Improved outcome into the 1990s for infants weighing 500-999 g at birth

AIMS—To compare the survival and sensorineural disability rates in extremely low birthweight (ELBW) (500-999 g) infants born in 1991-2 with ELBW babies born in 1979-80 and 1985-7, and with normal birthweight infants born in the same time periods.METHODS—ELBW infants born in Victoria in 1991-2 were compared with regional cohorts of ELBW infants born in 1979-80 and 1985-7, and with contemporaneous normal birthweight (>2499 g) controls, and those of birthweight 500-749 g with those of birthweight 750-999 g.RESULTS—In 1979-80, 25.4% (89/351) ELBW live births survived to 2 years of age, increasing significantly to 37.9% (212/560) in 1985-7, and to 56.2% (241/429) in 1991-2. The rates of severe disability in survivors assessed were 12.4%, 6.6%, and 6.8% in the 1979-80, 1985-7, and 1991-2 ELBW cohorts, respectively. The rate of disability, overall, was significantly lower in the 1985-7 and 1991-2 ELBW cohorts compared with the 1979-80 ELBW cohort, but was significantly higher in 1991-2 ELBW infants than normal birthweight controls. Surviving children with birthweights <750 g had significantly higher rates of sensorineural disability compared with those of birthweight 750-999 g in 1979-80, but not in 1985-7 or 1991-2.CONCLUSIONS—Survival rates for ELBW babies in Victoria have progressively improved since the late 1970s. Sensorineural outcome for survivors born in 1985-7 has also improved compared with those born in 1979-80. However, there is no evidence that further reductions in adverse sensorineural outcomes into the 1990s, and these, as well as disabilities remain higher in ELBW than in normal birthweight babies.     

Educational outcome at 8 years for children who were born extremely prematurely: a controlled study

OBJECTIVE: To assess the educational outcome and utilization of special education resources at age 8 years in children who were born extremely prematurely, and to compare this outcome with a matched cohort of children born full-term. METHODS: All children with gestational age less than 28 weeks or birthweight of less than 1000 g, born at Royal North Shore Hospital from July 1985 through June 1990 were enrolled in a study of long-term outcome. A cohort of full-term children matched for age, sex and school with non-disabled extremely premature children was enrolled at age 8 years. Children were assessed using standardized measures of cognitive and academic achievement. Information was obtained from teachers regarding educational support and academic progress. RESULTS: Of 82 extremely premature children assessed at age 8 years, 8 (10%) had a severe disability, 13 (16%) had a mild or moderate disability and 61 (74%) were non-disabled (IQ > or = 85, no neurosensory disability). Thirty-five (43%) required special education support, 22 (27%) were below grade level in reading or mathematics and 25 (30%) were performing at grade level without support. Compared with controls, non-disabled extremely premature children had lower scores on standardized measures of academic achievement and were more likely to be reported by teachers as falling below grade level in reading (48% vs 13%; P < 0.001), mathematics (48% vs 10%; P < 0.001) and spelling (48% vs 17%; P < 0.002), and to require special education support (25% vs 4%; P = 0.004). CONCLUSION: Parents and professionals caring for extremely premature children need to be alert to the additional support that these children may require at school.     

Evaluation of neurodevelopmental outcome in highrisk infants in Australia

An understanding of the neurodevelopmental outcome of long-term survivors of neonatal intensive care is essential for the informed management of preterm or high risk infants. This annotation looks at the current status of neonatal follow-up services in Australasia and highlights problems in the collection and interpretation of data. It suggests that we should work towards achieving a consensus on standard definitions and test regimes and on national data collection.     

Economic outcome for intensive care of infants of birthweight 500–999 g born in Victoria in the post surfactant era

Objective: To determine the incremental cost of improving the outcome for extremely low birthweight (ELBW, birthweight 500–999 g) infants born in Victoria after the introduction of exogenous surfactant (the post surfactant era). Methodology: This was a geographically determined cohort study of ELBW children in Victoria, Australia of consecutive livebirths born in three distinct eras: (i) 1979–80 (n= 351); (ii) 1985–87 (n= 560); and (iii) 1991–92 (n= 429). Exogenous surfactant was first used in Victoria in March, 1991. The consumption of nursery resources per livebirth, and the survival and sensorineural disability rates at 2 years of age for each era were investigated. Utilities were assigned as follows: 0 for dead, 0.4 for severe disability, 0.6 for moderate disability, 0.8 for mild disability, and 1 for no disability. Utilities were multiplied for more than one disability. Dollar costs were assumed to be $1470 ($A 1992) per day of assisted ventilation, and one dose of exogenous surfactant was assumed to be equivalent to one third of a day of assisted ventilation. Cost-effectiveness (additional costs per additional survivor or life-year gained) and cost-utility (additional costs per additional quality-adjusted survivor or life-year gained) ratios were calculated for the pre-surfactant era (1985–87 vs 1979–80), and for the post surfactant era (1991–92 vs 1985–87). Results: Considering only the costs incurred during the primary hospitalization, cost-effectiveness and cost-utility ratios were lower (i.e. economically better) in the post surfactant era than in the pre-surfactant era (pre-surfactant vs post surfactant; S7040 vs$4040 per life year gained; $6700 vs$5360 per quality-adjusted life year gained). Both ratios fell with increasing birthweight. In contrast with the pre-surfactant era, cost-utility ratios were less favourable than cost-effectiveness ratios in the post surfactant era. With costs for long-term care of severely disabled children added, both cost ratios were higher in the post surfactant era. Conclusion: The incremental cost during the primary hospitalization of improving the outcome for ELBW infants has fallen in the post surfactant era.     

Surgery and the tiny baby: Sensorineural outcome at 5 years of age

O bjective : To determine whether an association exists between long-term sensorineural outcome and the need for surgery requiring general anaesthesia during the primary hospitalization in extremely preterm (> 27 weeks of gestational age) or extremely low birthweight (ELBW, birthweight > 1000g) infants.
Methodology : A geographically determined cohort study of extremely preterm or ELBW children in the State of Victoria, Australia. The study subjects were consecutive survivors with either gestational ages >27 weeks or birthweights >1000g born in the State of Victoria during 3 years from 1 January 1985. The main outcome measure was the rate of sensorineural disability at 5 or more years of age in relation to surgical procedures requiring general anaesthesia performed during the primary hospitalization.
Results : Of 221 children surviving to 5 years of age, 54 (24.4%) had at least one surgical operation requiring general anaesthesia during their primary hospitalization. The operations included the following: (i) ligation of ductus arteriosus ( n = 26); (ii) inguinal hernia repair ( n = 16); (iii) central nervous system surgery ( n = 4); (iv) gastrointestinal surgery ( n = 5); and (v) tracheostomy or bronchoscopy ( n = 5). Of the 221 survivors to 5 years of age, 218 (98.6%) were assessed for sensorineural impairments and disabilities. Of the 53 children who were assessed at 5 or more years of age and who had had surgery, 7 (13.2%) were severely disabled, 8 (15.1%) were moderately disabled, 12 (22.6%) were mildly disabled, and 26 (49.1%) were non-disabled. The overall rate of sensorineural disability was significantly higher in children who had been operated on compared with those who had not (Mann-Whitney U -test, z = 3.7, P > 0.001).
Conclusions : There is an adverse association between the need for surgery requiring general anaesthesia during the primary hospitalization and sensorineural outcome in extremely preterm or ELBW infants.     

Favourable neurological outcomes following delivery room cardiopulmonary resuscitation of infants < or = 750 g at birth

OBJECTIVE: To study short- and long-term outcomes of infants < or = 750 g birthweight who received cardiopulmonary resuscitation (CPR) in the delivery room. METHODOLOGY: A retrospective analysis of all inborn live births < or = 750 g birthweight from 1990 to 1996. Cardiopulmonary resuscitation was defined as positive pressure ventilation via an endotracheal tube and chest compressions. Univeriate analysis were conducted comparing patients according to the use of CPR or positive pressure ventilation alone. RESULTS: Cardiopulmonary resuscitation was administered to 16 infants: four received chest compressions only and 12 also received adrenaline. Cardiopulmonary resuscitation recipients had significantly lower Apgar scores at both 1 and 5 min, and had delayed onset of spontaneous respiration (P < 0.01). Seven patients died, and eight of nine survivors were free of major neurodevelopmental abnormalities at follow up. All CPR recipients with a 5 min Apgar score of < or = 5 and delayed onset of spontaneous respiration beyond 5 min had poor outcomes. CONCLUSION: Contrary to the majority of published evidence, delivery room CPR in our extremely small infants was not associated with a high risk of severe neurodevelopmental disability.     

Extremely low birthweight infants at 3 years: A developmental profile

This study documents the neurodevelopmental outcome at 3 years of 52 of 55 extremely low birthweight (ELBW) survivors (survival rate 49%) born in a tertiary maternity centre from July 1985 through December 1988, and examines more closely the developmental profile of the neurologically normal survivors. At 3 years, 6 (12%) children had severe neurodevelopmental impairment (severe cerebral palsy, blindness, deafness or a General Quotient (GQ)<70 on the Griffiths Scales), 11 (21 %) had mild to moderate impairment and 35 (67%) had no neurosensory impairment and normal development (GQ≥ 85). Significant risk factors for severe impairment were stage 3 or 4 retinopathy of prematurity (odds ratio [OR] 21.5), treatment with postnatal steroids (OR 21), grade III or IV intraventricular haemorrhage (OR 11) and supplemental oxygen at 'term'(OR 6.4). The developmental profile of the 35 neurologically normal children revealed a significant weakness in eye and hand coordination skills and a relative strength in hearing and speech skills. Early recognition of this developmental profile may allow implementation of more appropriate preschool programmes for ELBW children.     

Handicaps and health problems in 2 year old children of birth weight 500 to 1500 g

Fifty-nine infants of birthweight 500 to 999 g born in 1977 to 1980 and 132 infants of birthweight 1000 to 1500 g born in 1977 to 1978 were reviewed at two years corrected age. For the whole cohort, cerebral palsy was found in 12.6%, bilateral deafness in 1%, blindness in 1% and severe developmental delay in 12%. There was no significant difference in these disabilities between the groups of larger and smaller infants; 37.7% of the cohort was readmitted to hospital on at least one occasion, 35.6% of children had wheezing episodes and/or lower respiratory tract infections which together accounted for 51% of hospitalizations. The infants of birthweight 500 to 999 g tended to require more frequent and prolonged hospitalizations.
Dolicocephalic head shape, chest deformities, iatrogenic sequelae from intensive care, poor growth and cicatricial retrolental fibroplasia were significantly more frequent in children of birthweight 500 to 999 g. Parents reported that 39% of their children had 'colic', 31.6% had sleep disturbance and 25% had multiple behavioural problems. Low frustration tolerance, inability to wait, hypo- or hyperactivity and an inappropriate relationship with the mother as measured by the psychologist all occurred significantly more frequently in children of birthweight of less than 1000 g. This report confirms the belief that a comprehensive follow-up is required for very low birthweight (VLBW) children because significant health problems continue after primary hospitalization.     

Nursery Neurobiologic Risk Score and outcome at 18 months

The aim of this study was to confirm the predictive value of the nursery Neurobiologic Risk Score. Prospectively, 121 infants (mean birthweight 961 ± 179 g, gestation 27.0 ± 1.2 weeks) were followed at 18 months. The nursery Neurobiologic Risk Score was correlated to the developmental quotient ( r =– 0.54). From low (scores 0-4), to moderate (scores 5–7) to high (scores ≥8) risk groups, respectively, significant differences were found in mean developmental quotient (101 ± 9 vs 92 ± 19 vs 76 ± 24) and in prevalence of developmental quotients < 90 (12 vs 24 vs 71%), of cerebral palsy (4 vs 19 vs 41%), of severe disabilities (0 vs 24 vs 50%) and of any disability (16 vs 30 vs 71%). Sensitivity, specificity, positive and negative predictive values for any disability were 81, 54,49 and 84% for a score ≥ 5 and 56, 87, 71 and 78% for a score ≥ 8. The nursery Neurobiologic Risk Score was useful in predicting 18 months outcome of very premature infants.     

Prediction of outcome at 5 years from assessments at 2 years among extremely preterm children: a Norwegian national cohort study

Aim: To examine the predictive value of early assessments on developmental outcome at 5 years in children born extremely preterm. Methods: This is a prospective observational study of all infants born in Norway in 1999–2000 with gestational age (GA) <28 weeks or birth weight (BW) <1000 g. At 2 years of age, paediatricians assessed mental and motor development from milestones. At 5 years, parents completed questionnaires on development and professional support before cognitive function was assessed with Wechsler Preschool and Primary Scale of Intelligence‐Revised (WPPSI‐R) and motor function with the Movement Assessment Battery for children (ABC test). Results: Twenty‐six of 373 (7%) children had cerebral palsy at 2 and 29 of 306 (9%) children at 5 years. Of children without major impairments, 51% (95% CI 35–67) of those with and 22% (95% CI 16–28) without mental delay at 2 years had IQ <85 at 5 years, and 36% (95% CI 20–53 with and 16% (95% CI 11–21) without motor delay at 2 years had an ABC score >95th percentile (poor function). Approximately half of those without major impairments but IQ <85 or ABC score >95th percentile had received support or follow‐up beyond routine primary care. Conclusion: Previous assessments had limited value in predicting cognitive and motor function at 5 years in these extremely preterm children without major impairments.     

The long-term neurodevelopmental outcome for very low birthweight (VLBW) infants with 'dystonic' signs at 4 months of age

Abstract  As very low birthweight (VLBW) infants are at a high risk of developmental handicap, it is important to establish predictors of long-term adverse outcome at an early age so that early intervention can be instituted. Longitudinal neurodevelopmental assessments were performed in 107 VLBW infants at 1,4, 8 and 12 months corrected age. Eighteen were diagnosed as 'dystonic' at 4 months of age.
This study compared the outcomes at 4 and 6 years for 15 of the 18 dystonic with 75 of the 89 non-dystonic VLBW infants, respectively. At 9 years of age, nine dystonic and 54 non-dystonic infants were assessed on the Rutter Behaviour Questionnaire. Dystonic children had a lower mean General Cognitive Index (GCI; P= 0.001) and a higher incidence of disability as measured by the Burns Neuro-Sensori-Motor Developmental Assessment Scale (P = 0.0005) and Kitchen disability grading (P = 0.001). Even if the minor neurological aberrations of the premature dystonia syndrome in VLBW infants abate by one year of life, these infants still constitute a high-risk group for subsequent neurodevelopmental disability and therefore require close observation and probably early intervention.     

Retinopathy of prematurity in infants weighing 1000-1499 g at birth

Objectives: To review the incidence and severity of retinopathy of prematurity (ROP) in infants with birthweights 1000-1249 g and 1250-1499 g, to establish whether the upper weight limit for routine ophthalmological examination might safely be lowered. Methodology Prospective cohort study of infants born between 1 January 1977 and 31 December 1992 cared for in the neonatal nurseries at the Royal Women's Hospital, Melbourne. Data were retrieved on 1373 infants who survived their initial hospitalization. They comprised 657 with birthweights 1000-1249g (group 1) and 716 with birthweights 1250-1499g (group 2). There were 76 outborn infants in group 1 and 97 in group 2; the remaining infants were all born at the Royal Women's Hospital. Ocular examinations commenced at 2 weeks of age, when possible, and at 2-weekly intervals after that. Results In group 1, ROP was detected in 14.6% (96/657) and severe ROP (bilateral stage 3-5) in 5.0% (33/657). Five (0.8%) children required surgical intervention (reaching threshold disease); following surgery, one was legally blind, one had severely impaired vision, and the other three had near-normal vision. Another child was blind; he was born at 28 weeks gestational age with a birthweight of 1170g, and was transferred to a Level II hospital at 9 weeks chronological age with no detectable retinopathy. He returned 1 year later totally blind with detached retinae (grade 5 ROP). The prevalence of bilateral blindness in this group was 0.3% (2/657). In group 2, ROP was detected in 6.4% (46/716) and severe ROP in 0.8% (6/716). No children required surgery; three were found to be myopic at follow up but the corrected visual acuity was normal. No children in group 2 were blind. No significant difference was found between the rates of ROP in inborn and outborn infants. Conclusion In neonatal units with similar rates of ROP and visual outcome, routine ophthalmological examination in the neonatal nursery of infants weighing more than 1249g at birth is probably unnecessary.     

Changing survival and impairment rates at 18–24 months in outborn very low-birth-weight infants: 1984–1987 versus 1980–1983

Outcomes at 18–24 months corrected age of very low-birth-weight infants admitted to our Neonatal Intensive Care Unit in 1984–1987 (period 2) were compared with the outcomes of infants admitted in 1980–1983 (period 1) (total 1357 infants). In the 500–750–g birth-weight subgroup, the survival rate increased from 32 to 54% ( p = 0.002). Rates of moderate and severe impairment at 18–24 months (neurosensory deficit, or Bayley corrected mental developmental index ≤68) in this subgroup decreased from 41 to 15% ( p = 0.005), and in those without severe impairment, mean mental Bayley scores in periods 1 and 2 were 84 ± 18 and 90±16, respectively (p = 0.20). Analysis after exclusion of small-for-gestational-age infants gave similar results. In the small-for-gestational-age infants of birth weight 500–750 g, the survival rate increased but the impairment rate was unchanged between periods. It is concluded that outcomes improved in 1984–1987 compared with 1980–1983 only for infants with birth weight of 500–750 g.     

Changing survival and impairment rates at 18–24 months in outborn very low-birth-weight infants: 1984–1987 versus 1980–1983

Outcomes at 18–24 months corrected age of very low-birth-weight infants admitted to our Neonatal Intensive Care Unit in 1984–1987 (period 2) were compared with the outcomes of infants admitted in 1980–1983 (period 1) (total 1357 infants). In the 500–750–g birth-weight subgroup, the survival rate increased from 32 to 54% ( p = 0.002). Rates of moderate and severe impairment at 18–24 months (neurosensory deficit, or Bayley corrected mental developmental index <68) in this subgroup decreased from 41 to 15% ( p = 0.005), and in those without severe impairment, mean mental Bayley scores in periods 1 and 2 were 84 ± 18 and 90 ± 16, respectively (p = 0.20). Analysis after exclusion of small-for-gestational-age infants gave similar results. In the small-for-gestational-age infants of birth weight 500–750 g, the survival rate increased but the impairment rate was unchanged between periods. It is concluded that outcomes improved in 1984–1987 compared with 1980–1983 only for infants with birth weight of 500–750 g.     

The influence of growth on development outcome in extremely low birthweight infants at 2 years of age

OBJECTIVE: To determine if weight < 3rd and < 10th centile at 2 years in extremely low birthweight (ELBW) infants is associated with problems of development and motor skills, and whether this association is explained by perinatal risk status. METHODOLOGY: One hundred and ninety-eight of 226 (88%) surviving ELBW infants born between January 1987 and December 1992 were assessed at 2 years corrected age. Children were classified as being at low perinatal risk (n = 128) or high perinatal risk (n = 70) for adverse developmental outcome based on perinatal risk factors. Weight at 2 years was classified as < 3rd, 3rd-9th or > or = 10th centile for age and gender. Development was assessed using the Griffiths Mental Developmental Scales and motor skills using the Neurosensory Motor Developmental Assessment (NSMDA). RESULTS: For the total study group weight centile was strongly related to General Quotient (GQ) and motor abilities. For children < 3rd percentile (n = 48) mean (GQ) was 90.4 (SD, 15.9), for children between the 3rd-9th percentile (n = 49) 91.5 (SD, 17.9), and for children > or = 10th percentile (n = 99) mean GQ was 99.8 (SD, 8.6). The association with mean GQ and NSMDA category occurred for the high-risk subgroup and became non-significant in the low-risk subgroup if neurologically abnormal children were excluded. Other perinatal risk factors, exposure to breast milk, level of maternal education, marital status and history of feeding problems or infections over the 2 years did not confound this association. CONCLUSION: Low weight percentile at 2 years was related to adverse developmental outcome in ELBW infants at high perinatal risk or with neurological impairment, though minimal association was present for neurologically normal infants at low perinatal risk.     

Neurosensory outcome and growth at three years in extremely low birthweight infants: follow-up results from the Swedish national prospective study

A prospective national investigation comprising 633 extremely low birthweight (ELBW) infants born alive in the 2-y period 1990-1992 with a birthweight of ≤1000 g and gestational age of ≥23 completed weeks was conducted regarding neurosensory outcome and growth. Three-hundred and sixty-two (98%) surviving ELBW infants were assessed at a median age of 36 months, using a specially designed protocol. At follow-up, mean height, weight and head circumference in both boys and girls were significantly lower than the reference values. The incidence of cerebral palsy was 7% among all children and 14%, 10% and 3% in children born at 23-24, 25-26 and ≥27 gestational weeks, respectively. At least one obvious handicap was present in 14%, 9% and 3% of these three groups of children, respectively. After adjustment for gestational age, a significantly increased risk of handicap was found in children with intraventricular haemorrhage grade ≥3 and/or periventricular leucomalacia and in children with retinopathy of prematurity stage ≥3. The results show that more than 90% of ELBW children born at ≥25 completed gestational weeks were without neurosensory handicap at 36 months of corrected age. In infants born at 23-24 weeks of gestation, both survival and long-term outcome were less favourable.     

Mortality, Morbidity, Growth and Development of Babies Weighing 501–1000 Grams and 1001–1500 Grams at Birth

ABSTRACT. During the five-year period, January 1980 to December 1984, 149 babies of extremely low birthweight (ELBVV; 501–1000 g) and 296 of very low birthweight (VLBVV; 1001–1500 g) were admitted to King's College Hospital, Neonatal Intensive Care Unit. The survival rates were 51.7 % and 82.8 % respectively. There were more peri- and postnatal problems in the ELBVV babies than the VLBW babies and these differences were highly significant. All surviving babies born between January 1980 and December 1982 were followed up until aged two. The ELBW children had a higher incidence of neuro-developmental sequelae than those of VLBW especially when both major and minor problems were considered. Their developmental quotients were lower at one and two years. Significantly more ELBW children were of short stature and low weight (<3rd centile). By two years of age the differences between ELBW and VLBW children in stature and mean DQ had lessened.     

Cognitive outcome at 24 months is more predictive than at 18 months for IQ at 8-9 years in extremely low birth weight children

Background

It is unclear whether developmental assessment later or earlier in childhood is the better predictor of intelligence at 8 years of age. This is an important distinction as many clinical trials assess their final outcomes only in early childhood, assuming the results are valid for later childhood cognitive functioning.

Aims

To compare the ability of developmental assessment at 18 months with 24 months in predicting general intellectual functioning at 8–9 years of age in extremely low birth weight (ELBW, birthweight < 1000 g) children.

Study design

Cohort study.

Subjects

58 ELBW survivors born during 1997 at the Royal Women's Hospital, Melbourne, Australia.

Outcome measures

Cognitive assessments at each of 18 months, 24 months (Mental Developmental Index [MDI]) and 8–9 years (Full Scale IQ) of age, corrected for prematurity were compared by regression analysis and by the κ statistic (agreement beyond chance).

Results

Both the 18-month and the 24-month MDI were significantly predictive of Full Scale IQ at 8–9 years, but more so for the 24-month MDI, with 38% of variance explained compared with 34% of variance explained by the 18-month MDI. The 24-month MDI, expressed as categories of severe, moderate, mild or no developmental delay, was more predictive of categories of severe, moderate, mild or no intellectual impairment at 8–9 years (weighted κ = 0.43, P < 0.001) than was the 18-month MDI (weighted κ = 0.35, P = 0.001).

Conclusions

Cognitive assessment at 24 months is superior to cognitive assessment at 18 months in predicting IQ and intellectual impairment at 8–9 years of age in ELBW children.