Jacqueline M. McGrath

Necrotizing Enterocolitis Risk: State of the Science

Necrotizing enterocolitis (NEC) is the most common cause of gastrointestinal-related morbidity and mortality in the neonatal intensive care unit (NICU). Its onset is sudden and the smallest, most premature infants are the most vulnerable. Necrotizing enterocolitis is a costly disease, accounting for nearly 20% of NICU costs annually. Necrotizing enterocolitis survivors requiring surgery often stay in the NICU more than 90 days and are among those most likely to stay more than 6 months. Significant variations exist in the incidence across regions and units. Although the only consistent independent predictors for NEC remain prematurity and formula feeding, others exist that could increase risk when combined. Awareness of NEC risk factors and adopting practices to reduce NEC risk, including human milk feeding, the use of feeding guidelines, and probiotics, have been shown to reduce the incidence of NEC. The purpose of this review is to examine the state of the science on NEC risk factors and make recommendations for practice and research.

Temperament characteristics of premature infants in the first year of life.

ABSTRACT. Parenting preterm infants in the first months after hospital discharge is challenging. Although preterm infants are considered to be difficult, preterm temperament at less than 3 months is unknown empirically. The purpose of this analysis was to investigate the 6-week temperament characteristics of preterm infants in comparison with standardized norms of full-term infants. The sample of 74 infants with gestational ages at birth between 24 and 32 weeks were enrolled in a study of preterm infant neurobehavioral outcomes. Mothers rated temperament at 6 weeks, 6 months, and 12 months of age (adjusted for prematurity). At 6 weeks the premature infants were significantly less rhythmic (regular), more distractible (soothable), less approaching (more withdrawing), and less intense than standardized norms for full-term infants. From these data we conclude that premature infants may be initially more challenging to parent. Temperament moderated over time but remained significantly lower in persistence at 12 months. Considerable change in temperament in the first 12 months of life may be influenced by biological and environmental factors common to the premature birth experience.

State of the science: feeding readiness in the preterm infant.

Finding ways to consistently prepare preterm infants and their families for more timely discharge must continue as a focus for everyone involved in the care of these infants in the neonatal intensive care unit. The gold standards for discharge from the neonatal intensive care unit are physiologic stability (especially respiratory stability), consistent weight gain, and successful oral feeding, usually from a bottle. Successful bottle-feeding is considered the most complex task of infancy. Fostering successful oral feeding in preterm infants requires consistently high levels of skilled nursing care, which must begin with accurate assessment of feeding readiness and thoughtful progression to full oral feeding. This comprehensive review of the literature provides an overview of the state of the science related to feeding readiness and progression in the preterm infant. The theoretical foundation for feeding readiness and factors that appear to affect bottle-feeding readiness, progression, and success are presented in this article.

Nutritive sucking and neurobehavioral development in preterm infants from 34 weeks PCA to term.

PURPOSE To investigate changes in nutritive sucking patterns, behavioral state, and neurobehavioral development of preterm infants from the 34 weeks postconceptional age (PCA) to term. DESIGN Nonexperimental descriptive correlational design was used. METHODS A convenience sample included 66 preterm infants with a gestational age between 24 and 34 weeks at birth. Mean gestational age was 29.7 weeks, with a mean birthweight of 1379 grams. Instruments included the Kron Nutritive Sucking Apparatus, the Anderson Behavioral State Scale (ABSS), and the Brazelton Neonatal Behavioral Assessment Scale (BNBAS). A feeding procedure was administered at 34 and 40 weeks PCA with BNBAS administered at 40 weeks PCA. Data analysis strategies included t-tests, Spearman rho correlations, Wilcoxon matched-pairs signed-ranks test, and a Random Coefficients Model. RESULTS There were significant differences in number of sucks (p < 0.001), intensity of sucking pressures (p < 0.001), average time between sucks (p < 0.001), and average time between bursts (p < 0.001) from 34 weeks PCA to term. With maturation, it was noted that the preterm infants were significantly more alert during the sucking protocol from 34 weeks to term (p < 0.001). Yet, infant sucking parameters at 34 weeks PCA and term were not significantly related to the BNBAS or to the infants state. CLINICAL IMPLICATIONS These results demonstrate that high risk preterm infants mature significantly in their sucking behaviors and in their ability to maintain a more alert behavioral state from 34 weeks PCA to term. However, unlike full term infants--where state is positively correlated to feeding (sucking) success--the preterm infant state of alertness may not enhance sucking skills at 34 weeks PCA. These infants may be too stressed to manage both feeding and stimulation from the environment that is unavoidable when alert. However, this relationship does appear to change by 40 weeks PCA.

Feeding patterns of full-term and preterm infants at forty weeks postconceptional age.

ABSTRACT. Little research exists that addresses the differences in feeding skills between preterm (PT) infants at term and full-term (FT) infants. The purpose of this study was to quantify and examine the differences in sucking abilities of PT infants when measured at 40 weeks postconceptional age (PCA) and newly born FT infants. The sample consisted of 213 infants who were divided into three groups on the basis of their gestational age at birth (24–29 wk, 30–32 wk, and 38–42 wk). The Kron Nutritive Sucking Apparatus (KNSA) was used to examine the microstructure of sucking and feeding behaviors. There were significant differences among the three groups in several of the sucking variables: number of bursts (p = .005), intersuck interval (p = .0212), sucks per burst (p = .0003), suck width (p < .0001), intersuck width (p < .0001), mean maximum pressure (p < .0001), and intersuck width/interburst width (p = .02). The findings from this study demonstrate the importance of both maturation at birth and experience as factors influencing feeding behaviors.

Building relationships with families in the NICU: exploring the guarded alliance.

Extremely low-birthweight infants and their families experience prolonged hospitalization in the newborn intensive care unit (NICU). Prolonged hospitalization is particularly stressful for the family, leading to distress in most aspects of their lives, including separation of parents from each other and from other family members, a need for increased psychological support, and increased economic concerns. Based on these characteristics, these families appear to have needs more similar to that of families caring for chronically ill members. 1 Indeed, this initial hospitalization may be the prelude to coping and surviving with a chronic illness for many of these children and families. This article proposes the adaption of “guarded alliance” as a framework for developing relationships and providing care to families in the NICU. 2 This framework was derived from research with families of the chronically ill. Supportive research is used to justify the adoption of this framework for interactions with families in the NICU. In addition, linkages to family-centered care principles in critical care settings are also discussed.

Integrated Review of Cytokines in Maternal, Cord, and Newborn Blood: Part I—Associations With Preterm Birth

Preterm birth (PTB; spontaneous delivery prior to 37 weeks gestation) affects one out of eight infants born in the United States and is the most common cause of neonatal morbidity and mortality. Although the pathogenesis of PTB is multifactorial, a growing body of literature supports the hypothesis that one cause of PTB is inflammation in pregnancy. Investigators have implicated mediators of inflammation, most notably proinflammatory cytokines, as being associated with and perhaps a playing a causal role in the pathogenesis of preterm labor and adverse early fetal outcomes. Though researchers have pursued the association of cytokines with preterm labor and subsequent early adverse fetal outcomes as a line of research, there has been little integration of diverse findings across studies. This systematic review appraises the empirical evidence from human studies for the association of levels of cytokines in blood with preterm labor and adverse early fetal outcome to examine the current state of the science in this important area of biobehavioral research. The most consistent finding is that increased levels of proinflammatory cytokines, particularly interleukin (IL) 6, IL-β1, and tumor necrosis factor α (TNF-α), are associated with PTB as compared to levels found at term birth. However, there have been relatively few studies and results have not been consistent. Therefore, further research is needed to elucidate the association of these inflammatory mediators with adverse pregnancy outcomes.

A model of neurodevelopmental risk and protection for preterm infants.

The purpose of this article is to introduce a model of neurodevelopmental risk and protection that may explain some of the relationships among biobehavioral risks, environmental risks, and caregiving behaviors that potentially contribute to neurobehavioral and cognitive outcomes. Infants born before 30 weeks of gestation have the poorest developmental prognosis of all infants. These infants have lengthy hospitalization periods in the neonatal intensive care unit (NICU,) an environment that is not always supportive of brain development and long-term developmental needs. The model supports the premise that interventions focused on neuroprotection during the neonatal period have the potential to positively affect long-term developmental outcomes for vulnerable very preterm infants. Finding ways to better understand the complex relationships among NICU-based interventions and long-term outcomes are important to guiding caregiving practices in the NICU.

Gut Microbiome Developmental Patterns in Early Life of Preterm Infants: Impacts of Feeding and Gender.

Gut microbiota plays a key role in multiple aspects of human health and disease, particularly in early life. Distortions of the gut microbiota have been found to correlate with fatal diseases in preterm infants, however, developmental patterns of gut microbiome and factors affecting the colonization progress in preterm infants remain unclear. The purpose of this prospective longitudinal study was to explore day-to-day gut microbiome patterns in preterm infants during their first 30 days of life in the neonatal intensive care unit (NICU) and investigate potential factors related to the development of the infant gut microbiome. A total of 378 stool samples were collected daily from 29 stable/healthy preterm infants. DNA extracted from stool was used to sequence the V4 region of the 16S rRNA gene region for community analysis. Operational taxonomic units (OTUs) and α-diversity of the community were determined using QIIME software. Proteobacteria was the most abundant phylum, accounting for 54.3% of the total reads. Result showed shift patterns of increasing Clostridium and Bacteroides, and decreasing Staphylococcus and Haemophilus over time during early life. Alpha-diversity significantly increased daily in preterm infants after birth and linear mixed-effects models showed that postnatal days, feeding types and gender were associated with the α-diversity, p< 0.05–0.01. Male infants were found to begin with a low α-diversity, whereas females tended to have a higher diversity shortly after birth. Female infants were more likely to have higher abundance of Clostridiates, and lower abundance of Enterobacteriales than males during early life. Infants fed mother’s own breastmilk (MBM) had a higher diversity of gut microbiome and significantly higher abundance in Clostridiales and Lactobacillales than infants fed non-MBM. Permanova also showed that bacterial compositions were different between males and females and between MBM and non-MBM feeding types. In conclusion, infant postnatal age, gender and feeding type significantly contribute to the dynamic development of the gut microbiome in preterm infants.

An Integrated Review of Developmental Outcomes and Late‐Preterm Birth

OBJECTIVE To evaluate existing evidence on long-term developmental outcomes of late-preterm infants (LPI; infants born 34-36 6/7 weeks gestation). DATA SOURCES Computerized bibliographic databases and hand search for English language articles published between January 1995 and November 2010 yielded 817 articles. STUDY SELECTION Twelve studies (10 cohort and two cross-sectional) were identified that defined late-preterm (LP) birth as 34 to 36 6/7 weeks gestation and addressed growth and neurodevelopmental outcomes in LPI. DATA EXTRACTION Using a modified Downs and Black scale for assessing the quality of experimental and observational studies, two reviewers who were blind to each others ratings assessed study quality. Ratings ranged from 12.5 to 14 with moderate to very good interrater agreement. Kappa (κ) values were 0.83 (reporting), 0.63 (external validity), 0.73 (internal validity), and 0.83 (design) for the four subscales and 0.56 for the whole scale, with no major systematic disagreements between reviewers. DATA SYNTHESIS Studies were divided into five categories to include the following developmental outcomes: neurodevelopment, behavioral, cognitive, growth, and function. Using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines, synthesis of the findings is provided as an integrative review. CONCLUSION Significant variations in study populations, methodology, and definition of LP exist. Due to paucity and heterogeneity of the existing data especially in infants born 34 to 36 6/7 weeks, there is no clear characterization of the long-term risks, and future research is needed.