New Ballard Score, expanded to include extremely premature infants

Inaccuracy of Ballard scores before 28 weeks' gestation. National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

Ballard scores are commonly used to estimate gestational age (GA). The purpose of this study was to determine the accuracy of the New Ballard Score (NBS) for infants <28 weeks GA by accurate menstrual history and to evaluate NBS as an outcome predictor.

METHODS

Infants weighing 401 to 1500 g in 12 National Institute of Child Health and Human Development Neonatal Research Network centers had NBS performed before age 48 hours. Accuracy of NBS estimates of GA was assessed for infants with GA determined by accurate menstrual history. In a larger cohort of infants, NBS was included in regression models of the association of NBS and death, poor outcome, and duration of hospital stay.

RESULTS

At each week from 22 to 28 weeks GA by accurate menstrual history, NBS estimates exceeded GA by dates by 1.3 to 3.3 weeks, and estimates varied widely (range of widths of 95% CIs for the observations, 6.8 to 11.9 weeks). NBS did not contribute significantly to regression models of death, poor outcome, or duration of hospital stay.

CONCLUSIONS

Inaccuracies in GA determined by the NBS should be considered when treating extremely premature infants, particularly in decisions to forego or administer intensive care. Refinement of GA scoring systems is needed to optimize clinical benefit.

Randomized placebo-controlled trial of a 42-day tapering course of dexamethasone to reduce the duration of ventilator dependency in very low birth weight infants: outcome of study participants at 1-year adjusted age

OBJECTIVE

Ventilator-dependent preterm infants are often treated with a prolonged tapering course of dexamethasone to decrease the risk and severity of chronic lung disease. The objective of this study was to assess the effect of this therapy on developmental outcome at 1 year of age.

METHODS

Study participants were 118 very low birth weight infants who, at 15 to 25 days of life, were not weaning from assisted ventilation and were then enrolled in a randomized, placebo-controlled, double-blind trial of a 42-day tapering course of dexamethasone. Infants were examined at 1 year of age, adjusted for prematurity, by a pediatrician and a child psychologist. A physical and neurologic examination was performed, and the Bayley Scales of Infant Development were administered. All examiners were blind to treatment group.

RESULTS

Groups were similar in terms of birth weight, gestational age, gender, and race. A higher percentage of dexamethasone recipients had major intracranial abnormalities diagnosed by ultrasonography (21% vs 11%). Group differences were not found for Bayley Mental Development Index (median [range] for dexamethasone-treated group, 94 [50-123]; for placebo group, 90 [28-117]) or Psychomotor Development Index Index (median [range]) for dexamethasone-treated group, 78 (50-109); for placebo-treated group, 81 [28-117]). More dexamethasone-treated infants had cerebral palsy (25% vs 7%) and abnormal neurologic examination findings (45% vs 16%). In stratified analyses, adjusted for major cranial ultrasound abnormalities, these associations persisted (OR values for cerebral palsy, 5.3; 95% CI: 1.3-21.4; OR values for neurologic abnormality 3.6; 95% CI: 1.2-11.0).

CONCLUSIONS

A 42-day tapering course of dexamethasone was associated with an increased risk of cerebral palsy. Possible explanations include an adverse effect of this therapy on brain development and/or improved survival of infants who either already have neurologic injury or who are at increased risk for such injury.

Once-daily gentamicin dosing in newborn infants

OBJECTIVE

We developed a simplified gentamicin dosing protocol for all neonates using a loading dose and once-daily dosing that would have an equal or lower incidence of toxicity and an equal or improved effectiveness compared with a regimen with no loading dose that included use of divided daily dosing.

METHODS

All neonatal intensive care unit patients with a postnatal age </=7 days and started on gentamicin therapy at the discretion of the attending neonatologist were evaluated in this comparative cohort study. All peak and trough serum drug levels (SDL), pertinent demographic data, and markers of potential nephrotoxicity, ototoxicity, and cure were tracked prospectively during 132 consecutive, nonrandomized courses of therapy on a new gentamicin protocol. These were compared with data retrieved retrospectively throughout 103 consecutive, nonrandomized courses of therapy in a control group.

RESULTS

Initial measured peak SDL were higher (7.8 +/- 1.1 microgram/mL vs 6.1 +/- 1.0 microgram/mL) and trough SDL were lower (0.9 +/- 0.2 microgram/mL vs 2.7 +/- 0.6 microgram/mL) in the protocol term subset, compared with the control term subset (gestational age, >/=37 weeks; weight, >/=2500 g). One hundred percent of the initial and maintenance peak SDL in term protocol neonates were 5 to 12 micrograms/mL; compared with 84% of the initial and 61% of maintenance peak SDL in the term control group. One hundred percent of the initial and maintenance trough SDL were in the desired range of <2 micrograms/mL in term protocol neonates; compared with 70% of the initial and 94% of maintenance trough SDL in the term control group. No significant differences were found in any SDL in low birth weight neonates (gestational age <37 weeks or weight <2500 g and >1500 g) in the protocol compared with the control group. The very low birth weight (weight <1500 g) protocol neonates had a significantly higher mean initial trough SDL (2.3 +/- 0.7 micrograms/mL vs 1.5 +/- 0.6 micrograms/mL) and a lower incidence of initial trough SDL <2.0 micrograms/mL (30% vs 95%) than very low birth weight neonates in the control group. No differences were seen between groups in incidence of significant rise in serum creatinine or failure of hearing screen.

CONCLUSION

A loading dose followed by once-daily dosing was shown to result in SDL in the safe and therapeutic range in all term neonates in this study. In low birth weight neonates, this regimen resulted in peak and trough SDL throughout therapy that were similar to those observed in the control group. Delaying the initiation of maintenance once-daily dosing until 36 to 48 hours after the loading dose would be expected to result in a higher incidence of initial trough SDL in target range for very low birth weight neonates.

Maternal fever and neonatal depression: preliminary observations

The objectives of this study were to determine in term infants: (1) the importance of maternal fever (maternal temperature > 38 degrees C) as a risk factor for neonatal depression and (2) the clinical course of infants admitted to the Neonatal Intensive Care Unit (NICU) born to mothers with fever. For 2 years, 59 (0.24%) of 25,000 term infants had a 5-minute Apgar score < or = 5 and 22 (0.08%) infants were administered chest compressions with or without epinephrine as part of cardiopulmonary resuscitation (CPR) in the delivery room. The perinatal event most commonly associated with a 5-minute Apgar score < or = 5 was maternal fever in 19 infants (32%), with meconium + fetal heart rate (FTHR) abnormalities in 15 (25%), and FTHR abnormalities only in 13 (22%), additional associations (n = 13). By stepwise linear regression analysis, a 5-minute Apgar < or = 5 was related only to the initial infant temperature (p = 0.009, r = 0.33). Maternal fever noted in six infants (27%) was also commonly associated with CPR, as was the presence of meconium + FTHR abnormalities in seven (32%), and FTHR abnormalities only in four (18%). One hundred thirteen (7.5%) of the approximately 1,500 term infants born to mothers with maternal fever were admitted to the NICU. In addition to fever, the labor was complicated by meconium (in 16 infants), meconium + FTHR abnormalities (in 19 infants), and FTHR abnormalities only (in 11 infants). Resuscitative interventions in the delivery room included oxygen only in 43 infants, bag and mask ventilation in 38, continuous positive airway pressure in 10, intubation in 16, and CPR in six infants. Forty-nine infants (43%) had an initial temperature > 38 degrees C including 13 (11%) with an initial temperature > 39 degrees C. Twelve (10%) infants remained intubated on admission and five required ventilator support > 24 hours. One blood culture was positive although all mothers were pretreated with antibiotics. One infant developed hypoxic ischemic encephalopathy including seizures. Maternal fever is the perinatal event most frequently associated with a 5-minute Apgar score < or = 5 and a common association with the need for CPR. Clinicians attending the delivery of a mother with fever should anticipate the potential for neonatal depression; such awareness should facilitate appropriate preparation before delivery and potentially reduce the need for more intensive resuscitation.

Behavioral responses of newborns of insulin-dependent and nondiabetic, healthy mothers

The purpose of this study was to compare the behavioral responses of term newborns of insulin-dependent diabetic mothers (NDMs) with newborns of nondiabetic, healthy mothers. The research design involved matched controls with repeated measures. Participants included 40 NDMs matched with 40 newborns of nondiabetic, healthy mothers. The main outcome measures were the seven dimensions of the Neonatal Behavioral Assessment Scale (NBAS) and the modal response score. The results showed that NDMs performed significantly poorer than their matched controls on motor processes and reflex functioning. For all newborns, motor processes, autonomic stability, reflex functioning, and the modal performance score were better on Day 2 than Day 1. It was concluded that although NDMs' behavioral responses improved by Day 2, their overall pattern of responses could be described as listless or sluggish. Due to their poorer motor and reflex responses, NDMs may require increased efforts to facilitate sensitive maternal responding during their first days of life.

Developmental intervention for preterm infants diagnosed with periventricular leukomalacia

Preterm infants with periventricular leukomalacia (PVL) were evaluated to determine whether multi-sensory stimulation is safe and to assess whether it improved neurobehavior and neurodevelopment. Thirty preterm infants with documented PVL were randomly assigned to control (n= 15) or experimental (Group E) (n= 15) groups at 33 weeks post-conceptional age. Group E infants received 15 minutes of auditory, tactile, visual, and vestibular (ATVV) intervention twice a day, five days a week, for four weeks during hospitalization. Repeated measures ANOVA demonstrated that Group E infants experienced significant increases in heart and respiratory rate and a 0.72% drop in hemoglobin saturation, coinciding with a significant behavioral state shift from sleep to alertness during intervention. No differences were identified in neurobehavioral function and neurodevelopment, indicating that Group E suffered no injury. Group E had an average hospital stay nine days shorter than that of controls, with the associated cost savings of $213,840. The earlier hospital discharge indicates that ATVV intervention promotes alertness without compromising physiologic status in vulnerable infants.

The effects of prescribed versus ad libitum feedings and formula caloric density on premature infant dietary intake and weight gain

BACKGROUND

Although feedings that are organized on an ad lib basis (i.e., in response to infant cues of hunger and of satiation) could enhance an infant's self-regulatory capacities for feeding, ad lib feeding of fully nipple-fed premature infants in a special care nursery has not been examined.

OBJECTIVE

To study whether the caloric and protein intake and weight change of fully nipple-fed preterm infants differed by the feeding regimen (prescribed or ad lib) and by the caloric density of the formula (20- or 24-kcalories per ounce).

METHOD

The 78 infants who participated in the study were randomized to prescribed or ad lib feeding regimens and, within each regimen, were further randomized to receive either 20-calorie or 24-kcalorie per ounce formula. Dietary intake (volume/kg, caloric intake/kg) and weight change (grams/kg gained or lost) were assessed for each of the 5 study days. Multivariate data analysis was used to examine the effects of feeding regimen and caloric density on dietary intake and weight change, controlling biologic variables (infant gender, race, lung disease diagnosis, treatment with supplemental oxygen, gestational age and weight at birth, and weight on the day prior to full nipple-feeding).

RESULTS

Overall, the ad lib feeding regimen had a negative effect on volume intake and caloric intake. Weight gain was influenced by caloric intake, but not by feeding regimen or the caloric density of the diet. With increased full nipple-feeding experience, caloric intake of ad lib feeders approached that of the infants fed on the prescribed regimen.

CONCLUSIONS

Development of self-regulatory capacities through ad lib feeding experience was indicated by infant regulation of the volume of intake by the caloric density of the formula, an unexpected finding. Furthermore, the approach of the caloric intake of infants on the ad lib regimen to that of infants on the prescribed regimen suggests they had gained skill in regulating intake with experience. Whether or not the trend for similar intakes would continue beyond 5 days is a question for further study.

Hepatitis B vaccination of premature infants: a reassessment of current recommendations for delayed immunization

OBJECTIVE

Current American Academy of Pediatrics and United States Public Health Service Immunization Practices Advisory Committee recommendations for hepatitis B immunization in premature infants weighing <2 kg at birth born to hepatitis B surface antigen (HBSAg)-negative mothers are to delay the initiation of vaccination until such infants reach 2 kg or until 2 months of age. This proposal to delay vaccination at birth in these low-risk infants was based on limited studies not conducted in the United States. We sought to reassess current recommendations to delay administration of hepatitis B vaccine in low-risk premature infants by determining the immunogenicity of early hepatitis B vaccination in a US population and identifying variables associated with poor immunogenicity.

METHODS

A total of 148 infants <37 weeks' gestation born to mothers negative for HBSAg were recruited at birth and stratified to three birth weight groups: <1000 g, 1000 to 1500 g, and >1500 g. Recombinant hepatitis B vaccine was administered within the first week of life, at 1 to 2 months of age, and at 6 to 7 months of age. Serum obtained at birth and after the second and third doses of vaccine was tested for antibody to HBSAg. Variables associated with poor response were sought prospectively by collecting demographic and clinical data.

RESULTS

A total of 118 subjects (83%) completed the study. Postsecond dose sera were available for 117 infants and postthird dose sera were available for 112 infants. The seroprotection rate (attaining >/=10 mIU/mL HBS antibody) after two doses was low (25%) regardless of birth weight; infants weighing <1000 g at birth had the poorest response (11%). The seroprotection response rate after three doses of vaccine increased with birth weight; infants weighing </=1500 g at birth (groups 1 and 2) had lower rates of response (52% and 68%, respectively) than did infants weighing >1500 g at birth (group 3; 84% response rate). The seroprotection response rate of group 3 infants after three doses of vaccine, although low, could not be differentiated from the response rates reported for full-term infants using 95% confidence intervals. Of all infants who did not achieve protective levels of antibody after three doses of vaccine, 96% (26/27) weighed <1700 g at birth. The geometric mean HBS antibody levels in responders were 88 and 386 mIU/mL after two and three doses, respectively. Of 36 children with a birth weight >1500 g, 33 (91%) achieved levels of HBS antibody >100 mIU/mL after three doses of vaccine, compared with 25/35 (71%) of infants with birth weight <1500 g. Using logistic regression analysis, nonresponders were more likely than were responders to have been treated with steroids (26% vs 9%) and to have had a low birth weight (1037 g vs 1455 g). In addition, the seroresponse rate of black infants was more likely than that of white infants to be associated with poor weight gain (falling off 2 percentile ranks in weight) in the first 6 months of life: 22% of black and 60% of white children who failed to gain weight adequately responded to vaccination, compared with 92% of black and 70% of white children who were growing adequately. Of interest, the only infant with a birth weight of >1700 g who did not make protective levels of specific antibody after three doses of vaccine was 2300 g at birth, but had inadequate weight gain in the first 6 months of life.

CONCLUSIONS

This study supports current recommendations of the American Academy of Pediatrics and the Centers for Disease Control and Prevention for delaying the initiation of hepatitis B immunization beyond the first week of life for premature infants at low risk for hepatitis B infection, particularly in newborns weighing <1700 g at birth. In addition, we have identified variables other than birth weight that were associated with an inadequate immune response to early hepatitis B vaccination in premature infants, such as poor weight gain in the first 6 months of life

Repeated antenatal corticosteroids: size at birth and subsequent development

OBJECTIVE

The objective was to study the effects of repeated antenatal corticosteroids on birth size, growth, and development in preterm infants.

STUDY DESIGN

This observational study followed up for 3 years a prospective geographic cohort in the state of Western Australia of 477 singleton infants born at <33 weeks' gestation.

RESULTS

Birth weight ratio decreased with increasing number of corticosteroid courses (P =.001), and multivariate analyses confirmed a reduction in birth weight of as much as 9% (P =.014) and a reduction in head circumference of as much as 4% (P =.0024). There were no additional benefits in mortality or respiratory outcomes, and there was a trend toward more severe chronic lung disease. At age 3 years growth and severe disability outcomes did not appear to be related to increasing number of corticosteroid courses.

CONCLUSIONS

In this cohort study repeated corticosteroid courses were associated with adverse effects on size at birth without apparent benefits. These changes have the potential to affect later development.

Outcomes of children of extremely low birthweight and gestational age in the 1990's

Advances in perinatal care have improved the chances for survival of extremely low birthweight (< 800 g) and gestational age (< 26 weeks) infants. A review of the world literature and our own experience reveals that at 23 weeks gestation survival ranges from 2% to 35%. At 24 weeks gestation the range is 17% to 58%, and at 25 weeks gestation 35% to 85%. Differences in population descriptors, in the initiation and withdrawal of treatment and the duration of survival considered may account for the wide variations in the reported ranges of survival. Major neonatal morbidity increases with decreasing gestational age and birthweight. The rates of severe cerebral ultrasound abnormality range at 23 weeks gestation from 10% to 83%, at 24 weeks from 17% to 64% and at 25 weeks gestation from 10% to 22%. At 23 weeks gestation, chronic lung disease occurs in 57% to 70% of survivors, at 24 weeks in 33% to 89%, and at 25 weeks gestation in 16% to 71% of survivors. When compared to children born prior to the 1990's, the rates of neurodevelopmental disability have, in general, remained unchanged. Of 30 survivors reported at 23 weeks gestation nine (30%) are severely disabled. At 24 weeks gestation the rates of severe neurodevelopmental disability (including subnormal cognitive function, cerebral palsy, blindness and deafness) range from 17% to 45%, and at 25 weeks gestation 12% to 35% are similarly affected. In Cleveland, Ohio, we compared the outcomes of 114 children with birthweight 500-749 g born 1990-1992 to 112 infants born 1993-1995. Twenty month survival was similar (43% vs 38%). The use of antenatal and postnatal steroids increased (10% vs 54% and 43% vs 84%, respectively, P< 0.001), however the rates of chronic lung disease increased from 41% to 63% (P = 0.06). There was a significant increase in the rate of subnormal cognitive function at 20 months corrected age (20% vs 48%, P < 0.02) and a trend to an increase in the rate of cerebral palsy (10% vs 16%) and neurodevelopmental impairment. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.

Very low birth weight outcomes of the National Institute of Child Health and Human Development Neonatal Research Network, January 1993 through December 1994

OBJECTIVES

Our purpose was to determine the mortality and morbidity rates for infants weighing 501 to 1500 g according to gestational age, birth weight, and gender.

STUDY DESIGN

Perinatal data were collected prospectively on an inborn cohort from January 1993 through December 1994 by 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network and were compared with the corresponding data from previous reports. Sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death were evaluated.

RESULTS

Eighty-three percent of infants survived until discharge to home or to a long- term care facility (compared with 74% in 1988). Survival to discharge was 49% for infants weighing 501 to 750 g at birth, 85% for those 751 to 1000 g, 93% for those 1001 to 1250 g, and 96% for those 1251 to 1500 g. The majority of deaths occurred within the first 3 days of life. Mortality rates were greater for male than for female infants. Respiratory distress syndrome was the most frequent pulmonary disease (52%). Chronic lung disease (defined as an oxygen requirement at 36 weeks after conception) developed in 19%. Thirty-two percent of infants had evidence of intracranial hemorrhage. Periventricular leukomalacia was noted in 6% of infants who had ultrasonography after 2 weeks. The average duration of hospitalization for survivors was 68 days (122 days for surviving infants weighing 501 to 750 g, compared with an average of 43 days for surviving infants 1251 to 1500 g). Among infants who died, the average length of stay was 19 days.

CONCLUSIONS

The mortality rate for infants weighing between 501 and 1500 g at birth continues to decline. This increase in survival is not accompanied by an increase in medical morbidity. There are interactions between birth weight, gestational age, sex, and survival rates.

Early versus late surfactant treatment in preterm infants of 27 to 32 weeks' gestational age: a multicenter controlled clinical trial

OBJECTIVE

To investigate whether early (<1 hour after birth) surfactant administration would be superior to late treatment (2-6 hours after birth) in preterm infants.

STUDY DESIGN

Randomized controlled multicenter clinical trial.

PATIENTS AND METHODS

Prenatal randomization of all infants of 27 to 32 weeks' gestational age stratified by center after parental informed consent. Early treatment: 100 mg/kg body weight bovine surfactant (SF-RI1, Alveofact; Dr K. Thomae, Biberach, Germany) to infants requiring intubation after birth. Late treatment: identical dosage to infants requiring intubation up to 6 hours of age with the fraction of inspired oxygen >0.4 at 2 to 6 hours after birth. Primary endpoint: the time on mechanical ventilation. Main secondary endpoints: mortality, bronchopulmonary dysplasia, intraventricular hemorrhage >/=grade III, and periventricular leukomalacia. Sample size calculation: at least 280 infants to prove superiority of either approach (alpha = 0.05; beta = 0.90).

RESULTS

Enrollment of 317 infants, 154 randomized to early surfactant treatment, 163 to late surfactant treatment. Study infants (all following data intent-to-treat groups: early versus late surfactant) were similar with respect to: gestational age, 29.5 +/- 1.6 weeks versus 29.7 +/- 1.6 weeks; birth weight, 1227 +/- 367 g versus 1269 +/- 334 g; and the rate of prenatal corticosteroids, 79.9% versus 72.8%. Duration of mechanical ventilation: 3 days (0-8) versus 2 days (0-6) (median, interquartile); further outcome variables: death or bronchopulmonary dysplasia (day 28) 25.9% versus 23.9%, mortality 3.2% versus 1.8%, intraventricular hemorrhage >/=grade III 6.5% versus 3.7%, and periventricular leukomalacia 5.2% versus 5.5% not differing statistically.

CONCLUSION

In preterm infants with a high rate of prenatal glucocorticoids, early surfactant administration was not found to be superior to late treatment in terms of relevant outcome variables.

Lower incidence of necrotizing enterocolitis in infants fed a preterm formula with egg phospholipids

Necrotizing enterocolitis (NEC) causes approximately 4000 deaths/y and significant morbidity among U.S.-born preterm infants alone. Various combinations of inadequate tissue oxygenation, bacterial overgrowth, and enteral feeding with immaturity may cause the initial damage to intestinal mucosa that culminates in necrosis. Presently, there is not a way to predict the onset of the disease or to prevent its occurrence. As part of risk-benefit assessment, we compared disease in hospitalized preterm infants fed a commercial (control) preterm formula or an experimental formula with egg phospholipids for a randomized, double-masked, clinical study of diet and infant neurodevelopment. Infants fed the experimental formula developed significantly less stage II and III NEC compared with infants fed the control formula (2.9 versus 17.6%, p < 0.05), but had similar rates of bronchopulmonary dysplasia (23.4 versus 23.5%), septicemia (26 versus 31%), and retinopathy of prematurity (38 versus 40%). Compared with the control formula, the experimental formula provided 7-fold more esterified choline, arachidonic acid (AA, 0.4% of total fatty acids), and docosahexaenoic acid (0.13%). Phospholipids are constituents of mucosal membranes and intestinal surfactant, and their components, AA and choline, are substrates for intestinal vasodilatory and cytoprotective eicosanoids (AA) and the vasodilatory neurotransmitter, acetylcholine (choline), respectively. One or more of these components of egg phospholipids may have enhanced one or more immature intestinal functions to lower the incidence of NEC in this study. Regardless of the potential mechanism, a larger randomized trial designed to test the effect of this egg phospholipid-containing formula on NEC seems warranted.

Delivery room resuscitation decisions for extremely premature infants

BACKGROUND

Neonatologists are criticized for overtreating extremely premature infants who die despite invasive and costly care. Withholding resuscitation at delivery has been recommended as a way to minimize overtreatment. It is not known how decisions to forgo initiating aggressive care are made, or whether this strategy effectively decreases overtreatment.

OBJECTIVE

To identify whether physicians' or parents' preferences primarily determine the amount of treatment provided at delivery, to examine factors associated with the provision of resuscitation, and to assess whether resuscitation at delivery significantly postpones death in nonsurvivors.

METHODS

We evaluated delivery room resuscitation decisions and mortality for all infants born at 23 to 26 weeks gestation at the University of North Carolina Hospitals from November 1994 to October 1995. On the day of delivery, the attending neonatologist completed a questionnaire regarding discussion with the parents before delivery, the prognosis for survival estimated before delivery, the degree of certainty about the prognosis, parents' preference for the amount of treatment at delivery, and the degree of influence exerted by parents and physicians on the amount of delivery room treatment provided. Medical records were reviewed for demographics and hospital course.

RESULTS

Thirty-one of 41 infants were resuscitated (intubation and/or cardiopulmonary resuscitation) at delivery. Resuscitation correlated with increasing gestational age, higher birth weight, estimated prognosis for survival greater than or equal to 10%, and uncertainty about prognostic accuracy. Physicians saw themselves as primarily responsible for delivery room resuscitation decisions when the parents' wishes about initiating care were unknown, and as equal partners with parents when they agreed on the level of care. When disagreement existed, doctors always thought parents preferred more aggressive resuscitation, and identified parents as responsible for the increased amount of treatment at delivery. Twenty-four infants died before hospital discharge. The median age at death was 2 days when physicians primarily determined the amount of treatment at delivery, 1 day when parents primarily determined the amount of treatment, and < 1 day when responsibility was shared equally. The median age at death was < 1 day when physicians and parents agreed about the preferred amount of treatment at delivery and 1.5 days when they disagreed. The median age at death was < 1 day when parents' preferences were known before delivery and 4 days when parents' preferences were unknown.

CONCLUSIONS

Physicians resuscitated extremely premature infants at delivery when they were very uncertain about an infant's prognosis or when the parents' desires about treatment were unknown. When parents' preferences were known, parents usually determined the amount of treatment provided at delivery. Resuscitation at delivery usually postponed death by only a few days, decreasing prognostic uncertainty and honoring what physicians perceived were parents' wishes for care, without substantially contributing to overtreatment.

Transition time to full nipple feeding for premature infants with a history of lung disease

OBJECTIVE

To (a) explore the contribution of infant, environmental, and historical factors to the number of days from initiation to achievement of full nipple feeding (transition time) for premature infants with a history of lung disease; (b) examine differences in the contribution of infant and environmental factors to transition time made by historical era, either earlier (in the 1980s) or later (in the 1990s); and (c) compare, within eras, the contribution to transition time of infant and environmental factors for infants with each lung diagnosis, respiratory distress syndrome (RDS) without bronchopulmonary dysplasia (BPD) or BPD.

DESIGN

Data were collected at two midwestern hospitals from the records of premature infants with a diagnosis of either RDS without BPD or BPD. The influence on transition time of infant, environmental and historical factors was assessed with the Cox proportional hazards model. This analytic model, a form of regression analysis, also was used to explore how era influenced the contribution to transition time of infant and environmental factors. Finally, the contribution to transition time of infant and environmental factors was examined within diagnostic group for each era.

SAMPLE

The hospital records audited were for infants who were 32 weeks gestational age or less with weight appropriate for gestational age. The number in each diagnostic group for each era was (a) BPD--Early, n = 35; (b) RDS--Early, n = 21; (c) BPD--Late, n = 21; and (d) RDS--Late, n = 15).

RESULTS

All three types of factors (infant, environmental, and historical) contributed significantly (p < .05) to shortening or lengthening transition time. A diagnosis of BPD lengthened transition time only in the early era. Across both eras, the number of days on tube feedings significantly lengthened transition time, and the older the infant in postconceptional age (PCA) at initiation of nipple feeding, the shorter the transition time.

CONCLUSION

The contribution of infant, environmental, and historical factors to transition time confirmed the basic structure of the theoretical model of transition time for premature infants with a history of lung disease. The influence of era on the contributions to transition time of infant and environmental factors suggests that care policy and practice have shortened the transition time. Although the current findings support the basic structure of the theoretical model for infants with either RDS or BPD, the marginally significant (p < .10) shortening effect of PCA on transition time for infants with BPD in both eras suggests that advancement to full nipple feeding may be limited by neurodevelopmental capacities, including respiratory control. How these capacities can be supported for advancement to full nipple feeding is a challenge for nursing practice and research.

Should fewer premature infants be screened for retinopathy of prematurity in the managed care era?

OBJECTIVE

To determine appropriate upper limits for gestational age and birth weight when screening infants for retinopathy of prematurity (ROP).

DESIGN

Retrospective survey.

SETTING

Tertiary neonatal intensive care nursery.

PATIENTS

Seven hundred seven infants born July 1, 1990 to June 30, 1996 and screened for ROP according to the 1988 to 1996 American Academy of Pediatrics guidelines.

OUTCOME MEASURES

Maximum stage of ROP with respect to birth weight and gestational age.

RESULTS

No ROP more than Stage 1 was observed in infants with gestational ages >/=32 weeks or birth weights >/=1500 g. All cases of threshold and Stage 4 ROP were confined to infants with gestational ages </=30 weeks or birth weights <1200 g.

CONCLUSIONS

The latest American Academy of Pediatrics screening guidelines for ROP are discretionary for infants with birth weights >1500 g or gestational ages >28 weeks. If ROP screening is limited to infants with birth weights of </=1500 g, 34.2% fewer infants would require screening compared with the previous <1800 g recommendation, while missing no cases of ROP more than Stage 1. A gestational age cut-off of </=28 weeks, however, is less desirable, and could potentially miss several infants with more advanced retinopathy (including Stage 4). If ROP screening criteria were instead modified to include infants of gestational ages <32 weeks, the number of patients requiring screening could be reduced 29.1% compared with the previous recommendation of <35 weeks, again without missing any cases of ROP more than Stage 1. Use of such a screening strategy (birth weight <1500 g or gestational age <32 weeks) is predicted to save in excess of 1.5 million dollars annually in the United States, while missing no cases of ROP more than Stage 1.

Expression of platelet-derived growth factor-A mRNA in human placenta: effect of magnesium infusion in pre-eclampsia

The expression of platelet-derived growth factor-A (PDGF-A) mRNA was examined in the cotyledons of normal human placentae and those from patients with pre-eclampsia. These patients exhibited pre-delivery blood pressure of 154+/-4/99+/-4 mmHg (mean+/-SEM) and met the criteria established for pre-eclampsia. During labour they received MgSO4 infusion for various time intervals (4-25 h). The PDGF-A message was quantitated to beta-actin by the solution hybridization nuclease protection assay. Since the two groups differed in two parameters (pre-eclampsia and MgSO4 treatment), the direct comparison was not feasible. An analysis of covariance revealed a significant difference in the message between the pre-eclamptic and control groups (P<0.01); the gestational age was not a significant covariate for either group but the time on MgSO4 in pre-eclampsia group was significant (P<0.002). A linear regression analysis of PDGF-A mRNA values for the pre-eclamptic group showed a time-dependent downregulation of the message by MgSO4 (P<0.01, r=- 0.796). These results show a uniform expression of PDGF-A mRNA in cotyledons of normal human placenta between 35 and 40 weeks of gestation. Furthermore, MgSO4 has an inhibitory effect on the expression of this message which may have aside from its anticonvulsive action beneficial effect on the function of pre-eclamptic placenta.

Comparison of two strategies for surfactant prophylaxis in very premature infants: a multicenter randomized trial

INTRODUCTION

Previous trials of surfactant therapy in premature infants have demonstrated a survival advantage associated with prophylactic therapy as an immediate bolus, compared with the rescue treatment of established respiratory distress syndrome. The optimal strategy for prophylactic therapy, however, remains controversial. When administered as an endotracheal bolus immediately after delivery, surfactant mixes with the absorbing fetal lung fluid and may reach the alveoli before the onset of lung injury. This approach, however, causes a brief delay in the initiation of standard neonatal resuscitation, including positive pressure ventilation, and is associated with a risk for surfactant delivery into the right main stem bronchus or esophagus. As an alternative approach, surfactant prophylaxis may be administered in small aliquots soon after resuscitation and confirmation of endotracheal tube position. Although this strategy has substantial logistical advantages in clinical practice, its efficacy has not been established.

OBJECTIVE

The purpose of this study was to determine whether the established benefits of the immediate bolus strategy for surfactant prophylaxis could still be achieved using a postventilatory aliquot strategy after initial standard resuscitation and stabilization.

DESIGN

Multicenter randomized clinical trial with patients randomized before delivery to immediate bolus or postventilatory aliquot therapy.

PARTICIPANTS

Inborn premature infants delivered to mothers at an estimated gestational age of 24[0/7] to 28[6/7] weeks.

INTERVENTIONS

Those infants who were randomized to the immediate bolus strategy were intubated as rapidly as possible after birth, and a 3-mL intratracheal bolus of calf lung surfactant extract (Infasurf) was administered before the initiation of positive pressure ventilation. Those infants who were randomized to the postventilatory aliquot strategy received standard resuscitation measures with intubation by 5 minutes of age, if not required earlier. At 10 minutes after birth, 3 mL of surfactant was administered in 4 divided aliquots of 0.75 mL each. Patients in both groups were eligible to receive up to three additional doses of surfactant as rescue therapy in the neonatal intensive care unit, if needed.

OUTCOME MEASURES

The primary outcome variable was survival to discharge to home. Secondary variables included neonatal complications and requirement for oxygen therapy at 36 weeks' postmenstrual age.

RESULTS

Among three centers, 651 infants were enrolled and randomized before delivery. Survival to discharge to home was similar for the two strategies for surfactant therapy as prophylaxis: 76% for the immediate bolus group and 80% for the postventilatory aliquot group. In a secondary analysis, the rate of supplemental oxygen administration at 36 weeks' postmenstrual age was 18% for the immediate bolus group and 13% for the postventilatory aliquot group.

CONCLUSIONS

Survival to discharge to home was similar with immediate bolus and postventilatory aliquot strategies for surfactant prophylaxis. Because of its logistical advantages in the delivery room and its beneficial effects on prolonged oxygen requirements, we recommend the postventilatory aliquot strategy for surfactant prophylaxis of premature infants delivered before 29 weeks' gestation.

Low serum thyroxine on initial newborn screening is associated with intraventricular hemorrhage and death in very low birth weight infants

Transient hypothyroxinemia (TH) of prematurity has been correlated with poor neurodevelopmental outcome. However, the relationship between thyroid function and neonatal mortality and brain injury has not been described.

OBJECTIVE

To investigate the relationship between thyroid function and neonatal outcome.

METHODS

Review of infants weighing <1500 grams admitted to a single level III newborn intensive care unit (n = 342). Serum total T4 values of initial newborn screening of infants dying before hospital discharge were compared with those of surviving infants. Total T4 values from infants with and without intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) also were compared.

RESULTS

T4 values strongly correlated with gestational age (r = .56). Overall, 289 (85%) of 342 infants had TH. None of the infants had true congenital hypothyroidism. T4 values of infants with cystic PVL (n = 15) were not statistically different from those for infants who did not develop cystic PVL. Infants with IVH (n = 58) had a lower T4 value than did infants who did not develop IVH (5.4 +/- 3.4 microg/dL vs 7.8 +/- 3.6 microg/dL). Infants who died before hospital discharge (n = 24) had a lower T4 value than did infants discharged to home (3.4 +/- 2.2 vs 7.9 +/- 3.7 microg/dL). After controlling for potential confounding variables, T4 value remained associated with an increased odds of IVH (odds ratio: 1.2; 95% confidence interval: 1.05 to 1.4) and mortality (odds ratio: 2.3; 95% confidence interval 1.6 to 3.4).

CONCLUSIONS

In our population of very low birth weight infants, TH has an incidence of 85%. Very low T4 values on initial newborn screening are associated with increased odds of death and IVH. Additional investigation is needed to determine whether low serum thyroxine level contributes to IVH and neonatal death or whether it is simply an associated factor.

T cell receptor repertoire diversity and clonal expansion in human neonates

Newborn human infants, particularly those born prematurely, are susceptible to infection with a variety of microorganisms. We questioned whether limitations in the T cell repertoire contribute to the neonatal immunocompromised state. To describe developmental changes of the T cell repertoire, cDNA segments corresponding to third complementarity regions (CDR3) of human umbilical cord blood T cell receptors (TCR) from 24-41-wk gestational age were amplified with TCR family-specific probes. The resulting amplified CDRs were visualized by fingerprinting and single strand conformation polymorphism (SSCP) analysis. At 24-wk gestation there were no limitations in TCRBV family usage, and the degree of CDR3 size heterogeneity was not different from the adult. However, earlier in gestation, CDR3s were shorter for all families and gradually increased in size until term. The extent of oligoclonal expansion observed in cord blood was greater than in adult peripheral blood (p = 0.03). T cell oligoclonal expansion was greatest at 29-33-wk gestation and declined toward term. Expansions were detectable in both CD4+ and CD8+ subpopulations. Our findings indicate that the genetic mechanisms of repertoire diversification appear intact as early as 24 wk of gestation, but repertoire diversity is limited as a result of smaller CDR3 sizes. In addition, there was a developmentally regulated progression of oligoclonally expanded T cells. These differences in the TCRBV repertoire add to the body of evidence demonstrating immaturity of the neonatal immune system. However, the role that these subtle differences are likely to play in the relative immunodeficiency of the neonate remains to be determined.

Prenatal prediction of neonatal outcome in the extremely low-birth-weight infant

OBJECTIVE

Our goal was to identify prenatally available parameters that correlate with neonatal outcome and could be used for predicting such outcome in the extremely low-birth-weight pregnancy.

STUDY DESIGN

From 1990 through 1995, obstetric and neonatal data of live-born nonanomalous singleton infants with birth weights between 400 and 1000 gm were reviewed. Only cases in which ultrasonographic biometry, including biparietal diameter, abdominal circumference, and femur length, was performed < or =3 days before delivery were included. Overall survival (defined as alive at discharge) and survival without specific severe neonatal morbidities (namely, retinopathy of prematurity [stage 3 or 4], intraventricular hemorrhage [grade 3 or 4], periventricular leukomalacia, chronic lung disease, and deafness) were ascertained. The best combination of prenatal parameters for the prediction of overall survival and survival without severe morbidity was determined by backward stepwise logistic regression analyses.

RESULTS

The most significant prenatal predictors of overall survival were the obstetric estimate of gestational age and the abdominal circumference (chi2 = 11.8036, p = 0.0006 and chi2 = 8.1862, p < 0.005, respectively). Survival without severe morbidity was also predicted by the same combination of parameters (chi2 = 21.9079, p = 0.0001 and chi2 = 6.538, p = 0.01, respectively). The estimated fetal weight was not a significant independent predictor of either category of outcome (chi2 = 0.1249, p = 0.72 and chi2 = 0.0361, p = 0.85, respectively). On the basis of the regression formulas, curves displaying the probabilities of overall survival and survival without severe morbidity with any combination of gestational age and abdominal circumference were developed.

CONCLUSION

The combination of gestational age and the abdominal circumference measurements appears to be superior to any combination that included estimated fetal weight data for predicting neonatal outcome in the neonates weighing < or =1000 gm. We developed a mechanism for predicting neonatal outcome in this weight category on the basis of prenatally available parameters. This information could prove useful for both parental counseling and obstetric decision making.

Thyroxine screening values in premature infants

OBJECTIVES

Premature infants often have low thyroxine levels when compared to fullterm infants. We sought to determine gestational age specific normal ranges for thyroxine screening results for premature infants in neonatal intensive care units.

METHODS

Thyroid screening results for infants less than 38 weeks gestation admitted to two NICUs were examined. For each sample the thyroxine Z-score was computed using parameters from fullterm infants. The mean thyroxine Z-score was calculated for each gestational age for days of life 1, 2, 3-7, 8-14, 15-21, 22-28, and 29-60.

RESULTS

There were 1144 specimens obtained from 543 premature infants. The mean thyroxine Z-score was below 0 for almost every gestational age and days-of-life category. The mean thyroxine Z-score increased with gestational age, but did not rise with increasing postpartum age.

CONCLUSION

The data show that normal thyroxine Z-scores for premature infants are lower than for fullterm infants and remain low at least as long as the infants remain ill.

Effect of allopurinol on postasphyxial free radical formation, cerebral hemodynamics, and electrical brain activity

OBJECTIVE

Free radical-induced postasphyxial reperfusion injury has been recognized as an important cause of brain tissue damage. We investigated the effect of high-dose allopurinol (ALLO; 40 mg/kg), a xanthine-oxidase inhibitor and free radical scavenger, on free radical status in severely asphyxiated newborns and on postasphyxial cerebral perfusion and electrical brain activity.

METHODS

Free radical status was assessed by serial plasma determination of nonprotein-bound iron (microM), antioxidative capacity, and malondialdehyde (MDA; microM). Cerebral perfusion was investigated by monitoring changes in cerebral blood volume (delta CBV; mL/100 g brain tissue) with near infrared spectroscopy; electrocortical brain activity (ECBA) was assessed in microvolts by cerebral function monitor. Eleven infants received 40 mg/kg ALLO intravenously, and 11 infants served as controls (CONT). Plasma nonprotein-bound iron, antioxidative capacity, and MDA were measured before 4 hours, between 16 and 20 hours, and at the second and third days of age. Changes in CBV and ECBA were monitored between 4 and 8, 16 and 20, 58 and 62, and 104 and 110 hours of age.

RESULTS

Six CONT and two ALLO infants died after neurologic deterioration. No toxic side effects of ALLO were detected. Nonprotein-bound iron (mean +/- SEM) in the CONT group showed an initial rise (18.7 +/- 4.6 microM to 21.3 +/- 3.4 microM) but dropped to 7.4 +/- 3.5 microM at day 3; in the ALLO group it dropped from 15.5 +/- 4.6 microM to 0 microM at day 3. Uric acid was significantly lower in ALLO-treated infants from 16 hours of life on. MDA remained stable in the ALLO group, but increased in the CONT group at 8 to 16 hours versus < 4 hours (mean +/- SEM; 0.83 +/- 0.31 microM vs 0.50 +/- 0.14 microM). During 4 to 8 hours, delta CBV-CONT showed a larger drop than delta CBV-ALLO from baseline. During the subsequent registrations CBV remained stable in both groups. ECBA-CONT decreased, but ECBA-ALLO remained stable during 4 to 8 hours of age. Neonates who died had the largest drops in CBV and ECBA.

CONCLUSION

This study suggests a beneficial effect of ALLO treatment on free radical formation, CBV, and electrical brain activity, without toxic side effects.

Gestational assessment assessed

AIMS

To review the accuracy with which obstetric information on gestation is recorded in the neonatal records; and the reliability of the methods used for assessing gestational age after birth.

METHODS

Service information on all babies born in 1989, and research information on all babies of < 32 weeks gestation born in the Northern Region in 1990-91, were reviewed to determine the accuracy with which antenatally collected information had been recorded in the neonatal records after birth. A prospective study was also mounted to assess how reliably paediatric staff could assess the gestational age of babies born to mothers with certain obstetric dates under service conditions. Paediatric residents looked at 347 babies of > 32 weeks gestation, and senior staff looked at 105 babies of < 30 weeks gestation.

RESULTS

The best techniques for estimating gestation immediately after birth were only half as accurate (95% CI +/- 17 days) as estimates based on antenatal ultrasound at 15-19 weeks gestation. Assessments that relied on the tone, posture, and appearance of the baby at birth in those of < 32 weeks gestation were less reliable than assessments based on a retrospective review of when various reflex responses first appeared. They also tended to overestimate true gestation. Antenatal information of high quality was ignored, and arithmetic and transcription errors were introduced during the transfer of antenatal information into over 10% of postnatal records.

CONCLUSIONS

Current ultrasound techniques for "dating" pregnancy antenatally are better than any of the methods of postnatal assessment. Given the reliability of the antenatal information now available, it is regrettable that so many inaccuracies have been allowed to creep into the routine computation and recording of gestation at birth.

Neonatal neurologic characteristics of preterm twin infants <1,250 gm birth weight

The study objectives were to determine the incidence, time of onset, and clinical characteristics of neonatal neurologic injury in preterm twin infants <1,250 gm birth weight. Forty-one twin infants of birth weight 929 gm +/- 160 and 27.3 +/- 1.96 weeks gestation were evaluated and compared to 225 singleton infants <1,250 gm. Seventeen infants were monozygotic and 24 dizygotic. Six of the 9 monozygotic pregnancies were complicated by the polyhydramnios/oligohydramnios syndrome; a weight discordancy of >20% was observed in 8 of the monozygotic twin sets and polycythemia (hematocrit >65%) in 3 infants. Nine (22%) of the 41 infants died. Periventricular-intraventricular hemorrhage (PV-IVH) developed in 11 (27%) of 41 infants and was severe in 9 (22%) infants. IVH was noted on day 1 (n = 2), day 2 (n = 3), and day 3 (n = 6). IVH developed in 69 (30%) of the 225 singletons and was severe in 28 (12%) infants. Twin infants were more likely to have been delivered via cesarean section, to have required intubation in the delivery room, and to have been administered surfactant as compared with singletons (P < .01). It was concluded that preterm twin infants <1,250 gm are at high risk for developing severe IVH, and that the onset of IVH was within the first 3 postnatal days in all cases.

Heparin and the risk of intraventricular hemorrhage in premature infants

OBJECTIVE

This study was carried out to determine whether the routine use of low-dose heparin in umbilical catheter infusates increases the risk of intraventricular hemorrhage or alters the coagulation profile in premature infants.

METHODS

In a randomized, blinded trial, 113 infants born at less than 31 weeks' gestation were assigned to receive, in their umbilical catheter infusate, either 1 unit of heparin per milliliter (n = 55) or no heparin (n = 58). Prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and antithrombin III activity levels were determined at the start and the completion of the study. Cranial ultrasonography was performed during the first week of life.

RESULTS

There was no difference in the incidence of intraventricular hemorrhage between the heparin and no heparin groups, 35.8% and 31.5%, respectively (p = 0.6). Similarly, no difference was detected in the incidence of severe intraventricular hemorrhage (grades III/IV). Prothrombin time, activated partial thromboplastin time, and fibrinogen levels were not significantly different between the two groups. However, the use of heparin was associated with a lower antithrombin III activity level. Antenatal indomethacin use was associated with a 2.9 increased risk of intraventricular hemorrhage (95% confidence interval, 1.15 to 7.17).

CONCLUSION

A low dose of heparin added to umbilical catheter infusates does not increase the incidence or severity of intraventricular hemorrhage or significantly alter the coagulation profile in premature infants.

Usefulness of stable microbubble test of tracheal aspirate for the diagnosis of neonatal respiratory distress syndrome

OBJECTIVES

To compare the overall accuracy of the stable microbubble test (SM test) with measurement of level of surfactant protein A (SP-A) of tracheal aspirate for the diagnosis of respiratory distress syndrome (RDS).

METHODOLOGY

Tracheal aspirates were obtained from neonates on ventilatory support. The SM test was carried out on specimens of tracheal aspirate immediately after collection. Levels of SP-A in tracheal aspirates were determined by enzyme-linked immunosorbent assay (ELISA) method. The results of the SM test and SP-A level of the tracheal aspirates were compared against the clinical diagnosis of RDS based on clinical, radiological and bacteriological findings.

RESULTS

Both the median microbubble counts (6 microbubbles/mm2, range = 0-90) and median SP-A levels (100 micrograms/L, range = 0-67447) of infants with RDS were significantly lower than those of infants with no obvious lung pathology (P < 0.0001), and pneumonia (P < 0.0001). The SM test of tracheal aspirates had higher overall accuracy for the diagnosis of RDS than measurement of SP-A levels (94.6% vs 82.4%). When the receiver operating characteristic (ROC) curves of both tests for RDS were compared, the area under the ROC curve of the SM test was larger (0.9689) than that of the SP-A method (0.8965).

CONCLUSIONS

This study showed that the SM test of tracheal aspirate was a useful bedside diagnostic test for RDS. It could be carried out at any time after birth on infants requiring ventilatory support.

Amniotic fluid tumor necrosis factor-alpha and the risk of respiratory distress syndrome among preterm infants

OBJECTIVE

We examined the effect of exposure to amniotic fluid infection and cytokines on the pulmonary outcome of preterm infants.

STUDY DESIGN

A cohort of 136 preterm infants born to women in preterm labor had amniotic fluid cultures and tumor necrosis factor-alpha assays performed. Amniotic fluid was collected by transabdominal amniocentesis. Outcome measures included respiratory distress syndrome and length of oxygen and ventilator support. Logistic regression and Cox proportional hazards regression adjusted for birth weight and other confounders.

RESULTS

Respiratory distress syndrome developed in 67 (49%) of 136 infants. Elevated amniotic fluid tumor necrosis factor-alpha levels and amniotic fluid infection were significantly associated with respiratory distress syndrome. This association persisted after adjustment for birth weight. Infants exposed to tumor necrosis factor-alpha remained on supplemental oxygen and assisted ventilation longer and had longer hospital stays compared with nonexposed infants.

CONCLUSION

Prenatal exposure to tumor necrosis factor-alpha may be a risk factor for respiratory distress syndrome and its complications.

Light reduction and the electroretinogram of preterm infants

AIMS

To examine the effects of light on retinal development and function in preterm infants as measured by the electroretinogram (ERG). Secondary outcomes included visual acuity testing, the incidence of retinopathy of prematurity, and general wellbeing, reflected in feeding tolerance, rate of weight gain, and length of hospital stay.

METHODS

Eligibility criteria for enrollment were birthweight < or = 1250 g and gestational age < or = 31 weeks. Sixty one infants were randomly allocated by 6 hours after birth to a control or treatment group which wore 97% light filtering goggles for a minimum of four weeks or until the infant reached 31 weeks postmenstrual age.

RESULTS

There were no significant differences between the two groups in the numbers of electroretinograms performed at 36 weeks of postmenstrual age. Although the sample size was not large enough to exclude clinically important differences in secondary outcomes, no significant differences were observed between the groups in visual acuity testing at 4-6 months corrected age, incidence of retinopathy of prematurity, weight gain, or length of stay.

CONCLUSION

These data support the safety and feasibility of this intervention. A much larger study will be needed to determine whether light reduction to the eyes of very low birthweight infants will reduce the incidence of retinopathy of prematurity or enhance general well-being.

Role of Ureaplasma urealyticum and Chlamydia trachomatis in development of bronchopulmonary dysplasia in very low birth weight infants

OBJECTIVE

To investigate the relationship between Ureaplasma urealyticum and Chlamydia trachomatis colonization of the very low birth weight infant and the development of bronchopulmonary dysplasia (BPD).

METHODS

Endotracheal and/or nasopharyngeal aspirates and clinical data were obtained prospectively from 108 infants with a birth weight of < 1501 g and analyzed for U. urealyticum and C. trachomatis by culture and polymerase chain reaction (PCR).

RESULTS

U. urealyticum was detected by culture in 40 (37%) infants and by PCR in 49 (45%) infants on at least one occasion. BPD was present at 28 days in 26 of 40 (65%) U. urealyticum culture-positive infants and 39 of 68 (57%) culture-negative infants (relative risk (RR) 1.13, 95% confidence interval 0.83 to 1.54; P = 0.538). BPD was present at 28 days in 34 of 49 (69%) U. urealyticum PCR-positive infants and in 31 of 59 (53%) PCR-negative infants (RR 1.32, 95% confidence interval 0.97 to 1.79; P = 0.135). At 36 weeks postconceptional age culture-positive or PCR-positive infants were at no greater risk of BPD than infants with negative results (RR = 1.02, P = 0.92 and RR = 1.2, P = 0.523, respectively). In addition the presence of U. urealyticum was not associated with any significant difference in the length of hospital stay, days of ventilation, days of oxygen supplementation, birth weight or gestational age. C. trachomatis was detected in only 2 infants.

CONCLUSION

C. trachomatis was found infrequently in the airways of premature very low birth weight infants. U. urealyticum was frequently detected but its presence was not significant with regard to development of BPD, duration of ventilatory support, oxygen dependency and length of hospital stay.

Behavior of macrosomic and appropriate-for-gestational-age newborns

OBJECTIVE

To compare the behavior of macrosomic newborns who were vaginally delivered of healthy mothers without diabetes with that of non-macrosomic, appropriate-for-gestational-age (AGA) newborns.

DESIGN/SETTING

Newborns were recruited conveniently from a tertiary hospital. Newborns were examined at 12-24 and 36-48 hours of age, using the Brazelton Neonatal Behavioral Assessment Scale (NBAS).

PARTICIPANTS

Thirty macrosomic newborns who were delivered vaginally were matched with AGA newborns for ethnicity, maternal education, parity, and obstetric medications.

MAIN OUTCOME MEASURES

Dimensions scores derived from the individual NBAS items measured reflex functioning, response decrement, orientation, motor processes, range of state, autonomic stability, and regulation of state.

RESULTS

Macrosomic newborns performed weaker than AGA newborns on the reflex and motor dimensions. Both groups displayed improved motor scores on Day 2, but regulation of state scores were weaker. For orientation, AGA newborns scored higher on Day 1, and macrosomic newborns scored higher on Day 2.

CONCLUSIONS

Increased head, limb, and body mass of macrosomic newborns, compared with adjacent and overall muscle strength, might have interfered with the execution of coordinated movements. Nurses can inform mothers of changes they can expect in their newborns' behavior.

The pituitary-adrenal responses to exogenous human corticotropin-releasing hormone in preterm, very low birth weight infants

To evaluate the pituitary-adrenal reserve and to standardize the methodology of performing the human CRH (hCRH) stimulation test, we performed the hCRH test on 14 preterm (< 32 gestational weeks), very low birth weight infants, who did not receive antenatal or postnatal corticosteroid treatment, on days 7 and 14 of life. Blood samples were obtained 0 (baseline), 15, 30, and 60 min after an iv dose of hCRH (1 microgram/kg). The plasma ACTH concentration rose from a basal value of 5.7 +/- 0.6 pmol/L (mean +/- SEM) to 11.9 +/- 2.1 pmol/L (P < 0.005), 9.2 +/- 1.2 pmol/L (P < 0.005), and 7.7 +/- 0.8 pmol/L (P < 0.005) at 15, 30, and 60 min, respectively. The corresponding rises in serum cortisol from a basal concentration of 396 +/- 67 nmol/L were 509 +/- 71 nmol/L (P < 0.0001), 647 +/- 62 nmol/L (P < 0.0001), and 578 +/- 60 nmol/L (P < 0.0001). The plasma ACTH concentration consistently peaked early at 15 min, whereas the maximum cortisol response occurred 30 min post-hCRH stimulation. No significant differences were detected between the hCRH tests performed on days 7 and 14 (P > 0.15). Mechanical ventilation, infant gender, and mode of delivery did not significantly influence the hormonal responses (P > 0.25). We have defined in this study the pattern, the magnitude of the pituitary-adrenal response, and the timing of the peak concentrations of plasma ACTH and serum cortisol in relation to a standard iv dose of hCRH. The hCRH test in very low birth weight infants appears to be safe and reproducible, and produces a pituitary-adrenal response comparable to that seen in older children and adults, indicating that pituitary-adrenal function is mature at these early stages of gestation.

Dual-energy X-ray absorptiometry studies of bone mineral status in newborn infants

We studied bone mineral status using dual-energy X-ray absorptiometry (DXA) on 150 singleton newborn infants with birth weights 1002-3990 g and gestational ages (GA) 27-42 weeks. Eighty-five infants were preterm (< 38 weeks), and 79 infants were low birth weight (< or = 2500 g). In addition, we aimed to determined the predictive value of anthropometric measurements, race, and gender on variability in bone mineral status. Data were acquired using a whole body DXA scanner with a pediatric platform. Scan analyses were performed with software version V5.64P. Results showed a highly significant (p < 0.001 for all comparisons) correlation among the continuous independent variables, gestational age, birth weight, study weight, study bare weight, and study length, and between independent and each of the dependent variables, total body bone mineral content (TB BMC), TB area, and TB bone mineral density (TB BMD). The best single determinant of bone mineral status is body weight, accounting for 95% of TB BMC and TB area and for 86% of TB BMD variation. Body length was the only additional significant predictor of TB area. Inclusion of postnatal age (during the first week after birth), race, gender, or season, either individually or in combination, failed to improve bone mineral status explanation. By term (GA 38-42 weeks, birth weight 2700-3990 g), the mean TB BMC was 68.2 g, TB area 307.6 cm2, and TB BMD 0.221 g/cm2. We conclude that DXA can be performed even in small preterm infants during the newborn period. Our results can be used as a basis for further studies in physiologic and pathologic situations that might affect bone mineralization in infants.

Aldosterone cord levels in preterm newborn infants

We measured umbilical cord aldosterone concentrations in 64 premature newborn infants. The median serum aldosterone level was 74.5 ng dl-1 (range 22-280 ng dl-1). Of the studied perinatal factors, only gestational age and birthweight presented a significant influence on the umbilical cord aldosterone levels. Newborn infants with a gestational age of over 34 weeks and a birthweight of over 2000 g had a significantly higher aldosterone cord level than those aged 34 weeks or younger and 2000 g or less in weight.

Is fetal neurologic and physical development accelerated in preeclampsia?

OBJECTIVE

Our objective was to determine whether the Ballard score, a maturity score for neonatal neuromuscular and physical development, is more advanced in preterm infants of preeclamptic women than in controls.

STUDY DESIGN

A matched cohort study design was used. One hundred women with strictly defined preeclampsia (new-onset hypertension, proteinuria, and hyperuricemia) were matched for gestational age, race, and gender to 100 normotensive women with preterm delivery. All patients had an assigned antenatal gestational age based on ultrasonography before 24 weeks. The gestational age, based on antenatal ultrasonography and last menstrual period, was compared with the Ballard score given at the time of neonatal physical examination within the first 12 hours after delivery. The difference in gestational age between the Ballard score and antenatal ultrasonography (Ballard score - ultrasonography) was calculated for each patient. Results are expressed as median and range and are compared with a Student t test.

RESULTS

The mean gestational age at delivery by antenatal ultrasonography in patients with severe preeclampsia was 32.06 +/- 2.74 and 32.03 +/- 2.70 weeks, respectively. The median difference between scores in patients with severe preeclampsia and normal patient were 1.3 +/- 1.8 and 1.5 +/- 1.6 weeks, respectively (p = 0.41).

CONCLUSION

On the basis of criteria defined by the Ballard score, preeclampsia was not associated with accelerated fetal neurologic and physical development.

Cerebellar vermis measurement at cranial sonography for assessing gestational age in the newborn weighing less than 2000 grams

Prognosis of the very low birth weight infant depends more on gestational age than birth weight, but clinical assessment of gestational age of very low birth weight infants is inaccurate. We wished to determine how well cerebellar vermis dimensions might predict gestational age in infants of birth weight less than 2000 g. We obtained suitable midline sagittal images of the cerebellar vermis at cranial sonography, performed via the anterior or posterior fontanelle, in 41 infants, from the regional neonatal intensive care unit whose gestational age was known. We measured the cerebellar vermis area and diameter on the hard-copy image provided the margins of the vermis were clearly visible, the cerebellar tonsils were excluded from the image, and the anterior and posterior divisions of the corpus medullare were visible on the image. Vermis diameter was measured from the base of the fourth ventricle to the junction of folium and tuber vermis. Vermis area was calculated using a stereological method using a test system of regularly spaced points randomly placed over a magnified image of the cerebellar vermis. We generated regression equations for estimating gestational age using combinations of birth weight, vermis area, or vermis diameter for the 26 infants with birth weight of less than 2000 g for whom the cerebellar vermis measurements were obtained within one week of birth. Vermis area and diameter correlated very highly. They both can be used for predicting gestational age. The addition of either vermis area or diameter to birth weight improves accuracy of gestational age assessment. If birth weight was presumed to be unknown, cerebellar vermis area or diameter allow prediction of gestational age to within +/- 1.3 weeks (1 standard error) or +/- 2.5 weeks, using a 95% prediction interval. If the same method of reporting is applied to the New Ballard Score, the New Ballard Score predicts gestational age +/- 1.7 weeks (1 standard error) or +/- 3.4 weeks, using a 95% prediction interval.

Contributions of experience to the development of musical processing in infancy

Full-term infants' performance in detection of melodic alterations appeared to be influenced by perceptual experience from 6 months to 1 year of age, and an experiment with infants born prematurely supported the hypothesis that experience affects music processing in infancy. These findings suggest parallel developmental tendencies in the perception of music and speech that may reflect general acquisition of perceptual abilities for processing of complex auditory patterns. This acquisition may contribute to the cultural enfranchisement of infants through perceptual experience.

Individualized developmental care for very-low-birth-weight premature infants

Forty very-low-birth-weight neonatal intensive care unit (NICU) infants with birth weights < or = 1,250 g were randomly assigned to treatment or control groups. Behavior of the treatment infants was systematically evaluated, and individualized developmentally oriented care plans were implemented to enhance stability. Treatment babies required fewer days of intermittent mandatory ventilation and continuous positive airway pressure and achieved full enteral feedings sooner. Length of hospital stay and hospital charges were less for treatment than control infants. There were favorable effects on treatment infants' behavioral performance at 42 weeks' postconceptional age. These results support the hypothesis that behaviorally sensitive, developmentally oriented care improves medical and neurodevelopmental outcome in the NICU.

Immediate commencement of amino acid supplementation in preterm infants: effect on serum amino acid concentrations and protein kinetics on the first day of life

To determine whether the general reluctance to begin amino acid administration to preterm infants from birth onward might lead to loss of lean body mass and impairment of growth, we measured amino acid levels and protein kinetics in 18 preterm infants. Nine infants received amino acids (1.15 +/- 0.06 gm.kg-1.day-1) and glucose (6.05 +/- 1.58 gm.kg-1.day-1), whereas the other nine infants received only glucose (6.48 +/- 1.30 gm.kg-1.day-1) from birth onward. Protein kinetics on the first postnatal day were measured with a stable isotope dilution technique with [1-13C]leucine as a tracer. No statistically significant differences were noted in blood pH, base excess, urea concentration, or glucose levels. Both total amino acid concentration and total essential amino acid concentration were significantly lower and were below the reference range in the nonsupplemented group. Plasma amino acid levels of five essential amino acids (methionine, cystine, isoleucine, leucine, arginine) were below the reference range in the nonsupplemented group, whereas only cystine was below the reference range in the supplemented group. Nitrogen retention was improved significantly by the administration of amino acids (-110 +/- 44 mg nitrogen per kilogram per day in the glucose-only group vs +10 +/- 127 mg nitrogen per kilogram per day in the group given glucose and amino acids; p = 0.001); leucine oxidation was not significantly increased in the supplemented group (41 +/- 13 mumol.kg-1.hr-1 vs 46 +/- 16 mumol.kg-1.hr-1). Leucine balance also improved significantly (-41 +/- 13 mumol.kg-1.hr-1 vs -8 +/- 16 mumol.kg-1.hr-1; p = 0.01) because of a combination of an increased amount of leucine being used for protein synthesis and a lower amount of leucine coming from protein breakdown. Plasma cystine concentration, the only amino acid below the reference range in the supplemented group, was highly predictive for protein synthesis in that group. We conclude that the administration of amino acids to preterm infants from birth onward seems safe and prevents the loss of protein mass.

Influence on fetal growth of exposure to tobacco smoke during pregnancy

We analysed the effect of exposure to tobacco smoke during pregnancy on fetal growth parameters in 129 term newborns. Children were classified into four depending on exposure on the basis of a questionnaire completed by the mother. The results confirmed that tobacco smoking reduced weight, length, cranial and thoracic perimeters at birth when exposure was due to either active or passive smoking. Weight deficits of infants whose mothers smoked heavily (458 g) were higher than those whose mothers were exposed to passive smoking (192 g). We conclude that passive smoking is a very important variable and should be taken into account in any study of neonatal growth parameters.

Prevalence of low birth weight and preterm delivery in relation to the interval between pregnancies among white and black women

BACKGROUND

The higher mortality rate among black infants than among white infants in the United States results largely from the greater frequency of low birth weight and prematurity among black infants. Higher rates of low birth weight and preterm delivery have been associated with shorter intervals between pregnancies.

METHODS

We studied a racially mixed population of women in military families, who had access to free, high-quality health care. A total of 1992 white and black women had two consecutive, singleton pregnancies during the study period. We determined the outcome of the second of each pair of pregnancies and the length of time between the pregnancies.

RESULTS

Short interpregnancy intervals (calculated from delivery to the next conception) were more frequent among black than among white women. A total of 7.7 percent of the 298 black women and 3.2 percent of the 1628 white women delivered premature, low-birth-weight infants (P < 0.001). Among the black women, an interpregnancy interval of less than nine months was associated with a significantly greater prevalence of preterm delivery and low birth weight in the neonates (11.6 percent, vs. 4.4 percent for longer interpregnancy intervals; P = 0.020). Among the white women, only intervals of less than three months between pregnancies were associated with a greater prevalence of prematurity and low birth weight in the infants (11.8 percent vs. 2.8 percent; P < 0.001). Of the black women, 46.3 percent had interpregnancy intervals of less than nine months; 4.2 percent of the white women had interpregnancy intervals of less than three months.

CONCLUSIONS

A short interval between pregnancies is a risk factor for low birth weight and preterm delivery, and such intervals are more common among black than among white women. The relative frequency of intervals of less than nine months between pregnancies may be an important factor in the wide disparity in pregnancy outcomes between white and black women in the United States.

Ultrasonographic detection of abnormal fetal growth with the gestational age-independent, transverse cerebellar diameter/abdominal circumference ratio

OBJECTIVES

We prospectively evaluated the accuracy of a gestational age-independent method of detecting abnormal growth, the transverse cerebellar diameter/abdominal circumference ratio, and compared this with standard ultrasonographic methods of growth assessment.

STUDY DESIGN

We prospectively studied 825 low-risk obstetric patients and 250 patients having risk factors for fetal macrosomia (n = 92) or growth retardation (n = 158). Measured fetal parameters included the biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference, and femur length. The estimated fetal weight, head circumference/abdominal circumference, cerebellar diameter/abdominal circumference, and femur length/abdominal circumference ratios were calculated. Reference curves for these parameters were created from a cross-sectional analysis of the low-risk group. Univariate analysis was used to determine the sensitivity, specificity, predictive values, and odds ratios of each individual parameter in identifying a small- or large-for-gestational-age infant. A multivariate logistic regression model with a variable selection procedure was then used to determine whether significance remained when we controlled for other parameters.

RESULTS

Within the low-risk group, the transverse cerebellar/abdominal circumference ratio was gestational age independent between 14 and 42 weeks with a mean of 13.68 +/- 0.96. A value exceeding 2 SD of the mean was significantly associated with birth or a small-for-gestational-age infant, being abnormal in 98% and 71% of asymmetrically and symmetrically growth-retarded infants, respectively. Significance was maintained in the multivariate regression model. The ratio was not helpful in detecting the large-for-gestational-age infant.

CONCLUSION

The fetal transverse cerebellar diameter/abdominal circumference ratio is an accurate, gestational age-independent method of identifying the small-for-gestational-age but not the large-for-gestational-age infant.

Comparison of the efficacy of fiberoptic and conventional phototherapy for neonatal hyperbilirubinemia

A comparative evaluation of the efficacy of fiberoptic phototherapy using the Ohmeda Billiblanket fiberoptic device, conventional phototherapy using daylight fluorescent lamps, and a combination of the two forms of phototherapy was made in 165 term healthy infants and 105 preterm infants with hyperbilirubinemia. In the term infants, the 24-hour decline rate for fiberoptic phototherapy was 9.2% +/- 1.6% (mean +/- SEM) versus 21.5% +/- 1.8% for daylight phototherapy (p < 0.01), and the overall decline rate was 0.49% +/- 0.03%/hr versus 0.70% +/- 0.04%/hr (p < 0.001). Combination phototherapy, with a 24-hour decline rate of 29.9% +/- 1.0% and an overall decline rate of 0.97% %/- 0.04%/hr, was significantly better than daylight phototherapy in both respects (p < 0.01 and < 0.01, respectively). The duration of exposure for fiberoptic phototherapy was significantly longer than that for daylight phototherapy, which in turn was significantly longer than that for combination phototherapy. Response to exposure in the preterm infants was significantly better than that in the term infants with the respective types of phototherapy. The nursing personnel unanimously felt more comfortable with fiberoptic phototherapy, which did not disturb the swaddled infants as much as conventional phototherapy. The parents also felt more reassured. Fiberoptic phototherapy proved adequate in controlling hyperbilirubinemia in preterm infants; in term infants, failures often occurred. Combination phototherapy can be recommended for severe or rapidly increasing jaundice in preterm infants, but its efficacy in term infants is uncertain.

Amino acid solutions for premature neonates during the first week of life: the role of N-acetyl-L-cysteine and N-acetyl-L-tyrosine

Tyrosine and cyst(e)ine are amino acids that are thought to be essential for preterm neonates. These amino acids have low stability (cyst(e)ine) or low solubility (tyrosine) and are therefore usually present only in small amounts in amino acid solutions. Acetylation improves the stability and solubility of amino acids, facilitating a higher concentration in the solution. We compared three commercially available amino acid solutions, Aminovenös-N-päd 10%, Vaminolact 6.5%, and Primène 10%, administered to 20 low-birth-weight neonates on total parenteral nutrition from postnatal day 2 onward. Aminovenös-N-päd 10% contains acetylated tyrosine and acetylated cysteine; the other solutions do not contain acetylated amino acids and differ in the amount of tyrosine and cysteine added. On postnatal day 7, plasma amino acids were measured together with urinary excretion of amino acids and the total nitrogen excretion; 38% of the intake of N-acetyl-L-tyrosine and 53% of the intake of N-acetyl-L-cysteine were excreted in urine. Plasma levels of N-acetyl-L-tyrosine (331 +/- 74 mumol/L) and N-acetyl-L-cysteine (18 +/- 29 mumol/L) were higher than those of tyrosine (105 +/- 108 mumol/L) and cystine (11 +/- 9 mumol/L), respectively. Plasma tyrosine levels in the groups receiving small amounts of tyrosine remained just below the reference range. We show a linear correlation of plasma cystine with the intake of cysteine (r = .75, p = 0.01), but not with N-acetyl-L-cysteine. The estimated intake of cysteine should be 500 mumol.kg-1.d-1 in order to obtain levels comparable with those shown in normal term, breast-fed neonates. Nitrogen retention did not differ among the three groups (247 to 273 mg.kg-1.d-1).(ABSTRACT TRUNCATED AT 250 WORDS)