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

Risk of neurodevelopmental impairment for outborn extremely preterm infants in an Australian regional network

OBJECTIVE

To compare neurodevelopmental outcomes at 2-3 years in extremely premature outborn and inborn infants.

DESIGN

Population-based retrospective cohort study.

SETTING

Geographically defined area of New South Wales (NSW) and the Australian Capital Territory (ACT) served by a network of 10 neonatal intensive care units (NICUs).

PATIENTS

All premature infants <29 weeks gestation born between 1998 and 2004 in the setting.

INTERVENTION

At 2-3 years, corrected age, 1473 children were assessed with either the Griffiths Mental Developmental Scales (GMDS) or the Bayley Scales of Infant Development (BSID-II).

MAIN OUTCOME MEASURE

Moderate/severe functional disability (FD) defined as: developmental delay (GMDS general quotient (GQ) or BSID-II mental developmental index (MDI)) > 2 standard deviations (SD) below the mean; cerebral palsy (CP) requiring aids; sensorineural or conductive deafness (requiring amplification); or bilateral blindness (visual acuity <6/60 in better eye).

RESULTS

At 2-3 years, moderate/severe functional disability does not appear to be significantly different between outborn and inborn infants (adjusted OR 0.782; 95% CI 0.424-1.443). However, there were a significant number of outborn infants lost to follow up (23.3% versus 42.9%).

CONCLUSION

In this cohort, at 2-3 years follow up neurodevelopmental outcome does not appear to be significantly different between outborn and inborn infants. These results should be interpreted with caution given the limitation of this study.

The impact of low birth weight, perinatal conditions, and sociodemographic factors on educational outcome in kindergarten

OBJECTIVE

To assess the relative effects and the impact of perinatal and sociodemographic risk factors on long-term morbidity within a total birth population in Florida.

METHODS

School records for 339 171 children entering kindergarten in Florida public schools in the 1992-1993, 1993-1994, or 1994-1995 academic years were matched with Florida birth records from 1985 to 1990. Effects on long-term morbidity were assessed through a multivariate analysis of an educational outcome variable, defined as placement into 9 mutually exclusive categories in kindergarten. Of those categories, 7 were special education (SE) classifications determined by statewide standardized eligibility criteria, 1 was academic problems, and the reference category was regular classroom. Generalized logistic regression was used to simultaneously estimate the odds of placement in SE and academic problems. The impact of all risk factors was assessed via estimated attributable excess/deficit numbers, based on the multivariate analysis.

RESULTS

Educational outcome was significantly influenced by both perinatal and sociodemographic factors. Perinatal factors had greater adverse effects on the most severe SE types, with birth weight <1000 g having the greatest effect. Sociodemographic predictors had greater effects on the mild educational disabilities. Because of their greater prevalence, the impact attributable to each of the factors (poverty, male gender, low maternal education, or non-white race) was between 5 and 10 times greater than that of low birth weight and >10 times greater than that of very low birth weight, presence of a congenital anomaly, or prenatal care.

CONCLUSIONS

Results are consistent with the hypothesis that adverse perinatal conditions result in severe educational disabilities, whereas less severe outcomes are influenced by sociodemographic factors. Overall, sociodemographic factors have a greater total impact on adverse educational outcomes than perinatal factors.

Educational disabilities of neonatal intensive care graduates

OBJECTIVE

To determine the relationship between perinatal and sociodemographic factors in low birth weight and sick infants hospitalized at regional neonatal intensive care units (NICUs) and subsequent educational disabilities.

METHOD

NICU graduates born between 1980 and 1987 at nine statewide regionalized level III centers were located in Florida elementary schools (kindergarten through third grade) during academic year 1992-1993 (n = 9943). Educational disability was operationalized as placement into eight mutually exclusive types of special education (SE) classifications determined by statewide standardized eligibility criteria: physically impaired, sensory impaired (SI), profoundly mentally handicapped, trainable mentally handicapped, educable mentally handicapped, specific learning disabilities, emotionally handicapped, and speech and language impaired (SLI). Logistic regression was used to estimate the odds of placement in SE for selected perinatal and sociodemographic variables.

RESULTS

Placement into SE ranged from .8% for SI to 9.9% for SLI. Placement was related to four perinatal factors (birth weight, transport, medical conditions [congenital anomalies, seizures or intraventricular hemorrhage] and ventilation), and five sociodemographic factors (child's sex, mother's marital status, mother's race, mother's educational level, and family income). Perinatal factors primarily were associated with placement in physically impaired, SI, profoundly mentally handicapped, and trainable mentally handicapped. Perinatal and sociodemographic factors both were associated with placement in educable mentally handicapped and specific learning disabilities whereas sociodemographic factors primarily were associated with placement in emotionally handicapped and SLI.

CONCLUSIONS

Educational disabilities of NICU graduates are influenced differently by perinatal and sociodemographic variables. Researchers must take into account both sets of these variables to ascertain the long-term risk of educational disability for NICU graduates. Birth weight alone should not be used to assess NICU morbidity outcomes.

Very low birthweight boys at the age of 19

Using linked data from the Swedish Medical Birth Registry and the National Service Enrollment Register, long term follow up (to 18-19 years age) was made of 260 surviving singleton boys whose birthweight was less than 1500 g from a total of 150 229 boys born between 1973-5. These boys were shorter and lighter than boys who weighed more at birth, they had more visual and hearing impairments, were at much higher risk of cerebral palsy and other signs of mental impairment, evident as lower intelligence test scores and shorter schooling. No significant excess of asthma, back problems, or headaches were found.

A follow-up study of infants < or = 2000 g birthweight treated in central Queensland

OBJECTIVE

This follow-up study was undertaken in an effort to ascertain the morbidity in the survivors of infants < or = 2000 g birthweight cared for in the two Rockhampton intensive care nurseries.

METHODOLOGY

The records of all infants < or = 2000 g delivered in or transferred to Rockhampton during the 11 year period 1979 through 1989 inclusive were extracted. Efforts were made to contact and examine all of these children. Those found to be disabled were assessed as being mildly, moderately or severely affected.

RESULTS

Of the 482 infants of birthweight < or = 2000 g treated in the period under review, 393 survived to be discharged from hospital. Eight were known to have died subsequently. Of the remaining 385 children, 288 (74.8%) were able to be contacted and their health status determined. A total of 36 infants were found to have significant disabilities. Twenty-four were mildly affected, five moderately and seven severely affected. Severe disability in infants of < or = 1000 g was 16% (3/19).

CONCLUSIONS

The incidence of disability was established in 74.8% of the surviving population. It was not dissimilar to the incidence of disability in similar birthweight groups in some Australian tertiary centres for the years under study. It is emphasized that the follow-up was incomplete and recognized that the survival rates and incidence of disability in survivors has improved in tertiary centres since the time frame of this study.

Developmental patterns of heart rate and variability in prematurely-born infants with apnea of prematurity

At equivalent post-conceptional ages, prematurely-born infants have higher heart rates and reduced heart rate variability, relative to full-term neonates. Premature birth might exert long-lasting effects on central and peripheral mechanisms that control cardiovascular activity. We assessed development of heart rate and heart rate variability in symptomatic preterm infants up to 6 months of age. Fifty 6.5-h evening recordings of EKG and breathing were obtained from prematurely-born infants (gestational ages: 24-35 weeks). Cardiac R-R intervals were captured with a resolution of +/- 0.5 msec. One-min epochs were selected from three periods of regular respiration in recordings from premature infants and 72 recordings of full-term infants at comparable post-conceptional ages. Mean heart rate and heart rate variability were determined for each recording. At 40 weeks post-conception, prematurely-born infants with apnea of prematurity showed higher heart rates and reduced heart rate variability than did full-term neonates. These differences between premature and full-term infants persisted throughout the next 6 months in those infants born prior to 30 weeks gestation, and in those infants born at 30-35 weeks who experienced respiratory distress syndrome (RDS) during the neonatal period. The findings suggest that premature delivery, or complications thereof, exerts long-lasting effects on cardiac control.

Advances in neonatology. View from a practicing pediatrician

After reviewing the many problems that may be seen by the physician in follow-up care of the preterm infant and family, it is important to take a step back and evaluate the infant as a whole. In the vast majority of instances, the preterm infant will turn out to be normal. In an unfortunate minority, there may be difficult problems that the baby, parents, and caretakers must face. The pediatrician must remain diligent to attend to those problems that are correctable and to assist patients to their full potential.

Long-term outcome of infants born preterm

This chapter outlines some of the many long-term health problems to be expected in surviving preterm children. They have higher rates of sensorineural impairments (such as cerebral palsy, and visual, auditory and intellectual impairments) and sensorineural disabilities from these impairments, than children born at term. In addition, they grow poorly and have higher rates of other health problems, including poorer respiratory health in early childhood. There is little doubt that preterm children contribute disproportionately to the prevalence of health problems in childhood. However, there are still many gaps in our knowledge of the outcome for preterm survivors, particularly regarding outcome in adulthood. Obstetricians and neonatologists working in intensive care, as well as parents, want to know the long-term outcome for preterm children born today, not that of children born a generation ago when fewer preterm children (particularly those of extremely low birthweight) survived. Despite the many problems, the conclusion is that most preterm children are as healthy as term children, suffering only usual childhood illnesses; we feel confident that the majority make, and will continue to make, useful contributions to their families and the societies in which they live.