Maternal serum fructosamine levels and stillbirth: a case-control study of the Stillbirth Collaborative Research Network

OBJECTIVE

To evaluate the association between maternal fructosamine levels at the time of delivery and stillbirth.

DESIGN

Secondary analysis of a case-control study.

SETTING

Multicentre study of five geographic catchment areas in the USA.

POPULATION

All singleton stillbirths with known diabetes status and fructosamine measurement, and representative live birth controls.

MAIN OUTCOME MEASURES

Fructosamine levels in stillbirths and live births among groups were adjusted for potential confounding factors, including diabetes. Optimal thresholds of fructosamine to discriminate stillbirth and live birth.

RESULTS

A total of 529 women with a stillbirth and 1499 women with a live birth were included in the analysis. Mean fructosamine levels were significantly higher in women with a stillbirth than in women with a live birth after adjustment (177 ± 3.05 versus 165 ± 2.89 μmol/L, P < 0.001). The difference in fructosamine levels between stillbirths and live births was greater among women with diabetes (194 ± 8.54 versus 162 ± 3.21 μmol/L), compared with women without diabetes (171 ± 2.50 versus 162 ± 2.56 μmol/L). The area under the curve (AUC) for fructosamine level and stillbirth was 0.634 (0.605-0.663) overall, 0.713 (0.624-0.802) with diabetes and 0.625 (0.595-0.656) with no diabetes.

CONCLUSIONS

Maternal fructosamine levels at the time of delivery were higher in women with stillbirth compared with women with live birth. Differences were substantial in women with diabetes, suggesting a potential benefit of glycaemic control in women with diabetes during pregnancy. The small differences noted in women without diabetes are not likely to justify routine screening in all cases of stillbirth.

TWEETABLE ABSTRACT

Maternal serum fructosamine levels are higher in women with stillbirth than in women with live birth, especially in women with diabetes.

Stillbirth and fetal anomalies: secondary analysis of a case-control study

OBJECTIVE

Approximately 10% of stillbirths are attributed to fetal anomalies, but anomalies are also common in live births. We aimed to assess the relationship between anomalies, by system and stillbirth.

DESIGN

Secondary analysis of a prospective, case-control study.

SETTING

Multicentre, 59 hospitals in five regional catchment areas in the USA.

POPULATION OR SAMPLE

All stillbirths and representative live birth controls.

METHODS

Standardised postmortem examinations performed in stillbirths, medical record abstraction for stillbirths and live births.

MAIN OUTCOME MEASURES

Incidence of major anomalies, by type, compared between stillbirths and live births with univariable and multivariable analyses using weighted analysis to account for study design and differential consent.

RESULTS

Of 465 singleton stillbirths included, 23.4% had one or more major anomalies compared with 4.3% of 1871 live births. Having an anomaly increased the odds of stillbirth; an increasing number of anomalies was more highly associated with stillbirth. Regardless of organ system affected, the presence of an anomaly increased the odds of stillbirth. These relationships remained significant if stillbirths with known genetic abnormalities were excluded. After multivariable analyses, the adjusted odds ratio (aOR) of stillbirth for any anomaly was 4.33 (95% CI 2.80-6.70) and the systems most strongly associated with stillbirth were cystic hygroma (aOR 29.97, 95% CI 5.85-153.57), and thoracic (aOR16.18, 95% CI 4.30-60.94) and craniofacial (aOR 35.25, 95% CI 9.22-134.68) systems.

CONCLUSIONS

In pregnancies affected by anomalies, the odds of stillbirth are higher with increasing numbers of anomalies. Anomalies of nearly any organ system increased the odds of stillbirth even when adjusting for gestational age and maternal race.

TWEETABLE ABSTRACT

Stillbirth risk increases with anomalies of nearly any organ system and with number of anomalies seen.

Neurodevelopmental outcomes among extremely premature infants with linear growth restriction

OBJECTIVE

To compare neurodevelopmental outcomes in linear growth-restricted (LGR) infants born <29 weeks with and without weight gain out of proportion to linear growth.

STUDY DESIGN

We compared 2-year neurodevelopmental outcomes between infants with and without LGR and between LGR infants with and without weight gain out of proportion to linear growth. The outcomes were Bayley-III cognitive, motor, and language scores, cerebral palsy, Gross Motor Function Classification System (GMFCS) level ≥ 2, and neurodevelopmental impairment.

RESULT

In total, 1227 infants were analyzed. LGR infants were smaller and less mature at birth, had higher BMI, and had lower Bayley-III language scores (82.3 vs. 85.0, p < 0.05). Among infants with LGR, infants with high BMI had lower language scores compared with those with low-to-normal BMI (80.8 vs. 83.3, p < 0.05), and were more likely to have GMFCS level ≥2 and neurodevelopmental impairment.

CONCLUSION

Among infants with LGR, weight gain out of proportion to linear growth was associated with poorer neurodevelopmental outcomes.

Inhaled nitric oxide usage in preterm infants in the NICHD Neonatal Research Network: inter-site variation and propensity evaluation

OBJECTIVE

The use of inhaled nitric oxide (iNO) in preterm infants remains controversial. In October 2010, a National Institutes of Health consensus development conference cautioned against use of iNO in preterm infants. This study aims (1) to determine the prevalence and variability in use of iNO in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) before and after the consensus conference and (2) separately, to examine associations between iNO use and severe bronchopulmonary dysplasia (BPD) or death.

STUDY DESIGN

The NICHD NRN Generic Database collects data including iNO use on very preterm infants. A total of 13 centers contributed data across the time period 2008 to 2011. Infants exposed or not to iNO were compared using logistic regression, which included factors related to risk as well as their likelihood of being exposed to iNO.

RESULT

A total of 4885 infants were assessed between 2008 and 2011; 128 (2.6%) received iNO before day 7, 140 (2.9%) between day 7 and 28, and 47 (1.0%) at >28 days. Center-specific iNO use during 2008 to 2010 ranged from 21.9 to 0.4%; 12 of 13 sites reduced usage and overall NRN iNO usage decreased from 4.6 to 1.6% (P<0.001) in 2011. The use of iNO started between day 7 and day 14 was more prevalent among younger infants with more severe courses in week 1 and associated with increased risk of severe BPD or death (odds ratio 2.24; 95% confidence interval 1.23 to 4.07).

CONCLUSION

The variability and total use of iNO decreased in 2011 compared with 2008 to 2010. iNO administration started at ⩾ day 7 was associated with more severe outcomes compared with infants without iNO exposure.

Blood stream infection is associated with altered heptavalent pneumococcal conjugate vaccine immune responses in very low birth weight infants

OBJECTIVE

Sepsis in older children and adults modifies immune system function. We compared serotype-specific antibody responses to heptavalent pneumococcal conjugate vaccine (PCV7) in very low birth weight infants (<1500 g,VLBWs) with and without blood stream infection (BSI) during their birth hospitalization.

STUDY DESIGN

Retrospective analysis of prospectively collected data for the Neonatal Research Network study of PCV7 responses among VLBWs. Infants received PCV7 at 2, 4 and 6 months after birth with blood drawn 4 to 6 weeks after third dose. Serotype antibodies were compared between infants with or without a history of BSI. Regression models were constructed with BW groups and other confounding factors identified in the primary study.

RESULT

In all, 244 infants completed the vaccine series and had serum antibody available; 82 had BSI. After adjustment, BSI was not associated with reduced odds of serum antibody 0.35 μg ml(-1).

CONCLUSION

BSI was not associated with reduced odds of World Health Organization-defined protective PCV7 responses in VLBWs.

Injuries from the wichita falls tornado: implications for prevention

We examined the circumstances of death and injury among victims of the tornado that struck Wichita Falls, Texas, on 10 April 1979. We also assessed the protective measures taken by a representative sample of community residents who suffered no major injury in order to estimate the relative risk of injury to people directly in the tornado's path. Twenty-six (60 percent) of the 43 traumatic deaths and 30 (51 percent) of the 59 serious injuries occurred in people who, despite ample warning, went to their cars to drive out of the storm's path. These people had a risk of serious or fatal injury of 23 per 1000. People who remained indoors and in stationary homes were at relatively low risk (3 per 1000) if they took simple precautions; people in mobile homes were at greatest risk (85 per 1000). Current safety recommendations and housing codes for single family homes and mobile homes need to be amended to decrease the impact of future tornadoes on human health.

Association between early postnatal weight loss and death or BPD in small and appropriate for gestational age extremely low-birth-weight infants

OBJECTIVE

To examine the association between weight loss during the first 10 days of life and the incidence of death or bronchopulmonary dysplasia (BPD) in small for gestational age (SGA) and appropriate for gestational age (AGA) extremely low-birth-weight infants.

DESIGN/METHODS

This is a retrospective analysis of a cohort of ELBW (birth weight <1000 g) infants from the NICHD Neonatal Research Network's database. The cohort consisted of 9461 ELBW infants with gestational age of 24-29 weeks, admitted to Network's participating centers during calendar years 1994-2002 and surviving at least 72 h after birth. The cohort was divided into two groups, 1248 SGA (with birth weight below 10th percentile for gestational age) and 8213 AGA (with birth weight between 10th and 90th percentile) infants. We identified infants with or without weight loss during the first 10 days of life, which we termed as 'early postnatal weight loss' (EPWL). Univariate analyses were used to predict whether EPWL was related to the primary outcome, death or BPD, within each birth weight/gestation category (SGA or AGA). BPD and death were also analyzed separately in relation to EPWL. Logistic regression analysis was done to evaluate the risk of death or BPD in SGA and AGA groups, controlling for maternal and neonatal demographic and clinical factors found to be significant by univariate analysis.

RESULTS

SGA ELBW infants had a lower prevalence of EPWL as compared with AGA ELBW infants (81.2 vs 93.7%, respectively, P<0.001). In AGA infants, univariate analysis showed that death or BPD rate was lower in the group of infants with EPWL compared with infants without EPWL (53.4 vs 74.3%, respectively, P<0.001). The BPD (47.2 vs 64%, P<0.001) and death (13.8 vs 32.9%, P<0.001) rate were similarly lower in the EPWL group. The risk-adjusted odds ratios (ORs) showed that EPWL was associated with lower rate of death or BPD (OR 0.47, 95% CI: 0.37-0.60). In SGA infants, on univariate analysis, a similar association between EPWL and outcomes was seen as shown in AGA infants: death or BPD (55.9 vs 75.2%, P<0.001), BPD rate (48.3 vs 62.1%, P=0.002) and rate death (19 vs 40.8%, P<0.001) for those with or without EPWL, respectively. Multiple logistic regression showed that as in AGA ELBW infants, EPWL was associated with lower risk for death or BPD (OR 0.60, 95% CI: 0.41-0.89) among SGA infants.

CONCLUSIONS

SGA infants experienced less EPWL when compared with their AGA counterparts. EPWL was associated with a lower risk of death or BPD in both ELBW AGA and SGA infants. These data suggest that clinicians who consider the association between EPWL and risk of death or BPD should do so independent of gestation/birth weight status.

Changes in mortality and morbidities among infants born at less than 25 weeks during the post-surfactant era

OBJECTIVES

To compare mortality and death or major morbidity (DOMM) among infants <25 weeks estimated gestational age (EGA) born during two post-surfactant era time periods.

STUDY DESIGN AND PATIENTS

Comparative cohort study of very low birthweight (501-1500 g) infants <25 weeks EGA in the NICHD Neonatal Research Network born during two post-surfactant era time periods (group I, 1991-1994, n=1408; group II, 1995-1998, n=1348). Perinatal and neonatal factors were compared, and group related mortality and DOMM risk were evaluated.

RESULTS

Mortality was higher for group I (63.1% v 56.7%; p=0.0006). Antenatal steroids (ANS) and antenatal antibiotics (AABX), surfactant (p<0.0001), and bronchopulmonary dysplasia (p=0.0008) were more prevalent in group II. In a regression model that controlled for basic and delivery factors only, mortality risk was greater for group I than for group II (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2 to 1.7); the addition of AABX and surfactant, or ANS (OR 0.97, 95% CI 0.79 to 1.2) to the model appeared to account for this difference. There was no difference in DOMM (86.8% v 88.4%; p=0.2), but risk was lower for group I in regression models that included ANS (OR 0.70, 95% CI 0.52 to 0.94).

CONCLUSION

Survival to discharge was more likely during the more recent period because of group differences in ANS, AABX, and surfactant. However, this treatment shift may reflect an overall more aggressive management approach. More consistent application of treatment has led to improving survival of <25 week EGA infants during the post-surfactant era, but possibly at the cost of greater risk of major in-hospital morbidities.

Soluble L-selectin, a marker of immune activation, in neonatal infection

L-Selectin is an adhesion molecule shed from the surface of lymphocytes and granulocytes upon activation. Soluble L-selectin in the plasma can thus reflect immune activation and is elevated in several pathological states. Our objective was to evaluate plasma levels of L-selectin as an immune activation marker in neonates and to determine whether it can serve as a marker of infection, either neonatal or congenital, or if it is affected by the mode of delivery and obstetrical or perinatal complications. A solid-phase ELISA was used on 89 sera from neonates less than 2 days of age, according to the manufacturer's instructions. Levels of soluble L-selectin in the neonate were lower than those of older infants and children and comparable to the levels seen in adults. There was no difference between levels of soluble L-selectin of premature (median, 1172 ng/ml) and full-term babies (median, 1151 ng/ml) or between babies born via vaginal (median, 1233 ng/ml) or cesarean delivery (median, 1146 ng/ml). Conditions such as preeclampsia or administration of steroids to the mother did not affect the levels of L-selectin in the neonate. In contrast, the presence of maternal clinical chorioamnionitis resulted in an increase in levels of L-selectin in the neonate (median, 1377 vs 1072 ng/ml, p = 0.02), as did neonatal sepsis (median, 1331 vs 1149 ng/ml, p = 0.026). Soluble L-selectin, and thus immune activation level, is highest in neonates with neonatal infection and needs to be further evaluated as a surrogate marker for diagnosing sepsis in the neonate.

Effects of early erythropoietin therapy on the transfusion requirements of preterm infants below 1250 grams birth weight: a multicenter, randomized, controlled trial

OBJECTIVES

Infants of </=1250 g birth weight receive multiple erythrocyte transfusions during their hospitalization. We hypothesized that early erythropoietin (Epo) and iron therapy would 1) decrease the number of transfusions received (infants 401-1000 g birth weight; trial 1) and 2) decrease the percentage of infants who received any transfusions (1001-1250 g birth weight; trial 2).

METHODS

A total of 172 infants in trial 1 and 118 infants in trial 2 were randomized to treatment (Epo, 400 U/kg 3 times weekly) or placebo/control. Therapy was initiated by 4 days after birth and continued through the 35th postmenstrual week. All infants received supplemental parenteral and enteral iron. Complete blood and reticulocyte counts were measured weekly, and ferritin concentrations were measured monthly. Transfusions were administered according to protocol. Phlebotomy losses and transfusion data were recorded.

RESULTS

Treated and placebo/control infants in trial 1 received a similar number of transfusions (4.3 +/- 3.6 vs 5.2 +/- 4.2, respectively). A similar percentage of treated and control infants in trial 2 received at least 1 transfusion (37% vs 46%). Reticulocyte counts were higher in treated infants during each week of the study in both trials. Hematocrits were higher among treated infants from week 2 on in both trials. Ferritin concentrations were higher in placebo/controls than in treated infants at weeks 4 and 8 in trial 1 and at week 4 in trial 2. No adverse effects of Epo or supplemental iron occurred.

CONCLUSION

The combination of early Epo and iron as administered in this study stimulated erythropoiesis in infants who were </=1250 g at birth. However, the lack of impact on transfusion requirements fails to support routine use of early Epo.neonate, intravenous iron, donor exposure.

Missed opportunities for congenital syphilis prevention in an urban southeastern hospital

BACKGROUND

Despite recent declines in syphilis rates nationally, recent outbreaks suggest that prevention of congenital syphilis remains an ongoing public health problem.

GOALS

To identify missed opportunities for congenital syphilis prevention during prenatal care.

STUDY DESIGN

Retrospective medical record review of 157 live birth or stillbirth deliveries that involved cases of congenital syphilis from Grady Memorial Hospital (Atlanta, GA).

RESULTS

The hospital congenital syphilis prevalence was 8.2 cases per 1,000 live births. Six percent of case patients were HIV positive. Opportunities for earlier maternal screening, treatment, or diagnosis were missed in 60% of case patients who received timely prenatal care. Congenital syphilis cases attributable to preventable missed opportunities were significantly more common among case patients with fewer prenatal visits (66% versus 28%, P = 0.01).

CONCLUSION

Provider efforts to reduce congenital syphilis in high-risk populations receiving prenatal care should focus on (1) screening patients at the first opportunity, at both the first prenatal visit and during the third trimester (i.e., 28 weeks); (2) performing on-site testing and same-day treatment; (3) providing appropriate treatment to infected women with penicillin allergy; (4) referring sex partners for treatment to prevent reinfection; and (5) screening all pregnant women attending emergency clinics.

Adverse effects of early dexamethasone treatment in extremely-low-birth-weight infants. National Institute of Child Health and Human Development Neonatal Research Network

BACKGROUND

Early administration of high doses of dexamethasone may reduce the risk of chronic lung disease in premature infants but can cause complications. Whether moderate doses would be as effective but safer is not known.

METHODS

We randomly assigned 220 infants with a birth weight of 501 to 1000 g who were treated with mechanical ventilation within 12 hours after birth to receive dexamethasone or placebo with either routine ventilatory support or permissive hypercapnia. The dexamethasone was administered within 24 hours after birth at a dose of 0.15 mg per kilogram of body weight per day for three days, followed by a tapering of the dose over a period of seven days. The primary outcome was death or chronic lung disease at 36 weeks' postmenstrual age.

RESULTS

The relative risk of death or chronic lung disease in the dexamethasone-treated infants, as compared with those who received placebo, was 0.9 (95 percent confidence interval, 0.8 to 1.1). Since the effect of dexamethasone treatment did not vary according to the ventilatory approach, the two dexamethasone groups and the two placebo groups were combined. The infants in the dexamethasone group were less likely than those in the placebo group to be receiving oxygen supplementation 28 days after birth (P=0.004) or open-label dexamethasone (P=0.01), were more likely to have hypertension (P<0.001), and were more likely to be receiving insulin treatment for hyperglycemia (P=0.02). During the first 14 days, spontaneous gastrointestinal perforation occurred in a larger proportion of infants in the dexamethasone group (13 percent, vs. 4 percent in the placebo group; P=0.02). The dexamethasone-treated infants had a lower weight (P=0.02) and a smaller head circumference (P=0.04) at 36 weeks' postmenstrual age.

CONCLUSIONS

In preterm infants, early administration of dexamethasone at a moderate dose has no effect on death or chronic lung disease and is associated with gastrointestinal perforation and decreased growth.

Very low birth weight outcomes of the National Institute of Child health and human development neonatal research network, January 1995 through December 1996. NICHD Neonatal Research Network

OBJECTIVES

To determine the mortality and morbidity for infants weighing 401 to 1500 g (very low birth weight [VLBW]) at birth by gestational age, birth weight, and gender.

STUDY DESIGN

Perinatal data were collected prospectively on an inborn cohort from January 1995 through December 1996 by 14 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 four percent of 4438 infants weighing 501 to 1500 g at birth survived until discharge to home or to a long-term care facility (compared with 80% in 1991 and 74% in 1988). Survival to discharge was 54% for infants 501 to 750 g at birth, 86% for those 751 to 1000 g, 94% for those 1001 to 1250 g, and 97% for those 1251 to 1500g. The incidence of chronic lung disease (CLD; defined as receiving supplemental oxygen at 36 weeks' postmenstrual age; 23%), proven necrotizing enterocolitis (NEC; 7%), and severe intracranial hemorrhage (ICH; grade III or IV; 11%) remained unchanged between 1991 and 1996. Furthermore, 97% of all VLBW infants and 99% of infants weighing <1000 g at birth had weights less than the 10th percentile at 36 weeks' postmenstrual age. Mortality for 195 infants weighing 401 to 500 g was 89%, with nearly all survivors developing CLD. Mortality in infants weighing 501 to 600 g was 71%; among survivors, 62% had CLD, 35% had severe ICH, and 15% had proven NEC.

CONCLUSIONS

Survival for infants between 501 and 1500 g at birth continued to improve, particularly for infants weighing <1000 g at birth. This improvement in survival was not associated with an increase in major morbidities, because the incidence of CLD, proven NEC, and severe ICH did not change. However, poor postnatal growth remains a major concern, occurring in 99% of infants weighing <1000 g at birth. Mortality and major morbidity (CLD, severe ICH, and NEC) remain high for the smallest infants, particularly those weighing <600 g at birth.

Sex differences in outcomes of very low birthweight infants: the newborn male disadvantage

OBJECTIVE

To determine the differences in short term outcome of very low birthweight infants attributable to sex.

METHODS

Boys and girls weighing 501-1500 g admitted to the 12 centres of the National Institute of Child Health and Human Development Neonatal Research Network were compared. Maternal information and perinatal data were collected from hospital records. Infant outcome was recorded at discharge, at 120 days of age if the infant was still in hospital, or at death. Best obstetric estimate based on the last menstrual period, standard obstetric factors, and ultrasound were used to assign gestational age in completed weeks. Data were collected on a cohort that included 3356 boys and 3382 girls, representing all inborn births from 1 May 1991 to 31 December 1993.

RESULTS

Mortality for boys was 22% and that for girls 15%. The prenatal and perinatal data indicate few differences between the sex groups, except that boys were less likely to have been exposed to antenatal steroids (odds ratio (OR) = 0.80) and were less stable after birth, as reflected in a higher percentage with lower Apgar scores at one and five minutes and the need for physical and pharmacological assistance. In particular, boys were more likely to have been intubated (OR = 1.16) and to have received resuscitation medication (OR = 1.40). Boys had a higher risk (OR > 1.00) for most adverse neonatal outcomes. Although pulmonary morbidity predominated, intracranial haemorrhage and urinary tract infection were also more common.

CONCLUSIONS

Relative differences in short term morbidity and mortality persist between the sexes.

Persistent pulmonary hypertension of the newborn in the era before nitric oxide: practice variation and outcomes

OBJECTIVES

In the era before widespread use of inhaled nitric oxide, to determine the prevalence of persistent pulmonary hypertension (PPHN) in a multicenter cohort, demographic descriptors of the population, treatments used, the outcomes of those treatments, and variation in practice among centers.

STUDY DESIGN

A total of 385 neonates who received >/=50% inspired oxygen and/or mechanical ventilation and had documented evidence of PPHN (2D echocardiogram or preductal or postductal oxygen difference) were tracked from admission at 12 Level III neonatal intensive care units. Demographics, treatments, and outcomes were documented.

RESULTS

The prevalence of PPHN was 1.9 per 1000 live births (based on 71 558 inborns) with a wide variation observed among centers (.43-6.82 per 1000 live births). Neonates with PPHN were admitted to the Level III neonatal intensive care units at a mean of 12 hours of age (standard deviation: 19 hours). Wide variations in the use of all treatments studied were found at the centers. Hyperventilation was used in 65% overall but centers ranged from 33% to 92%, and continuous infusion of alkali was used in 75% overall, with a range of 27% to 93% of neonates. Other frequently used treatments included sedation (94%; range: 77%-100%), paralysis (73%; range: 33%-98%), and inotrope administration (84%; range: 46%-100%). Vasodilator drugs, primarily tolazoline, were used in 39% (range: 13%-81%) of neonates. Despite the wide variation in practice, there was no significant difference in mortality among centers. Mortality was 11% (range: 4%-33%). No specific therapy was clearly associated with a reduction in mortality. To determine whether the therapies were equivalent, neonates treated with hyperventilation were compared with those treated with alkali infusion. Hyperventilation reduced the risk of extracorporeal membrane oxygenation without increasing the use of oxygen at 28 days of age. In contrast, the use of alkali infusion was associated with increased use of extracorporeal membrane oxygenation (odds ratio: 5.03, compared with those treated with hyperventilation) and an increased use of oxygen at 28 days of age.

CONCLUSIONS

Hyperventilation and alkali infusion are not equivalent in their outcomes in neonates with PPHN. Randomized trials are needed to evaluate the role of these common therapies.

Dexamethasone therapy increases infection in very low birth weight infants

BACKGROUND

Infection is a major complication of preterm infants, resulting in increased morbidity and mortality. We recently reported the results of a multicenter trial of dexamethasone initiated at 14 or 28 days in very low birth weight (VLBW) infants who were at risk for chronic lung disease; the results showed an increase in nosocomial bacteremia in the group receiving dexamethasone. This study is an in-depth analysis of bacteremia/sepsis and meningitis among infants enrolled in the trial.

METHODS

Data on cultures performed and antibiotic therapy were collected prospectively. Infections were classified as definite or possible/clinical.

RESULTS

A total of 371 infants were enrolled in the trial. There were no baseline differences in risk factors for infection. For the first 14 days of study, infants received either dexamethasone (group I, 182) or placebo (group II, 189). During this period, infants in group I were significantly more likely than those in group II to have a positive blood culture result (48% vs 30%) and definite bacteremia/sepsis/meningitis (22% vs 14%). Over the 6-week study period, 47% of those cultured had at least one positive blood culture result (53% in group I vs 41% in group II) and 25% of the infants had at least one episode of definite bacteremia/sepsis/meningitis (29% in group I vs 21% in group II). Among infants with definite infections, 46.8% were attributable to Gram-positive organisms, 26.6% to Gram-negative organisms and 26.6% to fungi. The factors present at randomization were evaluated for their association with infection. Group I assignment and H(2) blocker therapy (before study entry) were associated with increased risk of definite infection, whereas cesarean section delivery and increasing birth weight were associated with decreased risk.

CONCLUSIONS

Infants who received a 14-day course of dexamethasone initiated at 2 weeks of age were more likely to develop a bloodstream or cerebrospinal fluid infection while on dexamethasone therapy than were those who received placebo. Physicians must consider this increased risk of infection when deciding whether to treat VLBW infants with dexamethasone.

Enzyme-linked immunospot assay for the diagnosis of active Treponema pallidum infection during the various stages of syphilis

BACKGROUND

Specific serologic assays for syphilis cannot differentiate current infections from past infections and are inefficient to monitor efficacy of antibiotic therapy.

GOAL

To develop a new immunologic assay for the identification of active Treponema pallidum infection during the various stages of syphilis.

STUDY DESIGN

Peripheral blood mononuclear cells obtained from patients with syphilis in an STD clinic were tested for T. pallidum-specific circulating antibody-secreting cells (ASC) by an enzyme-linked immunospot assay (ELISPOT).

RESULTS

Specific ASC were demonstrated in all six patients with primary syphilis and in 14 of 16 patients diagnosed with secondary syphilis. ASCs were undetectable in five patients 8 to 16 days after appropriate therapy, but persisted in one case that was considered treatment failure. Among the 13 patients diagnosed with latent syphilis, six (46%) demonstrated ASC, reflecting antigenic stimulation.

CONCLUSION

The ELISPOT assay is effective for the diagnosis of primary and secondary syphilis. The presence of circulating ASC suggests persistent active infection in some patients during the latent disease stage.

Longitudinal growth of hospitalized very low birth weight infants

BACKGROUND

The interpretation of growth rates for very low birth weight infants is obscured by limited data, recent changes in perinatal care, and the uncertain effects of multiple therapies.

OBJECTIVES

To develop contemporary postnatal growth curves for very low birth weight preterm infants and to relate growth velocity to birth weight, nutritional practices, fetal growth status (small- or appropriate-for-gestational-age), and major neonatal morbidities (chronic lung disease, nosocomial infection or late-onset infection, severe intraventricular hemorrhage, and necrotizing enterocolitis).

DESIGN

Large, multicenter, prospective cohort study.

METHODS

Growth was prospectively assessed for 1660 infants with birth weights between 501 to 1500 g admitted by 24 hours of age to 1 of the 12 National Institute of Child Health and Human Development Neonatal Research Network centers between August 31, 1994 and August 9, 1995. Infants were included if they survived >7 days (168 hours) and were free of major congenital anomalies. Anthropometric measures (body weight, length, head circumference, and midarm circumference) were performed from birth until discharge, transfer, death, age 120 days, or a body weight of 2000 g. To obtain representative data, nutritional practices were not altered by the study protocol.

RESULTS

Postnatal growth curves suitable for clinical and research use were constructed for body weight, length, head circumference, and midarm circumference. Once birth weight was regained, weight gain (14.4-16.1 g/kg/d) approximated intrauterine rates. However, at hospital discharge, most infants born between 24 and 29 weeks of gestation had not achieved the median birth weight of the reference fetus at the same postmenstrual age. Gestational age, race, and gender had no effect on growth within 100-g birth weight strata. Appropriate-for-gestational age infants who survived to hospital discharge without developing chronic lung disease, severe intraventricular hemorrhage, necrotizing enterocolitis, or late onset-sepsis gained weight faster than comparable infants with those morbidities. More rapid weight gain was also associated with a shorter duration of parenteral nutrition providing at least 75% of the total daily fluid volume, an earlier age at the initiation of enteral feedings, and an earlier age at achievement of full enteral feedings.

CONCLUSIONS

These growth curves may be used to better understand postnatal growth, to help identify infants developing illnesses affecting growth, and to aid in the design of future research. They should not be taken as optimal. Randomized clinical trials should be performed to evaluate whether different nutritional management practices will permit birth weight to be regained earlier and result in more rapid growth, more appropriate body composition, and improved short- and long-term outcomes.

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.

Vitamin A supplementation for extremely-low-birth-weight infants. National Institute of Child Health and Human Development Neonatal Research Network

BACKGROUND

Vitamin A supplementation may reduce the risk of chronic lung disease and sepsis in extremely-low-birth-weight infants. The results of our pilot study suggested that a dose of 5000 IU administered intramuscularly three times per week for four weeks was more effective than the lower doses given in past trials.

METHODS

We performed a multicenter, blinded, randomized trial to assess the effectiveness and safety of this regimen as compared with sham treatment in 807 infants in need of respiratory support 24 hours after birth. The mean birth weight was 770 g in the vitamin A group and 769 g in the control group, and the respective gestational ages were 26.8 and 26.7 weeks.

RESULTS

By 36 weeks' postmenstrual age, 59 of the 405 infants (15 percent) in the vitamin A group and 55 of the 402 infants (14 percent) in the control group had died. The primary outcome - death or chronic lung disease at 36 weeks' postmenstrual age - occurred in significantly fewer infants in the vitamin A group than in the control group (55 percent vs. 62 percent; relative risk, 0.89; 95 percent confidence interval, 0.80 to 0.99). Overall, 1 additional infant survived without chronic lung disease for every 14 to 15 infants who received vitamin A supplements. The proportions of infants in the vitamin A group and the control group who had signs of potential vitamin A toxicity were similar. The proportion of infants with serum retinol values below 20 microg per deciliter (0.70 micromol per liter) was lower in the vitamin A group than in the control group (25 percent vs. 54 percent, P<0.001).

CONCLUSIONS

Intramuscular administration of 5000 IU of vitamin A three times per week for four weeks reduced biochemical evidence of vitamin A deficiency and slightly decreased the risk of chronic lung disease in extremely-low-birth-weight infants.

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.

Outcomes of very low birth weight twins cared for in the National Institute of Child Health and Human Development Neonatal Research Network's intensive care units

OBJECTIVE

The study's aim was to compare outcomes of very low birth weight twins with those of matched singletons.

STUDY DESIGN

With data from the Neonatal Research Network registry (May 1991 to December 1994), univariable and multivariable comparisons of very low birth weight twin pairs and singletons were performed in 2 subgroups: (1) all paired twins and singletons with birth weights between 401 and 1500 g and (2) all paired twins and singletons born at <28 weeks' gestation.

RESULTS

Twins constituted 19% of infants admitted with very low birth weight. Mothers of twins were more likely to receive prenatal care, have labor, have cesarean delivery, and receive antenatal glucocorticoids. Twins were more likely to have respiratory disease and to receive surfactant. Second-born twins had more early respiratory disease but similar longer-term outcomes. The risks of death, chronic lung disease, and grade III or IV intracranial hemorrhage were similar in twins and singletons.

CONCLUSIONS

Although very low birth weight twins compose a sizable proportion of admissions, in National Institute of Child Health and Human Development Neonatal Research Network intensive care units, twins and singletons have similar outcomes.

Decline in sepsis-associated neonatal and infant deaths in the United States, 1979 through 1994

BACKGROUND

Infant mortality in the United States has continued to decline in recent years, but changes in sepsis-associated deaths among infants have not been evaluated previously.

METHODS

Data from US death records were analyzed for the period 1979 through 1994 to assess trends in sepsis-associated deaths among newborns and older infants.

RESULTS

Annual neonatal mortality associated with sepsis declined by 25% from 50.5 deaths per 100 000 live births in 1979 through 1981 to 38.0 deaths per 100 000 live births in 1992 through 1994. Although infant mortality associated with sepsis declined from 71.7 to 56.4 per 100 000 live births over the same period, this decline was attributable to lower sepsis-related mortality among newborns. The rates of sepsis-associated deaths declined for both preterm and term deliveries. Approximately 2260 infants (1521 of whom were newborns) died of sepsis per year in 1992 through 1994. Sepsis-associated death was more likely to occur among infants who were male, black, preterm, or born in the South. Among black infants, the racial gap in sepsis-associated mortality was greater for term than for preterm infants.

CONCLUSIONS

Despite declines in the overall sepsis-related mortality among newborns, racial and regional gaps in mortality persisted over the 16-year study period. Almost half of the sepsis-related deaths occurred among infants who were born prematurely. Disproportionate rates of prematurity among blacks and infants born in the South may have contributed to persistently high sepsis-related mortality in these groups. Future efforts to reduce the incidence of sepsis-associated deaths will depend on targeting higher risk populations and reducing prematurity.

Maternal carriage of group B streptococci in developing countries

BACKGROUND

Group B streptococcus (GBS) is a leading cause of neonatal sepsis in many industrialized countries, but reports from the developing world infrequently identify this pathogen among newborns with sepsis. Studies of GBS colonization among women living in developing countries were reviewed to determine whether lower colonization rates might account for these findings.

METHODS

Literature was reviewed with the use of Medline Express (1980 to 1996) and Abstracts on Tropical Agriculture and Rural Development in the Tropics (1975 to 1995). The methods of each report were considered adequate if specimens were collected from the vagina and if selective broth media were used.

RESULTS

Thirty-four studies reported results of cultures from 7730 women; overall colonization was 12.7%. Among only those studies in which methods were adequate, 17.8% (675 of 3801) women were identified as colonized. Studies with adequate methods found significantly higher colonization rates (relative risk, 2.3; 95% confidence interval, 2.0 to 2.6) than those using inadequate methods. When analysis was restricted to reports with adequate methods, the prevalence of colonization by region was as follows: Middle East/North Africa, 22%; Asia/Pacific, 19%; Sub-Saharan Africa, 19%; India/Pakistan, 12%; and Americas, 14%.

CONCLUSION

Although there is significant geographic variation in the proportion of women colonized with GBS, the range of colonization reported from developing countries is similar to that identified in populations studied in the United States. Specimen collection and microbiologic methods are important factors in identification of women colonized with GBS.

A multicenter trial of two dexamethasone regimens in ventilator-dependent premature infants

BACKGROUND

Ventilator-dependent premature infants are often treated with dexamethasone. However, the optimal timing of therapy is unknown.

METHODS

We compared the benefits and hazards of initiating dexamethasone therapy at two weeks of age and at four weeks of age in 371 ventilator-dependent very-low-birth-weight infants (501 to 1500 g) who had respiratory index scores (mean airway pressure x the fraction of inspired oxygen) of 52.4 at two weeks of age. One hundred eighty-two infants received dexamethasone for two weeks followed by placebo for two weeks, and 189 infants received placebo for two weeks followed by either dexamethasone (those with a respiratory-index score of > or =2.4 on treatment day 14) or additional placebo for two weeks. Dexamethasone was given at a dose of 0.25 mg per kilogram of body weight twice daily intravenously or orally for five days, and the dose was then tapered.

RESULTS

The median time to ventilator independence was 36 days in the dexamethasone-placebo group and 37 days in the placebo-dexamethasone group. The incidences of chronic lung disease (defined as the need for oxygen supplementation at 36 weeks' postconceptional age) were 66 percent and 67 percent, respectively. Dexamethasone was associated with an increased incidence of nosocomial bacteremia (relative risk, 1.5; 95 percent confidence interval, 1.1 to 2.1) and hyperglycemia (relative risk, 1.9; 95 percent confidence interval, 1.2 to 3.0) in the dexamethasone-placebo group, elevated blood pressure (relative risk, 2.9; 95 percent confidence interval, 1.2 to 6.9) in the placebo-dexamethasone group, and diminished weight gain and head growth (P< 0.001) in both groups.

CONCLUSIONS

Treatment of ventilator-dependent premature infants with dexamethasone at two weeks of age is more hazardous and no more beneficial than treatment at four weeks of ages.

The epidemiology of necrotizing enterocolitis infant mortality in the United States

OBJECTIVES

This study examined trends and risk factors for infant mortality associated with necrotizing enterocolitis in the United States.

METHODS

Necrotizing enterocolitis-associated deaths and infant mortality rates from 1979 through 1992 were determined by means of US multiple cause-of-death and linked birth/infant death data.

RESULTS

Annual necrotizing enterocolitis infant mortality rates decreased from 1979 through 1986 but increased thereafter and were lower during the 3-year period before (1983 through 1985;11.5 per 100,000 live births) the introduction of surfactants than after (1990 through 1992; 12.3 per 100,000). Low-birthweight singleton infants who were Black male, or born to mothers younger than 17 had increased risk for necrotizing enterocolitis-associated death.

CONCLUSIONS

As mortality among low-birth weight infants continues to decline and smaller newborns survive early causes of death, necrotizing enterocolitis-associated infant mortality may increase.

The effect of antenatal phenobarbital therapy on neonatal intracranial hemorrhage in preterm infants

BACKGROUND

The administration of phenobarbital to pregnant women before delivery has been thought to decrease the frequency of intracranial hemorrhage in preterm infants. To evaluate this potential neuroprotective therapy further, we determined the effect of antenatal administration of phenobarbital on the frequency of neonatal intracranial hemorrhage and early death.

METHODS

We studied 610 women who were 24 to 33 weeks pregnant and who were expected to deliver their infants within 24 hours. The women were randomly assigned to receive either phenobarbital (10 mg per kilogram of body weight) or placebo intravenously, followed by maintenance doses until delivery or 34 weeks of gestation. The infants born to these women underwent cranial ultrasonography to detect the presence of intracranial hemorrhage.

RESULTS

There were 309 women in the phenobarbital group and 301 in the placebo group. A total of 247 women (80 percent) in the phenobarbital group and 235 (78 percent) in the placebo group delivered within 24 hours after infusion of the study drug or administration of the last maintenance dose. Intracranial hemorrhage or early death occurred in 83 of the 344 infants born to the women in the phenobarbital group (24 percent) and in 74 of the 324 born to the women in the placebo group (23 percent; risk ratio for the infants in the phenobarbital group, 1.1; 95 percent confidence interval, 0.8 to 1.4). Among infants born before 34 weeks' gestation in whom ultrasonographic studies were performed, intracranial hemorrhage was diagnosed in 70 of 311 infants in the phenobarbital group (23 percent) and 64 of 279 in the placebo group (23 percent; risk ratio, 1.0; 95 percent confidence interval, 0.8 to 1.4).

CONCLUSIONS

Antenatal administration of phenobarbital does not decrease the risk of intracranial hemorrhage or early death in preterm infants.

Vitamin A to prevent bronchopulmonary dysplasia in very-low-birth-weight infants: has the dose been too low? The NICHD Neonatal Research Network

OBJECTIVE

Inconsistent effects of vitamin A supplementation on prevention of bronchopulmonary dysplasia have been reported. Meta-analysis of these reports resulted in a relative risk of 0.69-1.02 for death or bronchopulmonary dysplasia associated with vitamin A supplementation. Effective dosage regimens or serum retinol concentrations have not been determined in previous reports. The purpose of this pilot study was to define a vitamin A regimen that produces serum retinol concentrations of 25-55 micrograms/dl.

STUDY DESIGN

In this three-phase study, 91 infants (mean birth weight 799-864 g) were enrolled. Vitamin A was administered three times/week for 4 weeks at an average daily dose of 986-2143 IU/day. Physical examinations were performed and serum retinol specimens were collected weekly to assess clinical signs of toxicity.

RESULTS

The majority of serum retinol concentrations remained < 25 micrograms/dl until an intramuscular vitamin A dose of 5000 IU/dose three times/week was used. No clinical signs of toxicity were associated with the higher dosage and higher serum concentrations of vitamin A.

CONCLUSION

A large clinical trial of vitamin A supplementation with 5000 IU/dose three times/week (25-114% more than the dose used in the three published clinical trials) is needed to assess whether vitamin A supplementation safely reduces the risk of bronchopulmonary dysplasia in very-low-birth-weight infants.

The global impact of neonatal infection

The 1996 World Health Report highlights the global importance of infectious diseases, especially among young children, and stresses the impact of new or emerging diseases. Neonatal infections are old diseases. What is needed is a new recognition that they are important causes of morbidity and mortality and that simple interventions are available that can make a significant impact on the incidences of infection and death related to infection.

Early-onset sepsis in very low birth weight neonates: a report from the National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

Early-onset sepsis (occurring within 72 hours of birth) is included in the differential diagnosis of most very low birth weight (VLBW) neonates. To determine the current incidence of early-onset sepsis, risk factors for disease, and the impact of early-onset sepsis on subsequent hospital course, we studied a cohort of 7861 VLBW neonates (401 to 1500 gm) admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991-1993).

METHODS

The NICHD Neonatal Research Network maintains a prospectively collected registry on all VLBW neonates born or cared for at participating centers. Data from this registry were analyzed retrospectively.

RESULTS

Blood culture-proven early-onset sepsis was uncommon, occurring in only 1.9% of VLBW neonates. Group B streptococcus was the most frequent pathogen associated with early-onset sepsis (31%), followed by Escherichia coli (16%) and Haemophilus influenzae (12%). Decreasing gestational age was associated with increased rates of infection. Antibiotic therapy for suspected sepsis is frequently initiated at birth in VLBW neonates. Almost half of the infants in this cohort were considered to have clinical sepsis and continued to receive antibiotics for 5 or more days, despite a negative blood culture result in 98% of cases. These findings underscore the difficulty of ruling out sepsis in the symptomatic immature neonate and the special concern for culture-negative clinical sepsis in the face of maternal antibiotic use. Neonates with early-onset sepsis were significantly more likely to have subsequent comorbidities, including severe intraventricular hemorrhage, patent ductus arteriosus, and prolonged assisted ventilation. Although 26% of VLBW neonates with early-onset sepsis died, only 4% of the 950 deaths that occurred in the first 72 hours of life were attributed to infection. For those infants discharged alive, early-onset sepsis was associated with a significantly prolonged hospital stay (86 vs 69 days; p <0.02).

CONCLUSIONS

Early-onset sepsis remains an important but uncommon problem among VLBW preterm infants. Improved diagnostic strategies are needed to enable the clinician to distinguish between the infected and the uninfected VLBW neonate with symptoms and to target continued antibiotic therapy to those who are truly infected.

Late-onset sepsis in very low birth weight neonates: a report from the National Institute of Child Health and Human Development Neonatal Research Network

OBJECTIVE

Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 7861 VLBW (401 to 1500 gm) neonates admitted to the 12 National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers during a 32-month period (1991 to 1993).

METHODS

The NICHD Neonatal Research Network maintains a prospectively collected registry of all VLBW neonates cared for at participating centers. Data from this registry were analyzed retrospectively.

RESULTS

Of 6911 infants who survived beyond 3 days, 1696 (25%) had one or more episodes of blood culture-proven sepsis. The vast majority of infection (73%) were caused by gram-positive organisms, with coagulase-negative staphylococci accounting for 55% of all infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of infection included intubation, respiratory distress syndrome, prolonged ventilation, bronchopulmonary dysplasia, patent ductus arteriosus, severe intraventricular hemorrhage, and necrotizing enterocolitis. Among infants with bronchopulmonary dysplasia, those with late-onset sepsis had a significantly longer duration of mechanical ventilation (45 vs 33 days; p <0.01). Late-onset sepsis prolonged hospital stay: the mean number of days in the hospital for VLBW neonates with and without late-onset sepsis was 86 and 61 days, respectively (p <0.001). Even after adjustment for other complications of prematurity, including intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia, infants with late-onset sepsis had a significantly longer hospitalization (p <0.001). Moreover, neonates in whom late-onset sepsis developed were significantly more likely to die than those who were uninfected (17% vs 7%; p <0.000 1), especially if they were infected with gram-negative organisms (40%) or fungi (28%). Deaths attributed to infection increased with increasing chronologic age. Whereas only 4% of deaths in the first 3 days of life were attributed to infection, 45% of deaths after 2 weeks were related to infection.

CONCLUSIONS

Late-onset sepsis is a frequent and important problem among VLBW preterm infants. Successful strategies to decrease late-onset sepsis should decrease VLBW mortality rates, shorten hospital stay, and reduce costs.

Interlaboratory variability of bilirubin measurements

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

Interlaboratory variability of bilirubin measurements

During an 8-month study, 14 laboratories used automated analytical systems to measure total bilirubin concentrations in lyophilized bovine specimens containing 38, 169, and 253 micromol/L bilirubin (2.2, 9.9, and 14.8 mg/dL, respectively). The measured mean +/- SD (n, range) were: 39 +/- 7 micromol/L (n = 90, 31-53) [2.3 +/- 0.4 mg/dL (1.8-3.1)]; 176 +/- 29 micromol/L (n = 89, 146-222) [10.3 +/- 1.7 mg/dL (8.5-13.0)]; and 260 +/- 43 micromol/L (n = 103, 208-316) [15.2 +/- 2.5 mg/dL (12.1-18.5)]. In comparison with target values, measurements were consistently lower at 4, higher at 6, and within +/- 4% at 4 laboratories for each of the three concentrations. The measured values for each concentration remained fairly constant during the study at each laboratory. We conclude that bilirubin measurements differed significantly from the established target values at most of the participating laboratories.

Very-low-birth-weight outcomes of the National Institute of Child Health and Human Development Neonatal Research Network, May 1991 through December 1992

OBJECTIVES

Our goals were to determine the mortality risk for infants weighing 501 to 1500 gm according to gestational age, birth weight, and gender and to document birth weight-related changes in mortality and morbidity over a 5-year time period.

STUDY DESIGN

In this observational study perinatal data were prospectively collected by the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from May 1991 through December 1992 and compared with the corresponding data from 1987 through 1990. Standard definitions were used to record sociodemographic factors, perinatal events, and the neonatal course to 120 days of life, discharge, or death.

RESULTS

The 1991 and 1992 cohort included 4279 in-born infants. Among their mothers 10% were < 18 years old; 55% were black, 31% were white, and 11% were Hispanic; 14% had received no prenatal care; and 20% had received antenatal corticosteroids. Multiple gestations accounted for 20% of the births. Fifty percent of the infants were delivered by cesarean section. During 1991 and 1992 the overall survival for infants weighing 501 to 1500 gm at birth was 81%, compared with 74% in 1987 and 1988. Survival at birth weight 501 to 750 gm was 44%; it was 81% at 751 to 1000 gm, 92% at 1001 to 1250 gm, and 95% between 1251 and 1500 gm. Female infants had a significantly greater chance of surviving than male infants at similar birth weights and gestational ages. At any given gestational age, smaller infants were less likely to survive. Survival in all birth weight categories increased between 1987 and 1992, without accompanying increases in medical morbidity. Major morbidity increased with decreasing birth weight and included late-onset septicemia 22%, chronic lung disease (oxygen dependence at 36 weeks' corrected age) 18%, severe intraventricular hemorrhage (grades III and IV) 11%, and necrotizing enterocolitis 5%. Twelve percent of all infants were treated with corticosteroids for chronic lung disease, including 36% of infants who were oxygen dependent at age 28 days. The mean length of hospital stay was 69 days for survivors and 18 days for infants who died.

CONCLUSIONS

Mortality for infants between 501 and 1500 gm at birth has declined over the past 5 years. There are interactions between birth weight, gestational age, gender, and survival rate. This increase in survival was not accompanied by an increase in medical morbidity.

Pseudomonas aeruginosa infection in very low birth weight infants: a case-control study

The perinatal histories and hospital courses of all neonates born at Grady Memorial Hospital who developed Pseudomonas aeruginosa sepsis or meningitis in the 5-year period 1989-1993 were reviewed. In addition a case-control study was performed to evaluate selected risk factors for this infection. Twenty-one patients had one or more blood cultures positive for P. aeruginosa. An additional patient had P. aeruginosa meningitis without bacteremia. All infections occurred after 5 days of age. The overall incidence of P. aeruginosa infection was 0.7/1000 live births. All cases occurred in infants < 1500 g at birth, for a birth weight-specific rate of 19.5/1000 livebirths in this weight class. Clinical manifestations of disease did not distinguish P. aeruginosa from other causes of fulminant neonatal sepsis. Fifty percent of cases died. Mortality was inversely related to postnatal age at diagnosis. The 22 cases were compared with 44 controls matched for birth weight, gestational age, sex, duration of hospital stay and admission date. Cases were more likely than controls to have a history of feeding intolerance, interrupted enteral intake and prolonged parenteral hyperalimentation. Case infants received intravenous antibiotics for a significantly longer period of time than did controls. There was an association between P. aeruginosa sepsis and necrotizing enterocolitis (36% cases vs. 7% of controls had prior or concurrent necrotizing enterocolitis, P < 0.01). In summary P. aeruginosa sepsis is primarily a late onset nosocomial infection in very low birth weight infants. The case fatality rate of 50% in this series emphasizes its continued importance.

Intravenous immune globulin prophylaxis of late-onset sepsis in premature neonates

To determine whether a single dose of intravenously administered immune globulin (IVIG) decreases late-onset sepsis in premature infants, we prospectively entered 753 neonates with birth weight 500 to 2000 gm, gestation < or = 34 weeks, and age < or = 12 hours into a multicenter, double-blind, controlled trial. Infants were randomly selected to receive a single intravenous infusion, 10 ml/kg, of either IVIG (500 mg/kg) or albumin (5 mg/kg) and were observed for 8 weeks for infection. Maternal and neonatal risk factors for infection did not differ between groups. Although serum IgG values before infusion were related to gestation (R = 0.62), the change in serum IgG or half-life of IgG after IVIG infusion was not (R < or = 0.09). The serum IgG concentration was increased (p < 0.05) in IVIG-treated patients for 8 weeks. There were 88 episodes of late-onset sepsis in 79 neonates (10.5%). Causative organisms included the following: Staphylococcus epidermidis (37 episodes), Enterococcus (9), Staphylococcus aureus (7), Candida (6), Escherichia coli (6), and multiple organisms (11). Sepsis, death, and death as a result of infection were unaffected by treatment. We conclude that a single infusion of IVIG, 500 mg/kg, shortly after birth was not effective prophylaxis for late-onset infection in premature neonates. Future studies of late-onset sepsis prophylaxis should consider IVIG with known pathogen-specific antibody concentrations against organisms causing these infections, in particular S. epidermidis.

Epidemiology of necrotizing enterocolitis

The descriptive epidemiology of necrotizing enterocolitis (NEC) is presented. Areas addressed include incidence, race, sex, age of onset, mortality rates, and endemic versus epidemic disease. Both descriptive and case control studies are reviewed to uncover clues relevant to the causes, pathogenesis, and prevention of NEC.

Recognition and medical management of necrotizing enterocolitis

The signs and symptoms associated with necrotizing enterocolitis (NEC) and the common scenarios in which NEC is observed are described to help physicians appreciate the breadth of this illness and to aid in the identification and diagnosis of those affected. An outline for medical management of infants with NEC is presented, based on the pathophysiology of this disease.

Immunoglobulin secretion by the normal and the infected newborn infant

The development of quantitative single-cell immunoassays has provided a novel opportunity to demonstrate the isotype-specific immunoglobulin responses in normal and infected neonates. The reverse enzyme-linked immunospot assay was used to determine the number of immunoglobulin-secreting cells (IgSCs) in peripheral blood. Baseline numbers of IgSCs were established in 69 uninfected term and preterm infants within 5 days of birth; values above the 99th percentile were considered elevated. The IgSCs were also measured in 266 infants with proved or suspected infections or congenital anomalies. A subset of newborn infants was retested weekly. Few IgSCs (mostly IgMSCs) were detected within 5 days of birth in uninfected neonates, but by 1 month 77% had increased numbers of IgSCs, primarily IgASCs. Sixty-three (24%) of 266 study infants had increased IgSCs on initial sampling (predominantly IgMSCs); these included infants as immature as 25 to 27 weeks of gestational age; elevations in IgSCs were most frequent in infants with intrauterine infections. Increased numbers of IgSCs were uncommon in infants with early-onset sepsis in the first 5 days but were frequent by the second week, consistent with acquisition of infection near the time of delivery. We conclude that the presence of elevated numbers of IgSCs soon after birth may be a useful surrogate marker of untreated intrauterine infection. The development of predominantly IgASCs in the first month of life suggests postnatal exposure to common mucosal antigens.

Clinical and serologic evaluation of neonates for congenital syphilis: a continuing diagnostic dilemma

Neonates born to women with reactive serologic tests for syphilis were studied; the total of 116 included 18 who were symptomatic, 60 asymptomatic but possibly infected, and 38 asymptomatic and probably uninfected. The fluorescent treponemal antibody-absorption (FTA-ABS) 19S IgM test and an IgM capture ELISA for Treponema pallidum, both treponema-specific assays, and the reverse enzyme-linked immunospot (RELISPOT), which detects immunoglobulin-secreting cells and is a nonspecific indicator of infection, were evaluated. Sensitivities among symptomatic neonates were 88% (IgM ELISA), 73% (FTA-ABS), and 78% (RELISPOT). Specificities ranged from 97% to 100%. A major problem has been the inability to identify which asymptomatic but possibly infected neonate is really uninfected. Among 41 such babies who had all three tests done, 93% were negative by all assays, suggesting they were uninfected or recently infected. Strategies to accurately identify the truly uninfected asymptomatic newborn would prevent the unnecessary hospitalization of all at-risk infants, resulting in improved quality of care and reduced costs.

Intravenous immune globulin therapy for early-onset sepsis in premature neonates

Newborn infants may have IgG deficiencies that increase their susceptibility to bacterial infection. To determine whether intravenous immune globulin (IVIG) therapy improves survival rates in early-onset sepsis, we prospectively entered 753 neonates (birth weight 500 to 2000 gm, gestation less than or equal to 34 weeks, age less than or equal to 12 hours) into a multicenter, double-blind, controlled trial. Blood culture specimens were obtained and infants randomly assigned to receive 10 ml (per kilogram) intravenously of a selected IVIG (500 mg/kg) or albumin (5 mg/kg) preparation. Maternal and neonatal risk factors were not different between groups. Thirty-one babies (4.2%) had early-onset sepsis; the causative organisms were group B streptococcus (12 babies), Escherichia coli (6), and others (13). Of these 31 neonates, 7 (23%) died. Total serum IgG was higher for 7 days after IVIG therapy than after albumin treatment (p less than 0.05). During these 7 days, 5 (30%) of 17 albumin-treated and none of 14 IVIG-treated patients died (p less than 0.05). The survival rate at 56 days of age, however, was not significantly improved. Group B streptococcus type-specific IgG antibody was significantly increased after IVIG treatment and appeared to be related to the amount of IVIG specific antibody. Infusion-related adverse reactions were less frequent in patients receiving IVIG therapy (0.5%) than in those receiving albumin. The IVIG therapy in neonates with early-onset sepsis, while reducing the early mortality rate, did not significantly affect the overall survival rate. Further studies are necessary to confirm these findings and to determine more effective therapeutic regimens.

Early-onset group B streptococcal sepsis: a current assessment

Group B streptococcus (GBS) is a common cause of early-onset sepsis in neonates. The most recent reviews describing incidence, diagnosis, treatment, and outcome evaluated data on patients from the early 1980s. To obtain current information about this disease, we retrospectively evaluated data on neonates with GBS early-onset sepsis from nine hospitals in the United States between Jan. 1, 1987, and Dec. 31, 1989. There were 245 infants with GBS bacteremia identified among 61,809 live births, resulting in an incidence of 0.32%. Ninety-six infants (39%) were preterm (less than 38 weeks of gestational age). Maternal risk factors for infected preterm and term infants were similar. Antibiotics were administered during parturition in 10% of infants with bacteremia. Mothers of preterm infants received antibiotics up to 48 hours before delivery; mothers of term infants received antibiotics less than 4 hours before delivery. All preterm infants with bacteremia had symptoms; 22% of term infants with bacteremia had no symptoms. Group B streptococcal meningitis was confirmed in 6.3% of infants. Although 86% survived, GBS sepsis increased the birth weight-specific mortality rate up to eightfold in preterm infants and more than 40-fold in term infants. Although the incidence of GBS early-onset sepsis is not changing, we speculate that the improved birth weight-specific survival rate and the changing clinical presentation are due to improved intrapartum and neonatal management.

Prevention of perinatal transmission of the hepatitis B virus. Outcome of infants in a community prevention program

OBJECTIVE

To assess the outcome of infants born to hepatitis B surface antigen (HBsAg)-positive mothers who received prenatal and infant care in a large, public health care system.

DESIGN

Follow-up of a cohort of infants born to HBsAg-positive mothers.

SETTING

Large, urban hospital providing prenatal care and obstetric services to county health departments.

PARTICIPANTS

Forty-two infants born to HBsAg-positive women.

INTERVENTIONS

Prenatal testing of women and immunoprophylaxis of infants with hepatitis B immune globulin at birth and hepatitis B vaccine at birth and ages 1 and 6 months.

RESULTS

All 42 infants received hepatitis B immune globulin and the first dose of vaccine. Of forty-one infants (98%) who received the second dose of vaccine, 37 received it by age 4 months. Thirty-two infants (76%) completed the three-dose vaccine series by age 12 months, and 34 infants (81%) completed the series by age 18 months. The rate of completion of the hepatitis B vaccine series was comparable to that of infants receiving the third dose of diphtheria-pertussis-tetanus vaccine. Of 26 infants who completed the hepatitis B vaccine series and had follow-up serologic testing, 24 (92%) had adequate levels of antibody to HBsAg. Only one infant who did not complete the vaccine series had serologic evidence of hepatitis B virus infection. No infant was HBsAg-positive.

CONCLUSIONS

Public programs serving urban populations can effectively deliver hepatitis B immunoprophylaxis to infants born to HBsAg-positive mothers.