Population-based study of infants born at less than 28 weeks' gestation in New South Wales, Australia, in 1992-3. New South Wales Neonatal Intensive Care Unit Study Group

Clinical risk models for preterm birth less than 28 weeks and less than 32 weeks of gestation using a large retrospective cohort

OBJECTIVE

To develop risk prediction models for singleton preterm birth (PTB) < 28 weeks and <32 weeks.

METHODS

Using a retrospective cohort of 267,226 singleton births in Ontario hospitals, we included variables from the first and second trimester in multivariable logistic regression models to predict overall and spontaneous PTB < 28 weeks and <32 weeks.

RESULTS

During the first trimester, the area under the curve (AUC) for prediction of PTB < 28 weeks for nulliparous and multiparous women was 68.5% (95% CI: 63.5-73.6%) and 73.4% (68.6-78.2%), respectively, while for PTB < 32 weeks it was 68.9% (65.5-72.3%) and 75.5% (72.3-78.7%), respectively. AUCs for second-trimester models were 72.4% (95% CI: 69.7-75.1%) and 78.2% (95% CI: 75.8-80.5%), respectively, in nulliparous and multiparous women. Predicted probabilities were well-calibrated within a wide range around expected base prevalence for the study outcomes.

CONCLUSIONS

Our prediction models generated acceptable AUCs for PTB < 28 weeks and <32 weeks with good calibration during the first and second trimester.

Growth and neurodevelopment in low birth weight versus normal birth weight infants from birth to 24 months, born in an obstetric emergency hospital in Haiti, a prospective cohort study

BACKGROUND

Low birthweight (LBW) infants are at higher risk of mortality and morbidity (growth, chronic disease and neurological problems) during their life. Due to the high incidence of (pre-) eclampsia in Haiti, LBW infants are common. We assessed the anthropometric growth (weight and length) and neurodevelopmental delay in LBW and normal birthweight (NBW) infants born at an obstetric emergency hospital in Port au Prince, Haiti, between 2014 and 2017.

METHODS

Infants were followed at discharge and 3, 6, 12, 15, 18, 21 and 24 months of corrected gestational age. At each visit they underwent a physical checkup (weight, length, physical abnormalities, identification of morbidities). At 6, 12, 18 and 24 months they underwent a neurodevelopmental assessment using the Bayley Scale III (motor, cognitive and communication skills). We modelled the trajectories between birth and 24 months of age of NBW compared to LBW infants for weight, length, and raw scores for Bayley III assessments using mixed linear models.

RESULTS

In total 500 LBW and 210 NBW infants were recruited of which 333 (46.7%) were followed up for 24 months (127 NBW; 60.5% and 206 LBW; 41.2%) and 150 died (LBW = 137 and NBW = 13). LBW and NBW babies gained a mean 15.8 g and 11.4 g per kg of weight from discharge per day respectively. The speed of weight gain decreased rapidly after 3 months in both groups. Both groups grow rapidly up to 6 months of age. LBW grew more than the NBW group during this period (22.8 cm vs. 21.1 cm). Both groups had WHZ scores <- 2 up to 15 months. At 24 months NBW babies scored significantly higher on the Bayley scales for gross motor, cognitive and receptive and expressive communication skills. There was no difference between the groups for fine motor skills.

CONCLUSION

LBW babies that survive neonatal care in urban Haiti and live up to 24 months of age, perform similar to their NBW for weight, length and fine motor skills. LBW babies are delayed in gross motor, cognitive and communication skills development. Further research on the clinical significance of these findings and long term implications of this neurodevelopmental delay is needed.

Use of clinician-performed ultrasound in the assessment of safe umbilical venous catheter tip placement

AIM

Safe tip placement of umbilical venous catheters (UVCs) in sick neonates is critical in minimising risk. We aimed to demonstrate the utility of clinician-performed ultrasound (CPU) in identifying UVCs that are placed within small intrahepatic portal vessels or within the heart despite the appearance of being well placed on X-ray.

METHODS

This was a retrospective observational study of preterm and term neonates who had a UVC placed and the position assessed by X-ray and/or CPU according to the Royal Prince Alfred Hospital level 3 neonatal intensive care unit (NICU) guideline. Cases were identified by exporting the records of all admissions between 1 April 2015 and 30 June 2016 from the NICU's data collection database. Paper-based medical records, NICU's data collection database records and the ultrasound reporting system were reviewed to determine X-ray and CPU findings.

RESULTS

A total of 157 neonates had 169 UVCs placed. CPU was performed in 77% (111). In 15 cases (14%), UVC placement on X-ray appeared appropriate based on estimated vertebral level; however, CPU demonstrated the line to be in an unsafe position (small intrahepatic portal vessel (3); right atrium (9); left atrium (3)).

CONCLUSIONS

Assessment of safe UVC placement by estimations according to vertebral level on X-ray alone is inadequate. CPU offers confident localisation of the UVC tip and enables corrective manipulation of intracardiac or intrahepatic UVCs in real time. We recommend CPU as an adjunct to X-ray to ensure safe UVC placement.

Deep learning predicts extreme preterm birth from electronic health records

OBJECTIVE

Models for predicting preterm birth generally have focused on very preterm (28-32 weeks) and moderate to late preterm (32-37 weeks) settings. However, extreme preterm birth (EPB), before the 28th week of gestational age, accounts for the majority of newborn deaths. We investigated the extent to which deep learning models that consider temporal relations documented in electronic health records (EHRs) can predict EPB.

STUDY DESIGN

EHR data were subject to word embedding and a temporal deep learning model, in the form of recurrent neural networks (RNNs) to predict EPB. Due to the low prevalence of EPB, the models were trained on datasets where controls were undersampled to balance the case-control ratio. We then applied an ensemble approach to group the trained models to predict EPB in an evaluation setting with a nature EPB ratio. We evaluated the RNN ensemble models with 10 years of EHR data from 25,689 deliveries at Vanderbilt University Medical Center. We compared their performance with traditional machine learning models (logistical regression, support vector machine, gradient boosting) trained on the datasets with balanced and natural EPB ratio. Risk factors associated with EPB were identified using an adjusted odds ratio.

RESULTS

The RNN ensemble models trained on artificially balanced data achieved a higher AUC (0.827 vs. 0.744) and sensitivity (0.965 vs. 0.682) than those RNN models trained on the datasets with naturally imbalanced EPB ratio. In addition, the AUC (0.827) and sensitivity (0.965) of the RNN ensemble models were better than the AUC (0.777) and sensitivity (0.819) of the best baseline models trained on balanced data. Also, risk factors, including twin pregnancy, short cervical length, hypertensive disorder, systemic lupus erythematosus, and hydroxychloroquine sulfate, were found to be associated with EPB at a significant level.

CONCLUSION

Temporal deep learning can predict EPB up to 8 weeks earlier than its occurrence. Accurate prediction of EPB may allow healthcare organizations to allocate resources effectively and ensure patients receive appropriate care.

Effects of targeting lower versus higher arterial oxygen saturations on death or disability in preterm infants

BACKGROUND

The use of supplemental oxygen in the care of extremely preterm infants has been common practice since the 1940s. Despite this, there is little agreement regarding which oxygen saturation (SpO₂) ranges to target to maximise short- or long-term growth and development, while minimising harms. There are two opposing concerns. Lower oxygen levels (targeting SpO₂ at 90% or less) may impair neurodevelopment or result in death. Higher oxygen levels (targeting SpO₂ greater than 90%) may increase severe retinopathy of prematurity or chronic lung disease.The use of pulse oximetry to non-invasively assess neonatal SpO₂ levels has been widespread since the 1990s. Until recently there were no randomised controlled trials (RCTs) that had assessed whether it is better to target higher or lower oxygen saturation levels in extremely preterm infants, from birth or soon thereafter. As a result, there is significant international practice variation and uncertainty remains as to the most appropriate range to target oxygen saturation levels in preterm and low birth weight infants.

OBJECTIVES

1. What are the effects of targeting lower versus higher oxygen saturation ranges on death or major neonatal and infant morbidities, or both, in extremely preterm infants?2. Do these effects differ in different types of infants, including those born at a very early gestational age, or in those who are outborn, without antenatal corticosteroid coverage, of male sex, small for gestational age or of multiple birth, or by mode of delivery?

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1966 to 11 April 2016), Embase (1980 to 11 April 2016) and CINAHL (1982 to 11 April 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials that enrolled babies born at less than 28 weeks' gestation, at birth or soon thereafter, and targeted SpO₂ ranges of either 90% or below or above 90% via pulse oximetry, with the intention of maintaining such targets for at least the first two weeks of life.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal to extract data from the published reports of the included studies. We sought some additional aggregate data from the original investigators in order to align the definitions of two key outcomes. We conducted the meta-analyses with Review Manager 5 software, using the Mantel-Haenszel method for estimates of typical risk ratio (RR) and risk difference (RD) and a fixed-effect model. We assessed the included studies using the Cochrane 'Risk of bias' and GRADE criteria in order to establish the quality of the evidence. We investigated heterogeneity of effects via pre-specified subgroup and sensitivity analyses.

MAIN RESULTS

Five trials, which together enrolled 4965 infants, were eligible for inclusion. The investigators of these five trials had prospectively planned to combine their data as part of the NeOProM (Neonatal Oxygen Prospective Meta-analysis) Collaboration. We graded the quality of evidence as high for the key outcomes of death, major disability, the composite of death or major disability, and necrotising enterocolitis; and as moderate for blindness and retinopathy of prematurity requiring treatment.When an aligned definition of major disability was used, there was no significant difference in the composite primary outcome of death or major disability in extremely preterm infants when targeting a lower (SpO₂ 85% to 89%) versus a higher (SpO₂ 91% to 95%) oxygen saturation range (typical RR 1.04, 95% confidence interval (CI) 0.98 to 1.10; typical RD 0.02, 95% CI -0.01 to 0.05; 5 trials, 4754 infants) (high-quality evidence). Compared with a higher target range, a lower target range significantly increased the incidence of death at 18 to 24 months corrected age (typical RR 1.16, 95% CI 1.03 to 1.31; typical RD 0.03, 95% CI 0.01 to 0.05; 5 trials, 4873 infants) (high-quality evidence) and necrotising enterocolitis (typical RR 1.24, 95% 1.05 to 1.47; typical RD 0.02, 95% CI 0.01 to 0.04; 5 trials, 4929 infants; I² = 0%) (high-quality evidence). Targeting the lower range significantly decreased the incidence of retinopathy of prematurity requiring treatment (typical RR 0.72, 95% CI 0.61 to 0.85; typical RD -0.04, 95% CI -0.06 to -0.02; 5 trials, 4089 infants; I² = 69%) (moderate-quality evidence). There were no significant differences between the two treatment groups for major disability including blindness, severe hearing loss, cerebral palsy, or other important neonatal morbidities.A subgroup analysis of major outcomes by type of oximeter calibration software (original versus revised) found a significant difference in the treatment effect between the two software types for death (interaction P = 0.03), with a significantly larger treatment effect seen for those infants using the revised algorithm (typical RR 1.38, 95% CI 1.13 to 1.68; typical RD 0.06, 95% CI 0.01 to 0.10; 3 trials, 1716 infants). There were no other important differences in treatment effect shown by the subgroup analyses using the currently available data.

AUTHORS' CONCLUSIONS

In extremely preterm infants, targeting lower (85% to 89%) SpO₂ compared to higher (91% to 95%) SpO₂ had no significant effect on the composite outcome of death or major disability or on major disability alone, including blindness, but increased the average risk of mortality by 28 per 1000 infants treated. The trade-offs between the benefits and harms of the different oxygen saturation target ranges may need to be assessed within local settings (e.g. alarm limit settings, staffing, baseline outcome risks) when deciding on oxygen saturation targeting policies.

Trends in Morbidity and Mortality of Extremely Preterm Multiple Gestation Newborns

OBJECTIVES

To examine the risk of mortality and major morbidities in extremely preterm multiple gestation infants compared with singletons over time.

METHODS

This is a retrospective study of 15,402 infants born ≤27 weeks' gestation, admitted to NICUs in the Australian and New Zealand Neonatal Network from 1995 to 2009. Mortality and major morbidities were compared between singletons and multiples across three 5-year epochs.

RESULTS

Extreme preterm multiples were more likely to have lower birth weight; higher maternal age; and higher rates of assisted conception, antenatal steroid use, and cesarean delivery compared with singletons. The mortality rate was significantly higher in multiples compared with singletons even as there was a trend of decreasing gestational-age stratified mortality in multiples over the time period investigated. The rates of major morbidities or composite adverse outcomes were not different between multiples and singletons across all epochs. The adjusted odds ratio (AOR) for mortality in multiples was significantly higher in multiples compared with singletons (AOR 1.20, 95% confidence interval [CI] 1.08-1.34). There were no differences in the adjusted odds for poor outcomes in multiples compared with singletons in the most recent epoch: mortality (AOR 1.00, 95% CI 0.84-1.19), major morbidity (0.95, 95% CI 0.81-1.10), and composite adverse outcome (0.96, 95% CI 0.83-1.11).

CONCLUSIONS

Over the 15-year period, the odds for mortality in extremely preterm NICU infants of multiple gestation was significantly higher compared with singletons. The adjusted odds of poor outcomes in multiples were not significantly different from that of singletons in the most recent epoch.

Outcomes for extremely premature infants

Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for 7 years and is now approximately 11.39%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23 to 24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal estimated date of confinement. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (<1000 g) remain at high risk for death and disability with 30% to 50% mortality and, in survivors, at least 20% to 50% risk of morbidity. The introduction of continuous positive airway pressure, mechanical ventilation, and exogenous surfactant increased survival and spurred the development of neonatal intensive care in the 1970s through the early 1990s. Routine administration of antenatal steroids during premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91% and 95% (compared with 85%-89%) avoids excess mortality; however, final analyses of data from these trials have not been published, so definitive recommendations are still pending. The development of neonatal neurocritical intensive care units may improve neurocognitive outcomes in this high-risk group. Long-term follow-up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages.The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, because therapy and supportive care continue to change, the outcomes of extremely low birth weight infants are ever evolving. Efforts to minimize injury, preserve growth, and identify interventions focused on antioxidant and anti-inflammatory pathways are now being evaluated. Thus, treating and preventing long-term deficits must be developed in the context of a "moving target."

Comparing minimally invasive and proactive initial management of extremely preterm infants

AIM

In 2005, we changed our minimally invasive departmental policy for infants born before 26 weeks of gestation to a proactive approach. This included structured guidelines as well as intubation and surfactant in the delivery room, if the parents agreed. The aim of this study was to evaluate the effect of this change of policy.

METHOD

We compared the Ages and Stages Questionnaire (ASQ) scores, mortality rates and use of mechanical ventilation before (1999-2003) and after (2005-2011) the introduction of the new policy.

RESULTS

Twenty-two per cent of 61 infants in the before group had an ASQ z-score of <-2 standard deviation at 18 months' corrected age, compared with 26% of 55 infants in the after group. Mortality decreased from 46% to 36% (p = 0.06) and the use of mechanical ventilation at any time during admission increased from 64% to 87% (p < 0.0001).

CONCLUSION

We demonstrated that changing our policy to a proactive approach to the initial care of infants born before 26 weeks did not result in a major increase in psychomotor deficit. However, the use of mechanical ventilation increased significantly and survival tended to improve.

Behavior and well-being of extremely low birth weight teenagers in Iceland

BACKGROUND

Preterm children are at risk for behavioral and emotional problems.

AIMS

To evaluate behavior and emotional well-being of extremely low birth weight (ELBW) teenagers born in Iceland in 1991-1995.

METHODS

Participants, 30 of 35 ELBW survivors (25 girls, 5 boys, mean age 16.8 years), were interviewed, underwent medical examination and answered the Youth Self-Report for ages 11-18 (YSR) of the Achenbach System of Empirically Based Assessment (ASEBA). The ELBW parents answered the ASEBA Child Behavior Checklist for ages 6-18 and the Autism Spectrum Screening Questionnaire (ASSQ). A comparison group of 30 teenagers (23 girls, 7 boys, mean age 16.5 years) answered the YSR questionnaire and their parents answered the CBCL and ASSQ questionnaires.

RESULTS

ELBW teenagers and parents report more behavior problems than the full term comparison teenagers and parents. They score significantly higher on the YSR and CBCL syndrome scales except for YSR and CBCL rule-breaking behavior and CBCL thought problems. The ELBW teenagers self-report on total competence, activities, social participation and academic performance was not significantly lower than the comparison teenagers. Parents of ELBW teenagers rated total competence, social participation and school performance of their children significantly lower than parents of comparison teenagers. The YSR Positive Qualities Scale was not significantly different between the two teenage groups. Two ELBW teenagers scored above cut-off points on the ASSQ questionnaire and none of the comparison teenagers. Bullying was reported by 20% of ELBW parents compared to none of the comparison group.

CONCLUSION

ELBW teenagers experience emotional, behavior and social challenges. The teenagers value their positive qualities, activities and academic performance similar to peers.

An update on the prevalence of cerebral palsy: a systematic review and meta-analysis

AIMS

The aim of this study was to provide a comprehensive update on (1) the overall prevalence of cerebral palsy (CP); (2) the prevalence of CP in relation to birthweight; and (3) the prevalence of CP in relation to gestational age.

METHOD

A systematic review and meta-analysis was conducted and reported, based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement. Population-based studies on the prevalence of CP in children born in 1985 or after were selected. Statistical analysis was carried out using computer package R, version 2.14.

RESULTS

A total of 49 studies were selected for this review. The pooled overall prevalence of CP was 2.11 per 1000 live births (95% confidence interval [CI] 1.98-2.25). The prevalence of CP stratified by gestational age group showed the highest pooled prevalence to be in children weighing 1000 to 1499g at birth (59.18 per 1000 live births; 95% CI 53.06-66.01), although there was no significant difference on pairwise meta-regression with children weighing less than 1000g. The prevalence of CP expressed by gestational age was highest in children born before 28 weeks' gestation (111.80 per 1000 live births; 95% CI 69.53-179.78; p<0.0327).

INTERPRETATION

The overall prevalence of CP has remained constant in recent years despite increased survival of at-risk preterm infants.

Survival and neurodevelopmental outcome of ELBW children at 5 years of age: comparison of two cohorts born 10 years apart

AIM

To examine survival and outcome of extremely low-birth-weight (ELBW) children (birth weight < 1000 g) in two 5-year periods, 10 years apart.

METHODS

In a retrospective population-based study, information on all ELBW children born in Iceland in 1991-1995 and in 2001-2005 was obtained from the National Birth Registry, hospital charts and medical records. The two periods were compared.

RESULTS

In 1991-1995, 102 of 22.261 newborn children (0.5%) were extremely low birth weight compared with 70 of 20.923 newborns (0.33%) in 2001-2005 (p = 0.04). At 5 years of age, 52% (35/67) of live-born children born in 1991-1995 were alive compared with 63% (31/49) of children born in 2001 - 2005 (p = 0.2). Six ELBW children (17%) born 1991-1995 were diagnosed with disabilities at 5 years of age, three with major neurodevelopmental disabilities compared with six (19%) born 2001-2005, thereof one with severe neurodevelopmental disabilities (p = 0.57).

CONCLUSION

The incidence of childhood disabilities in ELBW children in Iceland remains stable despite an increase in survival rate. The severity of neurodevelopmental disabilities has decreased.

Disabilities and health of extremely low-birthweight teenagers: a population-based study

AIM

Evaluation of long-term outcome of extremely low-birthweight (ELBW) teenagers born in Iceland in 1991-1995.

METHOD

Participants, 30 of 35 ELBW survivors and 30 full term control teenagers (14-19 years), were assessed for disabilities, health problems and learning difficulties. Results of national standardized tests in mathematics and Icelandic language were compared with results of neurodevelopmental assessment at 5 years of age.

RESULTS

A quarter of the ELBW teenagers had disabilities. All were initially diagnosed with neurodevelopmental disorders early in life and neurosensory and/or intellectual disabilities were confirmed later in childhood. Chronic lung disorders, neurological problems and psychiatric disorders were most common health problems. Growth parameters were within normal limits for most of the ELBW teenagers. Learning difficulties affected 57% of the ELBW teenagers, 20% attended special education classes and 37% required special teaching. Results of national standardized tests were significantly lower for ELBW survivors and were significantly related to the results of neurodevelopmental assessment at 5 years of age.

INTERPRETATION

A quarter of ELBW teenagers have disabilities albeit most of them mild. Chronic health problems and learning difficulties affect many ELBW survivors. Changes with time emphasize need of long-term follow-up.

NeOProM: Neonatal Oxygenation Prospective Meta-analysis Collaboration study protocol

BACKGROUND

The appropriate level of oxygenation for extremely preterm neonates (<28 weeks' gestation) to maximise the greatest chance of survival, without incurring significant morbidity, remains unknown. Infants exposed to lower levels of oxygen (targeting oxygen saturations of <90%) in the first weeks of life are at increased risk of death, cerebral palsy, patent ductus arteriosus, pulmonary vascular resistance and apnoea, whilst those maintained in higher levels of oxygen (targeting oxygen saturations of >90%) have been reported to have greater rates of morbidity including retinopathy of prematurity and chronic lung disease. In order to answer this clinical dilemma reliably, large scale trial evidence is needed.

METHODS/DESIGN

To detect a small but important 4% increase in death or severe disability in survivors, over 5000 neonates would need to be recruited. As extreme prematurity affects 1% of births, such a project undertaken by one trial group would be prohibitively lengthy and expensive. Hence, the Neonatal Oxygenation Prospective Meta-analysis (NeOProM) Collaboration has been formed. A prospective meta-analysis (PMA) is one where studies are identified, evaluated, and determined to be eligible before the results of any included studies are known or published, thereby avoiding some of the potential biases inherent in standard, retrospective meta-analyses. This methodology provides the same strengths as a single large-scale multicentre randomised study whilst allowing greater pragmatic flexibility. The NeOProM Collaboration protocol (NCT01124331) has been agreed prior to the results of individual trials being available. This includes pre-specifying the hypotheses, inclusion criteria and outcome measures to be used. Each trial will first publish their respective results as they become available and the combined meta-analytic results, using individual patient data, will be published when all trials are complete. The primary outcome to be assessed is a composite outcome of death or major disability at 18 months - 2 years corrected age. Secondary outcomes include several measures of neonatal morbidity. The size of the combined dataset will allow the effect of the interventions to be explored more reliably with respect to pre-specified patient- and intervention-level characteristics.

DISCUSSION

Results should be available by 2014.

Survival and major disability rate in infant born at 22-25 weeks of gestation

Our aim was to evaluate the literature on survival and major disability rate in preterm infants born at 22- 25 weeks of gestational age (GA). Thirty-three studies were identified and reviewed. Survival was lower in population-based studies (2% at 22, 13% at 23, 35% at 24, and 56% at 25 weeks) than in center-based study (15% at 22, 41% at 23, 58% at 24, and 74% at 25 weeks). The severe disability rate was slightly higher in population-based studies than in center-based studies at 23 (29 vs. 32%) and at 24 (30 vs. 27%) week of GA, whereas it was similar in population and center-based studies at 25 (21 vs. 22%) weeks of GA. Survival rate seems to improve with time, whereas the change of severe disability rate cannot be adequately evaluated due to the paucity of available data. We conclude that the survival of infants born at 22 weeks is still an uncommon event, whereas the survival of infants born at 23, and mostly at 24 and 25 weeks of GA is significant in the majority of studies.

Prevalence, type, distribution, and severity of cerebral palsy in relation to gestational age: a meta-analytic review

The aim of this review is to determine the relationship between gestational age (GA) and prevalence, type, distribution, and severity of cerebral palsy (CP). Epidemiological studies with cohorts expressed by GA were assessed. A comprehensive meta-analysis and meta-regression was performed on four fetal age categories. Studies of children with CP as a target population were added. Twenty-six articles met the inclusion criteria. The prevalence of CP decreases significantly with increasing GA category: 14.6% at 22 to 27 weeks' gestation, 6.2% at 28 to 31 weeks, 0.7% at 32 to 36 weeks, and 0.1% in term infants. Interestingly, a significant decrease in prevalence of CP starts only from a GA of 27 weeks onwards. In preterm infants, spastic CP is predominant. In term infants, the non-spastic form of CP is more prevalent than in preterm infants. Bilateral spastic CP is most prevalent in both preterm and term infants. However, the proportion of unilateral spastic CP in term infants is substantial. No relationship could be detected between severity of CP and GA. There is a strong need for an international, well-described, and generally accepted classification system for subtypes and severity of CP.

An overview of mortality and sequelae of preterm birth from infancy to adulthood

Survival rates have greatly improved in recent years for infants of borderline viability; however, these infants remain at risk of developing a wide array of complications, not only in the neonatal unit, but also in the long term. Morbidity is inversely related to gestational age; however, there is no gestational age, including term, that is wholly exempt. Neurodevelopmental disabilities and recurrent health problems take a toll in early childhood. Subsequently hidden disabilities such as school difficulties and behavioural problems become apparent and persist into adolescence. Reassuringly, however, most children born very preterm adjust remarkably well during their transition into adulthood. Because mortality rates have fallen, the focus for perinatal interventions is to develop strategies to reduce long-term morbidity, especially the prevention of brain injury and abnormal brain development. In addition, follow-up to middle age and beyond is warranted to identify the risks, especially for cardiovascular and metabolic disorders that are likely to be experienced by preterm survivors.

Using hospital discharge data for determining neonatal morbidity and mortality: a validation study

BACKGROUND

Despite widespread use of neonatal hospital discharge data, there are few published reports on the accuracy of population health data with neonatal diagnostic or procedure codes. The aim of this study was to assess the accuracy of using routinely collected hospital discharge data in identifying neonatal morbidity during the birth admission compared with data from a statewide audit of selected neonatal intensive care (NICU) admissions.

METHODS

Validation study of population-based linked hospital discharge/birth data against neonatal intensive care audit data from New South Wales, Australia for 2,432 babies admitted to NICUs, 1994-1996. Sensitivity, specificity and positive predictive values (PPV) with exact binomial confidence intervals were calculated for 12 diagnoses and 6 procedures.

RESULTS

Sensitivities ranged from 37.0% for drainage of an air leak to 97.7% for very low birthweight, specificities all exceeded 85% and PPVs ranged from 70.9% to 100%. In-hospital mortality, low birthweight (< or =1500 g), retinopathy of prematurity, respiratory distress syndrome, meconium aspiration, pneumonia, pulmonary hypertension, selected major anomalies, any mechanical ventilation (including CPAP), major surgery and surgery for patent ductus arteriosus or necrotizing enterocolitis were accurately identified with PPVs over 92%. Transient tachypnea of the newborn and drainage of an air leak had the lowest PPVs, 70.9% and 83.6% respectively.

CONCLUSION

Although under-ascertained, routinely collected hospital discharge data had high PPVs for most validated items and would be suitable for risk factor analyses of neonatal morbidity. Procedures tended to be more accurately recorded than diagnoses.

Perinatal care at the borderlines of viability: a consensus statement based on a NSW and ACT consensus workshop

Perinatal care at the borderlines of viability demands a delicate balance between parents' wishes and autonomy, biological feasibility, clinicians' responsibilities and expectations, and the prospects of an acceptable long-term outcome - coupled with a tolerable margin of uncertainty. A multi-professional workshop with consumer involvement was held in February 2005 to agree on management of this issue in New South Wales and the Australian Capital Territory. Participants discussed and formulated consensus statements after an extensive consultation process. Consensus was reached that the "grey zone" is between 23 weeks' and 25 weeks and 6 days' gestation. While there is an increasing obligation to treat with increasing length of gestation, it is acceptable medical practice not to initiate intensive care during this period if parents so wish, after appropriate counselling. Poor condition at birth and the presence of serious congenital anomalies have an important influence on any decision not to initiate intensive care within the grey zone. Women at high risk of imminent delivery within the grey zone should receive appropriate and skilled counselling with the most relevant up-to-date outcome information. Management plans can thus be made before birth. Information should be simple, factual and consistent. The consensus statements developed will provide a framework to assist parents and clinicians in communication, decision making and managing these challenging situations.

Neonatal intensive care at borderline viability--is it worth it?

BACKGROUND

Very preterm infants at the borderline of viability, especially those <25 weeks of gestational age, have survived in increasing numbers in recent years, but concerns persist about their long-term outcome and their consumption of scarce hospital resources.

AIMS

To determine incremental changes in long-term outcome and consumption of resources by very preterm infants in the 1990s.

DESIGN

Cohort study.

PATIENTS

Consecutive livebirths with gestational ages 23-27 weeks born in the state of Victoria in two discrete eras, 1991-1992 (n=401) and 1997 (n=208), and randomly selected contemporaneous normal birthweight (NBW, birthweight >2499 g) controls (1991-1992 n=265, 1997 n=198).

MAIN OUTCOME MEASURES

Survival, and neurosensory impairments, disabilities and utilities, and consumption of hospital resources to 2 years of age.

RESULTS

Compared with 1991-1992, in 1997 more infants were offered intensive care and the survival rate was higher at each week of gestation, and overall (absolute increase in survival 16%; 95% confidence interval, 8%, 24%). The largest increases in the survival and quality-adjusted survival rates were in infants at 23 weeks (31% and 20%, respectively). The incremental resource costs of improving survival and quality-adjusted survival were similar in infants of 23-24 weeks compared with those of 25-27 weeks (e.g., 112 vs. 105 days of assisted ventilation per additional survivor, or 167 vs. 180 days of assisted ventilation per additional quality-adjusted survivor, respectively).

CONCLUSIONS

Increased intensive care in the late 1990s for infants at the borderline of viability was associated with improved outcomes, at incremental costs that were not excessive compared with slightly more mature infants.

Handicap neuro-sensoriel grave de l’enfant grand prématuré

OBJECTIVE

Advances in perinatal care have resulted in a sharply increasing survival rate among very preterm infants. However, there is some concern about the later neurodevelopmental outcome of those infants who survive. In this paper, we review the prevalence estimates of motor (cerebral palsy), sensorineural and cognitive impairments and their recent time-trends in very preterm infants.

METHOD

A review of studies describing neurodevelopmental outcome of very preterm infants in Europe, Australia and America North.

RESULTS

The gestational age-specific prevalences of cerebral palsy (CP) were 72-86 for extremely preterm children (<28 weeks), 32-60 for very preterm (28-31 weeks) and 5-6 for moderate preterm (32-36 weeks), and 1.3-1.5 for term children per 1000. The live birth prevalence for CP remained unchanged in extremely and very preterm infants since 1990. The prevalence estimates of moderate and severe cognitive impairments are 15 to 25% in very preterm children. Less than 4% of very preterm infants develop severe hearing or visual loss.

CONCLUSION

This review indicates that very preterm infants have high risk of disability. Most studies have been conducted between 1985 and 1995. Thus, these results should be interpreted with caution before generalisation to recent cohorts.

The EPIBEL study: outcomes to discharge from hospital for extremely preterm infants in Belgium

OBJECTIVE

To determine mortality and morbidity at discharge from the hospital of a large population-based cohort of infants who were born at <or=26 weeks' gestation.

METHODS

Perinatal data were collected on extremely preterm infants who were alive at the onset of labor and born between January 1, 1999, and December 31, 2000, in all 19 Belgian perinatal centers.

RESULTS

A total of 525 infants were recorded. Life-supporting care was provided to 322 liveborn infants, 303 of whom were admitted for intensive care. The overall survival rate of liveborn infants was 54%. Of the infants who were alive at the age of 7 days, 82% survived to discharge. Vaginal delivery, shorter gestation, air leak, longer ventilator dependence, and higher initial oxygen need all were independently associated with death; gender, plurality, and surfactant therapy were not. Among the 175 survivors, 63% had 1 or more of the 3 major adverse outcome variables at the time of discharge (serious neuromorbidity, chronic lung disease at 36 weeks' postmenstrual age, or treated retinopathy of prematurity). The chance of survival free from serious neonatal morbidity at the time of hospital discharge was <15% (21 of 158) for the admitted infants with a gestation <26 weeks.

CONCLUSIONS

If for the time being prolongation of pregnancy is unsuccessful, then outcome perspectives should be discussed and treatment options including nonintervention explicitly be made available to parents of infants of <26 weeks' gestation within the limits of medical feasibility and appropriateness.

Survival of very preterm infants: Epipage, a population based cohort study

OBJECTIVE

To evaluate the outcome for all infants born before 33 weeks gestation until discharge from hospital.

DESIGN

A prospective observational population based study.

SETTING

Nine regions of France in 1997.

PATIENTS

All births or late terminations of pregnancy for fetal or maternal reasons between 22 and 32 weeks gestation.

MAIN OUTCOME MEASURE

Life status: stillbirth, live birth, death in delivery room, death in intensive care, decision to limit intensive care, survival to discharge.

RESULTS

A total of 722 late terminations, 772 stillbirths, and 2901 live births were recorded. The incidence of very preterm births was 1.3 per 100 live births and stillbirths. The survival rate for births between 22 and 32 weeks was 67% of all births (including stillbirths), 85% of live births, and 89% of infants admitted to neonatal intensive care units. Survival increased with gestational age: 31% of all infants born alive at 24 weeks survived to discharge, 78% at 28 weeks, and 97% at 32 weeks. Survival among live births was lower for small for gestational age infants, multiple births, and boys. Overall, 50% of deaths after birth followed decisions to withhold or withdraw intensive care: 66% of deaths in the delivery room, decreasing with increasing gestational age; 44% of deaths in the neonatal intensive care unit, with little variation with gestational age.

CONCLUSION

Among very preterm babies, chances of survival varies greatly according to the length of gestation. At all gestational ages, a large proportion of deaths are associated with a decision to limit intensive care.

Management decisions in extremely premature infants

Survival rates in excess of 25% at 23 weeks' gestation and in excess of 50% at 24 weeks' gestation have been reported among live births in the 1990s within tertiary perinatal care centres in the USA and Australia. Decisions about medical management at these gestational ages can no longer be based merely on whether survival is possible. Relevant moral considerations include the primacy of the newborn's best interests, parental autonomy, physicians' duties of beneficence and non-maleficence, and distributive justice. There is significant variability between developed nations in the survival of extremely premature infants among cohorts born within perinatal tertiary care centres. This is, at least to some degree, the result of differences in the aggressiveness of obstetrical and neonatal management at these gestational ages. There is also great variability in the prevalence of major neurodevelopmental disability among survivors. Moreover, the prevalence of major disabilities does not inform quality-of-life considerations adequately. Despite similar gestational age ranges over which the benefit:burden ratio of aggressive obstetric and neonatal care is questioned in developed countries, there is marked variation in the frequency with which it is provided within these ranges. This is understandable given the relevant moral values and the different ways in which competing values will be balanced by different individuals, cultures and societies; the increasing survival of extremely premature infants, but the persistence of high (but widely variable) prevalences of major disabilities reported among survivors and even higher prevalences of mild-to-moderate neurodevelopmental sequelae; our imperfect ability to estimate an individual extremely premature infant's prognosis; and the complexities of estimating the quality of life from the individual's own perspective.

Outcomes for high risk New Zealand newborn infants in 1998-1999: a population based, national study

OBJECTIVE

To determine short term morbidity and mortality outcomes, provision of care, and treatments for a national cohort of high risk infants born in 1998-1999 and admitted to New Zealand neonatal intensive care units (NICUs).

SETTING

All level III (six) and level II (13) NICUs in New Zealand.

METHODS

Prospective audit by the Australian and New Zealand Neonatal Network (ANZNN) of all infants defined as "high risk" (born at < 32 weeks gestation or < 1500 g birth weight, or received assisted ventilation for four hours or more, or had major surgery). Data were collected from birth until discharge home or death.

RESULTS

There were 3368 high risk infants (3.0% of all live births), comprising 1241 (37%) < 32 weeks gestation, 1084 (32%) < 1500 g, 3156 (94%) who received assisted ventilation, and 243 (7%) who received major surgery (categories overlap). Most infants (87%) received some care in tertiary hospitals, and 13% were cared for entirely in non-tertiary hospitals. Survival was 91% for infants < 32 weeks gestation, 97% for infants > or = 32 weeks gestation who received assisted ventilation, and 92% for infants > or = 32 weeks gestation who had major surgery. The proportion of very preterm infants who survived free of early major morbidity was 11%, 28%, 53%, 81%, and 90% for infants born at < 24, 24-25, 26-27, 28-29, and 30-31 weeks gestation respectively.

CONCLUSIONS

These unique population based national data provide contemporary information on the care and early morbidity and mortality outcomes for all high risk infants, whether cared for in hospitals with level III or level II NICUs.

Comparison of management strategies for extreme prematurity in New Jersey and the Netherlands: outcomes and resource expenditure

OBJECTIVE

To quantify differences in resource expenditure in the perinatal period and long-term outcome of extremely premature infants who received systematically different approaches to neonatal intensive care.

METHODS

Perinatal management, mortality, prevalence of disabling cerebral palsy (DCP), and resource expenditure of 2 population-based inception cohorts of extremely premature infants born in the mid-1980s were compared. Electronic fetal monitoring, tocolysis, cesarean section delivery, and assisted ventilation were used to characterize management approaches. Participants included all live births at 23 to 26 weeks' gestation in a 3-county area of central New Jersey (NJ) from 1984 to 1987 (N = 146) and throughout the Netherlands (NETH) in 1983 (N = 142). Mortality and the prevalence of DCP were the primary outcomes. Numbers of hospital days with and without assisted ventilation were the measures of resource expenditure.

RESULTS

Electronic fetal monitoring (100% vs 38%), cesarean section (28% vs 6%), and assisted ventilation (95% vs 64%) were all more commonly used in NJ than in NETH. Ten percent of NJ deaths occurred without assisted ventilation, compared with 45% of Dutch deaths. A total of 1820 ventilator days were expended per 100 live births in NJ, compared with 448 in NETH. The increase in the number of nonventilator days (3174 vs 2265 days per 100 live births) did not reach statistical significance. Survival to age 2 (46 vs 22%) and the prevalence of DCP among survivors (17.2 vs 3.4%) were significantly greater in NJ at age 2 than in NETH at age 5.

CONCLUSIONS

Near universal initiation of intensive care in NJ, compared with selective initiation of intensive care in NETH, was associated with 24.1 additional survivors per 100 live births, 7.2 additional cases of DCP per 100 live births, and a cost of 1372 additional ventilator days per 100 live births.

Outcomes of children of extremely low birthweight and gestational age in the 1990s

Advances in perinatal care have improved the chances for survival of extremely low birthweight (<800 grams) and gestational age (<26 weeks) infants. A review of the world literature reveals that among regional populations, survival at 23 weeks' gestation ranges from 2 to 35%, at 24 weeks' gestation 17 to 62% and at 25 weeks' gestation 35 to 72%. These wide variations may be accounted for by differences in population descriptors, in the criteria used for starting or withdrawing treatment, in the reported duration of survival and differences in care. Major neonatal morbidity increases with decreasing gestational age and birthweight. At 23 weeks' gestation, chronic lung disease occurs in 57 to 86% of survivors, at 24 weeks in 33 to 89% and at 25 weeks' gestation in 16 to 71% of survivors. The rates of severe cerebral ultrasound abnormality range from 10 to 83% at 23 weeks' gestation, 9 to 64% at 24 weeks and 7 to 22% at 25 weeks' gestation Of 77 survivors at 23 weeks' gestation, 26 (34%) have severe disability (defined as subnormal cognitive function, cerebral palsy, blindness and/or deafness). At 24 weeks' gestation, the rates of severe neurodevelopmental disability range from 22 to 45%, and at 25 weeks' gestation 12 to 35%. When compared with children born prior to the 1990s, the rates of neurodevelopmental disability have, in general, remained unchanged. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.