Longitudinal growth of hospitalized very low birth weight infants.

BACKGROUND: The interpretation of growth rates for very low birth weight infants is obscured by limited data, recent changes in perinatal care, and the uncertain effects of multiple therapies. OBJECTIVES: To develop contemporary postnatal growth curves for very low birth weight preterm infants and to relate growth velocity to birth weight, nutritional practices, fetal growth status (small- or appropriate-for-gestational-age), and major neonatal morbidities (chronic lung disease, nosocomial infection or late-onset infection, severe intraventricular hemorrhage, and necrotizing enterocolitis). DESIGN: Large, multicenter, prospective cohort study. METHODS: Growth was prospectively assessed for 1660 infants with birth weights between 501 to 1500 g admitted by 24 hours of age to 1 of the 12 National Institute of Child Health and Human Development Neonatal Research Network centers between August 31, 1994 and August 9, 1995. Infants were included if they survived >7 days (168 hours) and were free of major congenital anomalies. Anthropometric measures (body weight, length, head circumference, and midarm circumference) were performed from birth until discharge, transfer, death, age 120 days, or a body weight of 2000 g. To obtain representative data, nutritional practices were not altered by the study protocol. RESULTS: Postnatal growth curves suitable for clinical and research use were constructed for body weight, length, head circumference, and midarm circumference. Once birth weight was regained, weight gain (14.4-16.1 g/kg/d) approximated intrauterine rates. However, at hospital discharge, most infants born between 24 and 29 weeks of gestation had not achieved the median birth weight of the reference fetus at the same postmenstrual age. Gestational age, race, and gender had no effect on growth within 100-g birth weight strata. Appropriate-for-gestational age infants who survived to hospital discharge without developing chronic lung disease, severe intraventricular hemorrhage, necrotizing enterocolitis, or late onset-sepsis gained weight faster than comparable infants with those morbidities. More rapid weight gain was also associated with a shorter duration of parenteral nutrition providing at least 75% of the total daily fluid volume, an earlier age at the initiation of enteral feedings, and an earlier age at achievement of full enteral feedings. CONCLUSIONS: These growth curves may be used to better understand postnatal growth, to help identify infants developing illnesses affecting growth, and to aid in the design of future research. They should not be taken as optimal. Randomized clinical trials should be performed to evaluate whether different nutritional management practices will permit birth weight to be regained earlier and result in more rapid growth, more appropriate body composition, and improved short- and long-term outcomes.

Incidence and timing of germinal matrix/intraventricular hemorrhage in low birth weight infants.

Incidence and time of onset of germinal matrix/intraventricular hemorrhage (GM/IVH) were prospectively ascertained in 1,105 infants weighing < or = 2,000 g at birth, a cohort comprising about 85% of all births of that weight born from September 1984 to June 1987 in the central New Jersey counties of Ocean, Monmouth, and Middlesex. Cranial ultrasonography was performed as nearly as possible to age 4 hours, 24 hours, and 7 days. Each scan was reviewed by two independent readers and, if necessary, a third; consensus was achieved on scan of first diagnosis of GM/IVH in 965 of the 1,079 infants with assessable scans. The cumulative incidence of GM/IVH in the first week of life was 24.6% (265/1,079). In the 965 infants with consensus diagnoses, the first scan, at 4.9 +/- 2.2 hours, yielded the highest incidence--10.6% (95/899). Incidence by the second scan (25.1 +/- 4.9 hours) was 6.0% (49/813), and by the third scan (7.2 +/- 0.8 days), 9.0% (64/715). The iterative algorithm for interval-censored data developed by Turnbull (J R Stat Soc [B] 1976;8:290-5) was used to estimate the most likely time of onset based on time of first diagnosis. From 34% to 44% of hemorrhages were present at the first opportunity to scan, which in these data was at age 1 hour. At least a third of GM/IVH in infants < or = 2,000 g appears to be of congenital or immediate postnatal onset.

The central New Jersey neonatal brain haemorrhage study: design of the study and reliability of ultrasound diagnosis.

Over a 34-month period, 1105 newborns weighing between 501 and 2000 g at birth were enrolled in a prospective study of the aetiology and consequences of neonatal brain haemorrhage. The three participating hospitals care for approximately 85% of births in the study weight range in Middlesex, Monmouth and Ocean counties, New Jersey. Cranial ultrasonographic imaging through the anterior fontanelle was carried out a mean age of 4.9 +/- 2.2 hours, 25.5 +/- 4.8 hours and 7.2 +/- 0.8 days to detect haemorrhage and other brain lesions. In 93.2% of study infants, scans were read by two independent expert readers (blind to the clinical status of the child) with submission of the scan to a third reader in cases of disagreement. Confirmation of both presence or absence and, when present, scan of first diagnosis of germinal matrix and/or intraventricular haemorrhage (GM/IVH) by two independent readers was achieved in 76.3% of study infants. The first two readers agreed as to presence or absence of GM/IVH in 82.4% of infants (Kappa = 0.56). Interobserver agreement was affected by the reported scan quality and by the number of scans available, but not by the hospital of origin, race or birthweight of the infant.