Classifying brain damage in preterm infants

Brain Damage in the Preterm Infant: Clinical Aspects and Recent Progress in the Prevention and Treatment

Although the prevalence of brain injury and related neurodevelopmental disabilities resulting from preterm birth are major public health concerns, there are no definite neuroprotective strategies to prevent or reduce brain injury. The pattern of brain injury seen in preterm infants has evolved into more subtle lesions that are still essential to diagnose regarding neurodevelopmental outcomes. There is no specific effective method for the treatment of premature infant brain injury, and the focus of clinical treatment is still on prevention. Prevention of this injury requires insight into the pathogenesis, but many gaps exist in our understanding of how neonatal treatment procedures and medications impact cerebral hemodynamics and preterm brain injury. Many studies provide evidence about the prevention of premature infant brain injury, which is related to some drugs (such as erythropoietin, melatonin, mesenchymal stem cells, etc.). However, there are still some controversies about the quality of research and the effectiveness of therapy. This review aims to recapitulate the results of preclinical studies and provide an update on the latest developments around etiological pathways, prevention, and treatment.

Deficits in Seizure Threshold and Other Behaviors in Adult Mice without Gross Neuroanatomic Injury after Late Gestation Transient Prenatal Hypoxia

Intrauterine hypoxia is a common cause of brain injury in children resulting in a broad spectrum of long-term neurodevelopmental sequela, including life-long disabilities that can occur even in the absence of severe neuroanatomic damage. Postnatal hypoxia-ischemia rodent models are commonly used to understand the effects of ischemia and transient hypoxia on the developing brain. Postnatal models, however, have some limitations. First, they do not test the impact of placental pathologies on outcomes from hypoxia. Second, they primarily recapitulate severe injury because they provoke substantial cell death, which is not seen in children with mild hypoxic injury. Lastly, they do not model preterm hypoxic injury. Prenatal models of hypoxia in mice may allow us to address some of these limitations to expand our understanding of developmental brain injury. The published rodent models of prenatal hypoxia employ multiple days of hypoxic exposure or complicated surgical procedures, making these models challenging to perform consistently in mice. Furthermore, large animal models suggest that transient prenatal hypoxia without ischemia is sufficient to lead to significant functional impairment to the developing brain. However, these large animal studies are resource-intensive and not readily amenable to mechanistic molecular studies. Therefore, here we characterized the effect of late gestation (embryonic day 17.5) transient prenatal hypoxia (5% inspired oxygen) on long-term anatomical and neurodevelopmental outcomes in mice. Late gestation transient prenatal hypoxia increased hypoxia-inducible factor 1 alpha protein levels (a marker of hypoxic exposure) in the fetal brain. Hypoxia exposure predisposed animals to decreased weight at postnatal day 2, which normalized by day 8. However, hypoxia did not affect gestational age at birth, litter size at birth, or pup survival. No differences in fetal brain cell death or long-term gray or white matter changes resulted from hypoxia. Animals exposed to prenatal hypoxia did have several long-term functional consequences, including sex-dichotomous changes. Hypoxia exposure was associated with a decreased seizure threshold and abnormalities in hindlimb strength and repetitive behaviors in males and females. Males exposed to hypoxia had increased anxiety-related deficits, whereas females had deficits in social interaction. Neither sex developed any motor or visual learning deficits. This study demonstrates that late gestation transient prenatal hypoxia in mice is a simple, clinically relevant paradigm for studying putative environmental and genetic modulators of the long-term effects of hypoxia on the developing brain.

Cardio-Respiratory Events and Food Autonomy Responses to Early Uni-Modal Orofacial Stimulation in Very Premature Babies: A Randomized, Controlled Study

Uni-modal orofacial stimulation (OFS) for preventing very preterm infants’ oral disorders is highly controversial. Our study sought to demonstrate that OFS reduced cardio-respiratory events and improved food autonomy in a population of very preterm infants. Our study was randomized, controlled, prospective, and unicentric. The preterm included were born between 26–29 weeks gestational age (GA) with a corrected postnatal age <33 weeks GA. They were randomized into two groups: the experimental group underwent OFS, according to a protocol established, over 10 consecutive days, and the control group underwent no OFS. The primary outcome was the number of cardiorespiratory events: apnea–bradycardia (with or without desaturations) or number of isolated desaturations, which were evaluated at four separate times. Measurements occurred during the first, fourth and eighth independent feedings. Seventeen patients were included in the experimental group and 18 in the control group. The number of cardiorespiratory events for all independent feeding times was significantly reduced in the OFS group (p = 0.003) with univariate analysis, but not with multivariable analysis. The quantity of milk ingested during the first autonomous feeding was higher in the experimental group. The acquisition of food autonomy and the duration of hospitalization were similar in the two groups. While our study does not affirm that an early unimodal OFS improves premature infants’ cardiorespiratory evolution and/or the acquisition of food autonomy, it does indicate an improved food efficiency during their first autonomous feedings.

Posture and movement in very preterm infants at term age in and outside the nest

OBJECTIVE

The objective of this study is to evaluate the use of nests on general movements (GM) and posture in very preterm infants at term age.

METHOD

Seventeen high-risk preterm infants-less than 30 weeks of gestation (GA)-underwent a video recording, lying in supine position, with or without nest. Posture, GM quality, and movements made around the child's midline, as well as abrupt movements and frozen postures-in extension or flexion of the four limbs-were analyzed.

RESULTS

Nest did not modify quality of GM. Children significantly adopted a curled-up position. The nest system was associated with an increase in movements toward or across the midline, as well as reduction of the hyperextension posture and head rotation movements. Frozen postures in flexion or extension, as well as abrupt movements of the four limbs, were reduced but not significantly.

CONCLUSIONS

Nest helps very preterm infants to adopt semi-flexed posture and facilitates movements across the midline and reduces movements of spine hyperextension, without GM global quality modifications.

Correlation of quantitative texture analysis of cranial ultrasound with later neurobehavior in preterm infants

The purpose of the study was to evaluate the association between a quantitative texture analysis of early neonatal brain ultrasound images and later neurobehavior in preterm infants. A prospective cohort study including 120 preterm (<33 wk of gestational age) infants was performed. Cranial ultrasound images taken early after birth were analyzed in six regions of interest using software based on texture analysis. The resulting texture scores were correlated with the Neonatal Behavioural Assessment Scale (NBAS) at term-equivalent age. The ability of texture scores, in combination with clinical data and standard ultrasound findings, to predict the NBAS results was evaluated. Texture scores were significantly associated with all but one NBAS domain and better predicted NBAS results than clinical data and standard ultrasound findings. The best predictive value was obtained by combining texture scores with clinical information and ultrasound standard findings (area under the curve = 0.94). We conclude that texture analysis of neonatal cranial ultrasound-extracted quantitative features that correlate with later neurobehavior has a higher predictive value than the combination of clinical data with abnormalities in conventional cranial ultrasound.

Timing of cord clamping in very preterm infants: more evidence is needed

In December 2012, the American College of Obstetricians and Gynecologists published a Committee Opinion entitled "Timing of umbilical cord clamping after birth." It stated that "evidence exists to support delayed cord clamping in preterm infants, when feasible. The single most important benefit for preterm infants is the possibility for a nearly 50% reduction in IVH." However, the Committee Opinion added that the ideal timing of umbilical cord clamping has yet to be determined and recommended that large clinical trials be conducted in the most preterm infants. Published randomized controlled trials include <200 infants of <30 weeks' gestation, with assessments of neurodevelopmental outcome in less than one-half of the children. This is a major gap in the evidence. Without reliable data from randomized controlled trials that optimally include childhood follow-up evaluations, we will not know whether delayed cord clamping may do more overall harm than good. Ongoing trials of delayed cord clamping plan to report childhood outcomes in >2000 additional very preterm infants. Current recommendations may need to change when these results become available. Greater international collaboration could accelerate resolution of whether this promising intervention will improve disability-free survival in about 1 million infants who will be born very preterm globally each year.

A novel molecular microbiologic technique for the rapid diagnosis of microbial invasion of the amniotic cavity and intra-amniotic infection in preterm labor with intact membranes

PROBLEM

The diagnosis of microbial invasion of the amniotic cavity (MIAC) has been traditionally performed using traditional cultivation techniques, which require growth of microorganisms in the laboratory. Shortcomings of culture methods include the time required (days) for identification of microorganisms, and that many microbes involved in the genesis of human diseases are difficult to culture. A novel technique combines broad-range real-time polymerase chain reaction with electrospray ionization time-of-flight mass spectrometry (PCR/ESI-MS) to identify and quantify genomic material from bacteria and viruses.

METHOD OF STUDY

AF samples obtained by transabdominal amniocentesis from 142 women with preterm labor and intact membranes (PTL) were analyzed using cultivation techniques (aerobic, anaerobic, and genital mycoplasmas) as well as PCR/ESI-MS. The prevalence and relative magnitude of intra-amniotic inflammation [AF interleukin 6 (IL-6) concentration ≥ 2.6 ng/mL], acute histologic chorioamnionitis, spontaneous preterm delivery, and perinatal mortality were examined.

RESULTS

(i) The prevalence of MIAC in patients with PTL was 7% using standard cultivation techniques and 12% using PCR/ESI-MS; (ii) seven of ten patients with positive AF culture also had positive PCR/ESI-MS [≥17 genome equivalents per PCR reaction well (GE/well)]; (iii) patients with positive PCR/ESI-MS (≥17 GE/well) and negative AF cultures had significantly higher rates of intra-amniotic inflammation and acute histologic chorioamnionitis, a shorter interval to delivery [median (interquartile range-IQR)], and offspring at higher risk of perinatal mortality, than women with both tests negative [90% (9/10) versus 32% (39/122) OR: 5.6; 95% CI: 1.4-22; (P < 0.001); 70% (7/10) versus 35% (39/112); (P = 0.04); 1 (IQR: <1-2) days versus 25 (IQR: 5-51) days; (P = 0.002), respectively]; (iv) there were no significant differences in these outcomes between patients with positive PCR/ESI-MS (≥17 GE/well) who had negative AF cultures and those with positive AF cultures; and (v) PCR/ESI-MS detected genomic material from viruses in two patients (1.4%).

CONCLUSION

(i) Rapid diagnosis of intra-amniotic infection is possible using PCR/ESI-MS; (ii) the combined use of biomarkers of inflammation and PCR/ESI-MS allows for the identification of specific bacteria and viruses in women with preterm labor and intra-amniotic infection; and (iii) this approach may allow for administration of timely and specific interventions to reduce morbidity attributed to infection-induced preterm birth.

Intraventricular hemorrhage and neurodevelopmental outcomes in extreme preterm infants

OBJECTIVE

Not many large studies have reported the true impact of lower-grade intraventricular hemorrhages in preterm infants. We studied the neurodevelopmental outcomes of extremely preterm infants in relation to the severity of intraventricular hemorrhage.

METHODS

A regional cohort study of infants born at 23 to 28 weeks' gestation and admitted to a NICU between 1998 and 2004. Primary outcome measure was moderate to severe neurosensory impairment at 2 to 3 years' corrected age defined as developmental delay (developmental quotient >2 SD below the mean), cerebral palsy, bilateral deafness, or bilateral blindness.

RESULTS

Of the 1472 survivors assessed, infants with grade III-IV intraventricular hemorrhage (IVH; n = 93) had higher rates of developmental delay (17.5%), cerebral palsy (30%), deafness (8.6%), and blindness (2.2%). Grade I-II IVH infants (n = 336) also had increased rates of neurosensory impairment (22% vs 12.1%), developmental delay (7.8% vs 3.4%), cerebral palsy (10.4% vs 6.5%), and deafness (6.0% vs 2.3%) compared with the no IVH group (n = 1043). After exclusion of 40 infants with late ultrasound findings (periventricular leukomalacia, porencephaly, ventricular enlargement), isolated grade I-II IVH (n = 296) had increased rates of moderate-severe neurosensory impairment (18.6% vs 12.1%). Isolated grade I-II IVH was also independently associated with a higher risk of neurosensory impairment (adjusted odds ratio 1.73, 95% confidence interval 1.22-2.46).

CONCLUSIONS

Grade I-II IVH, even with no documented white matter injury or other late ultrasound abnormalities, is associated with adverse neurodevelopmental outcomes in extremely preterm infants.

Quality of life of early school-age French children born preterm: a cohort study

OBJECTIVES

To describe the health-related quality of life (HRQL) of a cohort of children aged 6-10 years who were born preterm; and to determine whether sociodemographic factors, neonatal features and neurocognitive status were affecting their HRQL.

STUDY DESIGN

All singleton infants born between 24 and 32 weeks of gestation between January 1997 and December 2001 at the study hospital, who were still alive in 2007 (age 6-10 years), and who had undergone complete clinical paediatric follow-up were included in the study. Maternal and perinatal data were obtained by chart review and regular clinical examination. The 'Battery for Rapid Evaluation of Cognitive Functions' (BREV) was used for cognitive evaluation when children were aged 4-8 years. HRQL data were collected in 2007 using the 'Vécu et Santé Perçue de l'Adolescent et de l'Enfant' (VSP-A) questionnaire (parent version). The HRQL of the preterm children was compared with that of a French reference population.

RESULTS

Of 202 children who fulfilled the inclusion criteria, 82 children participated in the study. Their mean age was 7.9 years [standard deviation (SD) 1.4], mean birth weight was 1130.0 g (SD 361.4), 23 children were born before 28 weeks of gestation, 46 were female and 11 had major neurocognitive disorders. These data were not significantly different for the non-respondents (n=120). Parents of preterm children reported a significantly lower perception of HRQL of their child compared with parents of children in the reference population, as reflected by VSP-A global index scores and scores for the 'body image', 'vitality', 'psychological well-being' and 'school performance' dimensions. In multivariate analyses, three factors were found to be significantly associated with at least one dimension in the VSP-A scale in the preterm children: presence of major neurocognitive disorders, negatively correlated with 'vitality', 'relationships with friends', 'physical well-being' and 'school performance' dimensions; maternal parity, positively correlated with the 'psychological well-being' dimension; and socio-economic status of family, positively correlated with the 'relationships with friends' dimension. The maximum R(2) was 15%.

CONCLUSION

In addition to neurocognitive disorders, other variables such as socio-economic status of the family have a significant impact on the HRQL of preterm children at 6-10 years of age. Given the low proportion of variability in HRQL explained by the models, there is a need to explore other factors (e.g. environmental).

Intraventricular hemorrhage and developmental outcomes at 24 months of age in extremely preterm infants

Whether intraventricular hemorrhage increases the risk of adverse developmental outcome among premature infants is controversial. Using brain ultrasound, we identified intraventricular hemorrhage and white matter abnormalities among 1064 infants born before 28 weeks' gestation. We identified adverse developmental outcomes at 24 months of age using a standardized neurologic examination and the Bayley Scales of Infant Development Mental and Motor Scales. In logistic regression models that adjusted for gestational age, sex, and public insurance, isolated intraventricular hemorrhage was associated with visual fixation difficulty but no other adverse outcome. Infants who had a white matter lesion unaccompanied by intraventricular hemorrhage were at increased risk of cerebral palsy, low Mental and Motor Scores, and visual and hearing impairments. Except when accompanied or followed by a white matter lesion, intraventricular hemorrhage is associated with no more than a modest increase (and possibly no increase) in the risk of adverse developmental outcome during infancy.

Comparative analysis of perinatal and postnatal factors, and general movement in extremely preterm infants

STUDY AIM

To describe general movement in extremely premature infants and examine correlations with risk factors for antenatal, perinatal, and postnatal morbidity.

STUDY TYPE

Prospective, single-center study. Nineteen patients were followed up.

METHODOLOGY

The infants' general movement was analyzed using video recordings. Qualitative and quantitative assessments were performed during the writhing movement (WM) period and fidgety movement (FM) period. The quality of the general movements (GMs) and the scores achieved were then correlated with antenatal, perinatal, and postnatal factors.

RESULTS

Infants' motor activity fluctuated during the WM period, especially in extremely premature infants where poor repertoire is often observed. No correlations were found between WMs and obstetric factors. Gestational age correlated with WMs' quality (p=0.023). WMs correlated with factors of postnatal morbidity such as chronic lung disease (CLD) (p=0.034) and nosocomial infections (p=0.05). At 3 months corrected age, the spontaneous movement quality are correlated with neurological explorations such as US brain (p=0.032), MRI (p=0.039), EEG (p=0.036), and neurological follow-up assessments (p=0.015).

CONCLUSION

Prudence must be used when performing the analysis of general movement in extremely preterm infants. WMs may be influenced by perinatal morbidity, and possibly by the severe brain immaturity of these infants. WMs correlate with CLD and nosocomial infections. Analysis of general movement in infants of 3 months corrected age is a valuable means to detect neurological disorders.

Antenatal variables associated with severe adverse neurodevelopmental outcome among neonates born at less than 32 weeks

OBJECTIVE

To determine the association between antenatal factors and severe adverse neurodevelopmental outcome (ANDO) in preterm infants.

STUDY DESIGN

Neurodevelopmental follow-up was performed in a cohort of babies born at <32.0 weeks' gestation with birth weight <1500 grams between 1999 and 2006. Logistic regression analysis was used to relate obstetric, perinatal and neonatal ultrasonographic predictors to severe ANDO, defined as cerebral palsy or neurodevelopmental impairment, including sensory damage and adjusted development quotient <70.

RESULTS

88.6% (195/220) of surviving babies underwent follow up for a median of 24 months (range 12-96); 45 of them (23%) had ANDO, which was severe in 28 (14.3%). Abnormal ultrasonographic findings (intraventricular hemorrhage grades 3 or 4, periventricular leukomalacia, or ventriculomegaly) were observed in 18 cases (9.2%) and they were significantly associated with severe ANDO (OR 11.8 95% CI 4.0-34.0). Only gestational age at delivery (OR 0.80 95% CI 0.66-0.97), but not intrauterine infection, was independently related to severe ANDO. Infants with severe ANDO born before 28 weeks presented lower umbilical artery pH (7.24±0.1 vs 7.31±0.06, p=0.005) and a significantly higher rate of cesarean delivery (85.7% vs 50%, OR 6 95%CI 1.3-26.3, p=0.03) compared with infants without severe ANDO.

CONCLUSION

Gestational age at delivery and low umbilical artery pH at less than 28 weeks, but not intrauterine infection, are independent risk factors for severe ANDO in babies with birth weight <1500g.

Mechanisms of injury to white matter adjacent to a large intraventricular hemorrhage in the preterm brain

The purpose of this article is to investigate the hyperechoic lesion seen adjacent to a lateral ventricle that contains blood but is not distended. The literature on ependymal barrier dysfunction was reviewed in search of mechanisms of injury to the white matter adjacent to an intraventricular hemorrhage. The clinical literature on the clinical diagnosis of periventricular hemorrhagic infarction was also reviewed to find out how frequently this diagnosis was made. Support was found for the possibility that the ventricular wall does not always function as an efficient barrier, allowing ventricular contents to gain access to the white matter where they cause damage. Hemorrhagic infarction may not be the only or the most frequent mechanism of white matter damage adjacent to a large intraventricular hemorrhage.

Heart rate characteristics and neurodevelopmental outcome in very low birth weight infants

BACKGROUND

Sepsis in very low birth weight (VLBW) infants has been associated with an increased risk of adverse developmental outcome. We have identified abnormal heart rate characteristics (HRCs) that are predictive of impending sepsis, and we have developed a summary measure of an infant's abnormal HRCs during the neonatal hospitalization that we refer to as the cumulative HRC score (cHRC).

OBJECTIVE

In this study, we tested the hypothesis that increasing cHRC is associated with an increasing risk of adverse neurodevelopmental outcome in VLBW infants.

METHOD

Data were collected on 65 VLBW infants whose HRCs were monitored while in the neonatal intensive care unit and who were examined at 12 to 18 months adjusted age. Using the Bayley Scale of Infant Development-II, we identified delays in early cognitive function (i.e., Mental Developmental Index <70) and psychomotor development (i.e., Psychomotor Developmental Index <70). Cerebral palsy (CP) was diagnosed using a standard neurological examination.

RESULT

Increasing cHRC score was associated with an increased risk of CP (odds ratio per 1 standard deviation increase in cHRC: 2.6, 95% confidence limits: 1.42, 5.1) and delayed early cognitive development [odds ratio: 2.3 (1.3; 4.3)]. These associations remain statistically significant when adjusted for major cranial ultrasound abnormality. There was an association of increasing cHRC and delayed psychomotor development, which did not reach statistical significance [odds ratio: 1.7 (1.0, 3.0)].

CONCLUSION

Among VLBW infants, the cumulative frequency of abnormal HRCs, which can be assessed non-invasively in the neonatal intensive care unit, is associated with an increased risk of adverse neurodevelopmental outcome.

Evaluation of a tool to screen at preschool age for minor cognitive disorders liable to affect schooling among children born premature

PURPOSE

To evaluate a detection tool designed to help paediatricians identify, at preschool age, minor neurocognitive disorders that interfere with normal schooling.

METHODS

One hundred-and-fourteen preterm singletons born between 1997 and 2001 at less than 32 weeks of amenorrhoea, in a tertiary perinatal care center, were invited to visit us for a medical examination and a rapid neurocognitive assessment (BREV) when they were aged between 4 and 8 years and were re-contacted at 6-10 years of age to evaluate their current schooling situation. Results of BREV and schooling parameters were compared.

RESULTS

Mean gestational age was 29 weeks and mean birth weight was 1,164 g. Fifteen children (13.2%) showed abnormal results on BREV testing and had unusual schooling histories. Among the 68 children with normal BREV, 65 (95.6%) had achieved normal schooling. The sensitivity of the BREV test in this population for detection of minor disorders interfering with schooling was thus 83.3% (95% CI = 57.7-95.6) and the predictive value of a negative test was 95.6% (95% CI = 86.8-98.9). For the 57 children (50%) assessed before the age of 5 years, the sensitivity and the predictive value of a negative test were both 100%.

CONCLUSION

Our survey shows that the BREV test can, in a population of preschool children who were born premature, screen for minor neurocognitive disorders that impact schooling parameters. BREV assessment, used in the setting of follow-up of premature infants, would identify children in need of early remedial education before schooling under-attainment or failure developed.

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.

Functional magnetic resonance imaging of the sensorimotor system in preterm infants

OBJECTIVE

Preterm birth at <32 weeks' gestational age has a specific predilection for periventricular white matter injury. Early prediction of concomitant motor sequelae is a fundamental clinical issue. Recently, functional MRI was introduced as a noninvasive method for investigating the functional integrity of the neonatal brain. We aimed at implementing a unilateral passive forearm extension/flexion functional MRI paradigm in a routine clinical MRI setup to allow noninvasive mapping of the sensorimotor system in preterm infants and to relate the functional data to structural and behavioral data.

PATIENTS AND METHODS

Eight patients (median gestational age: 26.5 weeks; median birth weight: 885 g) were included. The functional MRI was performed at term-equivalent age (median: 39 weeks' postconceptional age) under chloral hydrate (50 mg/kg) sedation. In 5 of 8 patients, functional MRI data acquisition was successful. This resulted in 10 functional data sets (5 for passive stimulation of each forearm).

RESULTS

Unilateral stimulation was associated with mainly bilateral activation of the primary sensorimotor cortex (n = 7 of 10 data sets), the prevailing hemodynamic response being a negative blood oxygenation level-dependent signal. Positive blood oxygenation level-dependent response or failure to activate the sensorimotor cortex (n = 3 of 10 data sets) were seen in those patients with aberrant structural/behavioral indices.

CONCLUSIONS

Our data show the feasibility of passive unilateral sensorimotor stimulation during neonatal clinical MRI protocols. The bilateral activation pattern observed at this age is compatible with a bilaterally distributed sensorimotor system. Our data validate initial accounts for a raised incidence of negative blood oxygenation level-dependent responses in the primary sensorimotor cortex at this developmental stage. The negative blood oxygenation level-dependent response is likely to reflect a reduction of the oxy/deoxy-hemoglobin ratio during a maturational stage characterized by rapid formation of synapses, yet ineffective processing. Positive blood oxygenation level-dependent responses or failure to activate the sensorimotor cortex may be an early indicator of abnormal development and will have to be followed up carefully.

Brain cooling for preterm infants

There is strong evidence that prolonged, moderate cerebral hypothermia initiated within a few hours after severe hypoxia-ischemia and continued until resolution of the acute phase of delayed cell death can reduce neuronal loss and improve behavioral recovery in term infants and adults after cardiac arrest. This review examines the evidence that mild to moderate hypothermia is protective after hypoxia-ischemia in models of preterm brain injury and evaluates the potential risks. Induced hypothermia likely has potential to significantly reduce disability. Cautious, systematic trials are essential before hypothermia can be used in these vulnerable infants.

Which factors affect the occurrence of severe cerebral lesions in preterm neonates who are born with intrauterine infection?

OBJECTIVE

The purpose of this study was to evaluate which factors affect the occurrence of neonatal ultrasonographic evidence of severe cerebral lesions in the presence of intrauterine infection.

STUDY DESIGN

From a cohort of 567 singleton neonates who were born between 24.0 and 31.6 weeks of gestation, we identified the 180 infants with histologic and/or clinical evidence of intrauterine infection. We excluded stillbirths and congenital anomalies. Obstetric and neonatal variables were related to evidence of severe neonatal ultrasonographic cerebral lesions with the use of logistic regression analysis.

RESULTS

Severe cerebral lesions were identified in 10% of infants (18/180). After we controlled for variables that were clinically relevant, logistic regression analysis demonstrated that ultrasound evidence of severe neonatal cerebral lesions was associated independently with antenatal administration of corticosteroids (adjusted odds ratio, 0.3; 95% CI, 0.11-0.88; P = .03) and occurrence of placental abruption (adjusted odds ratio, 5.4; 95% CI, 1.4-20.7; P = .02).

CONCLUSION

Antenatal administration of corticosteroids in the presence of intrauterine infection has a protective effect on the risk of ultrasonographic evidence of severe neonatal cerebral lesions.

Neonatal cranial ultrasound lesions and developmental delays at 2 years of age among extremely low gestational age children

BACKGROUND

Studies of the relationship between ultrasound images from preterm newborns and developmental delay most often are based on small samples defined by birth weight and exclude infants not testable with standardized assessments.

METHODS

We evaluated associations between ultrasound-defined lesions of the brain and developmental delays at 24 months' corrected age in 1017 children born before the 28th postmenstrual week. Brain ultrasound scans were read for concordance on 4 lesions: intraventricular hemorrhage, moderate/severe ventriculomegaly, white matter echodense/hyperechoic lesions, and white matter echodense/hypoechoic lesions and 2 diagnoses-periventricular leukomalacia and periventricular hemorrhagic infarction. Certified examiners, who were not aware of the infants' ultrasound findings, administered the Bayley Scales of Infant Development-Second Edition. Children with an impairment (eg., blindness) that precluded testing with the Bayley Scales and those for whom >2 test items were omitted were classified using the Vineland Adaptive Behavior Scales Motor Skills Domain instead of the Psychomotor Development Index and the Adaptive Behavior Composite instead of the Mental Development Index.

RESULTS

Fully 26% of all of the children had delayed mental development (ie, Mental Development Index < 70), and 31% had delayed psychomotor development (ie, Psychomotor Development Index < 70). Ultrasound abnormalities were more strongly associated with low Psychomotor Development Index than with low Mental Development Index. Children without cranial ultrasound abnormality had the lowest probability (23% and 26%) of delayed mental or psychomotor development. Moderate/severe ventriculomegaly was associated with a more than fourfold increase in the risk of psychomotor delay and an almost threefold increase in the risk of mental delay. Echolucency was the next best predictor of delayed mental and psychomotor development. The probability of low scores varied with the number of zones involved and with the location of echolucency. At particularly high risk were infants with bilateral cerebellar hemorrhage, co-occurring ventriculomegaly and echolucency bilateral echolucency, or echolucency located posteriorly.

CONCLUSIONS

Focal white matter damage, as characterized by echolucent/hypoechoic lesion, and diffuse damage, as suggested by late ventriculomegaly, are associated with delayed mental and psychomotor development.

Cerebral palsy

Extreme prematurity confers about a 100-fold increase in the risk of cerebral palsy (CP), relative to birth at term gestation. Although CP is primarily a disorder of movement, many children with this disorder have other impairments which may affect their quality of life and life expectancy. Epidemiologic and clinical studies of cerebral palsy have benefited from recent efforts to develop greater uniformity of definition and classification. Particularly noteworthy is the development of the Gross Motor Function Classification System, which is a reliable and valid measure used with increasing frequency in observational and experimental studies. Also of great importance are efforts to quantify reliably the quality of life for children with cerebral palsy, thereby providing a target for medical and community interventions that aim to increase participation and well-being among affected children. During the late 1970s and early 1980s, the rate of CP actually rose, presumably as a result of increased survival of especially vulnerable infants who otherwise would have died. In developed countries over the past two decades (late 1980s to present), CP rates have been either stable or decreasing. Although considerable effort is being directed at prevention, the only perinatal interventions for which there is strong evidence of a beneficial effect on both mortality and the risk of CP is antenatal treatment of the mother with glucocorticoid.

Clinical data predict neurodevelopmental outcome better than head ultrasound in extremely low birth weight infants

OBJECTIVE

To determine the relative contribution of clinical data versus head ultrasound scanning (HUS) in predicting neurodevelopmental impairment (NDI) in extremely low birth weight infants.

STUDY DESIGN

A total of 2103 extremely low birth weight infants (<1000 g) admitted to a National Institute of Child Health and Human Development Neonatal Research Network center who underwent HUS within the first 28 days, a repeat one around 36 weeks' postmenstrual age, and neurodevelopmental assessment at 18 to 22 months corrected age were selected. Multivariate logistic regression models were developed with clinical or HUS variables. The primary outcome was the predictive abilities of the HUS performed before 28 days after birth and closer to 36 weeks postmenstrual age, either alone or in combination with "Early" and "Late" clinical variables.

RESULTS

Models with clinical variables alone predicted NDI better than models with only HUS variables at both 28 days and 36 weeks (both P < .001), and the addition of the HUS data did not improve prediction. NDI was absent in 30% and 28% of the infants with grade IV intracranial hemorrhage or periventricular leukomalacia, respectively, but was present in 39% of the infants with a normal HUS result.

CONCLUSIONS

Clinical models were better than HUS models in predicting neurodevelopment.

A multi-modal 2D/3D registration scheme for preterm brain images

Periventricular leukomalacia (PVL) is a neonatal brain pathology occurring on preterms with a very low birth weight (<1500 g). Next to ultrasound (US) imaging, which is the first and most common step, magnetic resonance image (MRI) volumes are used for the inspection of this pathology. Since on both modalities, up to now, we still lack a golden standard for the quantification of the pathology cross-validation through a multi-modal registration is highly beneficial to the clinical diagnosis. In this article we present a semi-automatic 2D US-3D MRI registration scheme combining an interactive initialization step, B-spline image interpolation, a mutual information based metric and an evolutionary algorithm optimization scheme.

Perinatal brain damage causation

The search for causes of perinatal brain damage needs a solid theoretical foundation. Current theory apparently does not offer a unanimously accepted view of what constitutes a cause, and how it can be identified. We discuss nine potential theoretical misconceptions: (1) too narrow a view of what is a cause (causal production vs. facilitation), (2) extrapolating from possibility to fact (potential vs. factual causation), (3) if X, then invariably Y (determinism vs. probabilism), (4) co-occurrence in individuals vs. association in populations, (5) one cause is all that is needed (single cause attribution vs. multicausal constellations), (6) drawing causal inferences from very small numbers of observations (the tendency to generalize), (7) unstated causal inferences, (8) ignoring heterogeneity, and (9) failing to consider alternative explanations for what is observed. We hope that our critical discussion will contribute to fruitful research and help reduce the burden of perinatal brain damage.

Follow-up of a randomized, placebo-controlled trial of dexamethasone to decrease the duration of ventilator dependency in very low birth weight infants: neurodevelopmental outcomes at 4 to 11 years of age

OBJECTIVE

High doses of dexamethasone reduce the risk of chronic lung disease among premature infants but may increase the risk of developmental impairments. The objective of this study was to compare developmental outcomes beyond infancy for children who, as neonates, participated in a randomized trial of dexamethasone.

PATIENTS AND METHODS

One hundred eighteen children with birth weights <1500 g were randomly assigned at 15 to 25 days of life to a 42-day tapering course of dexamethasone or placebo. All 95 survivors were assessed by using standardized measures of developmental outcome at least once at or beyond 1 year of age, and 84 were examined at 4 to 11 years. For this follow-up study, the outcome of primary interest was death or major neurodevelopmental impairment, which was defined as cerebral palsy, cognitive impairment, or blindness.

RESULTS

On the basis of each child's most recent follow-up, the rates of major neurodevelopmental impairments were 40% for the dexamethasone group and 20% for the placebo group. The higher impairment rate for the dexamethasone group was mainly attributed to a higher prevalence of cerebral palsy. Rates of the composite outcome of death or major neurodevelopmental impairment were 47% and 41%, respectively.

CONCLUSION

A 42-day tapering course of dexamethasone, which was shown previously to decrease the risk of chronic lung disease in very low birth weight infants, does not increase the risk of the composite outcome of death or major neurodevelopmental impairment.

Predictors of umbilical artery acidosis in preterm delivery

OBJECTIVE

The purpose of this study was to investigate the significance of preterm acidosis and its risk factors.

STUDY DESIGN

From a cohort of 786 consecutive singleton neonates who were born after spontaneous or iatrogenic preterm delivery at 24.0-33.6 weeks of gestation from January 1993 to December 2005 with an evaluation of umbilical artery pH at delivery, we extracted demographic, obstetric, neonatal, and placental histologic variables and related them to umbilical artery evidence of fetal acidemia, which was defined as pH <7.10. Excluded were stillbirths and neonates with major congenital anomalies. Fetal distress was defined as nonreassuring fetal hearth rate tracing or biophysical profile or appearance of thick meconium at delivery. Statistical analysis included 1-way analysis of variance and logistic regression with a probability value of <.05 considered significant.

RESULTS

Neonates with umbilical cord evidence of acidosis (n = 34) were born more frequently after abruption (P < .001), fetal distress (P < .001), and by cesarean delivery (P < .04) and were born less frequently after a complete course of corticosteroids (P = .03) and labor (P = .05) than nonacidotic babies (n = 752). Acute inflammatory lesions at placental histologic evaluation were less frequent (P = .049), and placental vascular lesions were more common in acidotic than in nonacidotic preterm neonates (P = .039). Logistic regression analysis demonstrated that cord acidosis was associated independently with the occurrence of abruptio placentae (odds ratio, 7.3; 95% CI, 2.9, 18.8), fetal distress (odds ratio, 12.0; 95% CI, 4.9, 18.3), and vascular placental lesions (odds ratio, 2.8; 95% CI, 1.2, 6.8)

CONCLUSION

In preterm infants, umbilical artery acidosis is significantly more common in the presence of placental abruption, fetal distress, and histologic evidence of placental vascular disease.

Interleukin-1beta, interleukin-18, and interferon-gamma expression in the cerebrospinal fluid of premature infants with posthemorrhagic hydrocephalus--markers of white matter damage?

Posthemorrhagic hydrocephalus (PHHC) represents a major complication of preterm birth. The aim of this study was to determine whether cerebrospinal fluid (CSF) levels of the pro-inflammatory cytokines IL-1beta, IL-18, and interferon (IFN)-gamma are altered in the CSF of preterm infants with PHHC and may serve as a marker of white matter damage (WMD). Twenty-seven preterm infants with PHHC were included in the study; 13 of them had signs of cystic WMD (cWMD) on ultrasound examinations. CSF sample 1 was obtained at first ventriculostomy, sample 2 at shunt implantation. Results were compared with a control group of 20 age-matched patients without neurologic diseases. IL-1beta concentrations were elevated in CSF sample 1 of PHHC patients without WMD and in sample 1 of patients with cWMD. Concentrations of IL-18 were increased in both samples of patients without WMD and in sample 2 of patients with cWMD. CSF levels of IFN-gamma were elevated in sample 1 of PHHC patients with cWMD. The pro-inflammatory cytokine IL-1beta and IL-18 levels in the CSF are elevated in patients with PHHC. Higher IFN-gamma levels are detected in a subgroup of patients developing cWMD, indicating its involvement in the pathogenesis of cWMD in the context of PHHC.

[Mode of delivery and neurosonographic findings in premature infants]

INTRODUCTION

Fetal and preterm infant brain is especially vulnerable to hemorrhagic and ischemic damage at the end of the second and at the beginning of the third trimester. This is due to vascular, cellular and anatomic characteristics of the brain during development. In premature babies, there is a physiological instability and limited autoregulation of cerebral circulation. Hemorrhagic and ischemic damages often occur together, though pathophysiological processes leading to lesions are different.

MATERIAL AND METHODS

The paper deals with a detailed analysis of 860 ultrasound brain scans of prematurely born children. The examinations were performed at the Ultrasound Department of the Institute of Child and Youth Health Care in Novi Sad. 707 vaginally born premature infants and 153 premature infants born by Cesarean section were examined The bleeding was graded according to the Papile classification.

RESULTS AND DISCUSSION

Out of 384 children with diagnosed grade I hemorrhage, 75 premature infants (19.5%) were born by Cesarean section. In the group of children with grade II hemorrhage, operative deliveries account for 14.7%. From the total of 85 children with grade III hemorrhage, (intraventricular bleeding with chamber dilatation), only 6 premature infints were born by Cesarean section (7%). Intra-parenchymal bleeding was diagnosed in a very small number of premature infants: 0.32% of all diagnosed hemorrhages were grade IV hemorrhages. In this group there were no children born by Cesarean section. The increase of hemorrhage grade is accompanied by a greater rate of pelvic presentation and manual assistance by Bracht. There were 240 prematurely born children with no echosonographicallY diagnosed hemorrhage, 38% of all examined premature infants. From this number, 13.3% of neonates were born by Cesarean section.

CONCLUSION

In the etiology of neonatal intracranial hemorrhage, especially prematurely born ones, apart from the trauma, which plays a major role, other factors are also important, above all fetal distress, perinatal hypoxia and junctional immaturity of all organs.

Isolated parenchymal lesions on cranial ultrasound in very preterm infants in the context of maternal infection

AIM

To explore the associations between a clinical diagnosis of maternal infection (CDMI) and findings on the initial cranial ultrasound scan in very preterm infants.

METHODS

Among infants born at less than 32 weeks gestation, cases of CDMI and controls were identified on the basis of routinely available obstetric data. Neonatal cranial ultrasound scans carried out soon after birth were retrospectively reviewed for evidence of parenchymal echodensity (PED), intraventricular haemorrhage (IVH) or PED contiguous with IVH.

RESULTS

Any PED was identified in 20/40 (50%) cases of CDMI and 9/30 (30%) of controls. Logistic regression was used to adjust for differences between the two study groups. When compared with normal scans, isolated PED was more likely with CDMI odds ratio, OR (95% confidence interval, CI), 41.8 (2.64, 662) and lower Apgar score at 5 min 2.89 (1.05, 7.98). IVH was more likely with lower gestational age, OR for each completed week of gestation 0.64 (0.46, 0.88) and a protective effect of female sex, OR 0.25 (0.063, 0.98), PED contiguous with IVH was more likely with lower gestational age OR 0.59 (0.336, 1.04).

CONCLUSIONS

CDMI may be associated with isolated PED in very preterm infants. We speculate that isolated PED (including "flares") identify infants who have sustained early brain injury because of intrauterine infection. Isolated PED may be a useful intermediate outcome in perinatal cohort studies.

Cerebrospinal fluid obstruction and malabsorption in human neonatal hydrocephaly

INTRODUCTION

The pathophysiology involved in human neonatal high-pressure hydrocephalus (HC) includes both cerebrospinal fluid (CSF) malabsorption and obstruction.

OBJECTIVE

The aim was to estimate the relative contribution between CSF malabsorption and obstruction in three different etiological groups of neonatal high-pressure HC by assessment of specific CSF biomarkers indicative of growth factor- and fibrosis-related CSF malabsorption (transforming growth factor beta-1 (TGF beta-1), aminoterminal propeptide of type 1 collagen (PC1NP)].

MATERIALS AND METHODS

Patients were subdivided into three groups. Group A: spina bifida HC (n=12); group B: non-haemorrhagic triventricular HC (n=4); and group C: posthaemorrhagic HC (n=6). To exclude for confounding differences in pro-inflammatory state between the three groups, interleukin-6 (IL-6) CSF concentrations were assessed. Consecutively, the CSF concentrations of TGF beta-1 and PC1NP were compared between the different groups.

RESULTS

Median CSF concentrations of IL-6 were low and did not differ between groups. Median CSF concentrations of PC1NP were significantly lower in group A (median: 180 ng/ml, range 90-808) than in group C (median: 1,060, range 396-1194; p=0.002). TGF beta-1 concentrations were significantly higher in group C (median 355 pg/ml, range 129-843) than in groups A (median 103, range 78-675 pg/ml) and B (median 120 pg/ml, range 91-188; p=0.01 and 0.03, respectively).

CONCLUSIONS

In neonatal posthaemorrhagic HC, high concentrations of malabsorption-related biomarkers contrast with lower concentrations in SB and non-haemorrhagic triventricular HC. During the early development of high pressure HC in SB neonates, CSF biomarkers strongly indicate that CSF obstruction contributes more to the development of HC than malabsorption.

A population-based study of 518 very preterm neonates from high-risk pregnancies: Prognostic value of umbilical and cerebral artery Doppler velocimetry for mortality before discharge and severe neurological morbidity

OBJECTIVE

To evaluate in everyday practice the predictiveness of fetal umbilical artery and cerebral artery Doppler examination for mortality before discharge and for severe neurological morbidity among very preterm neonates from high-risk pregnancies.

METHODS

Data came from a population-based study (EPIPAGE) of all births before 33 weeks' gestation during 1 year in nine French regions. We examined the prognostic value of Doppler findings among the liveborn singletons delivered after pregnancies with maternal hypertension or antenatal suspicion of small-for-gestational-age status.

RESULTS

This study included 518 fetuses. Predischarge mortality for infants with abnormal umbilical artery Doppler findings was not significantly higher than for those with normal findings. Mortality for infants with abnormal cerebral artery Doppler findings was significantly higher in the bivariate analysis (crude OR: 3.5 (1.6-7.4)). After adjustment, the association between mortality and abnormal cerebral artery Doppler findings remained significant in the subgroup with an abnormal umbilical artery Doppler assessment (OR: 5.1 (1.1-23)). There was no significant association between neurological morbidity and Doppler findings.

CONCLUSION

The prognostic value of Doppler examinations appears lower in this study than in previous hospital series. This suggests the need for quality control and improvements in these examinations.

Magnetic resonance imaging in preterm infants

MR imaging of the premature infant poses a number of challenges with regard to safety, sequence optimization and recognition of the normal appearances of the developing brain. In this paper we discuss these challenges, and review the common intracerebral abnormalities associated with premature birth. Although the outcome for very-low-birth-weight babies has improved over the last decade, there remains a significant risk of subsequent development of neurological disability. The relationship between MRI abnormalities and long-term outcome is considered.

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.

Cerebral palsy among very preterm children in relation to gestational age and neonatal ultrasound abnormalities: the EPIPAGE cohort study

OBJECTIVE

To estimate the prevalence of cerebral palsy at 2 years of age among children born very preterm, according to gestational age, infant gender, plurality, and neonatal cranial ultrasound abnormalities.

METHODS

All infants born between 22 and 32 weeks of gestation in 9 regions of France in 1997 were included in this prospective, population-based, cohort study. The main outcome measure was cerebral palsy prevalence at 2 years. Of the 2364 survivors eligible for follow-up evaluation, 1954 (83%) were assessed at 2 years of age.

RESULTS

Among the 1954 children assessed at 2 years, 8.2% had cerebral palsy. Bilateral spastic cerebral palsy, hemiplegia, and monoplegia accounted for 72%, 9%, and 10% of cases, respectively. Fifty percent of the children with cerebral palsy walked independently at the age of 2, 31% were unable to walk but could sit independently, and 19% could not sit (unable to maintain head and trunk control). The prevalence of cerebral palsy was 20% at 24 to 26 weeks of gestation, compared with 4% at 32 weeks. On the basis of ultrasound findings in the neonatal period, we found that 17% of children with isolated grade III intraventricular hemorrhage and 25% of children with white matter damage (ie, ventricular dilation, persistent echodensities, or cystic periventricular leukomalacia) had cerebral palsy, compared with 4% of children with normal ultrasound scans.

CONCLUSIONS

Despite recent improvements in survival rates, cerebral palsy remains highly prevalent among very preterm children. Severe cranial ultrasound abnormalities predict motor disability strongly, but one third of infants with cerebral palsy had no ultrasound abnormalities.

Variable interpretation of ultrasonograms may contribute to variation in the reported incidence of white matter damage between newborn intensive care units in New Zealand

BACKGROUND

The incidence of cerebral white matter damage reported to the Australian and New Zealand Neonatal Network (ANZNN) varies between neonatal intensive care units (NICUs).

HYPOTHESIS

Differences in the capture, storage, and interpretation of the cerebral ultrasound scans could account for some of this variation.

METHODS

A total of 255 infants of birth weight <1500 g and gestation <32 weeks born between 1997 and 2002 and drawn equally from each of the six NICUs in New Zealand were randomly selected from the ANZNN database. Half had early cerebral ultrasound scans previously reported to ANZNN as normal, and half had scans reported as abnormal. The original scans were copied, anonymised, and independently read by a panel of three experts using a standardised method of reviewing and reporting.

RESULTS

There was considerable variation between NICUs in methods of image capture, quality, and completeness of the scans. There was only moderate agreement between the reviewers' reports and the original reports to the ANZNN (kappa 0.45-0.51) and between the reviewers (kappa 0.54-0.64). The reviewers reported three to six times more white matter damage than had been reported to the ANZNN.

CONCLUSION

Some of the reported variation in white matter damage between NICUs may be due to differences in capture and interpretation of cerebral ultrasound scans.

Duration of labor and risk of cerebral white-matter damage in very preterm infants who are delivered with intrauterine infection

OBJECTIVE

The purpose of this study was to assess whether the duration of labor has any effect on the occurrence of cerebral white-matter damage in very preterm infants who are delivered in the presence of intrauterine infection.

STUDY DESIGN

From a cohort of infants who were born spontaneously at <32 weeks of gestation for whom placental information was available and who survived 7 days from birth, 126 infants had clinical, laboratory, or histologic evidence of intrauterine infection. Among them, variables were compared between those infants with white-matter damage (defined as intraventricular hemorrhage grade 3 plus, periventricular leukomalacia, or ventriculomegaly not associated with hydrocephaly [n = 13]) and those infants without it (n = 113). Comparisons were made with t test, chi-squared test, and survival analysis; a probability value of <.05 was considered significant.

RESULTS

There were no differences between the 2 groups in gestational age at delivery and rates of labor or cesarean delivery. Duration of active labor (66 +/- 45 minutes vs 88 +/- 75 minutes; P =.49) and of clinical chorioamnionitis (310 +/- 186 minutes vs 529 +/- 544 minutes; P =.44) were similar in cases with and without neonatal white-matter damage.

CONCLUSION

In 126 infants who were born at <32 weeks of gestation with intrauterine infection, we found no correlation between the duration of labor or clinical chorioamnionitis and neonatal white-matter damage.

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.

Antenatal events causing neonatal brain injury in premature infants

Understanding possible causes of neonatal brain injury is important for perinatal nurses because neonatal brain injury predicts subsequent infant mortality and morbidity in the premature infant. The pathogenesis of the brain injury, germinal matrix/intraventricular hemorrhage and white matter damage, is usually related to a hypoxic event. The hypoxic event may occur in utero, resulting from various conditions, such as maternal infection, maternal alcohol consumption, maternal smoking, placental bleeding disorders, maternal hypercoagulability conditions, metabolic disorders (diabetes and hyperthyroidism), and oligohydramnios. Strategies for prevention beginning before and in pregnancy are needed.

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.

Variation in the interleukin-6 gene is associated with impaired cognitive development in children born prematurely: a preliminary study

The pro-inflammatory cytokine IL-6 may be neurocytopathogenic, and elevated levels are associated with impaired neurological outcome among children born prematurely. However, the precise mechanisms underlying this association remain unclear. The rare C (rather than G) variant at position -572 in the IL-6 gene is associated with an increased IL-6 synthetic response. If IL-6 mediates cerebral injury, we would anticipate the -572 C allele to be associated with impaired childhood development. We have examined this hypothesis, studying 113 Caucasian children born at < or =32 wk gestation. Cognitive and motor functions were assessed using the Griffiths Developmental Scales at 2 y and British Ability Scales (2nd Ed.) and the ABC Movement Score at 51/2 y. Performance (median, interquartile range) in all three scales was worse in the 10 carriers of the C allele than for those with GG genotype: Griffiths Developmental Quotient: C allele, 92.4 (89.9-96.6) versus CG 100.9 (96.7-104.8), p = 0.002; General Cognitive Ability: C allele, 88.0 (80.3-102.8) versus GG 103.0 (92.0-112.0), p = 0.037; Movement ABC score: C allele 8.3 (6.6-20.3) versus GG 4.0 (1.0-9.5), p = 0.081. The presence of the rare (> or =1) IL-6 -572 C-allele (CC+GC genotypes) is associated with impaired cognitive development among children born before 32 wk gestation. These data support a role for IL-6 in the genesis of neurologic impairment in such children.

Morbilidad a los dos años de edad en niños con un peso al nacimiento menor de 1.500 g

OBJECTIVES

To determine morbidity at 2 years' corrected age in a cohort of neonates with a birth weight of less than 1,500 g born in 1999-2000 in a tertiary hospital in the Autonomous Community of Madrid.

PATIENTS AND METHODS

An observational longitudinal follow-up study was performed in a cohort of 213 infants with a birth weight of < 1,500 g. Of these, 188 (87%) completed the 2-year follow-up. Various types of neurosensorial disability were studied, paying special attention to the main impairments: vision, hearing and motor impairment, and low development quotient.

RESULTS

Among the patients initially included in the study, 87% completed the follow-up; 17.1% had one or more major sequela. We found one case (0.4%) of bilateral neurosensorial deafness and one case of bilateral blindness. At the age of 2 years, 5.8 % (11/188) had cerebral palsy, 14.9% had a development quotient below 85 and 18% had not reached the 3rd percentile for weight. Factors of poor neurological prognosis were subnormal head size at the age of 2 years and white matter disease (including persistent intraparenchymal periventricular echodensity and ventriculomegaly or irregular shape) as ultrasound findings.

CONCLUSIONS

Less than a fifth of the very low birth weight infants presented severe sequelae at 2 years of follow-up. Factors of poor neurological prognosis were subnormal head size at 2 years and the presence of white matter disease on ultrasonography. The findings on growth and development were worrying, since 18 % of the patients had not reached the 3rd percentile for weight at 2 years' corrected age.

Magnetic resonance and ultrasound brain imaging in preterm infants

Cranial ultrasonography has been used to identify brain injury in preterm neonates for more than two decades. More recently, magnetic resonance imaging has been used to evaluate brain development and pathology in these infants. In this review we describe how well findings from these two imaging modalities agree with histology findings and neuro-developmental outcome. In addition, we discuss studies comparing ultrasound and magnetic resonance imaging findings.

Chronic neonatal hypoxia leads to long term decreases in the volume and cell number of the rat cerebral cortex

Preterm birth results in significant neurodevelopmental disability. The neonatal rodent model of chronic sublethal hypoxia faithfully mimics the effect of preterm birth on the developing brain. We employed this model to test the hypothesis that the hypoxia that accompanies preterm birth results in inappropriate signaling of apoptotic mechanisms in developing brain. We performed cortical cell counts, determinations of neuronal size and Western analyses of the apoptosis related proteins, Bcl-2 and Bax, in rat pups who were raised in chronic hypoxia (FiO2 9.5%) beginning on postnatal day 3 (P3) and extending for either 10 (P13) or 30 (P33) days. A third group of animals was exposed to 30 days of hypoxia followed by an additional 30 days in a normoxic environment (P63) to assess the potential for recovery from the initial effects of hypoxia. Age matched control pups were raised in room air throughout the experimental time period. Assessment of cortical cell number revealed a 25% reduction (P < 0.01) in total cell number following 30 days of hypoxic rearing. Glia were significantly reduced by 34% and 41% after 10 and 30 days of hypoxia, respectively, while neuron numbers were only significantly reduced (14%) after 30 days of hypoxia. Animals exposed to a hypoxic environment for 30 days followed by 30 days in a normoxic environment revealed some recovery of glial cell numbers, but no significant recovery of neuronal cell numbers. Measurement of cell size at both P13 and P33 revealed that neurons of layer III were significantly smaller in cross-sectional area in hypoxic compared with control rats (P < 0.01). However, no significant difference was noted in neuronal size following 30 days of normoxic recovery. Western blot analyses of Bcl-2 and Bax protein levels demonstrated a ratio favorable to Bax at multiple time points during the period of hypoxic exposure. These data suggest that chronic exposure to hypoxia during the perinatal period alters the production and maintenance of glial and neuronal cells and that glia and neurons demonstrate differential patterns of vulnerability and recovery following subsequent periods of normoxic exposure. It is hypothesized that the mechanisms responsible for these alterations in cortical cell number may depend on the state of differentiation of the different cell types at the time of hypoxic exposure.

Vascular endothelial growth factor and transforming growth factor-beta1 are highly expressed in the cerebrospinal fluid of premature infants with posthemorrhagic hydrocephalus

The expression of specific growth factors such as vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1) is of importance during brain development and in the pathogenesis of neurodegenerative disorders. VEGF and TGF-beta1 was studied in the cerebrospinal fluid (CSF) of neonates with posthemorrhagic hydrocephalus (PHHC) and nonhemorrhagic hydrocephalus. For determining the interference of inflammatory cytokine interaction with the expression of VEGF and TGF-beta1, IL-6 and IL-10 CSF concentrations were measured. Eighteen neonates who had PHHC and underwent serial reservoir puncture and nine neonates who had congenital nonhemorrhagic hydrocephalus (CHC) and underwent first shunt surgery were included in the study. CSF samples of 11 neonates with lumbar puncture for the exclusion of meningitis served as control subjects. VEGF, TGF-beta1, IL-6, and IL-10 concentrations in the CSF were measured by ELISA technique. VEGF concentrations in the CSF of patients with PHHC were significantly higher (median: 377 pg/mL; range: 101-1301 pg/mL) when compared with patients with CHC (median: 66 pg/mL; range: 3-1991; p < 0.001) and control subjects (median: 2 pg/mL; range: 0-12 pg/mL; p < 0.0001). TGF-beta1 CSF concentrations did not differ from control infants in all groups. Median IL-6 and IL-10 concentrations in the CSF were found to be low in all patient groups. Increased release of VEGF in the CSF of neonates with PHHC and nonhemorrhagic hydrocephalus may serve as an indicator of brain injury from progressive ventricular dilation. TGF-beta1 CSF concentrations are not elevated in the phase of acute fibroproliferative reactions in patients with PHHC.

Does interleukin-6 genotype influence cerebral injury or developmental progress after preterm birth?

OBJECTIVE

The severity of the proinflammatory response may determine outcome in the critically ill. Genetic variation in the promoter region of the gene encoding the proinflammatory cytokine interleukin-6 (IL-6; -174 CC genotype) may encode enhanced production of IL-6. Our objective was to determine whether the CC genotype is associated with worse early illness severity, neurologic injury, and lower developmental scores among surviving preterm children.

METHODS

Genotype was determined from dried blood spots that were taken for neonatal screening tests 7 days or more after birth; outcome was independently assessed as part of a longitudinal study of children of < or =32 weeks' gestational age.

RESULTS

CC genotype was associated with worse intensive care indices. Significant hemorrhagic brain injuries occurred in 5 (19%) of 27 children with CC genotype compared with 7 (6%) of 121 children with GC or GG genotype, and images consistent with white matter damage (ventriculomegaly or cystic periventricular leukomalacia) occurred in 9 (26%) of CC patients compared with 9 (7%) in GC/GG children. Disability occurred significantly more often in CC children: 8 (31%) compared with 16 (13%). A similar trend was also noted in children with cerebral palsy (15% compared with 7%, respectively). Developmental, cognitive, and motor scores at 2 years and 5.5 years were independent of genotype among children with or without disability.

CONCLUSIONS

In a population of surviving children who were born at < or =32 weeks' gestational age, variation of the gene that may increase IL-6 synthesis is associated with disabling brain injury but not cognitive development despite association with worse early critical care indices.

Increased serum levels of interleukin 6 are associated with severe intraventricular haemorrhage in extremely premature infants

BACKGROUND

Intraventricular haemorrhage (IVH) and periventricular leucomalacia (PVL) in premature infants presumably have many causes. It has been proposed that inflammatory processes in the fetomaternal unit play an important role in the pathogenesis of these lesions.

OBJECTIVE

To study the correlation of postpartum serum interleukin 6 (IL6) concentration as a marker of inflammation and neonatal cerebral morbidity in preterm infants < 28 weeks of gestational age.

METHODS

A total of 88 infants were grouped according to maximum serum IL6 levels within 12 hours post partum: group A (n = 50), < or = 100 pg/ml; group B (n = 38), > 100 pg/ml. Ultrasound studies and clinical assessment were performed routinely.

RESULTS

IVH was noted significantly more often in group B (24/38; 63%) than in group A (19/50; 38%) (p = 0.02). In a multiple logistic regression model, raised serum IL6 independently predicted development of severe IVH (odds ratio 8.4; 95% confidence interval 2.85 to 24.9; p = 0.0001).

CONCLUSIONS

Raised serum IL6 may serve as a marker for severe IVH in infants < 28 weeks of gestational age. Although cerebral morbidity in premature infants is determined by different variables, the identification of systemic inflammation can help to define the need for anti-inflammatory strategies to prevent cerebral morbidity.