Outcome of neonates less than 30 weeks gestation with histologic chorioamnionitis

Clinical dilemma of positive histologic chorioamnionitis in term newborn

BACKGROUND

Although histologic chorioamnionitis (HCA) is known to be associated with poor outcomes in preterm infants, its clinical significance among term infants is not clearly known.

OBJECTIVES

To investigate the utility of HCA in determining early onset clinical sepsis (EOCS) among term newborns.

METHODS

The incidence of HCA and EOCS in term infants born during 2008-2009 was evaluated in a single center retrospective study (n = 3417). The predictive value of HCA for determining EOCS in term infants admitted to the neonatal intensive care unit (NICU) for suspected sepsis (n = 388) was quantified. Outcome of otherwise healthy term infants in the nursery with HCA was also investigated.

RESULTS

Overall, 11% of term infants with HCA also had EOCS. HCA was associated with increased risk for EOCS (OR 2.6, 95% confidence interval 1.6-4.2, P < 0.001) among term infants admitted to the NICU for suspected sepsis. No cases of EOCS were found among otherwise well-appearing infants in the nursery with HCA. Multiple logistic regression analysis indicated that addition of HCA does not increase the power of a model combining C-reactive protein (CRP) and immature to total neutrophil ratio in determining EOCS.

CONCLUSION

Although HCA in term infants is associated with EOCS, it did not improve the ability of CRP and immature to total neutrophil ratio to predict EOCS. Routine placental examination may not contribute to the diagnosis of EOCS in term infants.

Outcomes of very-low-birth-weight infants exposed to maternal clinical chorioamnionitis: a multicentre study

BACKGROUND

Chorioamnionitis is a recognized risk factor of preterm delivery; however, controversy still persists concerning the relationship between maternal inflammation and neonatal morbidity and mortality.

OBJECTIVE

To determine the incidence of clinical chorioamnionitis and its relationship to morbidity and mortality among very-low-birth-weight (VLBW) infants.

METHODS

This was a retrospective analysis of prospectively collected data of VLBW neonates ≤ 32 weeks' gestational age (GA) admitted to collaborating units in the Spanish SEN1500 Network between January 2008 and December 2011. Clinical chorioamnionitis was defined by obstetricians based on clinical findings, and neonatal outcomes were compared between exposed and non-exposed infants by multivariate logistic regression analysis.

RESULTS

During the study period, 11,464 VLBW newborns were admitted to our units and 10,026 were ≤ 32 weeks' GA. Among them, 8,330 (83.1%) had complete data and were included. Of these, 1,480 (17.8%) were exposed to maternal clinical chorioamnionitis. The incidence was higher at lower GA and, after adjusting for confounding factors, exposed infants had higher risks of early-onset neonatal sepsis (EONS) (10.0 vs. 2.8%; aOR 3.102; 95% CI 2.306-4.173; p < 0.001) and necrotizing enterocolitis (NEC) (11.2 vs. 7.7%; aOR 1.300; 95% CI 1.021-1.655; p < 0.033), but lower risks of patent ductus arteriosus (PDA) (43.2 vs. 34.9%; aOR 0.831; 95% CI 0.711-0.971; p < 0.02) and late-onset bacterial sepsis (LONS) (36.6 vs. 32.5%; aOR 0.849; 95% CI 0.729-0.989; p < 0.035). There were no differences in mortality between the groups.

CONCLUSIONS

The incidence of maternal clinical chorioamnionitis is inversely related to GA at delivery, and in VLBW infants ≤ 32 weeks' GA it is associated with higher risks of EONS and NEC, but lower risks of PDA and LONS. We did not found differences in survival.

Antibiotic Therapy for Premature Rupture of Membranes and Preterm Labor and Effect on Fetal Outcome

In Germany almost 10 % of children are born before the end of 37th week of gestation. In at least one quarter of these cases, ascending infection of the vagina plays a causative role, particularly during the early weeks of gestation. If, in addition to the decidua, the amniotic membrane, amniotic fluid and the umbilical cord are also affected, infection not only triggers uterine contractions and premature rupture of membranes but also initiates a systemic inflammatory reaction on the part of the fetus, which can increase neonatal morbidity. Numerous studies and meta-analyses have found that antibiotic therapy prolongs pregnancy and reduces neonatal morbidity. No general benefit of antibiotic treatment was found for premature uterine contractions. But it is conceivable that a subgroup of pregnant women would benefit from antibiotic treatment. It is important to identify this subgroup of women and offer them targeted treatment. This overview summarizes the current body of evidence on antibiotic treatment for impending preterm birth and the effect on neonatal outcomes.

Histological chorioamnionitis and bronchopulmonary dysplasia: a retrospective cohort study

OBJECTIVE

To examine the association between histological chorioamnionitis (HC) with or without fetal inflammatory response (FIR) and bronchopulmonary dysplasia (BPD) in preterm infants.

STUDY DESIGN

We conducted a retrospective cohort study of infants born at <29 weeks gestation admitted to the neonatal intensive care unit from 2000 to 2006, who had placental histology. We compared the incidence of BPD among three groups: No HC group, HC without FIR group and HC with FIR group. The multivariable model based on generalized estimating equation was fitted to estimate the adjusted risk ratios (aRR) and 95% confidence intervals (CIs) for BPD and combined outcome of BPD or death.

RESULT

Of 529 infants, 84 (16%) had HC without FIR, 186 (35%) had HC with FIR and 259 (49%) had no HC. Compared with the no HC group, HC with and without FIR group infants were of lower gestational age and singleton births. Multivariable modeling based on generalized estimating equation revealed that HC with FIR is associated with decreased risk of both BPD (aRR 0.88, 95% CI 0.81 to 0.95) and the combined outcome of BPD or death (aRR 0.91, 95% CI 0.86 to 0.97). HC without FIR showed a trend toward reduction in BPD (aRR 0.93, 95% CI 0.86 to 1.00).

CONCLUSIONS

HC with FIR is associated with decreased risk of both BPD and the combined outcome of BPD or death in preterm infants.

The association between histological chorioamnionitis, funisitis and neonatal outcome in women with preterm prelabor rupture of membranes

OBJECTIVE

To determine the impact of histological chorioamnionitis (HCA) and funisitis on neonatal outcome in preterm prelabor rupture of membranes (PPROM) pregnancies.

METHODS

Women with PPROM between 24 + 0 to 36 + 6 weeks of gestation, admitted to the Department of Obstetrics and Gynecology at the University Hospital Hradec Kralove in the Czech Republic, between July 2008 and October 2010, were enrolled in the study (n = 231).

RESULTS

The incidence of early-onset sepsis (EOS) differed significantly in neonates born to women with and without HCA, after adjustment for gestational age (11% versus 1%, p = 0.011). The incidence of EOS in neonates was also significantly different, after adjustment for gestational age, in cases with and without funisitis (18% versus 4%, p = 0.002). The same was also found for retinopathy of prematurity (ROP) cases with and without funisitis (23% versus 4%, p = 0.014), after adjustment for gestational age.

CONCLUSIONS

HCA and funisitis increase the risk of adverse perinatal outcome in PPROM pregnancies.

Chorioamnionitis as a risk factor for necrotizing enterocolitis: a systematic review and meta-analysis

OBJECTIVE

To accumulate available evidence regarding the association between antenatal inflammation and necrotizing enterocolitis (NEC).

STUDY DESIGN

A systematic literature search was performed using Medline, Embase, Cochrane Library, ISI Web of Knowledge, and reference hand searches. Human studies published in English that reported associations between chorioamnionitis or other indicators of antenatal inflammation and NEC were eligible. Relevant associations were extracted and reported. Studies reporting associations between histological chorioamnionitis (HC) and NEC, HC with fetal involvement and NEC, and clinical chorioamnionitis and NEC were pooled in separate meta-analyses.

RESULTS

A total of 33 relevant studies were identified. Clinical chorioamnionitis was significantly associated with NEC (12 studies; n = 22 601; OR, 1.24; 95% CI, 1.01-1.52; P = .04; I(2) = 12%), but the association between HC and NEC was not statistically significant (13 studies; n = 5889; OR, 1.39; 95% CI, 0.95-2.04; P = .09; I(2) = 49%). However, HC with fetal involvement was highly associated with NEC (3 studies; n = 1640; OR, 3.29; 95% CI, 1.87-5.78; P ≤ .0001; I(2) = 10%). Selection based on study quality did not affect the results. No indications of publication bias were apparent. Multivariate analyses in single studies generally attenuated the reported associations. Several associations between other markers of antenatal inflammation and NEC are reported.

CONCLUSION

Currently available evidence supports a role for antenatal inflammation in NEC pathophysiology. This finding emphasizes the need to further study the underlying mechanisms and evaluate potential interventions to improve postnatal intestinal outcomes.

Chorioamnionitis and lung injury in preterm newborns

There is a strong evidence that histologic chorioamnionitis is associated with a reduction of incidence and severity of respiratory distress syndrome (RDS). Short-term maturational effects on the lungs of extremely premature infants seem to be, however, accompanied by a greater susceptibility of the lung, eventually contributing to an increased risk of bronchopulmonary dysplasia (BPD). Genetic susceptibility to BPD is an evolving area of research and several studies have directly related the risk of BPD to genomic variants. There is a substantial heterogeneity across the studies in the magnitude of the association between chorioamnionitis and BPD, and whether or not the association is statistically significant. Considerable variation is largely dependent on differences of inclusion and exclusion criteria, as well as on clinical and histopathological definitions. The presence of significant publication bias may exaggerate the magnitude of the association. Controlling for publication bias may conduct to adjusted results that are no longer significant. Recent studies generally seem to confirm the effect of chorioamnionitis on RDS incidence, while no effect on BPD is seen. Recent data suggest susceptibility for subsequent asthma to be increased on long-term followup. Additional research on this field is needed.

Predictors of bronchopulmonary dysplasia

Although significant advances in respiratory care have been made in neonatal medicine, bronchopulmonary dysplasia (BPD) remains the most common serious pulmonary morbidity in premature infants. The development of BPD is the result of the complex interactions between multiple perinatal and postnatal factors. Early identification of infants at the most risk of developing BPD through the use of estimators and models may allow a targeted approach at reducing BPD in the future.

Perinatal risk factors for bronchopulmonary dysplasia in extremely low gestational age infants: a pregnancy disorder-based approach

OBJECTIVE

To analyze risk factors for bronchopulmonary dysplasia (BPD) or death according to the condition leading to extremely preterm birth, preterm labor, or vascular disorders.

STUDY DESIGN

Retrospective study of all premature births before 28 weeks of gestation in a single Level III institution. Mother/infants were attributed to the "preterm labor" or "vascular disorder" group according to the condition leading to delivery. Characteristics and outcomes were compared between groups. Independent risk factors for BPD or the composite outcome "BPD or death" were identified within each group.

RESULTS

Three hundred ninety-six infants from 349 pregnancies were characterized for perinatal characteristics. BPD was significantly more frequent in the vascular disease group than in the preterm labor group (29% vs 11%, P < .01). Independent risk factors of BPD were a low gestational age in the preterm labor group and severe growth restriction in the vascular disease group.

CONCLUSION

Classification of preterm birth according to the condition leading to delivery might help to reduce confounding of risk factors for BPD. Intrauterine vascular disorders are significantly associated with BPD.

Histologic chorioamnionitis is associated with reduced risk of late-onset sepsis in preterm infants

BACKGROUND

Histologic chorioamnionitis (HCA) is implicated in the onset of preterm labor and delivery. Chorioamnionitis is a known risk factor for early-onset sepsis and may modulate postnatal immunity. Preterm infants are at greatly increased risk of late-onset sepsis (LOS), particularly with coagulase-negative staphylococci (CoNS), but the impact of HCA on the risk of LOS is unknown.

METHODS

Eight hundred thirty-eight preterm infants born at <30 weeks gestational age at a single tertiary center were included. Histologic examination of placenta and extraplacental membranes was performed, and clinical data were extracted from hospital databases. The influence of HCA on the incidence of early-onset sepsis and LOS was examined using logistic regression analysis and Cox proportional hazards regression.

RESULTS

Mean gestational age was 26.9 ± 1.9 weeks, and mean birth weight was 936 ± 277 g. Two hundred and seventy-six (33%) of 838 infants developed LOS. The presence of fetal or maternal HCA, or maternal HCA and fetal HCA alone, was associated with a significantly decreased risk of LOS with any organism. Histologic chorioamnionitis correlated with a significantly decreased risk of CoNS LOS.

CONCLUSIONS

HCA is associated with a significantly reduced risk of acquiring LOS, both with CoNS and other bacteria. Perinatal inflammation may enhance the functional maturation of the preterm immune system and provide protection against LOS in high-risk preterm infants.

Cluster analysis of placental inflammatory proteins can distinguish preeclampsia from preterm labor and premature membrane rupture in singleton deliveries less than 28 weeks of gestation

PROBLEM

Inflammation within the preterm placenta is common and leads to adverse outcomes for premature infants. The risks of complications are different between iatrogenic (e.g. PE) and spontaneous (e.g. PL and membrane rupture) causes of preterm delivery, suggesting different underlying biology contributes to these placental conditions.

METHOD OF STUDY

Thirty preterm singleton placentas from the following groups were analyzed: (i) severe PE, (ii) preterm premature membrane rupture (pPROM), and (iii) PL. Proinflammatory and anti-inflammatory cytokines, adhesion and angiogenic molecules were measured in placental lysates using a multiplex assay. K-means cluster analysis was used to generate patterns of protein level intensity.

RESULTS

Three cluster patterns were apparent. Placentas from PE had high levels of vascular endothelial growth factor (VEGF) combined with low levels of acute inflammatory proteins (IL-1β, IL-18, IL-6, TNF-α), low IL-1 RA, and high transforming growth factor β (TGF-β). PL and pPROM had higher anti-inflammatory IL-1 RA and thrombomodulin combined with lower VEGF, regardless of proinflammatory cytokines and adhesion molecules. Half of the PL and pPROM cases had clusters of heightened inflammatory responses (lower TGF-β clustered with higher intensity of inflammatory mediators).

CONCLUSION

Discriminating protein patterns were elucidated and may serve as a foundation from which to understand the biologic mechanisms underlying these pregnancy complications.

Targeting inflammation to prevent bronchopulmonary dysplasia: can new insights be translated into therapies?

Bronchopulmonary dysplasia (BPD) frequently complicates preterm birth and leads to significant long-term morbidity. Unfortunately, few therapies are known to effectively prevent or treat BPD. Ongoing research has been focusing on potential therapies to limit inflammation in the preterm lung. In this review we highlight recent bench and clinical research aimed at understanding the role of inflammation in the pathogenesis of BPD. We also critically assess currently used therapies and promising developments in the field.

Chorioamnionitis, respiratory distress syndrome and bronchopulmonary dysplasia in extremely low birth weight infants

OBJECTIVE

To determine if histologic chorioamnionitis (HC) in the presence of respiratory distress syndrome (RDS) augments adverse pulmonary outcomes in extremely low birth weight (ELBW) infants.

STUDY DESIGN

We retrospectively identified 184 ELBW infants who were born at and admitted to the neonatal intensive care units between June 2005 and June 2009.

RESULTS

The mean gestational age of the cases was 27 ± 2 weeks, and the mean birth weight was 791 ± 147 g. A total of 88% (161/184) of patients developed bronchopulmonary dysplasia (BPD). HC was observed in 71 of 238 infants (39%). When infants were divided on the basis of the presence or absence of HC and RDS, the incidence of moderate or severe BPD and duration of oxygen requirement were greater in the HC+RDS+ group than in the HC-RDS+ or HC+RDS- groups. The combination of prenatal (HC) and postnatal (RDS) injuries increased significantly the risk for BPD. In the multivariate analysis, the significant predictors of developing BPD were low gestational age (odds ratio (OR), 0.6; confidence interval (CI), 0.4 to 0.7) and exposure to both HC and RDS (OR, 4.7; CI, 1.1 to 20.2).

CONCLUSION

The HC and RDS work synergistically to induce lung injury in ELBW infants. Chorioamnionitis may interact with RDS to further increase the risk of BPD, despite either HC or RDS could not show independent significant association with BPD.

Neonatal and neurodevelopmental outcomes of very low birth weight infants with histologic chorioamnionitis

OBJECTIVE

To determine survival and neurodevelopmental outcomes at 18 months corrected age among very low birth weight infants ≤ 32 weeks gestation with histologic chorioamnionitis.

STUDY DESIGN

Observational, regionalized, single-center cohort study with prospective follow-up.

RESULTS

Of the 628 infants meeting the selection criteria, 303 (48%) were born to mothers with evidence of histologic chorioamnonitis. Neonates with histologic chorioamnonitis were of lower gestational age and birth weight. On univariate analysis, they were more likely to have hypotension, bronchopulmonary dysplasia, severe intraventricular hemorrhage, severe retinopathy of prematurity, early-onset sepsis, and death. Infants with histologic chorioamnonitis were more likely to have any neurodevelopmental impairment, specifically, mental delay with a lower mental developmental index. When adjusting for perinatal variables, histologic chorioamnonitis had a protective effect on mortality rates (adjusted OR = 0.44, 95% CI: 0.24-0.8; P = .01; n = 619), had a nonsignificant effect on neurodevelopmental impairment (adjusted odds ratio = 1.33, 95% CI: 0.82-2.17; P = .25; n = 496), and was associated with a 4-point lower mental developmental index at 18-months follow-up (adjusted difference -3.93, 95% CI: -7.52 to -0.33; P = .03; n = 496).

CONCLUSIONS

Although infants with histologic chorioamnonitis were at an increased risk for death and neurodevelopmental impairment, after multivariate analyses, histologic chorioamnonitis was not associated with adverse long-term outcomes. Results suggest fetal protection from treatment-responsive maternal infection and inflammation.

Toll-like receptors in pregnancy disorders and placental dysfunction

The Toll receptor was originally identified as a regulator of embryogenesis in Drosophila. Toll-like receptors (TLRs) in mammals recognize infectious agents and other danger signals. Activation of TLRs on trophoblast influences immune cell recruitment, cytokine secretion, and decidual responses to invading pathogens during pregnancy. Importantly, biological effects of TLR signal transduction at multiple maternal-fetal interfaces may contribute to several pregnancy pathologies associated with placental dysfunction, including pre-eclampsia, intrauterine growth restriction, and preterm labor. We herein discuss mechanisms by which TLRs regulate the maternal immune response during normal and abnormal gestation, and we highlight recent data that assign a role to TLRs in the pathophysiology of selected pregnancy-associated complications.

Expectant management of preterm premature rupture of membranes: is it all about gestational age?

OBJECTIVE

We sought to compare neonatal outcome in cases of uncomplicated preterm premature rupture of membranes (PPROM) (ie, no evidence of clinical chorioamnionitis, placental abruption, or fetal distress) with that of spontaneous preterm deliveries (PTDs) and to determine the effect of the latency period.

STUDY DESIGN

The study group included women with PPROM at gestational age 28⁰(/)⁷-33⁶(/)⁷ weeks (n = 488). Neonatal outcome was compared with a matched control group of women with spontaneous PTD (n = 1464).

RESULTS

Neonates in the uncomplicated PPROM group were at increased risk for composite adverse outcome (53.7% vs 42.0%; P < .001), mortality (1.6% vs 0.0%; P < .001), respiratory morbidity (32.8% vs 26.4%; P = .006), necrotizing enterocolitis, jaundice, hypoglycemia, hypothermia, and polycythemia. Neonatal adverse outcome was more likely in cases of latency period >7 days, oligohydramnios, male fetus, and nulliparity.

CONCLUSION

Consultation regarding prematurity-related morbidity in infants exposed to uncomplicated PPROM cannot be extrapolated from PTDs and should be stratified by the duration of the latency period and the other risk factors identified in the current study.

Antenatal steroids and neonatal outcome after chorioamnionitis: a meta-analysis

BACKGROUND

There is debate concerning the safety and efficacy of antenatal steroids in preterm labour with suspected intrauterine infection (chorioamnionitis).

OBJECTIVES

We performed a systematic literature review and meta-analysis aimed at evaluating the efficacy and safety of antenatal steroids in clinical and histological chorioamnionitis.

SEARCH STRATEGY

MEDLINE, EMBASE, BioMed Central and the Cochrane databases were searched using the terms 'chorioamnionitis OR intrauterine infection' and '*steroids OR *corticoids'.

SELECTION CRITERIA

Studies that reported selected neonatal outcome measures in preterm infants with clinical or histological chorio-amnionitis, according to antenatal steroid exposure, were eligible.

DATA COLLECTION AND ANALYSIS

Study selection, data extraction and data analysis were performed by two independent investigators. The meta-analysis techniques used included: Mantel-Haenszel analysis; an assessment of study heterogeneity using the Q statistic; and Egger's regression test and funnel plots, to assess publication bias.

MAIN RESULTS

Seven observational studies were included. In histological chorioamnionitis (five studies), antenatal steroids were associated with reduced mortality (OR = 0.45; 95% CI = 0.30-0.68; P = 0.0001), respiratory distress syndrome (OR = 0.53; 95% CI = 0.40-0.71; P < 0.0001), patent ductus arteriosus (OR = 0.56; 95% CI = 0.37-0.85; P = 0.007), intraventricular haemorrhage (IVH; OR = 0.35; 95% CI = 0.18-0.66; P = 0.001) and severe IVH (OR = 0.39; 95% CI = 0.19-0.82; P = 0.01). In clinical chorioamnionitis (four studies), antenatal steroids were associated with reduced severe IVH (OR = 0.29; 95% CI = 0.10-0.89; P = 0.03) and periventricular leucomalacia (OR = 0.35; 95% CI = 0.14-0.85; P = 0.02).

CONCLUSIONS

Antenatal steroids may be safe and reduce adverse neonatal outcome after preterm birth associated with chorioamnionitis. There is a need for randomised clinical trials to address this issue.

Moderate postnatal hyperoxia accelerates lung growth and attenuates pulmonary hypertension in infant rats after exposure to intra-amniotic endotoxin

To determine the separate and interactive effects of fetal inflammation and neonatal hyperoxia on the developing lung, we hypothesized that: 1) antenatal endotoxin (ETX) causes sustained abnormalities of infant lung structure; and 2) postnatal hyperoxia augments the adverse effects of antenatal ETX on infant lung growth. Escherichia coli ETX or saline (SA) was injected into amniotic sacs in pregnant Sprague-Dawley rats at 20 days of gestation. Pups were delivered 2 days later and raised in room air (RA) or moderate hyperoxia (O₂, 80% O₂ at Denver's altitude, ∼65% O₂ at sea level) from birth through 14 days of age. Heart and lung tissues were harvested for measurements. Intra-amniotic ETX caused right ventricular hypertrophy (RVH) and decreased lung vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2) protein contents at birth. In ETX-exposed rats (ETX-RA), alveolarization and vessel density were decreased, pulmonary vascular wall thickness percentage was increased, and RVH was persistent throughout the study period compared with controls (SA-RA). After antenatal ETX, moderate hyperoxia increased lung VEGF and VEGFR-2 protein contents in ETX-O₂ rats and improved their alveolar and vascular structure and RVH compared with ETX-RA rats. In contrast, severe hyperoxia (≥95% O₂ at Denver's altitude) further reduced lung vessel density after intra-amniotic ETX exposure. We conclude that intra-amniotic ETX induces fetal pulmonary hypertension and causes persistent abnormalities of lung structure with sustained pulmonary hypertension in infant rats. Moreover, moderate postnatal hyperoxia after antenatal ETX restores lung growth and prevents pulmonary hypertension during infancy.

Mechanisms of inflammatory lung injury in the neonate: lessons from a transgenic mouse model of bronchopulmonary dysplasia

The role of inflammation in the pathogenesis of bronchopulmonary dysplasia (BPD) is not well understood. By using a transgenic mouse expressing the inflammatory cytokine interleukin (IL)-1beta in the lung, we have shown that perinatal expression of IL-1beta causes a BPD-like illness in infant mice. We have used this model to identify mechanisms by which inflammation causes neonatal lung injury. Increased matrix metalloproteinase (MMP)-9 activity is associated with BPD. MMP-9 deficiency worsens alveolar hypoplasia in IL-1beta-expressing newborn mice, suggesting that MMP-9 has a protective role in neonatal inflammatory lung injury. The beta6 integrin subunit, an activator of transforming growth factor-beta, is involved in adult lung disease. Absence of the beta6 integrin subunit improves alveolar development in IL-1beta-expressing mice, suggesting that the beta6 integrin subunit is a pathogenetic factor in inflammatory lung disease in the newborn. The authors of clinical studies who have examined maternal inflammation as a risk factor for BPD have found variable results. We have shown that maternal IL-1beta production preceding fetal IL-1beta production prevents lung inflammation, alveolar hypoplasia, and airway remodeling in newborn IL-1beta-expressing mice. Thus, maternal inflammation may protect the newborn lung against subsequent inflammatory injury. In contrast, when maternal and fetal production of IL-1beta are induced simultaneously, the development of IL-1beta-induced lung disease in the newborn is not prevented.

Chorioamnionitis alters the response to surfactant in preterm infants

OBJECTIVE

To study the association between antenatal exposure to chorioamnionitis and the neonatal response to surfactant.

STUDY DESIGN

Prospective observational cohort of 301 preterm infants of gestational age < or = 32.0 weeks, 146 of whom received surfactant according to standardized criteria. Fraction of inspired oxygen (FiO(2)) requirement (using analysis of variance) and time to extubation (using Kaplan-Meier and Cox regression analyses) were compared between groups based on the presence of histological chorioamnionitis (HC) with or without fetal involvement (HC-, n = 88; HC + F-, n = 25; HC + F+, n = 33) and between infants who developed bronchopulmonary dysplasia (BPD) or died (n = 57) and BPD-free survivors (n = 89). Multiple logistic regression was performed to investigate the association between HC and BPD.

RESULTS

Compared with HC- infants, HC + F+ infants had significantly greater FiO(2) requirement and prolonged time to extubation postsurfactant, not accounted for by differences in gestational age and birth weight. Infants with BPD/death had a strikingly similar pattern of increased FiO(2) requirement postsurfactant. Moreover, in infants who received surfactant, HC + F+ status was associated with increased risk for BPD (odds ratio [OR] = 3.40; 95% confidence interval [CI] = 1.02-11.3; P = .047) and for BPD/death (OR = 2.72; 95% CI = 1.00-7.42; P = .049).

CONCLUSIONS

An impaired surfactant response was observed in preterm infants with severe chorioamnionitis and may be involved in the association between chorioamnionitis, mechanical ventilation, and the development of BPD.

The genetic susceptibility to respiratory distress syndrome

Previous studies to identify a genetic component to RDS have shown conflicting results. Our objectives were to evaluate and quantify the genetic contribution to RDS using data that comprehensively includes known environmental factors in a large sample of premature twins. Data from a retrospective chart review of twins born at < or =32 wk GA were obtained from two neonatal units. Mixed effects logistic regression (MELR) analysis was used to assess the influence of several independent covariates on RDS. A zygosity analysis, including the effects of additive genetic, common environmental and residual effects (ACE) factors, was performed to estimate the genetic contribution. Results reveal that the 332 twin pairs had a mean GA of 29.5 wk and birth weight (BW) of 1372 g. An MELR identified significant nongenetic covariates as male gender (p = 0.04), BW (p < 0.001), 5-min Apgar score (p < 0.001), and treating institution (p = 0.001) as significant predictors for RDS. The ACE model was used to estimate the genetic susceptibility to RDS by adjusting for the above factors. We found 49.7% (p = 0.04) of the variance in liability to RDS was the result of genetic factors alone. We conclude that there is a significant genetic susceptibility to RDS in preterm infants.

Histologic chorioamnionitis, fetal involvement, and antenatal steroids: effects on neonatal outcome in preterm infants

OBJECTIVE

The objective of the study was to study the effects of histologic chorioamnionitis (HC) with or without fetal involvement and antenatal steroid (AS) exposure on neonatal outcome in a prospective cohort of preterm infants.

STUDY DESIGN

The clinical characteristics and placental histology were prospectively collected in 301 infants born at a gestational age 32.0 weeks or less in the Erasmus University Medical Center.

RESULTS

In univariable analyses, HC without fetal involvement (n=53) was associated with decreased severe respiratory distress syndrome (RDS) (11% vs 28%; P<.05), whereas HC with fetal involvement infants (n=68) had more necrotizing enterocolitis (9% vs 2%; P<.05), intraventricular hemorrhage (IVH) (25% vs 12%; P<.05), and neonatal mortality (19% vs 9%; P<.05). In HC without fetal involvement infants, AS reduced the incidences of RDS (43% vs 85%; P<.05) and IVH (5% vs 39%; P<.01). In multivariable analyses, HC without fetal involvement was associated with decreased severe RDS (odds ratio, 0.22; 95% confidence interval, 0.05-0.93; P<.05) and increased early-onset sepsis (odds ratio, 2.22; 95% confidence interval, 1.02-4.83; P<.05).

CONCLUSION

In a prospective cohort of preterm infants, multivariable analyses reveal only a modest association between histologic chorioamnionitis and neonatal outcome.

Intrauterine inflammation, neonatal sepsis, and chronic lung disease: a 13-year hospital cohort study

OBJECTIVE To determine the impact of intrauterine inflammation of maternal (chorioamnionitis) and fetal (umbilical vasculitis) origin and neonatal sepsis on the development of neonatal chronic lung disease in preterm infants.

METHODS

This study was conducted at Royal Prince Alfred Hospital in Sydney, Australia. All infants born at <30 weeks' gestation, admitted to the NICU, and surviving to 36 weeks' corrected gestation during 1992-2004 were eligible. Infants with major congenital abnormalities and those without placental examination were excluded. Antenatal and perinatal data extracted from hospital databases were correlated with the independent, central neonatal database and diagnostic laboratory reports. Neonatal sepsis was categorized according to blood culture isolates into 3 groups: coagulase-negative staphylococci, other bacteria, and Candida species.

RESULTS

There were 798 eligible infants born during the study period, and 761 (95.4%) had placental examination. The mean gestational age was 27.4 +/- 1.5 weeks. Antenatal maternal steroids were given to 94.4%. Regression analysis showed that chorioamnionitis with umbilical vasculitis and increasing gestation were associated with reduced odds of chronic lung disease. Chorioamnionitis without umbilical vasculitis showed a trend to reduced odds of chronic lung disease. Birth weight at <3rd percentile and neonatal sepsis were associated with increased odds of chronic lung disease.

CONCLUSIONS

A fetal inflammatory response is protective for chronic lung disease. Neonatal sepsis is strongly associated with chronic lung disease, and the infecting organism is important. Coagulase-negative staphylococcal infection confers a risk for chronic lung disease similar to that of other bacteremias. Candidemia confers the greatest risk of chronic lung disease.

Cord immunoproteins as predictors of respiratory outcome in preterm infants

OBJECTIVE

The purpose of this study was to evaluate the role of cord blood proteins and antenatal factors in the prediction of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD).

STUDY DESIGN

The prospectively collected cohort included 163 infants. All infants were born between 1998-2002 in a single regional hospital before 32 weeks of gestation and survived the first hospitalization. Altogether, 107 cord blood proteins were analyzed. Twenty-two antenatal clinical factors were included in the data mining and logistic regression analyses.

RESULTS

The incidence of RDS was 64% and of BPD was 25%. Histologic chorioamnionitis protected from RDS (odds ratio [OR], 0.24; 95% confidence interval [CI], 0.11-0.53; P < .001). Besides the length of gestation, other clinical factors poorly predicted the outcomes. Matrix metalloproteinase-9 independently predicted RDS (OR, 8.3; 95% CI, 3.0-23.1; P < .001). Soluble glycoprotein 130 independently predicted BPD (OR, 6.07; 95%CI, 2.20-16.7; P < .001).

CONCLUSION

Specific antenatal immunologic activation predicts either acute or chronic respiratory disease in very preterm infants.

Ureaplasma colonization of amniotic fluid and efficacy of antenatal corticosteroids for preterm lung maturation in sheep

OBJECTIVE

The objective of the study was to assess the efficacy of maternal betamethasone for improving preterm lung function in the presence of inflammation induced by amniotic fluid Ureaplasma colonization.

STUDY DESIGN

Ewes bearing single fetuses were randomized to receive an intraamniotic injection of Ureaplasma parvum (serovar 6; 2 x 10(7) colony-forming units) or vehicle at 86 +/- 2 days of pregnancy (mean +/- SD: term is 150 days), followed by maternal intramuscular betamethasone (0.5 mg/kg) or saline, either 2 or 7 days before delivery of lambs at 123 +/- 1 d.

RESULTS

Amniotic fluid interleukin-8 was elevated by ureaplasmas (P = .049) but unaffected by betamethasone. Lung inflammation induced by ureaplasmas was not affected by betamethasone. Lung compliance was increased by Ureaplasma colonization (P = .009) and betamethasone (P = .042), and effects were additive. Lung surfactant was increased by Ureaplasma colonization (P < .001) and betamethasone 7 days (P = .001), but not 2 days, before delivery.

CONCLUSION

Inflammation improves preterm lung function because of increases in surfactant. Antenatal corticosteroids further augment lung function through an apparently independent mechanism.

Inflammatory mediators in the immunobiology of bronchopulmonary dysplasia

Inflammation is important in the development of bronchopulmonary dysplasia (BPD). Polymorphonuclear cells and macrophages and proinflammatory cytokines/chemokines denote early inflammation in clinical scenarios such as in utero inflammation with chorioamnionitis or initial lung injury associated with respiratory distress syndrome or ventilator-induced lung injury. The persistence and non-resolution of lung inflammation contributes greatly to BPD, including altering the lung's ability to repair, contributing to fibrosis, and inhibiting secondary septation, alveolarization, and normal vascular development. Further understanding of the role of inflammation in the pathogenesis of BPD, in particular, during the chronic inflammatory period, offers us the opportunity to develop inflammation-related prevention and treatment strategies of this disease that has long-standing consequences for very premature infants.

Placental histopathology in the extremely low birth weight infants

Our objective was to evaluate the placental histopathology (PH) in extremely low birth weight infants (ELBW, birth weight < 1000 g) and to determine if placental histopathological findings are associated with neonatal mortality in them. The PH of all ELBW infants (gestational age 23-30 weeks) born during a 3-year study period was prospectively evaluated and compared with term infants (gestational age > or = 37 weeks). Additionally PH of ELBW infants who expired within 28 days of life was compared with those who survived beyond 28 days. Student's t test, chi(2) test and Pearson's correlation coefficient tests were utilized for data analysis. The occurrences of placental infection (chorioamnionitis, HCA), umbilical cord inflammation (funisitis, vasculitis, and subacute necrotizing funisitis, analyzed collectively as HFV), and abruption were higher in ELBW (n = 105) compared to term infants (n = 61, p = 0.001, 0.0002, and 0.0002, respectively). Placental findings did not differ between the surviving (n = 71) and nonsurviving (n = 51) ELBW infants. Birth weight and gestational age were higher in the surviving group (p = 0.003 and 0.001, respectively). Placental abruption was found more commonly in the presence of HCA and HFV in ELBW infants as opposed to maternal hypertension in term infants. All ELBW placentas with HFV had concomitant findings of HCA whereas only 42% of ELBW placentas with HCA had findings of HFV compared to 24% in term infants (p = 0.09). There was a weak inverse correlation between HCA and birth weight in all (r = - 0.3, p = 0.01) but not in ELBW infants (r = 0.2, p = 0.07). We conclude that placental and umbilical cord inflammation and placental abruption are more commonly present in ELBW compared to term infants. However, these findings do not contribute to neonatal mortality in ELBW infants. Forty-two percent of placental (maternal) inflammation cases have concomitant cord (fetal) inflammation in ELBW infants. Finally HCA correlates inversely with birth weight in neonates.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.

Toll-like receptor-2 expression in normal and pathologic human placenta

Toll-like receptors (TLRs) are important components of the innate immune system and are expressed by trophoblast in normal full-term placenta. At present, not much is known about the role of TLRs during normal pregnancy and in pregnancy complicated by infection. In this study, we have used immunohistochemistry to investigate the expression of TLR2 in 58 placentas from second and third trimester with chorioamnionitis and 25 full-term placentas from uncomplicated pregnancies without chorioamnionitis. TLR2 was found to be localized to the cyto- and syncytio-trophoblast cell layer and to decidual stromal cells. The expression of TLR2 in placentas with chorioamnionitis was significantly lower than in placentas without chorioamnionitis. Furthermore, there was a significantly higher expression in placentas from liveborn children than in placentas from stillborn/aborted fetuses and also a higher expression in second- than in third-trimester placentas. These data suggest that TLR2 expression in the trophoblast could be involved in the response to infectious pathogens in the placenta.

FGF-10 is decreased in bronchopulmonary dysplasia and suppressed by Toll-like receptor activation

Many extremely preterm infants continue to suffer from bronchopulmonary dysplasia, which results from abnormal saccular-stage lung development. Here, we show that fibroblast growth factor-10 (FGF-10) is required for saccular lung development and reduced in the lung tissue of infants with bronchopulmonary dysplasia. Although exposure to bacteria increases the risk of bronchopulmonary dysplasia, no molecular target has been identified connecting inflammatory stimuli and abnormal lung development. In an experimental mouse model of saccular lung development, activation of Toll-like receptor 2 (TLR2) or Toll-like receptor 4 (TLR4) inhibited FGF-10 expression, leading to abnormal saccular airway morphogenesis. In addition, Toll-mediated FGF-10 inhibition disrupted the normal positioning of myofibroblasts around saccular airways, similar to the mislocalization of myofibroblasts seen in patients with bronchopulmonary dysplasia. Reduced FGF-10 expression may therefore link the innate immune system and impaired lung development in bronchopulmonary dysplasia.

Outcomes in Gestations Between 20 and 25 Weeks with Preterm Premature Rupture of Membranes

BACKGROUND

Preterm deliveries complicate 11% of all births within the United States. In the urban inner city population, this figure approaches approximately 18%. In one quarter to one third of these deliveries, preterm premature rupture of the membranes (PPROM) has been a causative factor.

OBJECTIVE

The purpose of this study was to evaluate outcomes of pregnancies complicated by preterm premature rupture of membranes at less than or equal to 24 weeks gestation at our institution.

METHODS

A retrospective review of 300 charts was performed on patients delivered at our institution from December 2003 to December 2004. Patients with gestational ages between 20 and 24 weeks with ruptured membranes were included in the study. Maternal, fetal, placental, and neonatal characteristics were reviewed.

RESULTS

A total of 16 infants were delivered. Seven infants were live born. The latency period was 4 days. The mean gestational age was 22 1/7 weeks. The average life span of the live born infants was noted to be 20 days. Chorioamnionitis was demonstrated in 85% of the placental specimens; in 57% of these specimens, group B streptococcus was noted to be the etiologic agent. Of the 16 infants delivered, only one infant is still alive and neurologically intact.

CONCLUSION

Various pathogens have been associated with PPROM and subsequent preterm delivery. The findings of this study suggest that within our population, group B streptococcus appears to be the primary causal agent associated with PPROM. Prevention of infection by early surveillance and patient education may help to decrease the incidence, but further investigation is warranted.

Intratracheal recombinant surfactant protein d prevents endotoxin shock in the newborn preterm lamb

RATIONALE

The susceptibility of neonates to pulmonary and systemic infection has been associated with the immaturity of both lung structure and the immune system. Surfactant protein (SP) D is a member of the collectin family of innate immune molecules that plays an important role in innate host defense of the lung.

OBJECTIVES

We tested whether treatment with recombinant human SP-D influenced the response of the lung and systemic circulation to intratracheally administered Escherichia coli lipopolysaccharides.

METHODS

After intratracheal lipopolysaccharide instillation, preterm newborn lambs were treated with surfactant and ventilated for 5 h.

MEASUREMENT

Survival rate, physiologic lung function, lung and systemic inflammation, and endotoxin level in plasma were evaluated.

MAIN RESULTS

In control lambs, intratracheal lipopolysaccharides caused septic shock and death associated with increased endotoxin in plasma. In contrast, all lambs treated with recombinant human SP-D were physiologically stable and survived. Leakage of lipopolysaccharides from the lungs to the systemic circulation was prevented by intratracheal recombinant human SP-D. Recombinant human SP-D prevented systemic inflammation and decreased the expression of IL-1beta, IL-8, and IL-6 in the spleen and liver. Likewise, recombinant human SP-D decreased IL-1beta and IL-6 in the lung and IL-8 in the plasma. Recombinant human SP-D did not alter pulmonary mechanics following endotoxin exposure. Recombinant human SP-D was readily detected in the lung 5 h after intratracheal instillation.

CONCLUSIONS

Intratracheal recombinant human SP-D prevented shock caused by endotoxin released from the lung during ventilation in the premature newborn.