Antecedents of cerebral palsy in a multicenter trial of indomethacin for intraventricular hemorrhage

Machine Learning Detects Intraventricular Haemorrhage in Extremely Preterm Infants

OBJECTIVE

To test the potential utility of applying machine learning methods to regional cerebral (rcSO₂) and peripheral oxygen saturation (SpO₂) signals to detect brain injury in extremely preterm infants.

STUDY DESIGN

A subset of infants enrolled in the Management of Hypotension in Preterm infants (HIP) trial were analysed (n = 46). All eligible infants were <28 weeks' gestational age and had continuous rcSO₂ measurements performed over the first 72 h and cranial ultrasounds performed during the first week after birth. SpO₂ data were available for 32 infants. The rcSO₂ and SpO₂ signals were preprocessed, and prolonged relative desaturations (PRDs; data-driven desaturation in the 2-to-15-min range) were extracted. Numerous quantitative features were extracted from the biosignals before and after the exclusion of the PRDs within the signals. PRDs were also evaluated as a stand-alone feature. A machine learning model was used to detect brain injury (intraventricular haemorrhage-IVH grade II-IV) using a leave-one-out cross-validation approach.

RESULTS

The area under the receiver operating characteristic curve (AUC) for the PRD rcSO₂ was 0.846 (95% CI: 0.720-0.948), outperforming the rcSO₂ threshold approach (AUC 0.593 95% CI 0.399-0.775). Neither the clinical model nor any of the SpO₂ models were significantly associated with brain injury.

CONCLUSION

There was a significant association between the data-driven definition of PRDs in rcSO₂ and brain injury. Automated analysis of PRDs of the cerebral NIRS signal in extremely preterm infants may aid in better prediction of IVH compared with a threshold-based approach. Further investigation of the definition of the extracted PRDs and an understanding of the physiology underlying these events are required.

Neurodevelopmental outcomes of premature infants with intraventricular hemorrhage across a lifespan

Neurodevelopmental impairment rates remain high among extremely preterm and very low birth weight infants. This review describes the rates of brain injury and neuro-developmental impairment at 2,3 years, early school age, adolescence, and young adulthood for survivors with intraventricular hemorrhage (IVH). Former preterm infants with a history of high-grade IVH are at the greatest risk of adverse neurodevelopmental outcomes. There is variability, however, in definitions of brain injury, methods for assessing brain injury, and definitions of adverse outcomes among multicenter networks. Despite differences in methods described in publications, perinatal grade III-IV intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and white matter injury are consistently associated with increased rates of adverse motor and cognitive outcomes in the first 2,3 years of life, at early school age, in adolescence and early adulthood. Effects of socioeconomic status on outcomes, however, increase with the increasing age of the child. In summary, although preterm survivors of IVH are at an increased risk of adverse outcomes across a lifetime, there is evidence that social and environmental factors contribute to recovery over time.

Neurodevelopmental Follow-up of Preterm Infants: What Is New?

There is increasing evidence of ongoing changes occurring in short-term and long-term motor and language outcomes in former premature infants. As rates of moderate to severe cerebral palsy (CP) have decreased, there has been increased awareness of the impact of mild CP and of developmental coordination disorder on the preterm population. Language delays and disorders continue to be among the most common outcomes. In conjunction with medical morbidities, there is increased awareness of the negative impact of family psycho-socioeconomic adversities on preterm outcomes and of the importance of intervention for these adversities beginning in the neonatal ICU.

Cord Blood Haptoglobin, Cerebral Palsy and Death in Infants of Women at Risk for Preterm Birth: A Secondary Analysis of a Randomised Controlled Trial

BACKGROUND

Antenatal exposure to intra-uterine inflammation results in precocious Haptoglobin (Hp) expression (switch-on status). We investigated the relationships between foetal Hp expression at birth with newborn and childhood outcomes.

METHODS

We evaluated cord blood samples from 921 newborns of women at imminent risk for preterm delivery randomised to either placebo (n = 471, birth gestational age (GA) median [min-max]: 31 [24-41] weeks) or magnesium sulphate (n = 450, GA 31 [24-42] weeks]). Primary outcome was infant death by 1 year and/or cerebral palsy (CP) ≥ 2 years of corrected age. Adjusted odd ratios (aOR) for neonatal and childhood outcomes were calculated controlling for GA, birth weight, sex, and magnesium exposure.

FINDINGS

Primary outcome occurred in 2.8% of offspring. Newborns were classified in three pre-defined categorisation groups by cord blood Hp switch status and IL-6 levels: inflammation-nonexposed (Category 1, n = 432, 47%), inflammation-exposed haptoglobinemic (Category 2, n = 449, 49%), and inflammation-exposed anhaptoglobinemic or hypohaptoglobinemic (Category 3, n = 40, 4%). Newborns, found anhaptoglobinemic or hypohaptoglobinemic (Category 3) had increased OR for intraventricular haemorrhage (IVH) and/or death (aOR: 7.0; 95% CI: 1.4-34.6, p = 0.02) and for CP and/or death (aOR: 6.27; 95% CI: 1.7-23.5, p = 0.006) compared with Category 2. Foetal ability to respond to inflammation by haptoglobinemia resulted in aOR similar to inflammation-nonexposed newborns. Hp1-2 or Hp2-2 phenotypes protected against retinopathy of prematurity (aOR = 0.66; 95% CI 0.48-0.91, p = 0.01).

INTERPRETATION

Foetal ability to switch-on Hp expression in response to inflammation was associated with reduction of IVH and/or death, and CP and/or death. Foetuses unable to mount such a response had an increased risk of adverse outcomes.Trial Registration: clinicaltrials.gov Identifier: NCT00014989.

The combined exposure to intra-amniotic inflammation and neonatal respiratory distress syndrome increases the risk of intraventricular hemorrhage in preterm neonates

OBJECTIVE

To evaluate the impact of combined exposure to intra-amniotic inflammation and neonatal respiratory distress syndrome (RDS) on the development of intraventricular hemorrhage (IVH) in preterm neonates.

METHODS

This retrospective cohort study includes 207 consecutive preterm births (24.0-33.0 weeks of gestation). Intra-amniotic inflammation was defined as an amniotic fluid matrix metalloproteinase-8 concentration >23 ng/mL. According to McMenamin's classification, IVH was defined as grade II or higher when detected by neurosonography within the first weeks of life.

RESULTS

(1) IVH was diagnosed in 6.8% (14/207) of neonates in the study population; (2) IVH was frequent among newborns exposed to intra-amniotic inflammation when followed by postnatal RDS [33% (6/18)]. The frequency of IVH was 7% (8/115) among neonates exposed to either of these conditions - intra-amniotic inflammation or RDS - and 0% (0/64) among those who were not exposed to these conditions; and (3) Neonates exposed to intra-amniotic inflammation and postnatal RDS had a significantly higher risk of IVH than those with only intra-amniotic inflammation [odds ratio (OR) 4.6, 95% confidence interval (CI) 1.1-19.3] and those with RDS alone (OR 5.6, 95% CI 1.0-30.9), after adjusting for gestational age.

CONCLUSION

The combined exposure to intra-amniotic inflammation and postnatal RDS markedly increased the risk of IVH in preterm neonates.

Multivariate Analysis and Machine Learning in Cerebral Palsy Research

Cerebral palsy (CP), a common pediatric movement disorder, causes the most severe physical disability in children. Early diagnosis in high-risk infants is critical for early intervention and possible early recovery. In recent years, multivariate analytic and machine learning (ML) approaches have been increasingly used in CP research. This paper aims to identify such multivariate studies and provide an overview of this relatively young field. Studies reviewed in this paper have demonstrated that multivariate analytic methods are useful in identification of risk factors, detection of CP, movement assessment for CP prediction, and outcome assessment, and ML approaches have made it possible to automatically identify movement impairments in high-risk infants. In addition, outcome predictors for surgical treatments have been identified by multivariate outcome studies. To make the multivariate and ML approaches useful in clinical settings, further research with large samples is needed to verify and improve these multivariate methods in risk factor identification, CP detection, movement assessment, and outcome evaluation or prediction. As multivariate analysis, ML and data processing technologies advance in the era of Big Data of this century, it is expected that multivariate analysis and ML will play a bigger role in improving the diagnosis and treatment of CP to reduce mortality and morbidity rates, and enhance patient care for children with CP.

Chorioamnionitis in the Development of Cerebral Palsy: A Meta-analysis and Systematic Review

CONTEXT

Chorioamnionitis (CA) has often been linked etiologically to cerebral palsy (CP).

OBJECTIVES

To differentiate association from risk of CA in the development of CP.

DATA SOURCES

PubMed, Cochrane Library, Embase, and bibliographies of original studies were searched by using the keywords (chorioamnionitis) AND ((cerebral palsy) OR brain).

STUDY SELECTION

Included studies had to have: (1) controls, (2) criteria for diagnoses, and (3) neurologic follow-up. Studies were categorized based on: (1) finding incidence of CP in a CA population, or risk of CP; and (2) incidence of CA in CP or association with CP.

DATA EXTRACTION

Two reviewers independently verified study inclusion and extracted data.

RESULTS

Seventeen studies (125 256 CA patients and 5 994 722 controls) reported CP in CA. There was significantly increased CP inpreterm histologic chorioamnionitis (HCA; risk ratio [RR] = 1.34, P < .01), but not in clinical CA (CCA). Twenty-two studies (2513 CP patients and 8135 controls) reported CA in CP. There was increased CCA (RR = 1.43, P < .01), but no increase in HCA in preterm CP. Increased HCA was found (RR = 4.26, P < .05), as well as CCA in term/near-term CP (RR = 3.06, P < .01).

CONCLUSIONS

The evidence for a causal or associative role of CA in CP is weak. Preterm HCA may be a risk factor for CP, whereas CCA is not. An association with term and preterm CP was found for CCA, but only with term CP for HCA.

Motor and cognitive outcome after specific early lesions of the brain - a systematic review

The aim of this systematic review was to study motor and cognitive outcome in infants with severe early brain lesions and to evaluate effects of side of the lesion, sex, and social economic status on outcome. A literature search was performed using the databases Pubmed and Embase. Included studies involved infants with either cystic periventricular leukomalacia (cPVL), preterm, or term stroke (i.e. parenchymal lesion of the brain). Outcome was expressed as cerebral palsy (CP) and intellectual disability (mental retardation). Median prevalence rates of CP after cPVL, preterm, and term stroke were 86%, 71%, and 29% respectively; of intellectual disability 50%, 27%, and 33%. Most infants with cPVL developed bilateral CP, those with term stroke unilateral CP, whereas after preterm stroke bilateral and unilateral CP occurred equally often. Information on the effects of sex and social economic status on outcome after specific brain lesions was very limited. Our findings show that the risk for CP is high after cPVL, moderate after preterm stroke, and lowest after term stroke. The risk for intellectual disability after an early brain lesion is lower than that for CP. Predicting outcome at individual level remains difficult; new imaging techniques may improve predicting developmental trajectories.

Neurodevelopmental outcomes of extremely preterm infants

Survival of extremely preterm infants has improved since 2000. Neurodevelopmental impairment rates remain high at the limits of viability. Although improved survival and neurodevelopmental impairment rates are associated with higher gestational age and more recent year of birth, significant variability in findings among geographic areas and networks is evident, and seems related to differences in population, management style, regional protocols, definitions, and outcome assessments. Outcome studies during adolescence and young adult age are needed to determine the long-term impact of extremely preterm birth.

Cytokines and neurodevelopmental outcomes in extremely low birth weight infants

OBJECTIVE

To determine if selected pro-inflammatory and anti-inflammatory cytokines and/or mediators of inflammation reported to be related to the development of cerebral palsy (CP) predict neurodevelopmental outcome in extremely low birth weight infants.

STUDY DESIGN

Infants with birth weights ≤1000 g (n = 1067) had blood samples collected at birth and on days 3 ± 1, 7 ± 1, 14 ± 3, and 21 ± 3 to examine the association between cytokines and neurodevelopmental outcomes. The analyses were focused on 5 cytokines (interleukin [IL] 1β; IL-8; tumor necrosis factor-α; regulated upon activation, normal T-cell expressed, and secreted (RANTES); and IL-2) reported to be most predictive of CP in term and late preterm infants.

RESULTS

IL-8 was higher on days 0-4 and subsequently in infants who developed CP compared with infants who did not develop CP in both unadjusted and adjusted analyses. Other cytokines (IL-12, IL-17, tumor necrosis factor-β, soluble IL rα, macrophage inflammatory protein 1β) were found to be altered on days 0-4 in infants who developed CP.

CONCLUSIONS

CP in former preterm infants may, in part, have a late perinatal and/or early neonatal inflammatory origin.

Perinatal death and neurological damage as a sequential chain of poor outcome

OBJECTIVE

We investigated the risk factors of perinatal death and neurological damage.

METHODS

Perinatal death and neurological damage were retrospectively investigated using a population-based study of 108 024 deliveries from 1998 to 2007. Main factors studied were asphyxia, growth restriction and preterm delivery < 34 weeks of gestation, since these three factors were most often associated with poor prognosis. The impact of each factor was identified by multiple regression analyses.

RESULTS

There were 459 perinatal deaths (4.3/1000) and 220 neurological damages (2.0/1000). Preterm delivery accounted for 50% of perinatal deaths and neurological damage, whereas it constituted 2.6% of total births. Multiple regression analyses showed that prematurity < 34 weeks (10-fold), asphyxia (10-fold) and growth restriction (2-fold) were independent and significant risk factors associated with poor outcomes, and that the magnitude was similar throughout the three consecutive critical events of fetal death, neonatal death and neurological damage.

CONCLUSIONS

Prematurity < 34 weeks, asphyxia and growth restriction are independent and persistent risk factors from perinatal death to neurological damage.

Neurobehavioral assessment predicts motor outcome in preterm infants

OBJECTIVE

To determine whether Neonatal Intensive Care Unit Network Neurobehavior Scales (NNNS) at 44 weeks predict motor outcome at 2 years in preterm infants from the Maternal Lifestyles Study (MLS).

STUDY DESIGN

Data were collected on all preterm infants (<36 weeks) in the MLS who underwent an NNNS at 44 weeks (n = 395) and neurologic examination at 12 to 36 months or Bayley Psychomotor Development Index (PDI) at 24 months (n = 270). Logistic regression analyzed NNNS summary scores associated with cerebral palsy (CP) or PDI <70, while controlling for birth weight

RESULTS

Eighteen of 395 infants (5%) had CP; 24 of 270 infants (9%) had PDI <70. CP was associated with low quality of movement (odds ratio [OR], 1.95; 95% CI, 1.24-3.06; P = .004) and high lethargy (OR, 1.67; 95% CI, 1.01-2.76; P = .045). The model contributed 19% of the variance in CP diagnosis at 12 to 36 months (R(2) = .19, P < .001). Low PDI was associated with low handling (OR, 1.83; 95% CI, 1.12-2.99; P = .017), low quality of movement (OR, 2.16; 95% CI, 1.38-3.38; P = .001), and hypotonia (OR, 1.63; 95% CI, 1.14-2.32; P = .007). The model contributed 26% of the variance in PDI <70 at 24 months (R(2) = 0.26, P < .001).

CONCLUSIONS

The neurobehavioral profile of under-arousal in 44-week-old preterm infants may predict poor motor outcome.

Collapse

Key Words

• neurobehavior
• outcomes
• elbw

Collapse

MESH Headings

• Adolescent
• Adult
• Cerebral Palsy/diagnosis
• Child, Preschool
• Cocaine-Related Disorders
• Developmental Disabilities/diagnosis
• Female
• Humans
• Infant
• Infant Behavior
• Infant, Extremely Low Birth Weight
• Infant, Newborn
• Infant, Premature
• Male
• Neurologic Examination
• Predictive Value of Tests
• Pregnancy
• Pregnancy Complications
• Young Adult

Collapse

Grants

• U10 DA024119-04 NIDA NIH HHS
• U10 DA024117-02 NIDA NIH HHS
• U10 DA024118-04 NIDA NIH HHS
• U10 HD021385-17S1 NICHD NIH HHS
• U10 HD021385-18S1 NICHD NIH HHS
• U10 DA024118 NIDA NIH HHS
• U10 DA024119-03 NIDA NIH HHS
• U10 HD042638-04S1 NICHD NIH HHS
• U10 DA024118-02 NIDA NIH HHS
• U10 DA024119 NIDA NIH HHS
• U10 HD021385-20S1 NICHD NIH HHS
• U10 DA024117-01 NIDA NIH HHS
• U10 DA024119-02S1 NIDA NIH HHS
• U10 HD021385 NICHD NIH HHS
• U10 DA024128 NIDA NIH HHS
• U10 DA024117 NIDA NIH HHS
• U10 HD042638 NICHD NIH HHS
• U10 HD021385-19S2 NICHD NIH HHS
• U10 DA024128-08 NIDA NIH HHS
• U10 DA024117-03 NIDA NIH HHS
• U10 DA024119-02 NIDA NIH HHS
• U10 HD042638-04 NICHD NIH HHS
• U10 DA024119-01 NIDA NIH HHS
• U10 DA024118-01 NIDA NIH HHS
• UG1 HD021385 NICHD NIH HHS
• U10 DA024117-04 NIDA NIH HHS
• U10 DA024118-03 NIDA NIH HHS
• U10 HD042638-03 NICHD NIH HHS
• U10 DA024119-02S2 NIDA NIH HHS
• U10 DA024128-06 NIDA NIH HHS
• U10 DA024128-07 NIDA NIH HHS
• U10 DA024128-09 NIDA NIH HHS

Collapse

Affiliation(s)

Bonnie E Stephens Department of Pediatrics, Alpert Brown Medical School, Providence, RI, USA.
Jing Liu
Barry Lester
Linda Lagasse
Seetha Shankaran
Henrietta Bada
Charles Bauer
Abhik Das
Rosemary Higgins

Collapse

Chorioamnionitis and brain damage in the preterm newborn

AIM

To evaluate the association between histological chorioamnionitis and brain damage (intraventricular hemorrhage and cystic periventricular leukomalacia) in the preterm newborn.

METHODS

This was a retrospective study on neonates born at less than 34 weeks gestational age, and their respective mothers, at three tertiary medical centers in the north of Portugal, from January 2001 to December 2002.

RESULTS

The study included 452 newborns (235 male/217 female; birth weight 1440 (515-2620) grams; gestational age 31 (23-33) weeks), 125 from mothers whose placenta showed signs of chorioamnionitis and 327 from mothers without the condition. The association between histological chorioamnionitis and: (1) intraventricular hemorrhage grades I-IV was OR 1.43 (95% CI 0.49-3.94); (2) intraventricular hemorrhage grades III and IV was OR 2.49 (95% CI 1.20-5.11); (3) cystic periventricular leukomalacia was OR 3.02 (95% CI 1.50-6.07). The association, adjusted for birth weight and gestational age, between chorioamnionitis and: (1) intraventricular hemorrhage grades III and IV was OR 0.94 (95% CI 0.39-2.28); (2) cystic periventricular leukomalacia was OR 1.94 (95% CI 1.03-4.61). The association between histological chorioamnionitis with funisitis and/or vasculitis and: (1) intraventricular hemorrhage grades I to IV was OR 1.27 (95% CI 0.52-3.10); (2) cystic periventricular leukomalacia was OR 2.08 (95% CI 0.72-5.98).

CONCLUSION

This study confirms the association between histological chorioamnionitis and cystic periventricular leukomalacia, but was unable to confirm the association between histological chorioamnionitis and intraventricular hemorrhage.

Indomethacin tocolysis and white matter injury in preterm infants

OBJECTIVE

This study aims to clarify the relationship between indomethacin tocolysis and neonatal white matter injury (WMI) in preterm infants.

METHODS

We conducted a retrospective review of preterm infants born at 24-32 weeks who had sufficient cranial ultrasound examinations (CUS) to determine the incidence and severity of abnormalities. Infants with normal CUS were compared on univariate and multivariate analyses with infants with the different forms of WMI.

RESULTS

On multivariate logistic regression analysis, indomethacin tocolysis was significantly correlated with periventricular echogenicity (PVE; OR 2.84 95% CI 1.41-5.7, p = 0.003), but not with periventricular leucomalacia (PVL; OR 1.83 95% CI0.6-5.6, p = 0.29). Indomethacin was not related to increased risk for periventricular-intraventricular hemorrhage or periventricular hemorrhagic infarction.

CONCLUSION

These findings suggest caution in the use of indomethacin as a tocolytic therapy.

Neurodevelopmental outcome of the premature infant

Advances in antenatal medicine and neonatal intensive care have successfully resulted in improved survival rates of preterm infants. These improvements have been most dramatic in infants born extremely low birth weight (ELBW, <or=1000 g) and at the limits of viability (22 to 25 weeks). But improvements in survival have not been accompanied by proportional reductions in the incidence of disability in this population. Thus, survival is not an adequate measure of success in these infants who remain at high risk for neurodevelopmental and behavioral morbidities. There is now increasing evidence of sustained adverse outcomes into school age and adolescence, not only for ELBW infants but for infants born late preterm.

Altered heart rhythm dynamics in very low birth weight infants with impending intraventricular hemorrhage

OBJECTIVE

Intraventricular hemorrhage remains an important problem among very low birth weight infants and may result in long-term neurodevelopmental disabilities. Neonatologists have been unable to accurately predict impending intraventricular hemorrhage. Because alterations in the autonomic nervous system's control of heart rhythm have been associated with intraventricular hemorrhage after its development, we sought to determine if early subtle alterations of heart rhythm could be predictive of impending intraventricular hemorrhage in very low birth weight infants.

METHODS

This case-control study included 10 newborn very low birth weight infants with intraventricular hemorrhage (5 grade IV, 4 grade III, and 1 grade II) and 14 control infants without intraventricular hemorrhage. Heart rhythm data from the first day of life before the development of intraventricular hemorrhage were evaluated. Detrended fluctuation analysis, a nonlinear fractal heart rate variability method, was used to assess the fractal dynamics of the heart rhythm. Fractal scaling exponents were calculated by using this analysis.

RESULTS

Twenty-four infants (mean +/- SD, birth weight: 845 +/- 213g: gestational age: 26.1 +/- 1.9 weeks) participated in the study. The short-term scaling exponent was significantly larger in infants who later developed intraventricular hemorrhage compared with those who did not (0.60 +/- 0.1 vs 0.45 +/- 0.1). A value of 0.52 resulted in 70% sensitivity and positive predictive value and 79% specificity and negative predictive value. The short-term scaling exponent was the only significant predictor of intraventricular hemorrhage.

CONCLUSIONS

Fractal dynamics of the heart rhythm is significantly altered in very low birth weight infants before developing intraventricular hemorrhage and may be predictive of impending intraventricular hemorrhage.

Does placental inflammation relate to brain lesions and volume in preterm infants?

OBJECTIVES

To evaluate the association between histologic inflammation of placenta and brain findings in ultrasound examinations and regional brain volumes in magnetic resonance imaging in very-low-birth-weight (VLBW) or in very preterm infants.

STUDY DESIGN

VLBW or very preterm infants (n = 121) were categorized into 3 groups according to the most pathologic brain finding on ultrasound examinations until term. The brain magnetic resonance imaging performed at term was analyzed for regional brain volumes. The placentas were analyzed for histologic inflammatory findings.

RESULTS

Histologic chorioamnionitis on the fetal side correlated to brain lesions in univariate but not in multivariate analyses. Low gestational age was the only significant risk factor for brain lesions in multivariate analysis (P < .0001). Histologic chorioamnionitis was not associated with brain volumes in multivariate analyses. Female sex, low gestational age, and low birth weight z score correlated to smaller volumes in total brain tissue (P = .001, P = .0002, P < .0001, respectively) and cerebellum (P = .047, P = .003, P = .001, respectively). In addition, low gestational age and low-birth-weight z score correlated to a smaller combined volume of basal ganglia and thalami (P = .0002).

CONCLUSIONS

Placental inflammation does not appear to correlate to brain lesions or smaller regional brain volumes in VLBW or in very preterm infants at term age.

Neuromotor outcome at 2 years of very preterm infants who were treated with high-frequency oscillatory ventilation or conventional ventilation for neonatal respiratory distress syndrome

OBJECTIVE

In a previous multicenter, randomized trial, elective use of high-frequency oscillatory ventilation was compared with the use of conventional ventilation in the management of respiratory distress syndrome in preterm infants <30 weeks. No difference in terms of respiratory outcome was observed, but concerns were raised about an increased rate of severe intraventricular hemorrhage in the high-frequency ventilation group. To evaluate outcome, a follow-up study was conducted until a corrected age of 2 years. We report the results concerning neuromotor outcome.

METHODS

Outcome was able to be evaluated in 192 of the 212 infants who survived until discharge from the neonatal unit: 97 of 105 infants of the high-frequency group and 95 of 104 infants of the conventional ventilation group.

RESULTS

In the infants reviewed, mean birth weight and gestational age were similar in the 2 ventilation groups. As in the overall study population, the following differences were observed between the high-frequency ventilation group and the conventional ventilation group: lower 5-minute Apgar score, fewer surfactant instillations, and a higher incidence of severe intraventricular hemorrhage. At a corrected age of 2 years, 93 of the 97 infants of the high-frequency group and 79 of the 95 infants of the conventional ventilation group did not present any neuromotor disability, whereas 4 infants of the high-frequency group and 16 infants of the conventional ventilation group had cerebral palsy.

CONCLUSIONS

Contrary to our initial concern about the increased rate of severe intraventricular hemorrhage in the high-frequency ventilation group, these data suggest that early use of high-frequency ventilation, compared with conventional ventilation, may be associated with a better neuromotor outcome. Because of the small number of patients studied and the absence of any explanation for this finding, we can conclude only that high-frequency oscillatory ventilation is not associated with a poorer neuromotor outcome.

The role of neonatal networks

A neonatal network is a collaboration involving more than one clinical site where a common protocol is used for a randomized trial, observational study, or quality improvement project. Because the prevalence of important outcomes (e.g., death or neurodevelopmental impairment) is low among neonates, multi-site studies have been an essential contributor to the identification of interventions for improving the health of neonates. In this review we summarize key aspects of the conduct of multi-site studies and describe some of the prominent accomplishments and contributions of neonatal networks. Important contributions of randomized trials and observational studies include the identification, and assessment, of potential strategies for prevention of cerebral palsy, chronic lung disease, and blindness due to retinopathy of prematurity. In addition, quality improvement projects by neonatal networks have greatly facilitated the dissemination of information about, and implementation of, evidence-based interventions.

Validation of the National Institutes of Health consensus definition of bronchopulmonary dysplasia

OBJECTIVE

A number of definitions of bronchopulmonary dysplasia (BPD), or chronic lung disease, have been used. A June 2000 National Institute of Child Health and Human Development/National Heart, Lung, and Blood Institute Workshop proposed a severity-based definition of BPD for infants <32 weeks' gestational age (GA). Mild BPD was defined as a need for supplemental oxygen (O2) for > or =28 days but not at 36 weeks' postmenstrual age (PMA) or discharge, moderate BPD as O2 for > or =28 days plus treatment with <30% O2 at 36 weeks' PMA, and severe BPD as O2 for > or =28 days plus > or =30% O2 and/or positive pressure at 36 weeks' PMA. The objective of this study was to determine the predictive validity of the severity-based, consensus definition of BPD.

METHODS

Data from 4866 infants (birth weight < or =1000 g, GA <32 weeks, alive at 36 weeks' PMA) who were entered into the National Institute of Child Health and Human Development Neonatal Research Network Very Low Birth weight (VLBW) Infant Registry between January 1, 1995 and December 31, 1999, were linked to data from the Network Extremely Low Birth Weight (ELBW) Follow-up Program, in which surviving ELBW infants have a neurodevelopmental and health assessment at 18 to 22 months' corrected age. Linked VLBW Registry and Follow-up data were available for 3848 (79%) infants. Selected follow-up outcomes (use of pulmonary medications, rehospitalization for pulmonary causes, receipt of respiratory syncytial virus prophylaxis, and neurodevelopmental abnormalities) were compared among infants who were identified with BPD defined as O2 for 28 days (28 days definition), as O2 at 36 weeks' PMA (36 weeks' definition), and with the consensus definition of BPD.

RESULTS

A total of 77% of the neonates met the 28-days definition, and 44% met the 36-weeks definition. Using the consensus BPD definition, 77% of the infants had BPD, similar to the cohort identified by the 28-days definition. A total of 46% of the infants met the moderate (30%) or severe (16%) consensus definition criteria, identifying a similar cohort of infants as the 36-weeks definition. Of infants who met the 28-days definition and 36-weeks definition and were seen at follow-up at 18 to 22 months' corrected age, 40% had been treated with pulmonary medications and 35% had been rehospitalized for pulmonary causes. In contrast, as the severity of BPD identified by the consensus definition worsened, the incidence of those outcomes and of selected adverse neurodevelopmental outcomes increased in the infants who were seen at follow-up.

CONCLUSION

The consensus BPD definition identifies a spectrum of risk for adverse pulmonary and neurodevelopmental outcomes in early infancy more accurately than other definitions.

Maternal infection and risk of cerebral palsy in term and preterm infants

OBJECTIVE

We tested the hypothesis that term and preterm infants exposed to maternal infection at the time of delivery are at increased risk of developing cerebral palsy (CP).

STUDY DESIGN

A population-based case-control study was conducted using Washington State birth certificate data linked to hospital discharge data. Cases (688) were children <or=6 years old, singleton births, hospitalized during 1987 to 1999 with an ICD-9 diagnosis code for CP. Controls were 3,068 singleton birth infants randomly selected from birth records for the same years without CP-related hospitalizations. Infection information was available only for the birth hospitalization.

RESULTS

Infants of women who had any infection during their hospitalization for delivery were at increased risk of CP (odds ratio (OR) 3.1, 95% confidence interval (CI) 2.3 to 4.2). This was observed for term deliveries (OR 1.8, 95% CI 1.1 to 2.8) and preterm deliveries (OR 2.3, 95% CI 1.3 to 4.2).

CONCLUSIONS

Our results suggest that maternal infection is a risk factor for CP in both term and preterm infants.

Neonatal intensive care neurology

The pediatric neurologist's role in the neonatal intensive care unit is described in four clinical settings: (1) assessment of outcome in neonatal encephalopathy, (2) treatment of seizures in full-term infants, (3) assessment and treatment of intraventricular hemorrhage with posthemorrhagic hydrocephalus, and (4) assessment of outcome in preterm infants. Emphasis is placed on the evidenced-based information available in these settings and on new therapies on the horizon. Using evidence-based information, the pediatric neurologist can accurately assess prognosis in the neonatal period, and this can provide the basis for a rational assessment of newer therapies in neonatal intensive care.

An evidence-based approach to predicting low IQ in very preterm infants from the neurological examination: outcome data from the indomethacin Indomethacin Intraventricular Hemorrhage Prevention Trial

We evaluated whether the degree of cerebral palsy (CP) at age 3 in very preterm children is predictive of full-scale intelligence quotient (FSIQ) <70 at age 8 by calculating likelihood ratios (LRs) for findings on the neurologic examination. Data from the follow-up phase of the Indomethacin Intraventricular Hemorrhage Prevention Trial, which includes periodic neurologic examination and neuropsychometric testing, were used. Information was available on 366 of 440 (83%) children with birth weight of 600 to 1250 g who survived. Neurologic examination at age 3 was grouped by presence and type of CP, and the Weschler Intelligence Scale for Children-Third Edition FSIQ at age 8 was grouped dichotomously (<70 or > or =70). CP was identified in 35 of 366 3-year-olds (9.5%). An FSIQ <70 was identified in 47 of 366 children at 8 years old (12.8%). FSIQ <70 occurred in 14 of 17 children with tri- or quadriplegia (82%), 8 of 18 children with di- or hemiplegia (44%), and 25 of 331 children without CP (7.5%). Useful LRs were calculated for tri- or quadriplegia (30), di- or hemiplegia (5.7), and children without CP (0.55). These LRs have greater impact on posttest odds for FSIQ <70 than those for birth weight <1000 g, history of bronchopulmonary dysplasia, and Stanford-Binet Intelligence Score <70 at age 3. We conclude that the neurologic examination at 3 years old predicts FSIQ <70 at age 8 with LRs that allow evidence-based parental counseling and intervention planning.

A limited range of measures of 2-D ultrasound correlate with 3-D MRI cerebral volumes in the premature infant at term

Two-dimensional (2-D) cranial ultrasound (US) is the principal method for the detection of cerebral injury in the newborn. The aim of this study was to compare 2-D sonographic methods with more advanced 3-D magnetic resonance imaging (MRI) for assessing brain structure. From July 1998 to November 2000, we conducted a prospective methodological study comparing 2-D cranial sonographic measurements with volumes of cerebrospinal fluid (CSF), white matter, grey matter and total volume of brain obtained using 3-D MRI. The study group comprised 63 infants (33 boys), mean gestational age 28 weeks (range 23 to 33 weeks), with imaging studies within 15 days of term equivalent. The highest correlations were between the occipital horn length and total brain volume (R2 = 0.30), the subarachnoid space and both CSF volume (R2 = 0.46) and relative intracranial space occupied by brain tissue (R2 = 0.48). Only 8 (30%) of the 2-D cranial US measures demonstrated good reproducibility. 2-D sonographic measures are limited in reflecting variations in overall cerebral structure, although certain measures, such as subarachnoid space and occipital lobe measures, may be useful in better defining cerebral parenchymal and CSF volumes.

Etiology of cerebral palsy

Cerebral palsy has a complex and multifactorial etiology. Approximately 5%-10% of cases can be ascribed to perinatal hypoxia, but the vast majority of cases are caused by the interplay of several risk factors and antenatal, perinatal, and neonatal events. The strongest risk factors include prematurity and low birth weight. The prevalence of cerebral palsy has remained constant despite improvements in obstetric and neonatal care. For a long time, the only causal factors explored to account for risk for cerebral palsy were complications of labor and delivery. As other periods have been investigated, new associations have come to light. The current understanding of contributors to the risk for cerebral palsy is still incomplete. Multiple causes may interact by way of excitotoxic, oxidative, or other converging pathophysiologic pathways. A single factor, unless present to an overwhelming degree, often may be insufficient to produce cerebral damage, whereas two or three interacting pathogenic assaults may overwhelm natural defenses and produce irreversible brain injury. The low prevalence of cerebral palsy makes the formal testing of preventative strategies difficult. There is a need for such strategies to be carefully assessed in well designed, multicenter, randomized, controlled trials before becoming part of clinical practice, however, so that the balance between harm and benefit is known in advance.

Does labor influence neonatal and neurodevelopmental outcomes of extremely-low-birth-weight infants who are born by cesarean delivery?

OBJECTIVE

The purpose of this study was to examine the influence of labor on extremely-low-birth-weight infants who were born by cesarean delivery with reference to neonatal and neurodevelopmental outcomes. We hypothesized that infants who are born by cesarean delivery without labor will have better outcomes than those infants who are born by cesarean delivery with labor.

STUDY DESIGN

This was a retrospective cohort study of extremely-low-birth-weight infants (birth weight, 401-1000 g) who were born by cesarean delivery and cared for in the National Institute for Child Health and Human Development Neonatal Network, during calendar years 1995 to 1997. A total of 1606 extremely-low-birth-weight infants were born by cesarean delivery and survived to discharge. Of these, 1273 infants (80.8%) were examined in the network follow-up clinics at 18 to 22 months of corrected age and had a complete data set (667 infants were born without labor, 606 infants were born with labor). Outcome variables that were examined include intraventricular hemorrhage grade 3 to 4, periventricular leukomalacia, and neurodevelopmental impairment.

RESULTS

Mothers in the cesarean delivery without labor group were older (P<.001), more likely to be married (P<.05), less likely to be supported by Medicaid (P<.01), more likely to have preeclampsia/hypertension (P<.001), more likely to receive prenatal steroids (P<.005), and less likely to have received antibiotics (P<.001). Infants who were born by cesarean delivery without labor had higher gestational age (P<.001), lower birth weight (P<.01), and were less likely to be outborn (P<.001). By univariate analysis, infants who were born by cesarean delivery with labor had a higher incidence of grade 3 to 4 intraventricular hemorrhage (23.3% vs 12.1%, P<.001), periventricular leukomalacia (8.5% vs 4.7%, P<.02), and neurodevelopmental impairment (41.7% vs 34.6%, P<.02). Logistic regression analysis that controlled for all maternal and neonatal demographic and clinical variables that were statistically associated with labor or no labor revealed that the significant differences in grade 3 to 4 intraventricular hemorrhage, periventricular leukomalacia, and neurodevelopmental impairment were no longer evident.

CONCLUSION

In extremely-low-birth-weight infants who were born by cesarean delivery and after control for other risk factors, labor does not appear to play a significant role in adverse neonatal outcomes and neurodevelopmental impairment at 18 to 22 months of corrected age.

Preterm outcomes research: a critical component of neonatal intensive care

While early preterm outcome studies described the lives of preterm survivors to justify the efforts required to save them, subsequent studies demonstrated their increased incidence of cerebral palsy, mental retardation, sensory impairments, minor neuromotor dysfunction, language delays, visual-perceptual disorders, learning disability and behavior problems compared to fullterm controls. Because infants born at the lower limit of viability require the most resources and have the highest incidence of neurodevelopmental disability, there is concern that resources have gone primarily to neonatal intensive care and are not available for meeting the followup, health, educational and emotional needs of these fragile infants and their families. Despite many methodological concerns, preterm outcome studies have provided insight into risk factors for and causes of CNS injury in preterm infants. Nevertheless, it remains difficult to predict neurodevelopmental outcome for individual preterm infants. Perinatal and neonatal risk factors are inadequate proxies for neurodevelopmental disability. Recent randomized controlled trials with one to five year neurodevelopmental followup have provided valuable information about perinatal and neonatal treatments. Recognizing adverse longterm neurodevelopmental effects of pharmacological doses of postnatal steroids is a sobering reminder of the need for longterm neurodevelopmental followup in all neonatal randomized controlled trials. Ongoing longterm preterm neurodevelopmental studies, analysis of changes in outcomes over time and among centers, and evaluation of the longterm safety, efficacy and effectiveness of many perinatal and neonatal management strategies and proposed neuroprotective agents are all necessary for further medical and technological advances in neonatal intensive care.

Ultrasound grading of cerebral ventricular dilatation in preterm neonates

OBJECTIVE

To compare three grading systems previously described for the measurement of cerebral ventricular dilatation in preterm neonates using ultrasound scans and then to compare these with expert clinical judgement.

METHODS

Eighty-one preterm neonates <1500 g birthweight or < 32 weeks' gestation, with normal, mild, moderate or severely dilated ventricles recorded predominantly during the first 2 weeks of life were selected to ensure a broad representation of ventricular size. Their cranial ultrasound scans obtained nearest to 6 weeks of age were studied. The ventricular index, the diagonal width in the coronal plane and the ventricular height in the parasagittal plane were measured adjacent to the foramen of Monro and were used to grade the degree of dilatation. In 20 of these neonates, this grading was compared with grading based on expert clinical judgement.

RESULTS

Grading according to the ventricular index defined 79% of the scans as normal. However, only 44% and 39% were considered to be normal according to vertical height and diagonal width, respectively. There was a high level of correlation between expert clinical judgement and grading based on ventricular height measurement (r = 0.812; area under receiver operating characteristic (ROC) curve = 0.922) and the diagonal width (r = 0.806; area under ROC curve = 0.935). Ventricular index correlated poorly with clinical judgement (r = 0.298; area under ROC curve = 0.604).

CONCLUSIONS

The measurement of ventricular height and the measurement of diagonal width correlated well with expert clinical judgement. The ventricular index correlated poorly and was less sensitive to mild dilatation. There was no correlation between the ventricular index and the other two measures. The ventricular height and the diagonal width are more appropriate for assessing ventricular dilatation in preterm neonates.

Change in cognitive function over time in very low-birth-weight infants

CONTEXT

Preterm very low-birth-weight (VLBW) infants have a high prevalence of neurodevelopmental disability when evaluated during the first several years of life. However, recent experimental data suggest that the developing brain may recover from or compensate for injury.

OBJECTIVE

To determine if there is cognitive improvement throughout early and middle childhood following VLBW birth.

DESIGN, SETTING, AND PARTICIPANTS

Follow-up data of 296 infants born weighing 600 to 1250 g who participated in a prospective, randomized, placebo-controlled intraventricular hemorrhage (IVH) prevention study performed at 3 northeastern US hospitals between September 1989 and August 1992 and who were serially evaluated at 36, 54, 72, and 96 months of corrected age (CA).

MAIN OUTCOME MEASURES

The age-normed Peabody Picture Vocabulary Test-Revised (PPVT-R) score and measures of intelligence.

RESULTS

Overall, the median PPVT-R score increased from 88 at 36 months of CA to 99 at 96 months of CA; when data from 36 and 96 months of CA were compared, 45% of children gained 10 points or more and 12.5% showed a 5- to 9-point increase in test scores. Similar findings were noted for full-scale and verbal IQ scores. Multivariate analyses demonstrated that increasing age, residence in a 2-parent household, and higher levels of maternal education were all significantly associated with higher PPVT-R scores (for each, P<.001). In addition, early intervention led to greater increases over time in PPVT-R scores among children whose mothers had less than a high school education compared with those with a high school education level or greater (P =.03 by test for interaction). Although most children showed improvement in PPVT-R scores with increasing CA, children with early-onset IVH and subsequent significant central nervous system injury had the lowest PPVT-R scores initially and the scores declined over time (P =.009 by test for interaction).

CONCLUSIONS

The majority of VLBW children had improvement in verbal and IQ test scores over time. Only children with early-onset IVH followed by significant central nervous system injury had low PPVT-R scores that declined over time.

Chorioamnionitis and brain injury

The limited available evidence supports a strong association of chorioamnionitis with neonatal encephalopathy and CP in the term infant. The association of chorioamnionitis with depressed Apgar scores or neonatal seizures and with CP is equivocal in the preterm infant. Different study results may be related to differences in study populations, perhaps specifically to differences in susceptibility by stages of neurologic development as well as differences in gene frequencies associated with inflammation and thrombophilia. We require further understanding of the normal roles of cytokines in brain development, pregnancy, and inflammatory homeostasis before clinical interventions directed at cytokines, their receptors, or the inflammatory process are considered.

Longitudinal, 15-year follow-up of children born at less than 29 weeks' gestation after introduction of surfactant therapy into a region: neurologic, cognitive, and educational outcomes

OBJECTIVE

To measure the primary and secondary school-age neurologic, cognitive, and educational outcomes in a cohort of extremely premature infants born after the introduction of exogenous surfactant therapy in a circumscribed region.

METHODS

Two hundred thirteen infants born at <29 weeks' gestation were cared for at a regional referral center during 1985-1987. At primary school age, neurologic and cognitive outcomes, educational achievement, school placement, health status, and socioeconomic status were determined by follow-up visit. At secondary school age, school placement and health status were evaluated by telephone interview.

RESULTS

One hundred thirty-two infants survived to school age, of whom 127 (96%) were evaluated in 1992-1995 and 126 (95%) were evaluated in 2000. Mean ages were 7.0 years at first follow-up and 14.1 years at second follow-up. At primary-school age follow-up, 19 children (15%) had cerebral palsy, 24 (19%) had a general cognitive index <70, and 41 (32%) were placed in a self-contained, special classroom. Thirty-nine children (31%) had no physical or educational impairment, whereas 27 (21%) had at least 1 severe disability. At secondary school age, cerebral palsy incidence remained unchanged, whereas 36 children (29%) were placed in a special classroom. Fifty-one children (41%) had no physical or educational impairment, whereas 24 (19%) had at least 1 severe disability. Neonatal intraventricular hemorrhage and low socioeconomic status were the strongest predictors of adverse outcomes.

CONCLUSIONS

Premature infants born in the surfactant era remain at high risk of neurodevelopmental compromise. Although many of these children do well, a significant minority will require intensive special educational services through secondary school age.

Acute side effects of surfactant treatment

There is increasing evidence from studies on animals and humans that surfactant administration may have a great impact on cerebral perfusion. These effects may result from direct pulmonary or hemodynamic changes (or a combination of both), but may also be due to rapid alterations of blood gases. Type of surfactant and mode of administration seem to play an important role. Results from the pertinent literature are summarised with a special emphasis on how to avoid potentially harmful side effects of surfactant therapy in preterm infants.

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.

Systematic review of chorioamnionitis and cerebral palsy

In a recent meta-analysis evaluating the relationship between chorioamnionitis and cerebral palsy, we found that chorioamnionitis is a risk factor for both cerebral palsy and cystic periventricular leukomalacia (cPVL). The current paper extends the meta-analysis by including studies published in the year 2000, and by further evaluating the causes of heterogeneity among individual study results. Using a random effects model, clinical chorioamnionitis was significantly associated with both cerebral palsy (RR 1.9, 95% CI 1.5-2.5) and cPVL (RR 2.6, 95% CI 1.7-3.9). Sources of heterogeneity included widely varying practices in the diagnosis of clinical chorioamnionitis, different gestational age characteristics, and varying study year. We conclude that based on the available literature, chorioamnionitis is a risk factor for both cerebral palsy and cPVL.

Public health issues related to infection in pregnancy and cerebral palsy

Cerebral palsy is the most common neuromotor developmental disability of childhood, affecting as many as 8,000 to 12,000 children born in the U.S. each year (corresponding to a prevalence rate of between 2 and 3 per 1000 children). Recent improvements in neonatal care have not resulted in a decline in the overall prevalence of cerebral palsy and, in fact, greater numbers of very preterm/very low birth weight infants are surviving with cerebral palsy and other developmental problems. Infection in pregnancy may be an important cause of the disorder. In preterm infants, there appears to be about a 2-fold increased risk for cerebral palsy from chorioamnionitis, and in term infants the estimated increased risk is about 4-fold. Provisionally, chorioamnionitis might account for 12% of spastic cerebral palsy in term infants and 28% of cerebral palsy in preterm infants. Studies of biochemical markers of fetal inflammation typically associated with infection also suggest that an inflammatory response may be an important independent etiologic factor. If a substantial proportion of cerebral palsy is attributable to acute amnionitis infection and/or neonatal sepsis, cerebral palsy should have decreased in the United States after administration of intrapartum antibiotics became widespread in response to publication of public health consensus guidelines for Group B streptococcus in 1996. However, failure to detect declines could have a number of explanations and these explanations illustrate the many public health challenges related to intrauterine infection and cerebral palsy. Given the gaps in our current knowledge about intrauterine infection and cerebral palsy, public health recommendations for timely and specific prevention activities are limited at this time.

Evidence-based neonatology: making a difference beyond discharge from the neonatal nursery

The number of controlled clinical trials in neonatal medicine has increased steadily over recent years. However, most of these trials examine only short-term outcomes during the initial hospital stay. To determine whether a common neonatal intervention does more good than harm, it is important to study its long-term efficacy and safety. This review summarizes randomized trials of neonatal therapies published between October 2000 and September 2001. Only trials that examine outcomes beyond the initial hospital discharge were considered. Four beneficial interventions were identified: promotion of breast-feeding, comprehensive follow-up care for high-risk, very low birthweight infants, cryotherapy for threshold retinopathy of prematurity, and extracorporeal membrane oxygenation for mature infants with severe respiratory failure. Indomethacin prophylaxis in extremely low birthweight infants is of questionable use. Thyroxine supplementation for premature infants and head cooling for asphyxiated term infants require further study and should not be prescribed outside of rigorous clinical trials.

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.

Topography of cerebral white-matter disease of prematurity studied prospectively in 1607 very-low-birthweight infants

The objective of this study was to evaluate to what extent (1) the characteristics of localization, distribution, and size of echodense and echolucent abnormalities enable individuals to be designated as having either periventricular hemorrhagic infarction or periventricular leukomalacia and (2) the characteristics of periventricular hemorrhagic infarction and periventricular leukomalacia are independent occurrences. The population for this study consisted of 1607 infants with birthweights of 500 to 1500 g, born between January 1991 and December 1993, who had at least one cranial ultrasound scan read independently by at least two ultrasonographers. The ultrasound data collection form diagrammed six standard coronal views. The cerebrum was divided into 17 zones in each hemisphere. All abnormalities were described as being echodense or echolucent and were classified on the basis of their size, laterality, location, and evolution. Eight percent (134/1607) of infants had at least one white-matter abnormality. The prevalence of white-matter disease decreased with increasing gestational age. Most abnormalities were small or medium sized and unilateral; only large echodensities tended to be bilateral and asymmetric. Large abnormalities, whether echodense or echolucent, were more likely than smaller abnormalities to be widespread, and the extent of cerebral involvement was independent of whether abnormalities were unilateral or bilateral. Large abnormalities were relatively more likely than small abnormalities to involve anterior planes. Small abnormalities, whether echodense or echolucent, or whether unilateral or bilateral, preferentially occurred near the trigone. Using the characteristics of location, size, and laterality/symmetry, we were able to allocate only 53% of infants with white-matter abnormalities to periventricular hemorrhagic infarction or periventricular leukomalacia. Assuming that periventricular leukomalacia and periventricular hemorrhagic infarction are independent and do not share risk factors, and that each occurs in approximately 5% of infants, we would have expected 0.25%, or about 4 individuals, to have abnormalities with characteristics of both periventricular leukomalacia and periventricular hemorrhagic infarction, whereas we found 63 such infants. Most infants with white-matter disease could not be clearly designated as having periventricular hemorrhagic infarction or periventricular leukomalacia only. Periventricular hemorrhagic infarction contributes to the risk of periventricular leukomalacia occurrence, or the two sorts of abnormalities share common risk antecedent factors. The descriptive term echodense or echolucent and the generic term white-matter disease of prematurity should be used instead of periventricular leukomalacia or periventricular hemorrhagic infarction when referring to sonographically defined white-matter abnormalities.

Risk factors for neurologic impairment among very low-birth-weight infants

Although cerebral palsy is the most common neurologic impairment among very low-birth-weight survivors, its etiology remains uncertain. Current research supports the role of both antenatal and neonatal factors in the pathogenesis of cerebral palsy among these extremely premature infants. Important antenatal risk factors include chorioamnionitis and multiple placental lesions. Maternal preeclampsia may provide neuroprotection. The major neonatal risk factors include severe cranial ultrasound abnormalities, chronic lung disease, hyperbilirubinemia, and possibly hypothyroxinemia.

Perinatal asphyxia: timing and mechanisms of injury in neonatal encephalopathy

This article summarizes the recent medical literature regarding perinatal asphyxia with respect to timing and mechanisms of injury for neonates who were clinically diagnosed with an encephalopathy in the newborn period. Multiple mechanisms of injury are reviewed, including genetic vulnerability, acquired inflammatory responses, and clotting defects that can lead to ischemic-induced brain damage. Before effective treatments for fetal and neonatal brain disorders can be developed, accurate and timely diagnoses of fetal or neonatal brain injury must be achieved. Specific subsets of children can then benefit from neuroprotective strategies that can target the specific developmental aspects of brain adaptation or plasticity relative to the specific etiology and timing of injury after asphyxia.

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.

Prognostic factors for walking attainment in very low-birthweight preterm infants

The purpose of this study was to compare the age of walking attainment between very low-birthweight (VLBW) preterm infants and normal term infants, and to determine the variables that affect the walking attainment in VLBW infants. Ninety-six VLBW preterm infants and 82 normal term infants were prospectively followed to determine their age of walking attainment and to monitor gross motor development with sequential clinic visits at 6, 9, 12 and 18 months corrected age. Perinatal and sociodemographic data were collected through review of medical records. The VLBW infants were significantly older at attainment of walking (median 14 months) than the term infants (median 12 months) after correction for prematurity. By the age of 18 months, all term infants had attained walking ability; while 11% of VLBW infants were still unable to walk. Multivariate proportional hazards regression analysis revealed that low gestational age was significantly associated with late attainment of walking in VLBW infants. With the adjustment for gestational age, prolonged ventilation (or oxygen therapy) and severe retinopathy of prematurity were significant predictors of late walking attainment. Our findings indicate that VLBW preterm infants have an increased risk of delayed attainment of walking. Furthermore, the contribution of low gestational age to the delayed walking attainment in VLBW infants may occur via the plausible pathways of neonatal respiratory distress and severe retinopathy of prematurity.

Long-term outcome in twin-twin transfusion syndrome treated with serial aggressive amnioreduction

OBJECTIVE

The purpose of this study was to determine long-term outcomes among pregnancies complicated by twin-twin transfusion syndrome and treated in a tertiary center with serial aggressive amnioreduction.

STUDY DESIGN

Thirty-three pregnancies with a diagnosis of twin-twin transfusion syndrome were treated with > or =1 amnioreduction. The perinatal outcome was assessed according to 15 parameters, whereas the main outcome at age > or =2 years was the absence of cerebral palsy.

RESULTS

Gestational age at diagnosis ranged from 14.5 to 33 weeks' gestation (median, 20.6 weeks' gestation), whereas gestational age at delivery was between 18.5 and 37 weeks' gestation (median, 30.5 weeks' gestation). The number of amnioreductions per pregnancy ranged from 1 to 15 (median, 2). At initial examination hydrops of the recipient and absence of the end-diastolic velocity of the umbilical artery in one of the twins were associated with poor prognosis. Fifty-one (77%) twins were born alive. At 24 months after birth both infants from 57% of the pregnancies (19/33) were alive, whereas at least one infant from 70% of the pregnancies (23/33) was alive. Thirty-three infants (78% of the survivors) were older than 36 months at last follow-up. Cerebral palsy was diagnosed in 2 of 42 infants (4.7%). One of the affected infants was born after the fetal death of the cotwin; the other infant was born with congenital cardiac malformations.

CONCLUSIONS

In the group of fetuses in which both twins were delivered alive after 27 weeks' gestation without congenital malformations and survived the neonatal period, no major neurologic handicaps developed in any of the infants. At initial examination both hydrops of the recipient and absence of end-diastolic flow velocity waveforms of the umbilical artery in one of the twins were poor prognostic signs.

The relationship between placental and other perinatal risk factors for neurologic impairment in very low birth weight children

Placental abnormalities reflect antenatal disease processes that may interact with other perinatal risk factors to affect long-term outcome. We performed a nested case control analysis of placental and clinical risk factors associated with neurologic impairment (NI) at 20-mo corrected age (60 cases and 59 controls) using data collected in a prospective study of very low birth weight (less than 1500 g) infants born between 1983 and 1991. In a preliminary analysis we explored the relationship between clinical infection and histologic chorioamnionitis (CA). Only histologic CA with a fetal vascular response correlated with either clinical CA or early onset neonatal sepsis. We then assessed the relative contribution of the nine risk factors (four placental and five clinical) associated with NI at the univariate level by multiple logistic regression. Three risk factors were independent predictors of NI: severe cranial ultrasound abnormalities (odds ratio 13.6, 95% confidence intervals 4.5-66.7), multiple placental lesions (odds ratio 13.2, 95% confidence intervals 1.3-137.0), and oxygen dependence at 36 wk (odds ratio 4.2, 95% confidence intervals 1.2-14.6). Finally, a series of logistic regressions was conducted with the dependent variable changing as we moved back along the causal chain to explore the relationships between risk factors operating at different stages. This analysis suggested that antenatal variables that were not independent predictors of NI by multiple logistic regression exerted their effects through the following intermediate pathways: fetal grade 3 histologic CA via chorionic vessel thrombi, clinical CA via grade 3 villous edema, and grade 3 villous edema via severe cranial ultrasound abnormalities.

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.

Other factors/conditions associated with cerebral palsy

The cause for most cases of cerebral palsy is unknown. There are however, risk factors that have been associated with this chronic neuromuscular disease. The objective of this article is to review the maternal and fetal conditions (other than asphyxia and infection) strongly associated with increased rate of cerebral palsy. What remains to be elucidated is whether or not these associations are causative.