Placentae and cord blood were obtained from term deliveries (n = 16) and preterm deliveries with or without intrauterine bacterial infection (n = 8 per group). We investigated whether the placenta expressed messenger RNAs of kynurenine metabolite-forming enzymes, the effects of infection in vivo on the expression of these enzymes by the placenta, the in vitro effects of bacterial endotoxin lipopolysaccharide on expression and kynurenine metabolite output by the placenta, and the kynurenine metabolite levels in umbilical cord blood.

RESULTS

Placentae expressed messenger RNA of tryptophan-degrading enzymes and synthesized several compounds. The expression of several enzymes increased significantly in placentae that were exposed to infection and/or lipopolysaccharide. Lipopolysaccharide also induced significant increases in placental kynurenine and quinolinic acid output. Kynurenine and quinolinic acid in cord blood of fetuses who were exposed to infection were elevated significantly.

CONCLUSION

Inflammatory mediated release of kynurenines from placentae exposes the fetus to significant amounts of potentially neurotoxic substances.

Fetal and neonatal inflammatory response and adverse outcome

This article will define the concept of fetal/neonatal inflammatory response, and examine the complex interaction between inflammation and neurotoxicity. There appear to be important interactions between infection/inflammation and hypoxia-ischaemia leading to cytokine release and subsequent brain injury. This article will also define adverse outcome and summarize the complexities inherent to neurodevelopmental assessment. Finally, this article will investigate the currently available evidence suggesting a link between inflammatory response and adverse neurodevelopmental outcome, and focus on those variables that need further study: timing and nature of the infectious/inflammatory process; established and new anti-insult strategies; morbidity in organs other than the brain; genetic influences; and environmental factors.

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.

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.

Antenatal corticosteroids: the good, the bad and the unknown

PURPOSE OF REVIEW

The purpose of this review was to summarize recently published clinical and animal-based studies of antenatal corticosteroids, describe current recommendations for practice, and suggest priority areas for future research.

RECENT FINDINGS

A single course of antenatal corticosteroids is known to improve newborn lung function after preterm birth and to reduce the risk of newborn death. Current evidence from animal and clinical studies suggests that additional numbers of courses do not further improve lung function and are associated with risks of adverse consequences. These risks principally include restricted intrauterine growth, altered brain development, postnatal insulin resistance and changes to the hypothalamic-pituitary-adrenal axis.

SUMMARY

The research challenges in this field are now centred on uncovering the mechanisms by which cortisol is involved in programming the fetus for its future metabolic life, and discovering ways in which the effectiveness and safety of antenatal glucocorticoids can be enhanced.

Hemorrhagic-ischemic cerebral injury in the preterm infant: current concepts

PV-IVH and adjacent white matter injury remains a significant problem in the premature infant. The potential mechanisms contributing to injury are complex and involve factors related to blood flow and its regulation, as well as cellular mediators including cytokines, free radical formation, and excitotoxin release. Although a reduction in the occurrence of severe IVH can be achieved with indomethacin, it does translate into long-term neurodevelopmental benefit. This reinforces the concept of a more diffuse injury to brain in sick premature infants than is apparent from the appearance of current neuroimaging techniques.

Cerebral palsy in very preterm infants: new epidemiological insights

The focus of this review is on new insights from recent epidemiological research on cerebral palsy in preterm infants. These include: 1) a better understanding of issues related to diagnosis and classification; 2) new information about the brain abnormalities underlying cerebral palsy in preterm infants; and 3) a better understanding of biological mechanisms that may underlie previously described epidemiological associations. Ongoing efforts to improve the diagnosis and classification of cerebral palsy have been enhanced by findings from serial examinations of cohorts of very preterm infants. Cranial ultrasonography through the anterior fontanelle of very preterm infants has provided information about grossly evident brain damage, found in about one-half of preterm infants who develop cerebral palsy. Insights into the pathophysiologic basis for certain epidemiologic associations have come from studies of experimental brain damage in animals and clinical studies of neurologic disorders in adults. Much of the current epidemiological research into the causes of cerebral palsy in preterm infants has focused on two potential mechanisms of brain damage. One mechanism involves insufficient cerebral perfusion; the other, cytokine-mediated damage, potentially triggered by events such as maternal infection (e.g., intrauterine or periodontal infection), neonatal infection (e.g., sepsis and necrotizing enterocolitis), and neonatal oxygen- or ventilator-induced lung injury. In addition to the preterm infant's increased exposure to such damaging factors, the high frequency of cerebral palsy in these infants might be due, in part, to insufficient levels of developmentally regulated protective substances, such as thyroid hormone and glucocorticoids. Models of causation currently are being investigated using recently developed methods for quantifying, with small quantities of blood, biomolecules that are suspected to either promote or protect against brain damage in the neonate. Clinical investigations now under way can be expected to identify strategies to be tested in clinical trials that could lower the risk of cerebral palsy in very preterm infants.

Long-term cognitive benefits of antenatal corticosteroids for prematurely born children with cranial ultrasound abnormalities

OBJECTIVE

Previous studies have examined possible long-term effects of antenatal corticosteroids, but not by the presence of neonatal brain lesions. This study of long-term neurodevelopmental outcomes of antenatal corticosteroid exposure among preterm, very-low-birth-weight infants investigated whether the effects are differential by the presence of neonatal brain injury.

STUDY DESIGN

Prospective cohort study of cognition, behavior, and cerebral palsy in 251 children (ages 6-8 years) born at < or = 32 weeks of gestation. This sample included 91 children with abnormal neonatal cranial ultrasound findings and 106 children who had been exposed to antenatal corticosteroids.

RESULTS

In children with abnormal cranial ultrasound findings, a complete course of antenatal corticosteroids was associated with an 8.7-point advantage in IQ (95% CI, 1.8, 15.6; P = .016), controlling for confounding factors. Both verbal and nonverbal cognitive scores were increased in a dose-response manner. The advantage was greater for infants born at < or = 28 weeks of gestation and in those with ventriculomegaly. In children with normal cranial ultrasound scans, cognitive function was not related to antenatal corticosteroid exposure. No statistically significant associations were observed between antenatal corticosteroid exposure and either childhood behavioral scores or cerebral palsy.

CONCLUSION

Antenatal corticosteroids appear to confer substantial long-term benefits on cognition of very-low-birth-weight infants with cranial ultrasound abnormalities.

Antenatal steroids are associated with a reduction in the incidence of cerebral white matter lesions in very low birthweight infants

AIMS

To investigate whether antenatal steroids reduce the incidence of cerebral white matter lesions in very low birthweight infants.

METHODS

A total of 224 newborn infants of < 31 weeks gestational age and weighing < 1500 g was studied between January 1998 and June 2000. Obstetric and neonatal information was obtained from the case notes. The study population was subdivided into two groups according to antenatal steroid exposure. A complete course of treatment consisted of two doses of 12 mg each of betamethasone given at an interval of 12-24 hours. Infants in group 1 were born to mothers who had not received betamethasone, or were delivered within 24 hours of receiving the first dose of steroid. Infants in group 2 were born to mothers who had received one or more complete courses of betamethasone and were delivered > 24 hours after receiving the first dose of steroid.

RESULTS

The two groups contained statistically similar proportions of boys and girls, and the infants had similar birth weights and survival rates. Those in group 2, compared with those in group 1, had a lower gestational age (p = 0.02) and a lower incidence of white matter lesions on cranial ultrasound scans (p = 0.03). Stepwise logistic regression analysis showed that gestational age (p = 0.0002) and a complete course of antenatal steroids (p = 0.02) had independent effects on cerebral white matter lesions.

CONCLUSIONS

These observations suggest that a complete course of antenatal steroids may have a protective effect against cerebral white matter lesions in very low birthweight infants.

Neurobiology of periventricular leukomalacia in the premature infant

Brain injury in the premature infant is a problem of enormous importance. Periventricular leukomalacia (PVL) is the major neuropathologic form of this brain injury and underlies most of the neurologic morbidity encountered in survivors of premature birth. Prevention of PVL now seems ultimately achievable because of recent neurobiologic insights into pathogenesis. The pathogenesis of this lesion relates to three major interacting factors. The first two of these, an incomplete state of development of the vascular supply to the cerebral white matter, and a maturation-dependent impairment in regulation of cerebral blood flow underlie a propensity for ischemic injury to cerebral white matter. The third major pathogenetic factor is the maturation-dependent vulnerability of the oligodendroglial (OL) precursor cell that represents the major cellular target in PVL. Recent neurobiologic studies show that these cells are exquisitely vulnerable to attack by free radicals, known to be generated in abundance with ischemia-reperfusion. This vulnerability of OLs is maturation-dependent, with the OL precursor cell highly vulnerable and the mature OL resistant, and appears to relate to a developmental window characterized by a combination of deficient antioxidant defenses and active acquisition of iron during OL differentiation. The result is generation of deadly reactive oxygen species and apoptotic OL death. Important contributory factors in pathogenesis interact with this central theme of vulnerability to free radical attack. Thus, the increased likelihood of PVL in the presence of intraventricular hemorrhage could relate to increases in local iron concentrations derived from the hemorrhage. The important contributory role of maternal/fetal infection or inflammation and cytokines in the pathogenesis of PVL could be related to effects on the cerebral vasculature and cerebral hemodynamics, to generation of reactive oxygen species, or to direct toxic effects on vulnerable OL precursors. A key role for elevations in extracellular glutamate, caused by ischemia-reperfusion, is suggested by demonstrations that glutamate causes toxicity to OL precursors by both nonreceptor- and receptor-mediated mechanisms. The former involves an exacerbation of the impairment in antioxidant defenses, and the latter, an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptor-mediated cell death. Most importantly, these new insights into the pathogenesis of PVL suggest potential preventive interventions. These include avoidance of cerebral ischemia by detection of infants with impaired cerebrovascular autoregulation, e.g. through the use of in vivo near-infrared spectroscopy, the use of free radical scavengers to prevent toxicity by reactive oxygen species, the administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptor antagonists to prevent glutamate-mediated injury, or the use of maternal antibiotics or anticytokine agents to prevent toxicity from maternal/fetal infection or inflammation and cytokines.

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.

Cerebral white matter damage in the preterm infant: pathophysiology and risk factors

Based on clinical, epidemiologic, and experimental studies, the aetiology of white matter damage, specifically periventricular leukomalacia (PVL), is multifactorial and involves pre- and perinatal factors possibly including genetic factors, hypoxic-ischaemic insults, infection, excess cytokines, free radical production, increased excitatory amino acid release, and trophic factor deficiencies. The article summarizes research findings about the aetiology of white matter damage and cerebral palsy in preterm infants. The information is organized according to specific antecedents, for which we present epidemiological and neurobiological data. The most important prenatal factor appears to be intrauterine infection. We discuss the evidence supporting the hypothesis that the foetal inflammatory response contributes to neonatal brain injury and later developmental disability. We recently established an animal model of excitotoxic lesions in the developing mouse brain. Brain damage was induced by intra-cortical injections of ibotenate, a glutamatergic agonist. When administered on post-natal day 5 ibotenate induced the formation of white matter cysts. Our animal model could be used to further explore the mechanisms involved in the formation of PVL. Potentially preventive strategies will be discussed.

Antenatal therapies and the developing brain

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

Possible strategies to protect the preterm brain against the fetal inflammatory response

The accruing evidence that a fetal inflammatory response is the link between antenatal infection and white matter damage in the preterm newborn infant offers room for speculation how this harmful sequence could be interrupted. Enhancement of endogenous protection, response modification, and damage limitation downstream could be helpful strategies for intervention design. Appropriate observational and experimental studies are needed before clinical interventions can be initiated.

Hypocarbia during the first 24 postnatal hours and white matter echolucencies in newborns < or = 28 weeks gestation

The purpose of the present study was to test the hypothesis that newborns < or = 28 wk gestation who have a PCO(2) measurement in the lowest gestational age-specific quartile (hypocarbia) on the first day of life are not at increased risk for ultrasonographic white matter echolucency (EL) after adjustment for confounders. The sample consisted of 799 infants < or = 28 wk gestation born during 1991-1993. Forty-eight infants with EL were classified as cases and compared with 751 controls, i.e. those without EL. We performed univariable comparisons, stratified analyses, and multivariable logistic regression. In the univariable analyses, hypocarbia on the first day of life was associated with an increased EL risk. The odds ratios for the hypocarbia-EL relationship were prominently elevated in the strata of infants who did not have other major risk factors for EL (e.g. gestational age 26-28 wk, normothyroxinemia, no characteristics of antenatal infection). In the multivariable analyses, the association diminished after adjustment with a hypocarbia propensity score (odds ratio = 1.7; 95 % confidence interval, 0.8-3.2) or with potential confounders.

Multiple courses of antenatal glucocorticoid treatment and fetal outcome

Thanks to the US National Institutes of Health Consensus Conference, the odds of antenatal use of glucocorticoids for preventing severe neonatal complications of premature delivery have significantly increased these last years. The belief that neonatal benefits last up to 7 days after the first course and administration of further courses is safe has led many obstetricians to prescribe multiple antenatal glucocorticoid courses. Whether multiple courses offer an advantage over a single course has not been demonstrated. In contrast, there are accumulating evidence suggesting that this practice may have short and long-term side effects. The potential benefits and side effects of multiple antenatal courses of glucocorticoids, extrapolated from experimental data and observational studies, are detailed in this review. Until the results of ongoing randomized trials with long term follow-up are available, the practice of giving multiple courses of glucocorticoids to women should be considered with the greatest caution.

Antecedents of cerebral palsy in very low-birth weight infants

Research from the last two decades provides directions for efforts to prevent CP in VLBW infants. The pathogenesis of CP seems to involve factors operating both during pregnancy and in the neonatal period. The most important prenatal factor appears to be intrauterine infection. Perinatal infection and other risk factors, such as the death of a co-twin, placental abruption, and cerebral ischemia, could trigger a cytokine cascade resulting in damage to the developing brain. The low frequency of intrauterine infection in mothers with preeclampsia might explain the apparent protective effect of this disorder. If the brain damage attributed to intrauterine infection and other risk factors involves cytokines as intermediates, then blockade of the proinflammatory cascade or promotion of endogenous inhibitors might prevent CP. Other potentially preventive strategies include corticosteroids given to mothers (but not those given to neonates) and thyroid hormone.

Neonatal acute respiratory failure

Acute respiratory failure is the most common problem seen in the preterm and term infants admitted to neonatal intensive care units. In preterm infants, the most common cause of acute respiratory failure is respiratory distress syndrome caused by surfactant deficiency. Acute respiratory failure in term and near term infants is usually a result of meconium aspiration syndrome, sepsis, pulmonary hypoplasia, and primary pulmonary hypertension of the newborn. The response to various methods of treatment may vary, depending on the severity of respiratory failure and the cause of the acute respiratory failure. We reviewed the evidence for efficacy and current utilization of newer treatment modalities, including exogenous surfactant administration, high frequency ventilation, inhaled nitric oxide therapy, antenatal steroids for the prevention of respiratory distress syndrome, and use of postnatal steroids for the prevention of chronic lung disease.