Lisa F. Brown

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.

Heart Rate Variability in Premature Infants During Feeding

Early mother-infant interaction, a potentially major contributor to the development of a premature infants behavioral and physiologic regulation, has received very little research attention. This study examined the development of physiologic regulation in relation to maternal-infant feeding interaction for 43 premature infants, from the time caregiving responsibility was transferred to the mother through each infants 4th postterm month. Infants and mothers were seen in a special care nursery just before discharge and in home at 1 and 4 months postterm age. General linear mixed models were used to examine the changes in infant heart rate variability (HRV) and Positive Affective Involvement and Sensitivity/Responsiveness scores over time and infant HRV over feeding conditions (prefeeding, feeding, and postfeeding). Significant differences were found for high-frequency and low-frequency HRV over time (p < .001 and p = .014, respectively). However, maternal feeding behavior did not show a significant effect of time (p = .24). The feeding condition effect on high-frequency HRV was significant (p < .001), with HRV lower during feeding compared to both prefeeding and postfeeding. Maternal feeding behavior was not associated with infant HRV. Discovering the ways in which maternal feeding behavior contributes to infant physiologic regulation may require study of the relationship of HRV to infant feeding behavior.

Integrated Review of Cytokines in Maternal, Cord, and Newborn Blood: Part II— Associations With Early Infection and Increased Risk of Neurologic Damage in Preterm Infants

A growing body of literature supports the relationship of maternal inflammation with preterm birth and adverse neonatal outcomes, including infection and central nervous system (CNS) dysfunction. Mediators of inflammation, most notably proinflammatory cytokines, have been implicated as having an association with and perhaps playing a causal role in the pathogenesis, leading to adverse neonatal outcomes. Even though the association of cytokines with early adverse neonatal outcomes has been actively pursued as a line of research, there has been little integration of diverse findings across studies. Therefore, the purpose of this systematic review was to appraise and classify empirical evidence from human studies for the association of cytokine levels in blood (serum, plasma, or cells; maternal, cord, or neonatal) with two adverse early outcomes in preterm infants: early infection and increased risk of neurologic damage. The review revealed that the proinflammatory cytokines most frequently linked with sepsis are in the interleukin (IL) 1 family as well as tumor necrosis factor α (TNF-α) and IL-6. The proinflammatory cytokines most frequently linked to neurologic insult in the reviewed studies were IL-1β, IL-6, and IL-8. In all cases where IL-1β was studied, the levels were increased when there was neurologic insult. A better understanding of the relationship of these inflammatory substances with these adverse conditions is needed for the future development of maternal and neonatal biobehavioral nursing research.

The Mother-Infant Feeding Tool

OBJECTIVE To describe the development and evaluation of an observation system to assess the process of mother-infant feeding interaction relevant to infant neuro-behavioral regulation: the Mother-Infant Feeding Tool. DESIGN Secondary analysis. SETTING Special care nursery just before discharge and in the home at 1 and 4 months postterm age. PARTICIPANTS Forty-three mother-infant dyads. METHODS Videotaped feeding interactions were examined to assess regulatory processes of mother-infant interaction. Data were collected at three times over the infants first 4 postterm months: before the infants discharge from the special care nursery and at 1 and 4 months postterm age in the home. RESULTS Across all three data points mothers rarely talked to their infants. CONCLUSION Further testing is needed, but the Mother-Infant Feeding Tool shows promise in assessing very early mother-infant feeding interactions.

Caring for a Preterm Infant at Home: A Motherʼs Perspective

The purpose of this phenomenological study was to examine the experiences of mothers of preterm infants during the first 6 months at home following discharge from a neonatal intensive care unit (NICU). A purposeful sample of 8 mothers was gathered and interviews were conducted over a 4-month period. Each interview was audio recorded and took place in the study participants home or another place of her choosing. Interviews were transcribed verbatim and analyzed independently with themes being identified and organized for each participant. From these analyses, the themes of fear, exhaustion, determination, and thankfulness were identified as being common to all study participants and became the basis for developing the essence of the phenomenon. The essence of this experience for these mothers was their resolve to do whatever was necessary to ensure the best possible outcomes for their infants. The data gathered from these personal interviews will serve to further inform our understanding of this important time from the perspective of those who experienced it, as well as aid in the design of interventions to address the specific needs of these mothers prior to NICU discharge.

A guided feeding intervention for mothers of preterm infants: Two case studies

PURPOSE The purpose of this study was to determine how mothers of preterm infants perceive the feasibility and acceptability of a guided feeding intervention. DESIGN AND METHODS In this multiple case study design, feasibility was assessed by retention of participants through all intervention sessions. Acceptability was assessed with a semi-structured interview. RESULTS Participants found the intervention useful for demonstrating and explaining behaviors that facilitate feeding, and helpful in dispelling previous, erroneous understandings about infant behaviors. PRACTICE IMPLICATIONS The results are encouraging. The intervention was found to be both feasible and acceptable. The effectiveness of this intervention needs to be assessed in a randomized controlled trial.

Sequential observation of infant regulated and dysregulated behavior following soothing and stimulating maternal behavior during feeding

PURPOSE To describe maternal behaviors occurring before infant regulated or dysregulated behavior at three times in early infancy and examine behavioral patterns over time with their prematurely born infants. DESIGN AND METHODS Video recordings of 37 dyads were coded on infant regulated and dysregulated behaviors following maternal soothing and stimulating behaviors. RESULTS At each time, infants showed more regulation after maternal soothing than after maternal stimulating. Further study is merited. PRACTICE IMPLICATIONS Knowing infant regulation and dysregulation following categories of maternal behavior could help mothers anticipate infant regulatory or dysregulatory behavior in response to their own behavior and identify supportive caregiving strategies.