Late preterm infants are defined as infants born between 340 /7 and 346 /7 weeks based on early ultrasound or 239 to 259 days since the first day of the last menstrual period.1 , 2 In 2006, late preterm infants constituted 5.9% and 9.2% of live-born infants in Canada and United States, respectively.3 , 4 Late preterm infants are a growing proportion of both live-birth infants and preterm infants. It is anticipated that this trend will continue due to improved medical surveillance to prevent fetal compromise and adverse maternal outcome, maternal characteristics, or history such as age, obesity, diabetes, or hypertension, and an increase in multiple births, artificial reproductive technologies, elective cesarean deliveries and inductions of labor.1 , 5 – 9
At birth, late preterm infants differ from term infants because they are at higher risk for morbidities.10 , 11 Studies have used Arkansas Medicaid claims data linked to state birth certificate data (2001–2005)10 and the obstetric electronic medical record database of Massachusetts General Hospital (October 1997-October 2000)11 to compare morbidities between late preterm infants and term infants. Findings revealed that late preterm infants had poorer outcomes including assisted ventilation, respiratory distress syndrome, hypoglycemia,10 apnea and bradycardia, and temperature instability.11 Although there was a wide variability in length of stay within late preterm infants, length of stay (in days) was comparable with term infants (ie, no increase) regardless of mode of delivery, that is, vaginal or cesarean delivery.11
The Canadian Paediatric Society supports both the early discharge of late preterm infants and implementation of appropriate models of postpartum follow-up of mothers and infants. However, other guidelines (eg, Association of Women's Health, Obstetric and Neonatal Nurses and Council of International Neonatal Nursing) clearly stipulate that late preterm infants should not be considered for early discharge.2 Others, such as the American Academy of Pediatrics, maintain a more neutral stance, recommending an individualized approach to the timing of discharge (Table 1 ). In the United States, decreasing length of stay for both vaginal and cesarean deliveries prompted the institution of state and federal laws in 1998, which decreased the proportion of newborns discharged early regardless of type of insurance (ie, private or Medicaid).20 In Canada, the rate of early discharge (length of hospital stay <2 days) has continued to rise, particularly for vaginal deliveries.21 Shorter lengths of hospital stays result in continuing care considerations as infants and their families transition from hospital- to community-based care.
Table 1-a: Guidelines for late preterm infants
Table 1-b: Guidelines for late preterm infants
Table 1-c: Guidelines for late preterm infants
The focus of this article is on the transitions of late preterm infants from hospital to home, specifically on the patterns of infant responses postdischarge from hospital through up to 6 weeks after birth, and postpartum care as an environmental support intended to facilitate this transition. The article examines gaps in provision of postpartum care of late preterm infants within the context of guidelines and models of postpartum care—home and clinic visits—of late preterm infants.
PATTERNS OF RESPONSES POSTDISCHARGE
Late preterm infants are biologically and developmentally immature and are, therefore, at increased risk of mortality and short-term morbidities, some of which may necessitate medical care with or without hospital readmission.
Mortality
Compared with full-term infants, late preterm infants are at higher risk of dying in the neonatal period (ie, neonatal mortality),22 , 23 particularly in the first few days of life,24 – 26 and in the first year of life (ie, infant mortality).24 , 26 In the United States, in 2002, neonatal mortality among late preterm infants was 4.1 per 1000 live births, hence markedly higher than the rate of 0.9 per 1000 live births reported among term infants.27 Similarly, infant mortality among late preterm infants was 7.7 per 1000 live births and among term infants was 2.5 per 1000 live births.27 A Canadian population-based study reported a 5.5-fold and 3.5-fold greater mortality rate in the neonatal and infant periods, respectively.25 Late preterm infants who are small for gestational age were identified to be even more vulnerable. Compared with term appropriate for gestational age infants, late preterm small for gestational age infants were 44 times and 22 times more likely to die in first month of life and first year of life, respectively.28 Neonatal and infant causes of death have been identified as congenital defects/anomalies,25 – 29 immaturity-related conditions as defined by the International Collaborative Effort (ie, maternal conditions such as cervical incompetence and chorioamnionitis associated with preterm birth or conditions related to being born with low birth weight or short gestation, or both, such as necrotizing enterocolitis),28 , 30 severe hypoxic-ischemic encephalopathy or asphyxia,25 , 28 infections, and sudden infant death syndrome.28
Morbidity
Late preterm infants have a 7-fold increased risk of morbidity compared with term infants.31 Independent risk factors for short-term morbidities also include being the firstborn and having a mother who experienced complications during labor and delivery. For non–breast-fed late preterm infants, male sex is an identified risk factor for neonatal morbidity.32 The risk of neonatal morbidity is higher for late preterm infants discharged early than for full-term infants discharged early, with the relative risk of readmission being almost 2-fold for the former.32 During the postpartum period, late preterm infants are at risk of feeding difficulties, poor growth and dehydration, clinical jaundice, symptoms prompting investigation for sepsis, temperature instability, and hypoglycemia.
Late preterm infants can experience poor growth, jaundice, and dehydration due to their inability to breast-feed adequately because of weak suction pressure33 or inadequate milk supply because of delayed lactogenesis, that is, the milk coming in after the third day following birth.34 Late preterm infants may take “considerably longer to feed normally” (35 (p66) because gastrointestinal motility and gastric emptying may be delayed. Hence, these infants do not demonstrate feeding capabilities of term infants, which is a benchmark used by clinicians to assess feeding readiness.35 Late preterm infants' immature and inconsistent feeding behaviors (eg, feeding cues, number of sucks, duration of sucking bursts, and sucking pressure) may create challenges for mothers to breast-feed effectively and establish and sustain an adequate milk supply.36 , 37 Late preterm infants are more likely to experience gastroesophageal reflux35 due to transient relaxation of the lower esophageal sphincter.38 The accompanying symptoms of reflux, such as frequent spitting up or vomiting, and apnea may further compromise feeding interactions and outcomes.
Late preterm infants may develop apnea as a result of an immature respiratory control center (eg, maturity of airway and chemical control of breathing), or immature respiratory reflexes (ie, immature coordination of suck, swallow, and breathing).39 In addition, apnea may be a presenting sign of other etiologies such as infection and hypoglycemia.39 A study examining term and late preterm infants experiencing apnea postdischarge found that apneic episodes were isolated events and there was a significant variability in diagnostic evaluation and, in many instances, the specific etiology could not be identified.40 Immaturity of the autonomic brain stem also increases the risk of sudden infant death syndrome in late preterm infants.41
Late preterm infants are more likely to experience hyperbilirubinemia because the imbalance of production and excretion bilirubin (ie, inefficient conjugation) due to hepatic immaturity is more pronounced with decreasing gestational age.42 Feeding difficulties may further exacerbate this imbalance, that is, enhance hyperbilirubinemia by increasing enterohepatic circulation of bilirubin.43 Furthermore, the hepatic system matures slowly during the postnatal period.42 Consequently, late preterm infants present with greater severity and more protracted jaundice than term infants.43 Late preterm infants are also at higher risk for developing kernicterus and its associated neurologic sequelae.44 – 47
Late preterm infants may be at an intermediate risk of acquiring sepsis in the postnatal period due to immunologic48 and gastrointestinal immaturity.35 The gastrointestinal system plays a dynamic role with the host immune system, such as preventing bacterial translocation. Furthermore, the intestinal microbial environment influences the innate and adaptive immune systems of the gastrointestinal system.35 Hence, intestinal barrier dysfunction and delay or impairment of the intestinal colonization process may predispose late preterm infants to infections.35 Nonspecific symptoms of infection such as temperature instability, hypoglycemia, hyperbilirubinemia, and respiratory distress are prevalent in late preterm infants because of their biologic and physiologic immaturity. Hence, late preterm infants are more likely than term infants to have investigations to rule out sepsis, resulting in further barriers to establishing breast-feeding.43
Temperature instability may continue to be an issue following birth because of immature epidermal barrier, high ratio of surface area compared with birth weight, and wide temperature gradient between the ambient and infant's temperature.48 Hypoglycemia may develop secondary to prolonged hypothermia because glucose is used to stimulate brown fat metabolism.37 , 39 Late preterm infants have limited glycogen stores, which may be exhausted quickly, and therefore their ability to produce and conserve heat is limited,39 as well as the activity of glucose-6-phosphate, which catalyzes the terminal step of the glycogenolysis and gluconeogenesis processes, may be delayed.43 Finally, late preterm infants may have limited milk intake because of feeding challenges. All of these factors collectively increase the likelihood of developing hypoglycemia37 , 48 when late preterm infants experience prolonged hypothermia.
Emergency department visits
In the immediate postnatal period, late preterm infants experiencing the morbidities described earlier may present for care in the primary care office (ie, family or pediatric clinic) or in the emergency department.49 Emergency department visits have been found to be more frequent among late preterm infants who are born at 36 weeks' gestational age.49 , 50 Jain and Cheng49 tracked newborn visits to emergency departments of tertiary pediatric hospitals in a large metropolitan areas. Data were collected over a 1-year period (July 2005-June 2006), and each newborn was followed for the first 31 days of life. Shahid and colleagues50 undertook a retrospective medical record review of all late preterm infants born at the Loyola University Medical. The time period for the study was January 2005 to December 2008, and each infant's medical record was reviewed from birth to 30 days after discharge. Age at presentation to emergency department varied between term and late preterm infants, in that more late preterm infants presented in the fourth week of life compared with the second week of life for term infants.49 The most common chief complaints included difficult breathing/stopped breathing, fever, jaundice, vomiting, and crying. Of those late preterm infants seen in the emergency department, 36.9% were readmitted to hospital. This rate was comparable with term infants.49 A review of California maternal and newborn/infant hospital discharge linked data for preterm infants noted that infants who are 35 weeks' gestational age have the greatest readmission costs ($92.9 million) among preterm infants born at less than 36 weeks' gestation. The database was for the period 1992–2000. It excluded infants born or admitted to military facilities. As well, it did not include births in out-of-state hospitals, private homes, or birthing centers with no reporting structures to Office of Statewide Health Planning and Development.51
Rehospitalization
Late preterm infants have been reported to have higher hospital readmission rates than term infants, particularly in the first 2 weeks of life.52 , 53 These patterns were observed in retrospective reviews of cohorts of late preterm compared with term infants. McLaurin and colleagues52 studied a large US database of commercially insured infants born in 2004 with enrollment that continued for about a year, whereas Escobar and colleagues53 studied infants born at 7 Kaiser Permanente Medical Care Program delivery services between October 1998 and March 2000. This predisposition for higher rehospitalization persists throughout the first year of life.52
Escobar and colleagues54 examined the distribution of rehospitalization among neonatal intensive care unit (NICU) survivors and found that infants 33 to 36 weeks' gestational age who had a hospital stay of less than 4 days had the highest rate of rehospitalization when compared with their counterparts with 4 or more day lengths of stay in the NICU, term infants with less than 4 days or more than 4 days length of stay in the NICU, and infants less than 32 weeks with all lengths of stay. Reasons for rehospitalization among 33 to 36 weeks' gestation infants with length of stay less than 4 days were jaundice, feeding difficulties, and rule-out sepsis.54 Jaundice was the leading cause of rehospitalization during the first 2 weeks of life for late preterm infants discharged early (ie, ≤3 days in hospital) and term infants, but not for late preterm infants, discharged late.52 Term infants, late preterm infants discharged early, and late preterm infants discharged late had similar leading causes of rehospitalization 2 weeks after discharge and before the infant's first birthday, namely, acute bronchiolitis.52 Digestive disorders were the other common diagnosis for rehospitalization in the long term.52 Rehospitalization rates of specific diagnosis/chief complaints vary across hospitals.53 A multiple readmission diagnosis was identified for many infants.32 , 53
Early discharge,50 , 52 , 55 never being admitted to NICU,32 , 53 and only nursery stay50 have been identified as significant factors associated with readmission to hospital for late preterm infants32 , 50 or infants 34 to 36 weeks' gestation.53 Varied definitions of early discharge have been used in studies examining readmission, including less than 48 hours,50 3 days or less in hospital,52 and a less than 2-night hospital stay.55 Of note, late preterm infants who were discharged late from the hospital in which they were born (ie, required prolonged hospital stays) had higher rates of rehospitalization and overall healthcare costs.52
Common reasons for readmission include hyperbilirubinemia, lactation, and infection. A brief overview is presented for each of these causes for readmission.
Hyperbilirubinemia
Hyperbilirubinemia was the leading cause of neonatal morbidity among healthy late preterm infants32 , 55 and the primary diagnosis for readmissions of late preterm infants.1 , 32 , 53 Late preterm infants were predominantly readmitted for jaundice on day 3 of age; most were readmitted for jaundice by 4 or 5.5 days of age, or first week of life.32 , 56 Terms infants were readmitted for jaundice at day 3 of life.55
Lactation
Breast-feeding is not always optimal among late preterm infants, given their physiologic and developmental immaturity (eg, rapid fatigue during feeding, inefficient breast-feeding, poor coordination of suck, swallow, and breathing, and decreased oromotor tone).57 Lactation-associated morbidities (eg, poor growth, jaundice, and dehydration) can increase late preterm infants' risk of hospitalization in the first 2 weeks following discharge when comparing them with non–breast-fed late preterm infants and term infants.32 , 49 , 55 – 57 A study that linked birth certificate and hospital discharge data for all live-born singleton infants delivered vaginally at a Massachusetts hospital and discharged early (ie, <2 nights hospital stay) reported that breast-fed late preterm infants discharged early are more likely to be readmitted than breast-fed term infants discharged early.55 A population-based cohort study examined risk factors for neonatal mortality or morbidity among late preterm infants. Infants born vaginally to singleton women residing in Massachusetts and delivering local hospitals from 1998 to 2002 were included in the study. In the findings, breast-feeding was an independent risk factor for neonatal readmission.32 Likelihood of readmission was no different when comparing late preterm infants and term infants who were not breast-fed.55
Infection
Readmission for infection has been found to be more common in the second week of age,55 , 58 with 50% of infants being readmitted by day 11 of age and 75% by day 15 of age.55 On average, term infants presented with infection 1 week after late preterm infants.55 Late preterm infants were 3 times more likely to be investigated for sepsis than full-term infants. Term infants suspected of infection had blood work drawn, whereas late preterm infants were more frequently treated with antibiotics for 7 days.11 The index of suspicion for infection may be higher in late preterm infants because signs and symptoms of infection are subtle and nonspecific and they are more susceptible to infection because their immune system is immature.11
Consequences of morbidities and readmission
Short-term morbidities influence healthcare utilization and increase costs of care. A study using Arkansas Medicaid claims data linked to state birth certificate data from 2001 through 2005 discovered that late preterm infants have higher outpatient expenditures during the first year of their life (adjusted marginal effect $108 [95% confidence interval: 58–158]).10 Another study52 using a national US database of commercially insured members found total healthcare costs were 3 times higher in the first year of life for late preterm infants than for term infants.52
Short-term morbidities, particularly those requiring rehospitalization for their management, can increase parental stress and hinder mother-infant interaction, thereby also contributing to depressive symptoms.59 Maternal depressive symptoms, in turn, have adverse consequences on all dimensions of child development: physical (eg, underweight), emotional (eg, delay in emotional development), cognitive (eg, language and IQ), and social (eg, social dysregulation, which impedes breast-feeding).60 – 63 Literature related to mothers' experience of caring for preterm infants indicates that they express feelings of greater parental stress,64 distress,65 and anxiety,66 , 67 which could contribute to increased depressive symptoms.59 , 68 These experiences have yet to be validated specifically for mothers of late preterm infants.
Clinicians who care for late preterm infants and their families in the postpartum period must be familiar with these patterns of response postdischarge to intervene appropriately. Comprehensive guidelines for postpartum care of late preterm infants will help ensure prudent monitoring and care of both mother and infant following discharge from hospital.43
POSTPARTUM CARE
Historically, home visits have been the only model of care implemented by European countries69 and Canada for the surveillance of maternal postpartum health. The intent of postpartum home visits by public health nurses is to address the health, social, and emotional needs of families.70 – 73 As evident from the earlier discussion on patterns of responses of late preterm infants following discharge, public health nurses may potentially encounter many challenges while providing care to mother-infant dyads in the postpartum period. A variety of system stressors, as a collective, have led to the introduction of alternate models of care including home visits, clinic visits, telephone follow-up, and a move away from universal provision of services (eg, home visits for high-risk populations only) in some countries (eg, Canada). Current trends in emergency department visits and readmission rates of late preterm infants suggest that the current approach to postpartum care may not be meeting the needs of late preterm infants and their families.
An extensive review of literature failed to identify guidelines and evidence for appropriate models for postpartum care in the community, specifically for late preterm infants. The current state of literature related to evidence-based clinical practice guidelines of postpartum care of late preterm infants and models of postpartum care are discussed later.
Clinical practice guidelines for postpartum care of late preterm infants
To the best of the researchers' knowledge, public health nurses' experience of caring for late preterm infants has not been studied. Hence, it is difficult to identify the range of clinical issues public health nurses attend to while caring for late preterm infants post–hospital discharge. Anecdotal evidence suggests that public health nurses have significant challenges in identifying interventions to promote effective and safe oral feeding in late preterm infants. Furthermore, care practices vary widely among nurses, creating uncertainty with regard to best practice. In caring for late preterm infants, public health nurses draw from their theoretical and scientific knowledge (ie, literature) or clinical experience of working with term and extremely preterm infants, which may or may not ensure application of best practices. There is also a paucity of literature on parents' experiences of caring for their late preterm infant. Customizing guidelines to address the clinical challenges experienced by public health and community nurses may increase evidence uptake into practice and impact clinical outcomes of late preterm infants. Guidelines that take into consideration parents' care concerns will ensure that their needs are met.
Guidelines developed for postpartum care of late preterm infants should stipulate the type of care provider, initiation and frequency of visits, duration of care, and recommendations related to prevention and management of morbidities encountered by late preterm infants.
Type of care provider
Although a meta-analysis showed that paraprofessionals with appropriate training achieved similar effects on maternal behavior as nurses, counselors, psychologists, or social workers,74 certain caveats require consideration. In a study examining prenatal and infancy home visits by paraprofessionals and nurses, different patterns of effects have been reported. For example, paraprofessionals have been found to have a positive effect on sensitive mother-infant interaction and home environments but no statistically significant effect on child outcome.75
In Canada, all public health nurses must be registered nurses. A shift away from this standard of care without exploring the potential impact of such a change on social relations between care provider and families could significantly impact establishing a trusting relationship. Families, particularly those from certain ethnic communities, may have certain expectations regarding qualifications of care providers. A synthesis of qualitative research76 concluded that positive encounters are important to identifying problems experienced by parents and fostering independent decision making and empowering mothers. Public health nurses are ideal home visitors because they already have formal training to attend to complex family and clinical situations. More importantly, family members view public health nurses as credible care providers who can teach families to identify health issues early and to proactively seek care.77
Initiation and frequency of visits
Among infants born at 34 weeks' gestation or later, having a scheduled outpatient or home visit within 72 hours postdischarge have been found to be protective factors against rehospitalization for causes other than jaundice. The adjusted odds ratios were 0.73 and 0.59, respectively.53 Receiving both a home visit as well as a scheduled outpatient visit within 72 hours increased risk of rehospitalization (adjusted odds ratio = 1.94).53
Duration of care
The postpartum (and postnatal for infants) period begins at birth; however, its duration varies from 6 to 8 weeks following delivery. Given the vulnerability of late preterm infants extending beyond this period, one may speculate that these infants may require close monitoring beyond the postpartum period.
Recommendations related to prevention and management of morbidities
Table 1 summarizes the available guidelines for postpartum care of the later preterm infants. As evident from this synthesis, when developing recommendations related to prevention and management of morbidities, particular attention should be given to lactation support both during hospitalization and postdischarge. Public health nurses will need to develop competencies to attend to breast-feeding issues, specifically as they relate to late preterm infants. Guidelines developed by the Academy of Breast-feeding Medicine19 should be reviewed when developing recommendations for postdischarge follow-up.
Given the potential negative effects of guidelines,78 it is imperative that guidelines be evaluated for efficacy and safety. Multiple models of care are employed within postpartum community services in provision of care to mother-infant dyads postdischarge from hospital. The effectiveness of implementing guidelines within various models of care needs to be examined, as well as the potential negative effects of certain models79 in attaining the goals of the guidelines. When evaluating the effectiveness of models in relation to attaining the goals of the guidelines, maternal confidence and knowledge should be evaluated as well as mothers' preferences for models of care.
Models of postpartum care
Given that late preterm infants are at higher risk of mortality and morbidities postdischarge than terms infants, emphasis should be given to universal provision of postpartum care as general preventative measures for all families with late preterm infants. This literature review found no research examining the effectiveness of various models of postpartum care implemented by public health nurses for late preterm infants and their families. What research is available74 , 75 largely concerns the effectiveness of different home visitors on the socioemotional and cognitive competency of low-income families and not necessarily those with late preterm infants. If there is a clinical component to these studies, it concerns the reduction of child maltreatment and not the morbidities associated with late preterm infants.
A retrospective study80 compared outcomes of infants who received home visits with particular attention given to prevention of jaundice and dehydration with those who did not receive a home visit following discharge from hospital. Readmission for jaundice and dehydration in the first 10 days of life was lower (0.6%) for newborns who received home visits than for those who did not receive a home visit (2.8%). A significant difference (P < .0001) was found in the number of infants who returned to the emergency department in the first 10 days of life for jaundice and dehydration; 3.5% in the no-home visit group compared with 0% in the home visit group. Almost 23% of newborns presenting in the emergency department were eventually readmitted to hospital. Home visiting was found to be cost-effective in reducing hospital utilization postdischarge compared with no-home visits, as well as $109.80 per child compared with $118.70 per child. The incremental cost-effective ratio when comparing home visit with no-home visit was –$181.82, indicating a cost savings of $181.82 for every newborn not using health services in the first 10 days of life.81 Availability of home phototherapy was identified as a central factor associated with decreased rehospitalization.53
Home visits offer certain advantages related to accessibility because they are convenient (ie, care provider comes to you, not inconvenienced with organizing childcare or bringing other children to clinic appoints) and eliminate transportation costs. For those providing care, the home environment offers additional knowledge about the family.74 A survey design study of public health nurses involved in a child promotion program in Sweden found that although both mothers and nurses valued the first home visits, there were differences in perspective. For nurses, advantages of a home visit related to promoting their work such as developing a more holistic understanding of the family and their context, encountering parents who were more relaxed and asked more questions, having adequate time, and the environment being more quiet and peaceful. For mothers, the home visit was more practical and facilitated a personal encounter that they viewed as an essential aspect of care.81
For low-risk infants and their mothers discharged early (ie, <48 hours), home visits by registered nurses led to similar clinical outcomes within 2 weeks following discharge when compared with hospital-based group follow-up within 72 hours after early postpartum discharge (ie, <48 or <36 hours)82 or hospital-based clinic visits by nurses83 or pediatric clinic visits by nurse practitioners or physicians.84 No significant differences were reported in newborn or maternal hospitalization or urgent care visits, breast-feeding discontinuation, maternal depressive symptoms,82 , 84 rate of infant weight gain, or daily breast-feeding frequency.83 First-time mothers have expressed concern around the competency of the nurse in relation to examining the infant.81 First-time mothers of low socioeconomic background, however, report low satisfaction with nurse encounters in both home and clinic visits.81
Despite overall evidence in support for neonatal home visits, it is difficult to advocate specifically for home or clinic visits, given the lack of evidence demonstrating the effectiveness and safety of each of these models for postpartum care of late preterm infants.
In conclusion, late preterm infants are a vulnerable population because their biologic and developmental immaturity increases risk of mortality and short-term morbidities following discharge. Universal provision of postpartum care to late preterm infants and their families following discharge from hospital has the potential to reduce the need for emergency visits and rehospitalizations. Evidence-based guidelines are required to direct care of late preterm infants and their families postdischarge from hospital. Guidelines should promote early detection and management of morbidities, thereby contributing to decreasing healthcare utilization (eg, readmission, urgent care, and emergency department visits) and parental stress postdischarge from hospital. Guidelines that attend to the needs of parents may facilitate responsive parenting and increase maternal confidence and knowledge related to the care of their late preterm infant. The public health nurse may be in an ideal position to provide such care, so he or she should be aware of the patterns of response postdischarge from hospital. As policy makers continue to redesign the way in which postpartum maternal healthcare services are organized and delivered, current models of postpartum care need to be systematically evaluated to determine which model(s)—home versus clinic visits—promote best practices detailed in the guidelines and their desired outcomes for late preterm infants and their families.
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