Cognition, school performance, and behavior in very low birth weight and normal birth weight children at 8 years of age: a longitudinal study.

Cognition, school performance, and behavior were assessed at 8 years of age in 132 very low birth weight (VLBW) children free of major sensorineural impairments, and the results were contrasted with a randomly selected control group of normal birth weight (NBW) children. Considering their fragile beginnings, the majority of VLBW children were developing normally and were reading and performing in most academic and social areas as well as the NBW children. However, VLBW children were significantly inferior to NBW children on tests of cognition, including tests of intelligence and visual memory, and on teacher's reports of motor skills and initiative. In addition, proportionally more VLBW children (20.5%) than NBW children (5.9%) were reported by their parents to be not coping at school.

The cost of improving the outcome for infants of birthweight 500-999 g in Victoria. The Victorian Infant Collaborative Study Group.

The aim of this study was to conduct an economic evaluation of neonatal intensive care for extremely low birthweight (ELBW) infants born in the state of Victoria. Two distinct eras (1979-80 and 1985-87) were compared. Follow-up data at 2 years of age were available for all 89 survivors from the 351 live births in 1979-80, and for 211 of 212 survivors from the 560 live births in 1985-87. The overall cost-effectiveness for ELBW infants during 1985-87 compared with 1979-80 was $104,990 ($A 1987) per additional survivor, or $5390 ($A 1987) per additional life year gained. Cost-effectiveness improved with increasing birthweight. If the quality of life of the survivors was considered, the economic outlook was more favourable. The cost per quality-adjusted life year gained was $5090 ($A 1987), approximately one-tenth of that obtained from the only previous full economic evaluation of neonatal intensive care. Although neonatal intensive care is expensive, it compares favourably with some other health care programmes, particularly as the outcome for ELBW infants continues to improve.

Audiologic assessment of extremely low birth weight infants: a preliminary report.

The aim of this study was to assess all relevant aspects of auditory function, including acuity and perception, of a cohort of extremely low birth weight (< 1000 g) children who survived to 8 years of age; 42 of the 59 consecutive survivors born over a 4-year period from January 1, 1977, had a full auditory assessment. Of the 42 children, 4 (9.5%) had a sensorineural hearing impairment, 5 (11.9%) had a conductive hearing impairment, 24 (57.1%) had figure/ground differentiation problems, and 20 (47.6%) had a short-term auditory memory problem. The 4 children with sensorineural hearing impairments had had significantly higher maximum concentrations of bilirubin in the newborn period (median 167 mumol/L vs 138 mumol/L and had required more intensive care; at 8 years of age they were significantly disadvantaged in verbal ability. The 5 children with conductive hearing impairments were not significantly different on any perinatal or other 8-year outcome variables. The proportion with figure/ground differentiation problems (57.1%) was significantly higher than in a normative population (11.7%, chi 2 = 24.2). Extremely low birth weight children with figure/ground differentiation problems were more likely to be restless in the classroom (45.0% [9/20]) than those without these problems (16.7% [2/12]), but the difference was not statistically significant (chi 2 = 2.7). Children with short-term auditory memory problems had significantly higher maximum bilirubin concentrations in the newborn period (median 152 mumol/L vs 137.5 mumol/L). At 8 years of age they had significantly reduced intelligence and reading ability.(ABSTRACT TRUNCATED AT 250 WORDS)

Is there a lower limit for birth-weight/gestational age and antenatal steroid therapy?

The aim of this study was to determine if there is a lower limit for birth-weight/gestational age below which antenatal steroid therapy may not improve fetal survival. The association between antenatal steroid therapy and survival to 2 years of age was assessed in 2 cohorts of children of birth-weight below 800 g or of gestational ages below 27 weeks. Antenatal steroid therapy was associated with significantly higher survival rates in infants of birth-weight 500-599 g and 700-799 g, and at gestational ages of 25 and 26 weeks. There were few survivors before 25 weeks and none below 500 g birth-weight. After adjustment for extraneous prognostic variables, antenatal steroid therapy was associated overall with approximately a doubling of the survival rates of infants of birth-weight 500-799 g, and of gestational ages 24-26 weeks. In the absence of maternal contraindications, if the goal is to deliver a surviving infant, this study suggests that the obstetrician may assist the survival chances of the tiniest and most immature infants by treating the mother with steroids before birth, with no apparent lower limit of birth-weight or gestational age.

Improvement in outcome for very low birthweight children: apparent or real?

OBJECTIVE: To determine whether improvement in the survival rate of infants with a birthweight of less than 1501 g was accompanied by an increase in the rate of neurological impairment or disability among the survivors. DESIGN, SETTING AND PATIENTS: Two cohorts of consecutive very low birthweight infants (birthweight less than 1501 g) in one tertiary perinatal centre were followed prospectively to eight years of age; for both cohorts, comparison groups of children of birthweight more than 1501 g were randomly selected from hospital births. INTERVENTIONS: The first cohort was born before the introduction of assisted ventilation (1966-1970), the second after assisted ventilation was well established (1980-1982). MAIN OUTCOME MEASURES: Comparisons between cohorts, at eight years of age, of the survival rates and the rates of severe sensorineural impairments and disabilities. RESULTS: The survival rate for very low birthweight infants to eight years of age almost doubled between these cohorts, from 37.1% to 67.8% (odds ratio [OR], 3.4; 95% confidence interval [CI], 2.5-4.7; chi 2 = 57.6; P much less than 0.0001). The biggest gain was the increase in non-disabled survivors at eight years of age, from 52.6% in the first cohort to 80.8% in the second cohort (OR, 3.5; 95% CI, 2.2-5.7; chi 2 = 26.7; P less than 0.0001). Furthermore, the rate of severe disabilities in survivors fell substantially, from 13.6% to 4.1% (OR, 0.31; 95% CI, 0.14-0.69; chi 2 = 8.3; P less than 0.01). Of specific impairments, the rate of severe sensorineural deafness fell substantially (3.2% to 0%: OR, 0.14, 95% CI, 0.02-0.81; chi 2 = 4.8; P less than 0.05), as did the rate of severe intellectual impairment (13.0% to 2.7%: OR, 0.25; 95% CI, 0.11-0.57; chi 2 = 10.7; P less than 0.002). Only the rate of cerebral palsy increased, but not significantly (2.6% to 6.8%; OR, 2.6; 95% CI, 0.89-7.6; chi 2 = 3.0). CONCLUSIONS: It has been possible to improve the survival rate of very low birthweight infants over time without increasing the number of severely disabled survivors. Whether the long-term outcome for these infants is continuing to improve with more recent advances in perinatal care remains to be determined.

Respiratory health and lung function in 8-year-old children of very low birth weight: a cohort study.

In comparison with a cohort of normal birth weight children, those of very low birth weight (less than 1501 g birth weight) had more wheezing illnesses and hospital readmissions for respiratory problems in the first 2 years of life; from 2 years to 8 years of age respiratory health was unrelated to birth weight. Lung function measurements at 8 years of age in very low birth weight children were similar to expected values; few children had severely abnormal lung function. On univariate analyses, forced vital capacity (FVC) and forced expired volume in 1 second (FEV1), but not flow rates, were lower in children who had survived bronchopulmonary dysplasia. However, the univariate analyses were misleading, because bronchopulmonary dysplasia occurred more frequently with lower birth weight, and lower birth weight in turn was strongly related to reduced FVC and FEV1. After adjusting for birth weight and other potential confounding variables, FVC and FEV1 were unrelated to bronchopulmonary dysplasia, and to neonatal ventilation. Flow rates were largely uninfluenced by perinatal events, but were reduced in children with asthma or recurrent bronchitis at 8 years of age. Passive smoking was unrelated to lung function at 8 years of age. However, the effects of passive or active smoking, or perinatal events, on respiratory function or health beyond 8 years of age in very low birth weight survivors remain to be determined.

Changing obstetric practice and 2-year outcome of the fetus of birth weight under 1000 g.

The aim of this study was to assess the outcome up to 2 years of age for the fetus of birth weight 500-999 g, over time and in association with changes in obstetric care. Two consecutive cohorts of infants of birth weight 500-999 g were compared from two eras, 1977-1982 and 1985-1987, and their outcome up to 2 years of age was determined with particular emphasis on the effect of various obstetric interventions at the time of birth, such as cesarean delivery, electronic fetal monitoring, antenatal steroid therapy, and tocolytic therapy. The outcome to 2 years was analyzed by logistic function regression to adjust for imbalances in confounding perinatal variables. In the latter era, the survival rate to 2 years increased significantly by almost 50%, and only 7% of the survivors were severely disabled. The rates of delivery by cesarean and of electronic fetal monitoring both increased significantly in the latter era, but neither was associated with the improved outcome. The only variable associated with an improved outcome that was amenable to obstetric intervention at the time of birth was antenatal steroid therapy, which was used equally in both eras. The obstetrician may aid the fetus of birth weight 500-999 g by giving the mother steroids to accelerate fetal lung maturity, but cesarean cannot be recommended as the routine mode of delivery unless there are recognized maternal or fetal indications.

Very low birth weight and growth to age 8 years. I: Weight and height.

We determined the heights and weights at ages 2, 5, and 8 years for the following three cohorts of children: group 1 with birth weights between 500 and 999 g; group 2 with birth weights between 1000 and 1499 g; and group 3 with birth weights more than 2500 g. By age 8 years, group 3 children were significantly heavier and taller than all children in groups 1 and 2 combined; group 1 children were significantly shorter than those in group 2, but their weights were similar. From ages 2 to 5 years, annual increments in weight and height were similar in all three groups; however, between ages 5 and 8 years, children in group 3 grew faster than those in groups 1 and 2 combined, and children in group 1 had smaller height increments than those in group 2. Of children with birth weights less than 1500 g, with a weight or height under the 10th percentile at age 2 years, only approximately one half were still below the 10th percentile for the corresponding measurement at age 8 years. Health variables determined before birth, such as maternal height or birth weight ratio, were more important than health after birth in predicting a height or weight below the 10th percentile at age 8 years in children with birth weights less than 1500 g.

Very low birth weight and growth to age 8 years. II: Head dimensions and intelligence.

The occipitofrontal circumference was measured in all available children in the following cohorts at ages 2, 5, and 8 years: group 1, consisting of 79 children with birth weight between 500 and 999 g; group 2, with 111 children with birth weight between 1000 and 1499 g; and group 3 with 56 children with birth weight greater than 2500 g; all were white with no signs of moderate or severe cerebral palsy. National Center for Health Statistics reference values indicated substantially more children with an occipitofrontal circumference lower than the 10th percentile, particularly at age 2 years, compared with Nellhaus reference data. Occipitofrontal circumference was the head measurement best correlated with the Full Scale IQ on the Wechsler Intelligence Scale for Children-Revised. Dolichocephaly, often seen in very-low-birth-weight children was unrelated to IQ, and correction of occipitofrontal circumference for dolichocephaly was rarely of clinical importance.

Survivors of extreme prematurity--outcome at 8 years of age.

Of 149 infants liveborn in a large maternity hospital in 1980 to 1982 and delivered between 24 and 29 completed weeks of gestation inclusive, 91 (61%) survived; 88 (97%) survivors were assessed at 8 years' corrected age; 77% of children were not disabled; disability was mild in 13%, moderate in 2% and severe in 4% of children. Although survival decreased with decreasing gestation, disability in survivors did not increase. An earlier assessment of the same children at approximately 2 years of age had been unduly pessimistic particularly for those born less than or equal to 26 weeks' gestation. The only other reports in the literature on outcome by gestation have all assessed the children in early childhood, and estimates of severe disability rates from these studies will probably also be too pessimistic. Since the rate of severe disabilities in infants of borderline viability is not much higher than in more mature infants the obstetrician should mainly consider survival chances for the fetus, and not be overly concerned with long-term neurological outcome, when making clinical decisions.

Inguinal hernia in very low birthweight children: a continuing risk to age 8 years.

The prevalence of inguinal hernia repair up to 8 years of age was determined in 205 inborn children of birthweight less than 1500 g who had survived to the age of 8 years; 37 (18.0%) of the children required surgery for inguinal hernia, significantly more frequently for boys than girls (32.0% and 3.9% respectively). The cumulative percentage of inguinal hernia operations in boys was 8.7% during primary hospitalization, 20.4% by 2 years, 30.1% by 5 years and 32.0% by 8 years; 36.4% (12 of 33) hernias in boys occurred beyond 2 years of age. The risk of hernia in boys was only marginally higher in those who required assisted ventilation and in those of birthweight less than 1000 g. Very low birthweight infants, particularly boys, are at risk of developing an inguinal hernia not only in infancy but also to at least 8 years of age.

Changing two-year outcome of infants weighing 500 to 999 grams at birth: a hospital study.

Survival and neurodevelopmental outcome to 2 years were determined for two cohorts of infants weighing 500 to 999 gm at birth, born in a tertiary maternity hospital. Live births increased over time from an annual average of 48.7 in the first era (January 1977 to March 1982) to 64.6 in the second era (January 1985 to December 1987), largely from referrals of additional mothers with pregnancy complications. In the first era, 33.6% (86/256) of infants survived to 2 years; the survival rate improved significantly to 45.9% (89/194) in era 2. After adjustment for birth weight, the odds ratio for survival in era 2 versus era 1 was 1.39 (95% confidence interval = 1.12, 1.73; p less than 0.01). One known survivor in each era was not seen at 2 years of age. In the first era, 59.3% (51/86) of 2-year-old children were free of disability compared with 68.5% (61/89) in era 2 (NS), but the Mental Development Index of the Bayley Scales improved significantly, from 90.0 in era 1 to 98.0 in era 2. For infants weighing less than 800 gm at birth, not only did the 2-year survival rate improve, adjusted for birth weight (odds ratio = 1.53; 95% confidence interval = 1.06, 2.20; p less than 0.05), but there was also a significant reduction in neurologic disabilities in survivors (p = 0.03). For infants weighing 800 to 999 gm at birth, there was a significant improvement in the survival rate, adjusted for birth weight (odds ratio = 1.37; 95% confidence interval = 1.04, 1.79; p less than 0.05), but the rate of neurologic disabilities was unchanged. Increased survival in our tertiary maternity center was achieved without increasing the annual number of severely disabled 2-year-old survivors.

Outcome to 8 years of infants less than 1000 g birthweight: relationship with neonatal ventilator and oxygen therapy.

The study involved a cohort of 59 consecutive survivors with birthweights less than 1000 g, born between 1977 and 1980, to 8 years of age. The aim of the report was to determine if those survivors who had received more oxygen and ventilator therapy differed in their outcome compared with those who had received less oxygen and ventilation. Children were graded into four groups, characterized by decreasing durations of oxygen and ventilation. Children who had received less oxygen and ventilation were more likely to be below the third percentile for weight at 2, 5 and 8 years but the trends were significant only at 2 and 5 years (P = 0.006, P = 0.013 and P = 0.19 respectively). The rate of cerebral palsy was 8% at 8 years; the only children with severe or moderate disabilities from their cerebral palsy were in the lowest oxygen and ventilation group (n = 4, P less than 0.02). The frequency of hospital re-admission and the duration of re-hospitalization did not vary significantly between the four groups at any age. The rates of recurrent wheezing episodes or asthma did not vary significantly between the groups. Although the cohort as a whole had some impairment of lung function compared with healthy full-term controls, there was no significant difference between the four groups. Contrary to expectations, our findings suggest lower rates of poor growth and adverse neurological outcomes with increasing durations of oxygen and ventilation in the newborn period.

Changing diagnosis of cerebral palsy in very low birthweight children.

The stability of the diagnosis of cerebral palsy from 2 to 5 years of age was examined in 83 children of birthweight under 1000 gm, and 112 of birthweight 1000 to 1500 gm. In 20 2-year-old children with cerebral palsy, the diagnosis persisted in 11 (55%, 95% confidence intervals 35.1 to 76.9%); 2 of 175 children (1.1%) free of cerebral palsy at 2 years of age subsequently developed the condition. Severe or moderate cerebral palsy at 2 years persisted in all eight children (100%). In 9 of 12 children in whom cerebral palsy at 2 years had disappeared by 5 years, minor neurologic abnormalities and left-hand preference occurred frequently but mean psychologic tests scores were similar to children always free of cerebral palsy. In this cohort, cerebral palsy at 2 years was not a static condition, but overestimated later prevalence.

Methods of delivery and resuscitation of very-low-birthweight infants in Victoria: 1982-1985.

This article describes the patterns of delivery and resuscitation for very-low-birthweight infants who were born in Victoria from 1982 to 1985. Caesarean delivery rates increased from 15% to 30% for infants of birthweights of 500-999 g, and from 39% to 52% for infants of birthweights of 1000-1499 g. In level-III hospitals, the proportion of live-born infants who did not receive active resuscitation fell from 32% to 18% for those who weighed 500-999 g, and from 28% to 15% for those who weighed 1000-1499 g. Time trends over the four years showed the management of very-low-birthweight infants to be in a state of rapid transition in all birth settings. At the same time there was a fall in the still-birth rate of infants of birthweights of 500-999 g. Still-births rates for infants of birthweights of 1000-1499 g remained unchanged, as did neonatal mortality rates in both weight groups.

Health and hospital readmissions of very-low-birth-weight and normal-birth-weight children.

Rehospitalizations and ongoing health problems at 5 years of age were contrasted between 197 very-low-birth-weight (VLBW) children and 47 normal-birth-weight children. At 5 years of age, the VLBW children had a mean of 1.7 hospital admissions and 8.5 days in a hospital; these means were significantly more than the 0.5 admissions and 1.7 days, respectively, for the normal-birth-weight children. Overall, respiratory tract problems and ear, nose, and throat surgery were the most common reasons for readmissions. Malformations and intensive care sequelae infrequently caused readmissions. No combination of sociodemographic or perinatal variables identified the VLBW children who were destined for hospital readmissions. At 5 years of age, the VLBW children, compared with the normal-birth-weight children, had significantly more ongoing sensorineural problems (29.9% and 10.6%, respectively), ongoing respiratory problems (39.6% and 19.1%, respectively), and other morbidities (31.0% and 17.0%, respectively). The VLBW children, compared with the normal-birth-weight children, had more hospital admissions during the first 5 years of life and more ongoing problems at 5 years of age.

Five-year outcome of infants of birthweight 500 to 1500 grams: relationship with neonatal ultrasound data.

Of 154 consecutive survivors of birthweight 500 to 1500 gm, 139 (90.3%) were seen at 5 years of age, corrected for prematurity, and 137 (89%) were able to be fully assessed by both the psychologist and pediatrician. All but two children had had serial cranial ultrasonography with a linear array real-time scanner in the neonatal period. At 5 years, of 39 children with cerebral ultrasound abnormalities detected during their primary hospitalization, seven (17.9%) had cerebral palsy, but 32 (82.1%) did not. A further three children with cerebral palsy at 5 years had had no cerebral abnormalities on ultrasound. Of the cerebral abnormalities diagnosed by ultrasound, ventricular dilation, with or without cerebroventricular hemorrhage, had the highest positive predictive value (40%) for cerebral palsy at 5 years. In the 127 children free from cerebral palsy at 5 years, two (1.6%) had severe intellectual impairment, both of whom had had normal cerebral ultrasonography. Although neonatal cranial ultrasonography with a linear array was somewhat predictive of cerebral palsy at 5 years, the majority of infants with abnormal scans had no severe sensorineural impairments at 5 years.

Selective improvement in cognitive test scores of extremely low birthweight infants aged between 2 and 5 years.

The cognitive development at 2 and 5 years of a cohort of extremely low birthweight (ELBW) children (birthweight 500-999 g) was compared with that of cohorts of larger very low birthweight (VLBW) children (birthweight 1000-1500 g) and normal birthweight (NBW) children (birthweight greater than 2500 g) to determine whether the improvements in cognitive function of ELBW infants between 2 and 5 years are apparent or real. At 2 years of age, ELBW children had a mean Mental Developmental Index (MDI) on the Bayley Scales of 90.4, significantly lower than the means of 100.3 for the larger VLBW children (P = 0.006), and 107.8 for the NBW children (P = 0.0002). However by 5 years the mean scores on the Wechsler Preschool and Primary Scales of Intelligence (WPPSI) full-scale for the ELBW and larger VLBW children were virtually identical (105.9 and 106.0 respectively)--but still lower than the mean WPPSI full-scale of 114.6 for the NBW children. After standardizing the MDI and WPPSI scores relative to the NBW children, the ELBW children improved between 2 and 5 years (paired t-test, t = 3.2, P = 0.004) whereas the larger VLBW infants did not. We postulate that ELBW children require more time than larger VLBW children after birth to compensate for perinatal and other stresses, and that developmental delay at 2 years may not always persist to 5 years.