Very low birthweight and normal birthweight infants. A comparison of continuing morbidity

Health and hospitalistions after discharge in extremely low birth weight infants

Apart from higher rates of mortality and adverse neurosensory outcome, extremely low birth weight (ELBW, birth weight 500-999 g) children have more hospital readmissions and other health problems in the early years after discharge than do normal birth weight (NBW, birth weight >2499 g) children. Respiratory illnesses, including lower respiratory infections, are the dominant cause for hospital readmission. ELBW survivors with bronchopulmonary dysplasia (BPD) have even more ill-health and hospital readmissions than do ELBW survivors without BPD. ELBW survivors require closer surveillance after discharge, not only for adverse neurosensory outcome, but also for other general health problems in early childhood.

Human milk reduces outpatient upper respiratory symptoms in premature infants during their first year of life

OBJECTIVE

To determine if ingestion of human milk after discharge reduces symptoms of infections in premature infants.

STUDY DESIGN

Follow-up of 39 infants with birth weights <2000 g, 24 of whom received any amount of human milk and 15 of whom received only formula after discharge, was carried out. Mothers were given a calendar on which they recorded any signs of infections and feeding and day-care information. Data were collected at 1 month after discharge and at 3, 7, and 12 months corrected age.

RESULTS

Results show no differences between groups in birth weight, gestation, gender, maternal age, parental tobacco use, number of siblings, and day-care attendance. Socioeconomic status score was higher in the human milk group. Infants who received human milk had fewer days of upper respiratory symptoms at 1 month after discharge (p<0.025) and at 7 months corrected age (p<0.025).

CONCLUSION

Ingestion of human milk post discharge is associated with a reduction of upper respiratory symptoms in premature infants during their first year of life.

Outcome at 14 years of extremely low birthweight infants: a regional study

OBJECTIVES

To determine the neurosensory outcome at 14 years of age of a regional cohort of extremely low birthweight (ELBW) children, to contrast their prognosis with normal birthweight (NBW) controls, and to determine the predictive value of assessments earlier in childhood.

DESIGN

Geographically determined cohort study.

SETTING

The state of Victoria, Australia.

PATIENTS

Consecutive ELBW survivors of birth weight 500-999 g (n = 88) born during 1979-1980, and 60 randomly selected contemporaneous NBW (birth weight > 2499 g) controls.

MAIN OUTCOME MEASURES

Rates of neurosensory impairments and disabilities at 14 years of age, and earlier in childhood.

RESULTS

Of 351 ELBW consecutive live births, 88 (25%) survived and 79 (90%) of the survivors were assessed at 14 years of age. Of the 79 ELBW children assessed, eight (10%) had cerebral palsy, five (6%) had bilateral blindness, four (5%) were deaf requiring hearing aids, and 36 (46%) had an intelligence quotient (IQ) < -1 SD compared with the mean for the NBW controls. Overall 11 (14%) ELBW children were severely disabled, 12 (15%) were moderately disabled, 20 (25%) were mildly disabled, and 36 (46%) had no disability. In contrast, only one (2%) of 42 NBW children assessed had a severe disability, six (14%) had a mild disability, and the remaining 35 (83%) were not disabled. Comparing psychological test scores for ELBW children with those for NBW controls, rather than test norms, avoided bias in the assessment of disability earlier in childhood. Relative to assessments earlier in childhood, the prediction of disability at 14 years of age was highly significant at each of 2, 5, and 8 years of age, but the accuracy progressively increased with age.

CONCLUSIONS

ELBW children have substantially higher rates of neurosensory impairments and disabilities at 14 years of age than NBW controls. Comparison of ELBW children with NBW controls avoids bias in the assessment of disability. Early childhood assessments are highly predictive of disability at 14 years of age.

Very low birthweight and asthma by age seven years in a national cohort

Several studies have suggested that very low birthweight (VLBW < 1500 g) is associated with increased rates of respiratory problems in childhood and that the presence of chronic lung disease further increases the risk. We aimed to assess rates of asthma at 7-8 years of age in a national cohort of VLBW infants born in 1986 and for whom perinatal data were available. Two hundred ninety-nine former VLBW children (96% of surviving children living in New Zealand) were assessed at a home visit. Parents were asked a comprehensive questionnaire, including three questions aimed at assessing morbidity from asthma: 1) was the child diagnosed as having asthma before age 7 years; 2) was the child still experiencing asthma at the age of 7 years; and 3) was the child prescribed daily medication for asthma at the age of 7 years. Overall, 50% of the cohort had been diagnosed with asthma before age 7, compared with 27% of a sample of New Zealand children assessed contemporaneously in an international study; 32% had asthma at age 7, and 11% were taking daily medication. All three categories of asthma were associated with a family history of asthma, but there was no association with any perinatal factors. A diagnosis of asthma before age 7 was more likely when the mother smoked in pregnancy (P < 0.005) and currently smoked (P < 0.01), and trended so when parents lacked high school qualifications and in Maori or Pacific Island families (P < 0.10). In contrast, daily medication was more frequent when parents had educational qualifications and in non-Maori or Pacific Island families (P < 0.05). On multiple logistic regression, a family history of asthma was a significant predictor for any and current asthma (P < 0.001) and daily medication (P < 0.05); maternal smoking in pregnancy was a significant predictor for any asthma (P < 0.05); and non-Maori or Pacific Island ethnicity was a significant predictor for asthma treatment (P < 0.05). We conclude that rates of childhood asthma are high in this VLBW cohort, but the high prevalence appears to be unrelated to perinatal factors, including respiratory morbidity. There are suggestions that social factors contribute to both asthma risk and treatment.

Hospital admissions in the first year of life in very preterm infants

OBJECTIVE

To analyse hospital readmissions to 1 year in infants < 33 weeks' gestation.

STUDY DESIGN

Cohort of very preterm infants born in Western Australia.

METHODS

Parental social class, history of asthma, race, gestational age, birthweight, sex, severity of respiratory disease and oxygen requirement at 28 days chronic lung disease (CLD), 36 weeks and term, maternal smoking, cohabitation with siblings, breast-feeding duration and hospital readmissions were recorded prospectively.

RESULTS

Data were available for 538 of 560 (96%) infants discharged. Eight died in the first year. Two hundred and twenty-five infants (42%) had 443 readmissions, of which 370 were medical and 73 surgical. Risk factors for medical readmission were Aboriginal race, male sex and CLD. Breast-feeding was protective. Risk factors for surgical admission were male sex, lower gestation, severe hyaline membrane disease, severe CLD and birthweight < 10th centile.

CONCLUSIONS

Readmission is common after very preterm birth. Risk factors for medical and surgical admission differ with CLD being the only perinatal factor associated with both medical and surgical admission.

Breastfeeding infants who were extremely low birth weight

OBJECTIVE

To compare the clinical effect of breastfeedings and bottle feedings in extremely low birth weight (ELBW) infants (birth weight </=800 g).

METHODS

A total of 12 ELBW infants (mean birth weight, 672 +/- 95 g; mean gestation, 26 +/- 2 weeks) served as their own controls in this prospective study comparing physiologic parameters during bottle and breastfeeding. The infants were put to breast the same week they began on bottle feedings of human milk or premature infant formula (mean gestation, 35 weeks). One breastfeeding and one bottle feeding were observed each day for 10 days. Pre- and postfeeding weights were measured, and oxygen saturation, respiratory rate, heart rate, and axillary temperature were monitored continuously and recorded every minute during feedings.

RESULTS

The infants demonstrated a higher oxygen saturation and a higher temperature during breastfeeding than during bottle feeding, and were less likely to desaturate to <90% oxygen during breastfeeding. Mean weight gain was greater during bottle feeding than during breastfeeding (31 vs 9 g).

CONCLUSIONS

Breastfeeding the ELBW infant is desirable from a standpoint of improved physiologic responses, but such practice requires breastfeeding support and possible supplementation to optimize weight gain.

Comparison of morbidities in very low birthweight and normal birthweight infants during the first year of life in a developing country

OBJECTIVE

To compare the morbidities in the very low birthweight (VLBW; < 1500 g) and normal birthweight (NBW; > or = 2500 g) Malaysian infants during the first year of life.

METHODOLOGY

Prospective observational cohort study of consecutive surviving VLBW infants and randomly sampled NBW infants born in the Kuala Lumpur Maternity Hospital between 1 December 1989 and 31 December 1992. Infants were followed up regularly during the first year of life, after correction for prematurity.

RESULTS

Compared with NBW infants (n = 106), VLBW infants (n = 127) had significantly higher risk of failure to thrive (odds ratio [OR] = 8.0, 95% confidence intervals [CI]: 1.1 to 354.3), wheezing (OR = 3.7, 95% CI: 1.6 to 9.3), rehospitalization (OR = 2.3, 95% CI: 1.1 to 5.0), cerebral palsy (OR = 8.6, 95% CI: 2.0 to 77.6), neurosensory hearing loss (OR = 12.0, 95% CI: 1.7 to 513.6) and visual loss (7.9 vs 0%, P = 0.002). The mean mental developmental index (MDI) and mean psychomotor developmental index (PDI) at 1 year of age were significantly lower among VLBW infants (MDI 99 [SD = 28], PDI 89 [SD = 25]) than NBW infants (MDI 106 [SD = 18], PDI 101 [SD = 18]) (95% CI for difference between means being MDI: -14.1 to -1.7; and PDI: -17.6 to -6.0). Logistic regression analysis showed that among VLBW infants: (i) male sex, Malay ethnicity and bronchopulmonary dysplasia were significant risk factors associated with wheezing; (ii) longer duration of oxygen therapy during the neonatal period, seizures after the post-neonatal period and wheezing were significant risk factors associated with rehospitalization; and (iii) longer duration of oxygen therapy during the neonatal period was a significant risk factor associated with adverse neurodevelopmental outcome during the first year of life.

CONCLUSIONS

Compared with NBW infants, VLBW Malaysian infants had significantly higher risks of physical and neuro-developmental morbidities.

Recurrent wheezing in very preterm infants

AIMS

To document the prevalence of, and identify risk factors for, recurrent wheezing treated with bronchodilators in the first year of life.

METHODS

Parental history and neonatal data were collected prospectively in a regional cohort of very preterm infants (< 33 weeks). Data on maternal smoking, siblings at home, breast feeding, respiratory symptoms, and hospital re-admissions were documented at 12 months.

RESULTS

Outcome data were available for 525/560 (95%) of survivors. The incidence of recurrent wheeze was 76/525 (14.5%) in very preterm infants and 20/657 (3%) in a cohort of term newborns. Significant risk factors for recurrent wheeze in very preterm infants were parental history of asthma, maternal smoking, siblings at home, neonatal oxygen supplementation at 28 days, 36, and 40 weeks of gestation.

CONCLUSIONS

Wheezing respiratory illnesses are common in very preterm infants. The factors involved are similar to those in more mature infants, with the addition of immaturity and neonatal lung injury.

Another outcome of neonatal intensive care: first year mortality and hospital morbidity

OBJECTIVE

To determine first year mortality and hospital morbidity after neonatal intensive care.

METHODOLOGY

Cohort study of 6077 surviving infants inborn in one regional hospital in 1988. Nine hundred and eighty-eight received neonatal intensive care and 103 were very low birthweight (VLBW).

RESULTS

For infants who required care in the neonatal intensive care unit (NICU), the relative risk of dying before their first birthday was 3.6 (95% confidence intervals [CI] 1.5-8.8). This increased risk was associated with low birthweight (LBW) rather than requirement for NICU care. Of all inborn survivors, 10.4% were readmitted to hospital in the first year and 2.4% more than once. The readmission rate was 20% for NICU survivors and 30% for VLBW infants. The risk of hospitalization was independently associated both with NICU admission (odds ratio 2.3, CI 1.9-2.9) and with VLBW (OR 1.8, CI 1.1-3.0). The NICU survivors also had multiple admissions and prolonged hospital stays.

CONCLUSIONS

Both low birthweight and neonatal illness requiring intensive care are important indicators of continuing medical vulnerability over the first year of life.

Rehospitalization and growth of infants with bronchopulmonary dysplasia: a matched control study

OBJECTIVE

To determine the risk of hospitalization and the growth during the first year of life in infants with bronchopulmonary dysplasia (BPD) and birthweight matched controls.

METHODOLOGY

The study population consists of 78 infants of 26 to 33 weeks gestation with BPD of whom 20 were discharged on home oxygen therapy. The 78 control infants were matched with the study infants for broad based birthweight categories. Infants were reviewed at 4, 8 and 12 months corrected for prematurity at which time the history of rehospitalization was recorded and growth parameters were measured.

RESULTS

Infants with BPD were found to have a higher overall rate of rehospitalization (58 vs 35%, relative risk (RR) 1.7, 95% confidence interval (Cl) 1.2-2.4) and were more likely to be readmitted for respiratory illnesses (39 vs 20%, RR 1.9, 95% Cl 1.1-3.2) and for poor growth (14 vs 1%, RR 14, 95% Cl 1.7-82) than the control group. Many infants, both study and control, remained below the 10th percentile at 1 year of age. More BPD infants were below the 10th percentile in weight at the 4 month visit than the control infants (30 vs 15%, P = 0.034). This difference was neither present at subsequent visits nor in the other major growth parameters. The 20 BPD infants who were on home oxygen therapy were more frequently hospitalized for concerns with failure to thrive (30 vs 9%, RR 3.3, 95% Cl 1.2-8.9) than the remaining 58 BPD infants. No significant differences were detected in the overall rate of rehospitalization. Poor growth at the corrected age of 1 year was similar in the two subgroups of infants.

CONCLUSIONS

BPD infants are at increased for risk rehospitalization during the first year of life. While many infants with BPD have growth failure, it is suggested that the provision of appropriate supplemental oxygen at home may result in those infants having similar growth patterns when compared to birthweight matched preterm infants without BPD.

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

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.

Health of very low birth weight children during their first eight years

To determine the impact of very low birth weight (VLBW) on medical outcomes during childhood, we compared the health of 249 VLBW children born from 1977 through 1979 with that of 363 normal birth weight (NBW) control children at 8 years of age. Measures included the rates of specific illnesses, surgical procedures and accidents, growth, and other physical findings. The number of medical conditions and surgical procedures was significantly greater in the VLBW children than in the NBW control children. Eighteen percent of VLBW versus 5% of NBW children had had respiratory conditions (p < 0.001), mainly before 3 years of age. Surgical procedures were more common both before and after 3 years of age, but accidents occurred with similar frequency. The VLBW children had significantly lower weight, height, and head circumference and more minor physical stigmata. Thus medical illness, surgical interventions, and poor growth attainment are part of the ongoing morbidity of VLBW children during childhood.

Identification of neurodevelopmental abnormality at four and eight months by the movement assessment of infants

The predictive validity of infant neuromotor evaluation by the Movement Assessment of Infants (MAI) was investigated in low-birthweight infants. Motor performance at four and eight months was examined in relation to neurodevelopmental outcome at 18 months of age. Correlations were equally strong between total MAI risk scores at four and eight months and performance on the Bayley Scales. Muscle tone observations were more discriminating at four months, and automatic reactions and volitional movement were most predictive at eight months. The MAI was highly sensitive to neurodevelopmental abnormality at four and eight months and more sensitive than the Bayley Motor Scale; both assessment tools had lower specificity at eight months. The high false-positive rate is attributed to transient neuromotor abnormalities and immaturity of motor function in low-birthweight infants with normal outcome.

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.

Recurrent respiratory symptoms in the first year of life following preterm delivery

Recurrent respiratory symptoms in the first year of life following preterm delivery were documented in two studies. In the first study a questionnaire was sent to all parents of preterm very low birth weight (VLBW) infants who had been admitted during a six-month period to the Neonatal Intensive Care Unit (NICU) at King's College Hospital (KCH) and who lived within the local district. Questionnaires were also sent to parents of a control group of infants who were recruited by random selection. All the controls lived locally and were delivered at KCH in the same six-month period as the study group, but were born at 37-41 weeks of gestation and had had no neonatal problems. The questionnaire documented frequency of cough and wheeze, medication and hospital admissions. Recurrent respiratory symptoms (wheeze or wheeze and cough) occurred in 65% of the preterm VLBW infants but only 33% of the controls p less than 0.001. Less than 10% of infants in either group had received bronchodilator therapy. Admission to hospital in both groups was more common amongst children who had recurrent wheeze (p less than 0.01). In the second study all preterm VLBW infants admitted to the NICU in a six-month period were followed prospectively over the first year of life. The nature and frequency of respiratory symptoms and frequency and length of re-admission was documented and related to the duration of neonatal ventilation. Twenty-three of the 44 preterm VLBW infants (53%) followed prospectively had recurrent wheeze and/or cough.(ABSTRACT TRUNCATED AT 250 WORDS)

Care of very low birthweight infants with limited neonatal intensive care resources

The advanced technology that is available to treat the tiniest infants has raised the legal and moral dilemma of where and how to distribute limited intensive care resources. In one neonatal intensive care unit it was determined that approximately 80% of its resources over a two-year period were utilized by very low birthweight infants, in spite of the fact that these infants comprised less than 50% of the total admissions to the unit. It was not possible to offer all very low birthweight infants full intensive care; to make this possible, it was calculated that resources would have to increase by 26%. In the present economic climate, and with limited numbers of nurses who are skilled in neonatal intensive care, the prospects for extra resources are poor. What action can or should be taken, legally and morally, when no facilities exist to treat a live-born infant who may possibly benefit from intensive care?