The clustering of disorders in infants born before the 28th week of gestation

Impact of Size for Gestational Age on Multivariate Analysis of Factors Associated with Necrotizing Enterocolitis in Preterm Infants: Retrospective Cohort Study

OBJECTIVE

Necrotizing enterocolitis (NEC) primarily affects preterm, especially small for gestational age (SGA), infants. This study was designed to (1) describe frequency and timing of NEC in SGA versus non-SGA infants and (2) assess whether NEC is independently associated with the severity of intrauterine growth failure.

STUDY DESIGN

Retrospective cohort study of infants without severe congenital malformations born <33 weeks' gestational age (GA) carried out from 2009 to 2021. The frequency and time of NEC were compared between SGA and non-SGA infants. Multivariate logistic regression was used to assess whether NEC was independently associated with intrauterine growth restriction. Severe growth restriction was defined as birth weight Z-score <  -2.

RESULTS

Among 2,940 infants, the frequency of NEC was higher in SGA than in non-SGA infants (25/268 [9.3%] vs. 110/2,672 [4.1%], respectively, p < 0.001). NEC developed 2 weeks later in SGA than non-SGA infants. In multivariate analysis, the adjusted odds of NEC increased with extreme prematurity (<28 weeks' GA) and with severe but not moderate growth restriction. The adjusted odds of NEC increased with urinary tract infection or sepsis within a week prior to NEC, were lower in infants fed their mother's own milk until discharge, and did not change over five epochs. NEC was independently associated with antenatal steroid (ANS) exposure in infants with birth weight (BW) Z-score < 0.

CONCLUSION

NEC was more frequent in SGA than in non-SGA infants and developed 2 weeks later in SGA infants. NEC was independently associated with severe intrauterine growth failure and with ANS exposure in infants with BW Z-score < 0.

KEY POINTS

· We studied 2,940 infants <33 weeks' GA.. · We assessed NEC.. · NEC was more frequent in SGA infants.. · NEC occurred 2 weeks later in SGA infants.. · NEC was associated with severe growth restriction..

Impact of fetal inflammatory response on the severity of necrotizing enterocolitis in preterm infants

OBJECTIVE

Neonates born with fetal inflammatory response (FIR) are at increased risk for adverse neonatal outcomes. Our objective was to determine whether FIR and its severity is associated with severity of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A case-control retrospective study of infants <33 weeks gestational age or <1500 g birthweight, including 260 with stage I-III NEC and 520 controls matched for gestational age. Placental pathology was evaluated, and FIR progression and its severity were defined according to Amsterdam classification.

RESULTS

In this study, mild FIR (i.e., stage 1 FIR) was present in 52 controls (10.0%) and 22 infants with stage I-III NEC (8.5%), while moderate to severe FIR (i.e., ≥stage 2 FIR) was present in 16 controls (3.1%) and 47 infants with stage I-III NEC (18.1%). Both stage and grade of FIR were associated with stage of NEC (P < 0.001). On multinomial logistic regression, stage III NEC was associated with stage of FIR (P < 0.001).

CONCLUSION

This is the first report demonstrating the association between progression and increasing severity of FIR and stage of NEC.

IMPACT

Fetal Inflammatory Response (FIR) and its progression and severity are associated with the stages of necrotizing enterocolitis (NEC). This is the first study demonstrating the impact of progression and severity of FIR on stage III NEC. These observations provide additional insight into understanding the impact of intrauterine exposure to inflammation on the severity of NEC in preterm infants.

Evaluation of white matter microstructural alterations in premature infants with necrotizing enterocolitis

Background

Preterm infants with necrotizing enterocolitis (NEC) are at high risk of adverse neurodevelopmental outcomes. The aim of this study was to explore the value of diffusion tensor imaging (DTI) combined with serum C-reactive protein (CRP) and procalcitonin (PCT) in evaluating alterations of white matter (WM) microstructure in preterm infants with NEC.

Methods

A retrospective cross-sectional study was conducted in which all participants were consecutively enrolled at The Third Affiliated Hospital of Zhengzhou University from June 2017 and October 2021. Data from 30 preterm infants with NEC [mean gestational age at birth 31.41±1.15 weeks; mean age at magnetic resonance imaging (MRI) 37.53±3.08 weeks] and 40 healthy preterm infants with no NEC were recorded (mean gestational age at birth 32.27±2.09 weeks; mean age at MRI 37.15±3.23 weeks). WM was used to obtain the fractional anisotropy (FA) and mean diffusivity (MD) values of the regions of interest (ROIs). Additionally, serum levels of CRP and PCT were determined. Spearman correlation analysis was performed between the WM-derived parameters, CRP level, and the PCT serum index.

Results

Preterm infants with NEC had reduced FA values and elevated MD values in WM regions [posterior limbs of the internal capsule (PLIC), lentiform nucleus (LN), frontal white matter (FWM)] compared to the control group (P<0.05). Additionally, the FA of the PLIC was negatively correlated with serum CRP (r=-0.846; P<0.05) and PCT (r=-0.843; P<0.05). Meanwhile, the MD of PLIC was positively correlated with serum CRP (r=0.743; P<0.05) and PCT (r=0.743; P<0.05, respectively). The area under the curve (AUC) of FA and MD combined with CRP and PCT in the diagnosis of WM microstructure alterations with NEC was 0.968, representing a considerable improvement in predicted efficacy over single indicators, including FA [AUC: 0.938; 95% confidence interval (CI): 0.840-0.950], MD (AUC: 0.807; 95% CI: 0.722-0.838), CRP (AUC: 0.867; 95% CI: 0.822-0.889), and PCT (AUC: 0.706; 95% CI: 0.701-0.758).

Conclusions

WM can noninvasively and quantitatively assess the WM microstructure alterations in preterm infants with NEC. WM combined with serum CRP and PCT demonstrated superior performance in detecting and evaluating WM microstructure alterations in preterm infants with NEC.

Data-driven longitudinal characterization of neonatal health and morbidity

Although prematurity is the single largest cause of death in children under 5 years of age, the current definition of prematurity, based on gestational age, lacks the precision needed for guiding care decisions. Here, we propose a longitudinal risk assessment for adverse neonatal outcomes in newborns based on a deep learning model that uses electronic health records (EHRs) to predict a wide range of outcomes over a period starting shortly before conception and ending months after birth. By linking the EHRs of the Lucile Packard Children's Hospital and the Stanford Healthcare Adult Hospital, we developed a cohort of 22,104 mother-newborn dyads delivered between 2014 and 2018. Maternal and newborn EHRs were extracted and used to train a multi-input multitask deep learning model, featuring a long short-term memory neural network, to predict 24 different neonatal outcomes. An additional cohort of 10,250 mother-newborn dyads delivered at the same Stanford Hospitals from 2019 to September 2020 was used to validate the model. Areas under the receiver operating characteristic curve at delivery exceeded 0.9 for 10 of the 24 neonatal outcomes considered and were between 0.8 and 0.9 for 7 additional outcomes. Moreover, comprehensive association analysis identified multiple known associations between various maternal and neonatal features and specific neonatal outcomes. This study used linked EHRs from more than 30,000 mother-newborn dyads and would serve as a resource for the investigation and prediction of neonatal outcomes. An interactive website is available for independent investigators to leverage this unique dataset: https://maternal-child-health-associations.shinyapps.io/shiny_app/.

Neurodevelopmental outcome of infants who develop necrotizing enterocolitis: The gut-brain axis

Necrotizing enterocolitis (NEC) poses a significant risk for neurodevelopmental impairment in extremely preterm infants. The gut microbiota shapes the development of the gut, immune system, and the brain; and dysbiosis drive neonatal morbidities including NEC. In this chapter, we delineate a gut-brain axis linking gut microbiota to the adverse neurological outcomes in NEC patients. We propose that in NEC, immaturity of the microbiome along with aberrant gut microbiota-driven immaturity of the gut barrier and immune system can lead to effects including systemic inflammation and circulating microbial mediators. This nexus of gut microbiota-driven systemic effects further interacts with a likewise underdeveloped blood-brain barrier to regulate neuroinflammation and neurodevelopment. Targeting deviant gut-brain axis signaling presents an opportunity to improve the neurodevelopmental outcomes of NEC patients.

Decreased Acetic Acid in the Stool of Preterm Infants Is Associated with an Increased Risk of Bronchopulmonary Dysplasia

Background: Short-chain fatty acids (SCFAs), microbial metabolites, have been minimally studied in neonatal pathophysiology but have been associated with disease outcomes in adults. The objective of this manuscript was to determine if SCFA levels in maternal breastmilk (BM) and stool from preterm neonates impacted the risk of neonatal morbidities. Methods: SCFA levels were quantified by liquid chromatography with tandem mass spectrometry on maternal BM and neonatal stool for preterm infants < 28 weeks’ gestation (N = 72) on postnatal days 14 and 28. SCFA levels in BM and stool of infants with and without bronchopulmonary disease (BPD) and retinopathy of prematurity (ROP) were compared. Logistic regression was applied to determine the association between stool acetic acid levels and disease. Results: Acetic, propionic, isobutyric, 2-methylbutyric, and isovaleric acid levels increased in BM and neonatal stool between days 14 and 28. Logistic regression demonstrated an inverse relationship between the quartile of fecal acetic acid level and the odds of BPD but not ROP on days 14 and 28. For each quartile increase in fecal acetic acid, the odds ratio (95% CI) of BPD was 0.41 (0.18, 0.83) for day 14 and 0.28 (0.09, 0.64) for day 28. Conclusions: Low acetic acid levels in the stool of preterm infants are associated with increased odds of BPD. These findings support a relationship between intestinal and pulmonary health in preterm infants.

Extreme prematurity: Risk and resiliency

Individuals born extremely preterm (before 28 weeks of gestation) comprise only about 0.7% of births in the United States and an even lower proportion in other high resource countries. However, these individuals account for a disproportionate number of children with cerebral palsy, intellectual deficit, autism spectrum disorder, attention deficit hyperactivity disorder, and epilepsy. This review describes two large multiple center cohorts comprised of individuals born extremely preterm: the EPICURE cohort, recruited 1995 in the United Kingdom and the Republic of Ireland, and the Extremely Low Gestational Age Newborn (ELGAN), recruited 2002-2004 in five states in the United States. The primary focus of these studies has been neurodevelopmental disorders, but also of interest are growth, respiratory illness, and parent- and self-reported global health and well-being. Both of these studies indicate that among individuals born extremely preterm the risks of most neurodevelopmental disorders are increased. Early life factors that contribute to this risk include perinatal brain damage, some of which can be identified using neonatal head ultrasound, bronchopulmonary dysplasia, and neonatal systemic inflammation. Prenatal factors, particularly the family's socioeconomic position, also appear to contribute to risk. For most adverse outcomes, the risk is higher in males. Young adults born extremely preterm who have neurodevelopmental impairment, as compared to those without such impairment, rate their quality of life lower. However, young adults born extremely preterm who do not have neurodevelopmental impairments rate their quality of life as being similar to that of young adults born at term. Finally, we summarize the current state of interventions designed to improve the life course of extremely premature infants, with particular focus on efforts to prevent premature birth and on postnatal efforts to prevent adverse neurodevelopmental outcomes.

Retinopathy of Prematurity Requiring Treatment Is Closely Related to Head Growth during Neonatal Intensive Care Unit Hospitalization in Very Low Birth Weight Infants

BACKGROUND

Retinopathy of prematurity (ROP) is caused by prenatal sensitization and postnatal insults to the immature retina. This process can be associated with the postnatal growth of preterm infants. We investigated whether ROP requiring treatment was associated with the postnatal growth failure of very low birth weight (VLBW) infants.

METHOD

From a cohort of VLBW infants (birth weight <1,500 g) registered in the Korean Neonatal Network from January 2013 to December 2017, 3,133 infants with gestational age (GA) between 24 and 28 weeks were included in the study. Postnatal growth failure was defined when the change in each anthropometric z-score between birth and discharge was <10th percentile of the total population. Propensity score matching (PSM) at 1:1 was performed to match the distribution of GA and postnatal morbidities between infants with and without ROP requiring treatment. Prenatal factors and ROP were analyzed by conditional logistic regression.

RESULTS

Of 3,133 enrolled infants, 624 (19.9%) were diagnosed with ROP requiring treatment. After PSM, ROP requiring treatment was associated with postnatal growth failure assessed by head circumference (adjusted odds ratio [aOR] 1.91, 95% confidence interval [CI] 1.18-3.09), but not weight (aOR 1.45, 95% CI 0.97-2.17) and length (aOR 1.21, 95% CI 0.81-1.82).

CONCLUSION

ROP requiring treatment was associated with poor head circumference growth, not with weight and length. Our findings suggest that ROP requiring treatment and poor head growth during NICU hospitalization are fundamentally related.

Postnatal Sepsis and Bronchopulmonary Dysplasia in Premature Infants: Mechanistic Insights into "New BPD"

Bronchopulmonary dysplasia (BPD) is a debilitating disease in premature infants resulting from lung injury that disrupts alveolar and pulmonary vascular development. Despite the use of lung-protective ventilation and targeted oxygen therapy, BPD rates have not significantly changed over the last decade. Recent evidence suggests that sepsis and conditions initiating the systemic inflammatory response syndrome in preterm infants are key risk factors for BPD. However, the mechanisms by which sepsis-associated systemic inflammation and microbial dissemination program aberrant lung development are not fully understood. Progress has been made within the last 5 years with the inception of animal models allowing mechanistic investigations into neonatal acute lung injury and alveolar remodeling due to endotoxemia and NEC. These recent studies begin to unravel the pathophysiology of early endothelial immune activation via pattern recognition receptors such as Toll Like Receptor 4 and disruption of critical lung developmental processes such as angiogenesis, extracellular matrix deposition, and ultimately alveologenesis. Here we review scientific evidence from preclinical models of neonatal sepsis-induced lung injury to new data emerging from clinical literature.

Epidemiology of Early and Late Onset Neonatal Sepsis in Very Low Birthweight Infants: Data From the German Neonatal Network

BACKGROUND

Sepsis is a major cause of death in neonates. Knowledge about epidemiology, risk factors, causative pathogens and outcome of neonatal sepsis is important to improve neonatal care. For Germany, only few data on neonatal sepsis in very low birth weight (VLBW) infants exist.

METHODS

Data from 14,926 preterm infants with birth weight <1500 g and gestational age between 22 0/7 weeks and 31 6/7 collected between January 2009 and December 2017 were analyzed for frequency of early-onset sepsis (EOS) and late-onset sepsis (LOS) and for causative pathogens. Risk factors for the development of EOS and LOS and outcomes after EOS and LOS were analyzed by multivariate logistic regression models.

RESULTS

EOS occurred in 1.1% of infants and LOS in 11.9%. Escherichia coli was the most common pathogen in EOS, coagulase-negative staphylococci in LOS. Multidrug-resistant organisms were detected in 8.4% of EOS and 3.9% of LOS cases. Risk factors for EOS were lower gestational age, intra-amniotic infection and spontaneous delivery. Risk factors for LOS were lower gestational age, small for gestational age, central lines, endotracheal ventilation and history of EOS. Both EOS and LOS were independently associated with adverse neonatal outcome.

CONCLUSIONS

These data from a large German neonatal cohort confirm neonatal sepsis as the most common cause of morbidity and mortality in VLBW infants, as well as E. coli and coagulase-negative staphylococci as the most prevalent pathogens. Multidisciplinary approaches such as antibiotic stewardship, hygiene and feeding strategies are necessary to further reduce the burden of sepsis in VLBW infants.

Neurodevelopmental impairment in necrotising enterocolitis survivors: systematic review and meta-analysis

AIM

To determine (1) the incidence of neurodevelopmental impairment (NDI) in necrotising enterocolitis (NEC), (2) the impact of NEC severity on NDI in these babies and (3) the cerebral lesions found in babies with NEC.

METHODS

Systematic review: three independent investigators searched for studies reporting infants with NDI and a history of NEC (PubMed, Medline, Cochrane Collaboration, Scopus). Meta-analysis: using RevMan V.5.3, we compared NDI incidence and type of cerebral lesions between NEC infants versus preterm infants and infants with medical vs surgical NEC.

RESULTS

Of 10 674 abstracts screened, 203 full-text articles were examined. In 31 studies (n=2403 infants with NEC), NDI incidence was 40% (IQR 28%-64%) and was higher in infants with surgically treated NEC (43%) compared with medically managed NEC (27%, p<0.00001). The most common NDI in NEC was cerebral palsy (18%). Cerebral lesions: intraventricular haemorrhage (IVH) was more common in NEC babies (26%) compared with preterm infants (18%; p<0.0001). There was no difference in IVH incidence between infants with surgical NEC (25%) and those treated medically (20%; p=0.4). The incidence of periventricular leukomalacia (PVL) was significantly increased in infants with NEC (11%) compared with preterm infants (5%; p<0.00001).

CONCLUSIONS

This study shows that a large proportion of NEC survivors has NDI. NEC babies are at higher risk of developing IVH and/or PVL than babies with prematurity alone. The degree of NDI seems to correlate to the severity of gut damage, with a worse status in infants with surgical NEC compared with those with medical NEC.

TRIAL REGISTRATION NUMBER

CRD42019120522.

Retinopathy of prematurity, visual and neurodevelopmental outcome, and imaging of the central nervous system

Recent findings indicate that retinopathy of prematurity (ROP), presently classified by clinical examinations of retinal vascular tissue, is associated with structural alterations of the central nervous system. Such alterations may be the correlate of the association between ROP and impaired long-term neurocognitive and visual development. The advent of imaging techniques such as structural and diffusion tensor magnetic resonance imaging of the brain, and optical coherence tomography of the retina, will allow the complete visual system to be characterized in greater detail. It has been suggested that ROP may be not only a vascular, but a neurovascular disease, being part of a spectrum that includes pathological development in both the retinal and cerebral neurovascular interphase. We review the present knowledge in the field and point to future directions for research to tackle these questions.

Algorithm for predicting threshold retinopathy of prematurity is insufficient and fundus examinations are still needed before 31 weeks

AIM

We evaluated the weight, insulin-like growth factor-1, neonatal, retinopathy of prematurity (WINROP) algorithm for very premature infants.

METHOD

Infants born before 32 weeks who had undergone fundus examinations in the neonatal intensive care unit at the University Hospital of Nancy were included in this French retrospective cohort study from July 2012 to July 2016. We evaluated how well the WINROP software predicted threshold retinopathy of prematurity (ROP).

RESULTS

We studied 570 infants with a mean gestational age of 28.7 ± 1.8 weeks and a mean birth weight of 1110 ± 297 g: 28.1% had ROP and 1.2% had threshold ROP. The overall WINROP sensitivity was 57.1%, specificity was 46.0%, predictive positive value was 1.3% and predictive negative value was 98.9%. At more than 30 weeks of gestation or 1250 g, these figures rose to a respective specificity of 100% and 95.7% and respective predictive negative value of 100% and 100%. There were independent associations between the severity of ROP and the Apgar score at five minutes, the duration of oxygen therapy and non-invasive ventilation.

CONCLUSION

WINROP worked better on preterm infants born from 31 weeks onwards or weighing over 1250 g. Fundus examinations remain necessary for infants born earlier or lighter.

Speed of Retinal Vascularization in Retinopathy of Prematurity: Risk and Protective Factors

Objective

The objective was to study the risk and protective factors involved in retinal vascular development of preterm infants with retinopathy of prematurity.

Methods

Between 2000 and 2017, 185 preterm infants were included in the protocol for retinopathy of prematurity. Risk factors associated with speed of retinal vascularization <0.5 disc diameter/week were studied in each of them.

Results

The statistically significant variables related to retinal vascular development <0.5 DD/w were intubation days, degree 3 of bronchopulmonary dysplasia, weight gain at 4-6 weeks, avascular temporal area, gestational age, number of transfusions, sepsis, number of risk factors, apnea at birth, presence of ductus arteriosus, and days of continuous positive airway pressure therapy. After the multivariate logistic regression analysis, only three variables were found to be significant: intubation days (p=0.005), degree 3 of bronchopulmonary dysplasia (p=0.022), and weight gain at 4–6 weeks (p=0.031).

Conclusion

In retinopathy of prematurity, degree 3 of bronchopulmonary dysplasia and intubation days cause delayed retinal vascular development, whereas greater postnatal weight gain favors an appropriate rate of retinal vascularization.

Platelet mass index can be a reliable marker in predicting the prognosis of retinopathy of prematurity in very preterm infants

BACKGROUND

Retinopathy of prematurity (ROP) is a proliferative vitreoretinopathy resulting from vascular defect of the retina. The present study evaluates platelets, which are involved in VEGF storage, transport and release, and their functions with regard to the prognosis of the disease. The objective was to suggest a simple minimal invasive method that will facilitate the management of the disease and help clinicians in predicting the prognosis.

METHODS

In this single center, retrospective, case-control study, we included a control group consisting of very preterm newborns (n = 83) at risk of ROP and a laser photocoagulation group including infants (n = 63) who received laser therapy during their follow-up examinations. The employed assessments included platelet counts and platelet mass index (PMI) which provide guidance in understanding platelet activity. In doing so, consideration was given to the first and second phases of ROP. The accuracy of prognostication was assessed with receiver operating characteristic analyses.

RESULTS

The study groups did not differ statistically significantly by platelet count during the first and second phases of ROP (p > 0.05) nor were the PMI measurements statistically significantly different between the study groups during the first phase of the disease (p > 0.05). PMI values of the study groups, however, differed significantly in the second phase of ROP (p < 0.05).

CONCLUSION

The present study found a significant difference between the two groups in PMI measurements which reflect increased VEGF levels during the neovascularization phase, which underlies the disease. This conclusion demonstrated that monitoring the PMI values in newborns at risk of ROP can be considered to be a minimally invasive method that by changing the retinal examination procedure in use today which is rather troublesome for both the physician and the newborn, can provide facilities in monitoring the disease for both the physician and the newborn.

Correlation of Retinopathy of Prematurity with Bronchopulmonary Dysplasia

Retinopathy of prematurity (ROP) and bronchopulmonary dysplasia (BPD) are diseases that occur only in preterm infants. The etiology of these disorders is multifactorial; however, it is believed that some of the factors in children presenting with BPD affect both the initiation and severity of ROP. The aim of the study was to evaluate the degree of clinical severity of ROP in infants with BPD compared to those without BPD.

Human Breast Milk: Exploring the Linking Ring Among Emerging Components

Maternal breast milk (BM) is a complex and unique fluid that evolution adapted to satisfy neonatal needs; in addition to classical nutrients, it contains several bioactive components. BM characteristically shows inter-individual variability, modifying its composition during different phases of lactation. BM composition, determining important consequences on neonatal gut colonization, influences both short and long-term development. Maternal milk can also shape neonatal microbiota, through its glycobiome rich in Lactobacilli spp. and Bifidobacteria spp. Therefore, neonatal nourishment during the first months of life seems the most important determinant of individual's outcomes. Our manuscript aims to provide new evidence in the characterization of BM metabolome and microbiome, and its comparison to formula milk, allowing the evaluation of each nutrient's influence on neonatal metabolism. This result very interesting since potentially offers an innovative approach to investigate the complex relationship between BM components and infant's health, also providing the chance to intervene in a sartorial way on diet composition, according to the nutritional requests. Future research, integrating metabolomics, microbiomics and stem cells knowledge, could make significant steps forward in understanding BM extraordinary properties and functions.

Retrospective cohort study shows that the risks for retinopathy of prematurity included birth age and weight, medical conditions and treatment

AIM

This study described the characteristics and risk factors of neonates who developed retinopathy of prematurity (ROP) and severe treatable ROP in two Egyptian neonatal intensive care units (NICUs).

METHODS

This retrospective cohort study comprised 108 preterm neonates who were screened for ROP after being admitted to the two NICUs run by Cairo University Hospital from June 2014 to May 2015. Patients were examined using digital fundus photography and indirect ophthalmoscopy was performed if ROP was detected.

RESULTS

Retinopathy of prematurity occurred in 75 patients. Late-onset sepsis, ventilation and hypercapnia were independently associated with ROP. Patients who developed severe treatable ROP had a younger gestational age (GA) than patients who did not develop ROP or developed mild or moderate ROP (29 weeks, range 27-33 weeks versus 32 weeks, range 28-36 weeks, p = 0.002) and a lower birthweight (1200 g, range 980-1590 g versus 1460 g, range 770-2475 g, p = 0.029). The risk factors associated with severe treatable ROP included the duration of admission, the duration of incubator oxygen, late-onset sepsis, intraventricular haemorrhage, total parenteral nutrition and the duration of caffeine citrate therapy.

CONCLUSION

This study showed that the risks for ROP were wide-ranging and included GA and weight, medical conditions and treatment.

The effects of thyroid function on retinopathy of prematurity

OBJECTIVES

To assess whether TSH and fT4 have a role in the angiogenesis of vaso-obliteration and neovascularization which are the basic pathophysiology of ROP.

METHODS

In this retrospective case-control study, the control group (n = 56) included preterm newborns with risk for ROP while the laser group (n = 63) was recruited from cases who developed severe neovascularization and needed laser photocoagulation therapy. Considering the first (vaso-obliteration) and second (neovascularization) phases of the disease, in this study we researched the distribution of thyroid function tests between groups.

RESULTS

With regard to the first phase of the disease, TSH and fT4 showed no significant differences between the control and laser groups accordingly (P > 0.05). Likewise, in the second phase of ROP, there was no significant difference between the control and laser groups with respect to TSH and fT4 levels (P > 0.05).

CONCLUSION

We found that between the study groups, the levels of thyroid function tests did not have any significant differences, either in the first or the second phases of ROP which are the principal pathophysiology of the disease. Therefore, it was concluded that thyroid hormone values were not informative markers in the course of the disease in preterm babies at risk of developing ROP.

Risk of recurrence of retinopathy of prematurity after initial intravitreal ranibizumab therapy

We report our experience with the use of intravitreal ranibizumab for the treatment of retinopathy of prematurity (ROP). A retrospective review was performed on 138 consecutive infants screened at a single centre over 18 months. Intravitreal ranibizumab was offered in selected cases requiring treatment, such as aggressive posterior ROP or poor mydriasis. 2 eyes of 1 infant received intravitreal ranibizumab alone and 8 eyes of 5 infants received combined intravitreal ranibizumab and laser therapy. 3 out of 8 eyes treated initially with intravitreal ranibizumab monotherapy had persistent disease requiring laser therapy, and 3 out of 5 eyes with initial regression suffered disease recurrence at a mean of 7.6 weeks post-injection. 2 eyes treated first with laser followed by intravitreal ranibizumab had disease regression without recurrence. Our cohort demonstrate a significant rate of persistent disease and recurrence in ROP eyes treated initially with intravitreal ranibizumab monotherapy, which is greater and earlier than that reported for intravitreal bevacizumab in the BEAT-ROP study. Intravitreal ranibizumab may be useful as an initial treatment in selected cases of ROP when laser therapy as first line is suboptimal. However, close monitoring is important and adjunctive laser therapy may subsequently be needed in a majority of cases.

Platelet mass index in very preterm infants: can it be used as a parameter for neonatal morbidities?

OBJECTIVE

Platelet mass index (PMI) is related to the platelet functionality. The aim of this study was to evaluate the correlation between PMI and the occurrence of various inflammation-related morbidities of prematurity, such as bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH) and sepsis in very low-birth weight (VLBW) infants.

METHODS

This retrospective analysis of VLBW infants admitted to a level 3 neonatal intensive care unit from October 2012 and 2014, n = 330. Platelet mass was calculated and recorded on the day of birth and between 3 and 7 days (second measure) for each patient. Statistical analysis included analysis of paired samples t test and independent samples t test.

RESULT

Among VLBW neonates, PMI values were lower in infants with ROP (p = 0.016), BPD (p = 0.002), IVH (p = 0.018) and NEC (p = 0.011) when compared with the control group in the second measurement.

CONCLUSIONS

In this study, we found that premature infants with BPD, NEC, ROP, IVH and sepsis had lower PMI levels in early postnatal life than infants without these diseases. This might be associated with the inflammatory process.

Sepsis as a risk factor for neonatal morbidity in extremely preterm infants

AIM

This study evaluated sepsis as a risk factor for neonatal morbidities and investigated the association between specific pathogens and neonatal morbidities.

METHODS

This was a nationwide Swedish prospective cohort study, consisting of the 497 extremely premature children, who were born before 27 weeks of gestation between 2004 and 2007 and survived their first year of life. Neonatal sepsis was evaluated as a risk factor for neonatal morbidity using multiple logistic linear regression analyses.

RESULTS

We found that 326 (66%) of the infants had at least one sepsis episode and coagulase-negative staphylococci was the most common pathogen. Definite sepsis, with an odds ratio (OR) of 1.6, was associated with severe bronchopulmonary dysplasia, but not clinical sepsis (OR 1.1). Definite sepsis was also associated with a prolonged hospital stay (OR 1.6). Sepsis was not significantly associated with a higher risk of retinopathy of prematurity or intraventricular haemorrhage.

CONCLUSION

Extremely preterm infants face a great risk of acquiring neonatal sepsis, with coagulase-negative staphylococci being the most common pathogen in this population. Definite sepsis seemed to be a risk factor for severe bronchopulmonary dysplasia and prolonged hospital stay, but the associations were weaker than in previous studies.

Late Enteral Feedings Are Associated with Intestinal Inflammation and Adverse Neonatal Outcomes

BACKGROUND

Morbidities of impaired immunity and dysregulated inflammation are common in preterm infants. Postnatal Intestinal development plays a critical role in the maturation of the immune system and is, in part, driven by exposure to an enteral diet.

OBJECTIVE

The aim of this study was to evaluate the influence of the timing of the first enteral feeding on intestinal inflammation and risk of disease.

METHODS

130 infants <33 weeks' gestation were studied. Maternal and infant data were abstracted from the medical record. Single and multiplex ELISA assays quantified cytokines from fecal and serum samples at two weeks postnatal age.

RESULTS

A delay in enteral feedings after the third postnatal day is associated with a 4.5 (95% CI 1.8-11.5, p=0.002) fold increase in chronic lung disease, 2.9 (1.1-7.8, p=0.03) fold increase in retinopathy of prematurity, and 3.4 (1.2-9.8, p=0.02) fold increase in multiple comorbidities compared to infants fed on or before the third day. Additionally, a delay in the initiation of feedings is associated with increased fecal IL-8 levels and a decreased IL-10:IL-8 ratio.

CONCLUSIONS

A delay in enteral feeding is associated with intestinal inflammation and increased risks of morbidities. To improve neonatal outcomes, early nutritional practices need to be reevaluated.

Systemic inflammation and cerebral palsy risk in extremely preterm infants

The authors hypothesized that among extremely preterm infants, elevated concentrations of inflammation-related proteins in neonatal blood are associated with cerebral palsy at 24 months. In 939 infants born before 28 weeks gestation, the authors measured blood concentrations of 25 proteins on postnatal days 1, 7, and 14 and evaluated associations between elevated protein concentrations and cerebral palsy diagnosis. Protein elevations within 3 days of birth were not associated with cerebral palsy. Elevations of tumor necrosis factor-α, tumor necrosis factor-α-receptor-1, interleukin-8, and intercellular adhesion molecule-1 on at least 2 days were associated with diparesis. Recurrent-persistent elevations of interleukin-6, E-selectin, or insulin-like growth factor binding protein-1 were associated with hemiparesis. Diparesis and hemiparesis were more likely among infants who had at least 4 of 9 protein elevations that previously have been associated with cognitive impairment and microcephaly. Repeated elevations of inflammation-related proteins during the first 2 postnatal weeks are associated with increased risk of cerebral palsy.

Noninvasive molecular fingerprinting of host-microbiome interactions in neonates

The early postnatal period is a critical window for intestinal and immune maturation. Intestinal development and microbiome diversity and composition differ between breast- (BF) and formula-fed (FF) infants. Mechanistic examination into host-microbe relationships in healthy infants has been hindered by ethical constraints surrounding tissue biopsies. Thus, a statistically rigorous analytical framework to simultaneously examine both host and microbial responses to dietary/environmental factors using exfoliated intestinal epithelial cells was developed. Differential expression of ∼1200 genes, including genes regulating intestinal proliferation, differentiation and barrier function, was observed between BF and FF term infants. Canonical correlation analysis uncovered a relationship between microbiome virulence genes and host immunity and defense genes. Lastly, exfoliated cells from preterm and term infants were compared. Pathways associated with immune cell function and inflammation were up-regulated in preterm, whereas cell growth-related genes were up-regulated in the term infants. Thus, coordinate measurement of the transcriptomes of exfoliated epithelial cells and microbiome allows inquiry into mutualistic host-microbe interactions in the infant, which can be used to prospectively study gut development or, retrospectively, to identify potential triggers of disease in banked samples.

Maternal inflammation modulates infant immune response patterns to viral lung challenge in a murine model

BACKGROUND

Chorioamnionitis, an inflammatory gestational disorder, commonly precedes preterm delivery. Preterm infants may be at particular risk for inflammation-related morbidity related to infection, although the pathogenic mechanisms are unclear. We hypothesized that maternal inflammation modulates immune programming to drive postnatal inflammatory processes.

METHODS

We used a novel combined murine model to treat late gestation dams with low-dose lipopolysaccharide (LPS) and to secondarily challenge exposed neonates or weanlings with Sendai virus (SeV) lung infection. Multiple organs were analyzed to characterize age-specific postnatal immune and inflammatory responses.

RESULTS

Maternal LPS treatment enhanced innate immune populations in the lungs, livers, and/or spleens of exposed neonates or weanlings. Secondary lung SeV infection variably affected neutrophil, macrophage, and dendritic cell proportions in multiple organs of exposed pups. Neonatal lung infection induced brain interleukin (IL)-4 expression, although this response was muted in LPS-exposed pups. Adaptive immune cells, including lung, lymph node, and thymic lymphocytes and lung CD4 cells expressing FoxP3, interferon (IFN)-γ, or IL-17, were variably prominent in LPS-exposed pups.

CONCLUSION

Maternal inflammation modifies postnatal immunity and augments systemic inflammatory responses to viral lung infection in an age-specific manner. We speculate that inflammatory modulation of the developing immune system contributes to chronic morbidity and mortality in preterm infants.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Finding novel molecular connections between developmental processes and disease

Identifying molecular connections between developmental processes and disease can lead to new hypotheses about health risks at all stages of life. Here we introduce a new approach to identifying significant connections between gene sets and disease genes, and apply it to several gene sets related to human development. To overcome the limits of incomplete and imperfect information linking genes to disease, we pool genes within disease subtrees in the MeSH taxonomy, and we demonstrate that such pooling improves the power and accuracy of our approach. Significance is assessed through permutation. We created a web-based visualization tool to facilitate multi-scale exploration of this large collection of significant connections (http://gda.cs.tufts.edu/development). High-level analysis of the results reveals expected connections between tissue-specific developmental processes and diseases linked to those tissues, and widespread connections to developmental disorders and cancers. Yet interesting new hypotheses may be derived from examining the unexpected connections. We highlight and discuss the implications of three such connections, linking dementia with bone development, polycystic ovary syndrome with cardiovascular development, and retinopathy of prematurity with lung development. Our results provide additional evidence that plays a key role in the early pathogenesis of polycystic ovary syndrome. Our evidence also suggests that the VEGF pathway and downstream NFKB signaling may explain the complex relationship between bronchopulmonary dysplasia and retinopathy of prematurity, and may form a bridge between two currently-competing hypotheses about the molecular origins of bronchopulmonary dysplasia. Further data exploration and similar queries about other gene sets may generate a variety of new information about the molecular relationships between additional diseases.

Understanding the roles that genes involved in normal human development can play in disease processes is an important part of predicting disease risk and designing novel treatment approaches. In this study, we have identified classes of disease that are associated with a surprisingly large number of genes involved in any of several tissue-specific developmental processes. To do so, we developed a novel approach whose strength comes from pooling genetic information across related diseases, overcoming problems ordinarily posed by limited information about individual gene-disease relationships. We demonstrate the method's efficacy both by examining its ability to highlight connections between gene sets and disease classes that are known to be related, and by demonstrating that the approach recovers expected broad classes of connections, such as those between heart development and cardiovascular disorders. However, by examining unexpected connections in this data set, we are able to develop new understanding of some surprising disease relationships, such as the one between dementia and osteoporosis. Such connections may lead to a better overall understanding of the role of development in lifelong health, as well as to the design of new methods to treat a range of diseases.

WINROP can modify ROP screening praxis: a validation of WINROP in populations in Sörmland and Västmanland

BACKGROUND

This study validates the newly developed WINROP algorithm aimed at detecting retinopathy of prematurity (ROP) requiring treatment at an early stage. The study was conducted at two middle-sized hospitals in Sweden, prospectively and retrospectively.

METHODS

A total of 104 children participated in this study. Their mean gestational age at birth was 28.7 weeks (range, 23.6-32.1 weeks), and their mean birth weight was 1208 g (range, 477-2340 g). Weekly weight measurements were used in WINROP to calculate the risk of developing ROP.

RESULTS

80% of infants (83/104) had no ROP, 15% (16/104) had mild ROP (stage 1 or 2), 5% (5/104) had severe ROP, and 2% (2/104) were treated for ROP. The alarm was registered at an average of 2 weeks postnatal age (range 1-6 weeks).

CONCLUSIONS

WINROP identified all the infants at risk for developing stage 3 ROP (100% sensitivity) and had a 59% specificity. The alarm was registered several weeks before screening for ROP began. WINROP can be used to complement conventional ROP screening.

Retinopathy of prematurity

The immature retinas of preterm neonates are susceptible to insults that disrupt neurovascular growth, leading to retinopathy of prematurity. Suppression of growth factors due to hyperoxia and loss of the maternal-fetal interaction result in an arrest of retinal vascularisation (phase 1). Subsequently, the increasingly metabolically active, yet poorly vascularised, retina becomes hypoxic, stimulating growth factor-induced vasoproliferation (phase 2), which can cause retinal detachment. In very premature infants, controlled oxygen administration reduces but does not eliminate retinopathy of prematurity. Identification and control of factors that contribute to development of retinopathy of prematurity is essential to prevent progression to severe sight-threatening disease and to limit comorbidities with which the disease shares modifiable risk factors. Strategies to prevent retinopathy of prematurity will depend on optimisation of oxygen saturation, nutrition, and normalisation of concentrations of essential factors such as insulin-like growth factor 1 and ω-3 polyunsaturated fatty acids, as well as curbing of the effects of infection and inflammation to promote normal growth and limit suppression of neurovascular development.

Perinatal clinical antecedents of white matter microstructural abnormalities on diffusion tensor imaging in extremely preterm infants

OBJECTIVE

To identify perinatal clinical antecedents of white matter microstructural abnormalities in extremely preterm infants.

METHODS

A prospective cohort of extremely preterm infants (N = 86) and healthy term controls (N = 16) underwent diffusion tensor imaging (DTI) at term equivalent age. Region of interest-based measures of white matter microstructure - fractional anisotropy and mean diffusivity - were quantified in seven vulnerable cerebral regions and group differences assessed. In the preterm cohort, multivariable linear regression analyses were conducted to identify independent clinical factors associated with microstructural abnormalities.

RESULTS

Preterm infants had a mean (standard deviation) gestational age of 26.1 (1.7) weeks and birth weight of 824 (182) grams. Compared to term controls, the preterm cohort exhibited widespread microstructural abnormalities in 9 of 14 regional measures. Chorioamnionitis, necrotizing enterocolitis, white matter injury on cranial ultrasound, and increasing duration of mechanical ventilation were adversely correlated with regional microstructure. Conversely, antenatal steroids, female sex, longer duration of caffeine therapy, and greater duration of human milk use were independent favorable factors. White matter injury on cranial ultrasound was associated with a five weeks or greater delayed maturation of the corpus callosum; every additional 10 days of human milk use were associated with a three weeks or greater advanced maturation of the corpus callosum.

CONCLUSIONS

Diffusion tensor imaging is sensitive in detecting the widespread cerebral delayed maturation and/or damage increasingly observed in extremely preterm infants. In our cohort, it also aided identification of several previously known or suspected perinatal clinical antecedents of brain injury, aberrant development, and neurodevelopmental impairments.

Systemic inflammation associated with severe intestinal injury in extremely low gestational age newborns

To define the role of systemic inflammation in infants with intestinal perforation (IP) and necrotizing enterocolitis (NEC), we measured 25 blood protein concentrations on days 1, 7 and 14 in 939 infants born before 28 weeks' gestation. On days 7 and 14, infants with NEC had elevated levels of C-reactive protein (CRP), serum amyloid A (SAA), IL-6 and IL-8. Infants with IP had elevated levels of CRP and insulin growth factor binding protein-1 on day 7 and elevated CRP, SAA, TNF-receptor-2 and matrix metalloproteinase-9 levels on day 14. A better understanding of systemic inflammation might help prevent and treat these disorders.

Early sepsis does not increase the risk of late sepsis in very low birth weight neonates

OBJECTIVE

To examine whether preterm very low birth weight (VLBW) infants have an increased risk of late-onset sepsis (LOS) following early-onset sepsis (EOS).

STUDY DESIGN

Retrospective analysis of VLBW infants (401-1500 g) born September 1998 through December 2009 who survived >72 hours and were cared for within the National Institute of Child Health and Human Development Neonatal Research Network. Sepsis was defined by growth of bacteria or fungi in a blood culture obtained ≤ 72 hours of birth (EOS) or >72 hours (LOS) and antimicrobial therapy for ≥ 5 days or death <5 days while receiving therapy. Regression models were used to assess risk of death or LOS by 120 days and LOS by 120 days among survivors to discharge or 120 days, adjusting for gestational age and other covariates.

RESULTS

Of 34,396 infants studied, 504 (1.5%) had EOS. After adjustment, risk of death or LOS by 120 days did not differ overall for infants with EOS compared with those without EOS [risk ratio (RR): 0.99 (0.89-1.09)] but was reduced in infants born at <25 weeks gestation [RR: 0.87 (0.76-0.99), P = .048]. Among survivors, no difference in LOS risk was found overall for infants with versus without EOS [RR: 0.88 (0.75-1.02)], but LOS risk was reduced in infants with birth weight 401-750 g who had EOS [RR: 0.80 (0.64-0.99), P = .047].

CONCLUSIONS

Risk of LOS after EOS was not increased in VLBW infants. Surprisingly, risk of LOS following EOS appeared to be reduced in the smallest, most premature infants, underscoring the need for age-specific analyses of immune function.

The use of the WINROP screening algorithm for the prediction of retinopathy of prematurity in a Chinese population

BACKGROUND

Retinopathy of prematurity (ROP) is a gestational age (GA)-related illness that can lead to blindness in premature infants. Timely screening of premature infants could improve visual prognosis.

OBJECTIVE

To evaluate the WINROP algorithm as a method of predicting severe ROP in a Chinese population.

METHODS

590 infants with a GA <32 weeks were entered into an online surveillance system (www.winrop.com) that included ROP evaluations and weekly weight measurements from birth to a corrected GA of 40 weeks. If the rate of weight gain decreased to a certain degree, the algorithm signaled an alarm that the infant was at risk for developing sight-threatening ROP. Each infant was categorized as having no, mild, or severe ROP.

RESULTS

Among the 590 infants with a GA <32 weeks, an alarm was triggered in 85 infants (14.4%), 50 of which developed severe ROP and were identified in this alarm group. Twenty-seven infants triggered the alarm signal in the first week after birth and 7 infants triggered the alarm at birth. Seven of the infants developed proliferative ROP and the median GA at birth for these infants was 31 weeks.

CONCLUSIONS

The WINROP system had a sensitivity of 87.5% in a Chinese population for the early identification of infants that developed severe ROP. Postnatal weight gain may help predict ROP in lower birth weight infants.

Very low birth weight neonates who survive early-onset sepsis do not have an increased risk of developing late-onset sepsis

BACKGROUND

Very low birth weight neonates (≤ 1500 g, VLBWs) have a high rate of infection and distinct baseline immune function compared with more mature populations. In critically ill children and adults, sepsis increases subsequent infection risk. It is unknown whether sepsis modifies the risk of subsequent infection in VLBWs.

METHODS

We conducted a retrospective cohort study of VLBWs≤32weeks of gestation at birth cared for in 312 neonatal intensive care units in the United States from 1997 to 2011 (n=103,376). Early-onset sepsis (EOS, culture-positive only) and late-onset sepsis (LOS, culture-positive or clinical) cases were identified. Cox proportional hazard models were used to control for clinical variables between neonates with and without EOS to determine if EOS modified risk of LOS, necrotizing enterocolitis (NEC), or death.

RESULTS

LOS occurred in 12,112/102,317 (11.8%) neonates without EOS and in 133/1059 (12.6%) of those with EOS. After adjustment for clinical variables, the risk of LOS was not different between neonates with or without a history of EOS (hazard ratio [HR]=0.92; 95% confidence interval [CI] 0.74, 1.16). EOS increased the risk of 120-day mortality (HR=1.78; 95% CI 1.49, 2.13).

CONCLUSIONS

In contrast to findings in children and adults, EOS was not associated with an increased risk of LOS in this cohort. Age-specific investigations are needed to determine if post-sepsis immunologic alterations are present.

Relationship between maternal serum C-reactive protein, funisitis and early-onset neonatal sepsis

The aim of this study was to determine whether maternal serum C-reactive protein (CRP) is of value in predicting funisitis and early-onset neonatal sepsis (EONS) in women with preterm labor or preterm premature rupture of membranes (PROM). This retrospective cohort study included 306 consecutive women with preterm labor or preterm PROM who delivered preterm singleton neonates (23-35 weeks gestation) within 72 hr of CRP measurement. The CRP level was measured with a highly sensitive immunoassay. The sensitivity, specificity, positive predictive value, and negative predictive value of an elevated serum CRP level (≥ 8 mg/L) were 74.1%, 67.5%, 32.8%, and 92.4% for funisitis, and 67.7%, 63.3%, 17.2%, and 94.6% for EONS, respectively. Logistic regression analysis demonstrated that elevated levels of serum CRP were significantly associated with funisitis and EONS, even after adjusting gestational age. The maternal serum CRP level obtained up to 72 hr before delivery is an independent predictor of funisitis and EONS in women with preterm labor or preterm PROM. A low serum CRP level (< 8 mg/L) has good negative predictive value in excluding funisitis and EONS, and may therefore be used as a non-invasive adjunct to clinical judgment to identify low-risk patients.

An update on necrotizing enterocolitis: pathogenesis and preventive strategies

Necrotizing enterocolitis (NEC) is one of the most critical morbidities in preterm infants. The incidence of NEC is 7% in very-low-birth-weight infants, and its mortality is 15 to 30%. Infants who survive NEC have various complications, such as nosocomial infection, malnutrition, growth failure, bronchopulmonary dysplasia, retinopathy of prematurity, and neurodevelopmental delays. The most important etiology in the pathogenesis of NEC is structural and immunological intestinal immaturity. In preterm infants with immature gastrointestinal tracts, development of NEC may be associated with a variety of factors, such as colonization with pathogenic bacteria, secondary ischemia, genetic polymorphisms conferring NEC susceptibility, anemia with red blood cell transfusion, and sensitization to cow milk proteins. To date, a variety of preventive strategies has been accepted or attempted in clinical practice with regard to the pathogenesis of NEC. These strategies include the use of breast feeding, various feeding strategies, probiotics, prebiotics, glutamine and arginine, and lactoferrin. There is substantial evidence for the efficacy of breast feeding and the use of probiotics in infants with birth weights above 1,000 g, and these strategies are commonly used in clinical practice. Other preventive strategies, however, require further research to establish their effect on NEC.

Pathogenesis and prevention of necrotizing enterocolitis

PURPOSE OF REVIEW

Necrotizing enterocolitis (NEC) remains the most common serious acquired gastrointestinal disorder affecting preterm infants. Here we review recent advances in our understanding of the pathogenesis of this multifactorial condition and consider the implications for practice and research.

RECENT FINDINGS

NEC is an important cause of mortality and serious morbidity in preterm infants. The risk is inversely proportional to gestational age and weight at birth. Fetal growth restriction and compromise may be additional specific risk factors. NEC, particularly severe NEC requiring surgical intervention and NEC with invasive infection, is associated with acute morbidity and mortality and adverse neurodevelopmental outcomes. The principal modifiable postnatal risk factors for NEC in preterm infants relate to enteral feeding practices including formula milk feeding, early and rapid advancement of enteral feed volumes, and exposure to H2-receptor antagonists.

SUMMARY

Our understanding of the pathogenesis of this condition remains incomplete. With the exception of feeding with human milk, only limited evidence is currently available to support interventions to prevent NEC. Promising strategies that merit further evaluation in randomized controlled trials include the use of prebiotics and probiotics and the avoidance of exposure to H2-receptor antagonists.

The risk of necrotizing enterocolitis after indomethacin tocolysis

BACKGROUND

Postnatal indomethacin is reportedly associated with an increased incidence of necrotizing enterocolitis (NEC) in preterm infants. Because indomethacin readily crosses the placenta, we hypothesized that antenatal indomethacin (AI) would increase the risk for NEC in preterm infants.

OBJECTIVE

The goal of this study was to explore the association between AI and NEC in preterm infants.

METHODS

Medical records of preterm infants, 23 to 32 weeks' gestational age, without major congenital anomalies, were reviewed. Maternal and neonatal data were abstracted. Association of AI within 15 days before delivery (predictor variable) and classification of NEC according to modified Bell's stage 2a or higher in the first 15 days after delivery (early NEC [primary outcome variable]) was explored by using bivariate analyses, multivariate logistic regression, and propensity score analysis.

RESULTS

Of 628 eligible infants, 63 received AI and 28 developed early NEC. AI exposure was significantly associated with multiple gestation, race, antenatal corticosteroids and magnesium sulfate, lower birth weight and gestational age, umbilical arterial catheter placement, respiratory distress syndrome, postnatal vasopressors and antibiotics, patent ductus arteriosus, sepsis, NEC, intraventricular hemorrhage, and mortality. On multivariate logistic regression controlling for covariates, AI was significantly associated with early NEC (adjusted odds ratio: 7.193 [95% confidence interval: 2.514-20.575]; number needed to harm: 5). The results remained significant when analyses were repeated using AI exposure within 5 days before delivery as a predictor variable; on analyses stratified according to gestational age; and on propensity score analysis.

CONCLUSIONS

AI was associated with NEC in preterm infants in the first 15 days of life in this study, as were multiple other clinical factors.