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.

Substrate disposal in metabolic disease: a comparison between rates of in vivo propionate oxidation and urinary metabolite excretion in children with methylmalonic acidemia.

The relative importance of endogenous metabolism and urinary metabolite excretion was assessed in vivo in six children with methylmalonic acidemia by examining the kinetics of the immediate precursor to methylmalonate, propionate. Total production and oxidation of propionate were measured by means of a continuous infusion of (1-13C)propionate and were compared with the urinary excretion of propionate metabolites. Propionate oxidation was substantial (mean 48.9 mumol/kg/hr +/- SD 18.0) and, in four children, exceeded urinary metabolite excretion (mean urinary excretion in all subjects 40 mumol/kg/hr +/- 25). The sum of urinary excretion and oxidation rates (88 mumol/kg/hr +/- 29) approximated the total propionate production (93.4 +/- 37.0), suggesting that these routes together constitute the major mechanisms of propionate disposal. These results suggest that propionate oxidation is an important route of disposal in methylmalonic acidemia. Variations in the relative proportions of propionate disposal through oxidation and urinary excretion may be one reason for the often poor correlation between clinical status and urinary metabolite excretion. Measurement of urinary metabolite concentration alone may not always reflect clinical status and responses to treatment accurately.

Outcome in infants of birth weight 500 to 999 g: a continuing regional study of 5-year-old survivors.

During 1979 and 1980, 351 infants of birth weight 500 to 999 g were born in the State of Victoria: 89 (25.4%) survived to the age of 2 years corrected for prematurity, and 83 were fully assessed by a multidisciplinary team; partial data were obtained on the remainder. At the age of 5 years, corrected for prematurity, 85/89 (96%) were evaluated by a multidisciplinary team, although not all children could be fully evaluated by the psychologists. Reports were available for another three children; one child was untraced. Of the survivors able to be classified at 5 years, 59/82 (72%) had no functional handicap. Functional handicaps was severe in 16 (19%), moderate in four (5%), and mild in three (4%). Functional handicaps were present in 50% (8/16) of outborn survivors compared with the 23% (15/66) for the inborn survivors (P = 0.02). Cerebral palsy was diagnosed in eight children at 5 years and in 12 children at 2 years. The diagnosis was stable for the children not ambulant at 2 years; five of seven 2-year-old children with mild cerebral palsy had "outgrown" the diagnosis by 5 years, but ataxic cerebral palsy was not identified in one child until 5 years. Six children were blind; four had severe sensorineural or mixed deafness, one more than at 2 years. Of 82 children assessed according to identical criteria for functional handicap at both 2 and 5 years, 52 (63%) remained in the same category at 5 years, three (4%) were judged to be more severely handicapped, and 27 (33%) were less severely handicapped. The 2-year evaluation of extremely low birth weight children often proved to be unduly pessimistic, for many showed improvement or recovery from functional handicaps and impairments by 5 years of age.

Children of birth weight less than 1000 g: changing outcome between ages 2 and 5 years.

Of 55 consecutive long-term survivors of birth weight 500 to 999 g, complete psychologic and pediatric data were available for 54 children at 2 years corrected age and for 50 at age at least 5 1/2 years. At the latter age, 60% (30 of 50) were not impaired, 10% (five of 50) had severe sensorineural or intellectual impairments, 10% (five of 50) had mild to moderately impairment, and 20% (10 of 50) had minor neurobehavioural abnormalities. Sensorineural deafness in one child and bilateral blindness in one remained stable over time, but of six children with spastic cerebral palsy at 2 years, only three retained this diagnosis at 5 1/2 years. The mean Mental Developmental Index (MDI) on the Bayley Scales at 2 years was 91.1, significantly below the test mean; by 5 1/2 years the mean full scale of the Wechsler Preschool and Primary Scales of Intelligence (WPPSI) was 101.8. The MDI correlated highly with the full-scale WPPSI (r = 0.7), but for individual children it was not always an accurate predictor of 5-year ability. Between 2 and 5 1/2 years there was a substantial reordering within four categories of impairment: findings in 27 children were improved, four were judged to become more severely impaired over time, and 19 did not change. We conclude that our 2-year assessment often underrated the potential of the children as expressed at 5 1/2 years, and that 2 years is too early for reliable classification of children of birth weight 500 to 999 g.

Effects of antenatal steroid therapy on mortality and morbidity in very low birth weight infants.

A cohort of 678 consecutive very low birth weight infants, liveborn in one tertiary institution during a 63-month period, was studied to investigate whether antenatal steroid therapy had any beneficial or harmful effects on mortality or morbidity over the first 2 years of life. Comparing the 244 babies who received treatment with the 434 controls, 195 (79.9%) and 265 (61.1%), respectively, were discharged home (P less than 0.001). Mortality in the treated group remained substantially lower and was almost halved after adjustment for birth weight, extreme immaturity, lethal malformations, and confounding obstetric variables (P = 0.001). Fatal cases of respiratory distress syndrome were less common in the treated group (P = 0.044). Of in-hospital survivors, those in the treated group required less positive pressure respiratory support (P = 0.003) and fewer days in oxygen (P = 0.018), and the incidences of bronchopulmonary dysplasia (P = 0.003) and patent ductus arteriosus (P = 0.002) were lower. Two-year survivors who had received treatment were heavier (P = 0.016) and had larger head circumferences (P = 0.029). These beneficial associations in the treated group were not at the expense of increased rates of infection or adverse neurologic outcome. We did not detect any adverse effects of antenatal steroid therapy on any relevant aspect of mortality or morbidity in infancy under circumstances in which the chances of finding substantial differences were high.

Outcome in infants with birth weight 500 to 999 gm: a regional study of 1979 and 1980 births.

During 1979 and 1980, 351 infants weighing 500 to 999 gm were born in the State of Victoria, Australia; 89 (25.4%) survived to 2 years of age. Survival was better for tertiary center births (29%) than for those born elsewhere (17%). Multidisciplinary teams reviewed 83 of the survivors at 2 years of age postterm; some data were available for the other six children. Overall, 22.5% of infants had severe functional handicap, 29.2% had either moderate or mild handicap, and 48.3% had no handicap. Severe functional handicap was present in 50% of outborn infants; this was significantly more common than in those born in tertiary centers (15.5%), and the Bayley Mental Developmental Index was also significantly lower in outborn infants. The prevalence of cerebral palsy (13.5%), bilateral blindness (3.4%), and severe sensorineural deafness (3.4%) did not differ significantly in the inborn and outborn infants. Singleton inborn infants of appropriate weight for gestational age had significantly less severe functional handicap (9.1%), compared with 37.5% for the group of infants who were either small for gestational age or one of multiple births. Six of the 18 outborn infants could have been transferred in utero, and improvements in immediate neonatal care were possible in seven other infants.