Management of the late preterm infant: not quite ready for prime time

Trends in morbidities of late preterm infants in the neonatal intensive care unit

OBJECTIVE

To characterize demographics and trends in length of stay (LOS), morbidities, and mortality in late preterm infants.

STUDY DESIGN

Cohort study of infants born between 34 0/7 and 36 6/7 weeks gestation between 1999 and 2018 without major congenital anomalies at Pediatrix Medical Group neonatal intensive care units (NICUs).

RESULTS

307,967 infants from 410 NICUs met inclusion criteria. The median (25th-75th percentile) LOS was 11 (8-16) days in the entire period. Postmenstrual age (PMA) at discharge increased during the cohort for all gestational ages (p < 0.001). There was a decrease in invasive ventilation, receipt of phototherapy, and reflux medications observed (p < 0.001).

CONCLUSION

In this large cohort, given 20 years of time for medical advancement, there was no significant improvement in the LOS of late preterm infants. All infants had an increased PMA at discharge, despite multiple practice changes that were observed.

A quality improvement project to increase breast milk feeding of hospitalized late preterm infants in China

BACKGROUND

The breastfeeding rates of late preterm infants are lower than both term and extremely preterm infants. To explore the interventions of increasing full breast milk feeding rate of hospitalized late preterm infants on the 7th day after birth (D7) and evaluate the effect of these quality improvement (QI) interventions.

METHODS

The full breast milk feeding (amount of enteral breast milk reached 120ml/kg/d on D7) rate of hospitalized late preterm infants during May 2017 and November 2017 was set as the baseline before intervention, and the specific aim of promoting breast milk feeding was put forward. The Pareto Chart was used to analyze the factors that affect breast milk feeding process, as well as the discussion of multidisciplinary experts. Key drivers were constructed, including informational materials and education about breast milk feeding, consultations and support on optimal breast milk initiation, initiating breast milk expression within one hour after birth, accurate measurement and recording of expressed breast milk, stimulating continuous and effective lactation, proper breast pump selection in and out of hospital and sending and preserving of expressed milk to NICU. Control chart was used to monitor the monthly change of full breast milk feeding rate until the aim was achieved and sustained.

RESULTS

The baseline of full breast milk feeding rate of late preterm infants was 10%, and the aim of QI was to increase the rate to 60% within a two-year period. Control chart dynamically showed the full breast milk feeding rate increased to 80% with the implementation of the interventions, achieved and made the aim of QI sustained.

CONCLUSION

QI interventions including breast milk feeding education, early postpartum breast milk pumping, kangaroo care to stimulate breast milk secretion, and convenient way of transporting breast milk to NICU, could significantly improve the full breast milk feeding rate of hospitalized late preterm infants.

Predicting NICU admissions in near-term and term infants with low illness acuity

OBJECTIVE

Describe NICU admission rate variation among hospitals in infants with birthweight ≥2500 g and low illness acuity, and describe factors that predict NICU admission.

STUDY DESIGN

Retrospective study from the Vizient Clinical Data Base/Resource Manager®. Support vector machine methodology was used to develop statistical models using (1) patient characteristics (2) only the indicator for the inborn hospital and (3) patient characteristics plus indicator for the inborn hospital.

RESULTS

NICU admission rates of 427,449 infants from 154 hospitals ranged from 0 to 28.6%. C-statistics for the patient characteristics model: 0.64 (Confidence Interval (CI) 0.62-0.65), hospital only model: 0.81 (CI, 0.81-0.82), and patient characteristic plus hospital variable model: 0.84 (CI, 0.83-0.84).

CONCLUSION/RELEVANCE

There is wide variation in NICU admission rates in infants with low acuity diagnoses. In all cohorts, birth hospital better predicted NICU admission than patient characteristics alone.

Earlier preterm birth is associated with a worse neurocognitive outcome in a rabbit model

Background

Preterm birth (PTB) and particularly late preterm PTB has become a research focus for obstetricians, perinatologists, neonatologists, pediatricians and policy makers alike. Translational models are useful tools to expedite and guide clinical but presently no model exists that contextualizes the late PTB scenario. Herein we aimed to develop a rabbit model that echo’s the clinical neurocognitive phenotypes of early and late PTB.

Methods

Time mated rabbit does underwent caesarean delivery at a postconceptional age (PCA) of either 28 (n = 6), 29 (n = 5), 30 (n = 4) or 31 (n = 4) days, term = 31 d. Newborn rabbits were mixed and randomly allocated to be raised by cross fostering and underwent short term neurobehavioral testing on corrected post-natal day 1. Open field (OFT), spontaneous alteration (TMT) and novel object recognition (NORT) tests were subsequently performed at 4 and 8 weeks of age.

Results

PTB was associated with a significant gradient of short-term mortality and morbidity inversely related to the PCA. On postnatal day 1 PTB was associated with a significant sensory deficit in all groups but a clear motor insult was only noted in the PCA 29d and PCA 28d groups. Furthermore, PCA 29d and PCA 28d rabbits had a persistent neurobehavioral deficit with less exploration and hyperanxious state in the OFT, less alternation in TMT and lower discriminatory index in the NORT. While PCA 30d rabbits had some anxiety behavior and lower spontaneous alteration at 4 weeks, however at 8 weeks only mild anxiety driven behavior was observed in some of these rabbits.

Conclusions

In this rabbit model, delivery at PCA 29d and PCA 28d mimics the clinical phenotype of early PTB while delivery at PCA 30d resembles that of late PTB. This could serve as a model to investigate perinatal insults during the early and late preterm period.

Effect of gestational disorders on preterm birth, low birthweight, and NICU admission

OBJECTIVE

Many modifiable maternal behaviors and experiences before and during pregnancy are associated with adverse health outcomes. The relationship between a number of maternal and gestational disorders and perinatal outcomes (preterm birth, low birth weight and neonatal intensive care unit (NICU)) admission in the Central New York population is determined using the Statewide Perinatal Data System, in a retrospective population-based cohort study.

METHODS

Singleton births excluding newborns with congenital anomalies among 165,739 women between 2004 and 2012 are included in this study. Multivariable logistic regression analysis is used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for maternal age, race, education, employment, parity, body mass index, smoking, drug use, depression, abortions, gender of child, prenatal care, and hospital level.

RESULTS

Previous preterm birth and vaginal bleeding are independent high-risk factors for all three perinatal outcomes, pre-pregnancy diabetes (OR 4.95, 95% CI 4.34, 5.64) for preterm birth and (OR 7.45, 95% CI 6.58, 8.44) for NICU admission; and gestational hypertension (OR 4.35, 95% CI 4.03, 4.70) for low birth weight. Among infections, bacterial vaginosis is retained in the multivariable model as a risk factor for preterm and low birth weight while hepatitis C is a risk factor for NICU admission.

CONCLUSIONS

Our findings suggest the continued importance of addressing the need to provide preconception and inter conception care for women since many modifiable risk factors are correlated and need to be addressed well before the woman becomes pregnant.

Using the Preterm Infant Breastfeeding Behavior Scale With Late Preterm Infants

Background

Feeding effectiveness of late preterm infants may vary between feedings and over time, creating confusion and frustration for parents and clinicians. An assessment tool for late preterm infants may assist mothers to recognize breastfeeding behavior more clearly. Although tools are available, none have been tested specifically with late preterm infants. We sought to determine the inter-rater reliability of the Preterm Infant Breastfeeding Behavior Scale scores for late preterm infants between mothers and a health professional.

Methods

A one-group observational non-experimental design assessed inter-rater reliability (24 hours [n =23] and 48 hours [n =11] after birth).

Results

The scale's six components were scored independently; agreement ranged from 81.8% to 100% for all components.

Conclusions

The tool was reliable and could be used to help clinicians and parents accurately understand feeding patterns and behaviors assisting with feeding decisions.

A comparison of the nutritive sucking performance of full term and preterm neonates at hospital discharge: A prospective study

BACKGROUND

Studies show that 40% to 70% of premature infants exhibit both immature and atypical feeding ability. To establish thresholds of performance and develop efficacious treatments for initiating and advancing oral feedings, we must first identify the nutritive sucking performance measures impacted by preterm birth.

AIMS

To compare objective measures of neonatal nutritive sucking between full term and preterm infants at hospital discharge.

STUDY DESIGN AND METHODS

This was a prospective observational study including full term (FT; N = 32) and preterm (PT; N = 44) infants. Nutritive sucking performance at discharge was assessed. The outcome measures of interest were means and coefficients of variability of nutritive sucking peak amplitude, frequency, duration, and smoothness, and feeding-related length of stay.

RESULTS

There was a significant difference in sucking performance between groups; FT infants demonstrated significantly lower mean suck frequency, with longer suck duration and greater suck smoothness as compared to PT. PT infants had significantly less variability in suck amplitude and frequency as compared to FT, while FT infants had significantly less variability in suck smoothness as compared to PT. Post hoc regression analyses found suck frequency alone accounted for 28% of the variance in feeding length of stay for PT; suck smoothness alone accounted for 34% of the variance in feeding length of stay for FT.

CONCLUSIONS

Suck frequency may be an important intervention target for PT infants having difficulty transitioning to oral feeding. Suck smoothness may be a sensitive marker for identifying infants at high risk for feeding challenges.

Does History of Prematurity Prompt Blood Pressure Evaluations at Primary Care Visits?

Prematurity is a risk factor for elevated blood pressure (BP). We performed a mixed-methods study of care patterns and awareness of early BP screening recommendations for infants born prematurely (IBP) by interviewing/surveying providers on practice- and provider-level BP screening. IBP’s records were reviewed for BP screening documentation, demographics, and gestational age (GA). Visits <33 months were reviewed for anthropometrics, BP, and comorbidities. Chi-square analysis evaluated BP screening by GA and comorbidities. Twenty-six of 49 practices completed interviews; 81% had infant BP equipment available; 4% had BP measurement protocol for IBP. Twenty-eight of 86 providers were aware of screening guidelines; none reported routine assessment. Twenty-eight of 118 IBP had ≥1 BP documented; 43% had BP ≥90th percentile. Screening did not differ by GA group. Kidney-related diagnosis was associated with more frequent BP screening (P = .0454). BP is not routinely measured though often elevated before age 3 in IBP.

Nutritional policies for late preterm and early term infants - can we do better?

Late preterm (LP) and early term (ET) infants can be considered the "great dissemblers": they resemble healthy full-term infants in appearance, but their immaturity places them at increased risk of poor short- and long-term outcomes. Nutritional requirements are greater than for full-term babies, but there are few good data on the nutritional requirements for LP and ET babies, leading to substantial variation in practice. Recent data indicate that rapid growth may be beneficial for neurocognitive function but not for body composition and later metabolic health. Breastfeeding the LP or ET infant can be challenging, and mothers of these infants may need additional support to breastfeed successfully. Future research should investigate nutritional requirements of LP and ET infants for optimal growth, addressing both short- and long-term outcomes and the potential trade-off between neurocognitive and metabolic benefits.

A Prospective Study of Causes of Illness and Death in Preterm Infants in Ethiopia: The SIP Study Protocol

BACKGROUND

With nearly 15 million annual preterm births globally, preterm birth is the most common cause of neonatal death. Forty to 60 % of neonatal deaths are directly or indirectly associated with preterm mortality. As countries aim to meet the Sustainable Development Goals to reduce neonatal mortality, significant reductions in preterm mortality are needed. This study aims to identify the common causes of preterm illness and their contribution to preterm mortality in low-resource settings. This article will describe the methods used to undertake the study.

METHODS

This is a prospective, multi-centre, descriptive clinical study. Socio-demographic, obstetric, and maternal factors, and clinical and laboratory findings will be documented. The major causes of preterm mortality will be identified using clinical, laboratory, imaging, and autopsy methods and use the national Ethiopian guidelines on management of preterm infants including required investigations to reach final diagnoses. The study will document the clinical and management protocols followed in these settings. The approach consists of clinical examinations and monitoring, laboratory investigations, and determination of primary and contributory causes of mortality through both clinical means and by post-mortem examinations. An independent panel of experts will validate the primary and contributory causes of mortality. To obtain the estimated sample size of 5000 preterm births, the study will be undertaken in five hospitals in three regions of Ethiopia, which are geographically distributed across the country. All preterm infants who are either born or transferred to these hospitals will be eligible for the study. Three methods (last menstrual period, physical examination using the New Ballard Score, and ultrasound) will be used to determine gestational age. All clinical procedures will be conducted per hospital protocol and informed consent will be taken from parents or caretakers prior to their participation in the study as well as for autopsy if the infant dies.

DISCUSSION

This study will determine the major causes of death and illness among hospitalized preterm infants in a low-resource setting. The result will inform policy makers and implementers of areas that can be prioritized in order to contribute to a significant reduction in neonatal mortality.

Mother's level of confidence in caring for her late preterm infant: A mixed methods study

AIM AND OBJECTIVES

To examine what it means to be a mother of a late preterm infant including a mother's level of confidence in caring for her late preterm infant over time and the effect of maternal depression of this experience.

BACKGROUND

Little is known about mothers' experiences of caring for their late preterm infants in the community, including their level of confidence and parenting stress within the context of a supported care environment by public health nurses.

DESIGN

A mixed methods study, sequential explanatory quantitative and qualitative study.

METHODS

A convenience sample of mothers with LPIs (n = 71) completed questionnaires on maternal confidence (3-4 weeks and 6-8 weeks), parenting stress (6-8 weeks), social support (6-8 weeks) and postpartum depression (6-8 weeks). A purposive sample of mothers (n = 11) underwent in-depth, semi-structured interviews.

RESULTS

Maternal confidence decreased from 3-4 weeks-6-8 weeks after delivery, and similar results were found for mothers who reported depressive symptoms. Narratives of the mothers suggested the decrease in maternal confidence over time was influenced by the demanding characteristics of the late preterm infant, the prospect of their rehospitalisation and the mother's reported interactions with public health nurses. Depression had an effect on maternal confidence; that is, the depressed mothers demonstrated less confidence about their caretaking role than the nondepressed mothers at 6-8 weeks. Mothers did not discuss mental health issues, which may reflect the protective effects of social support on emotional instability or an inability to recognise postpartum depression.

CONCLUSION

The confidence of mothers with LPIs decreased over the first 2 months following delivery and being home with their infants. Assisting mothers to meet their personal needs and the needs of their infant should promote maternal skills, which will likely increase maternal confidence related to the care of their late preterm infant.

RELEVANCE FOR CLINICAL PRACTICE

Characteristics of LPIs contributed more to parenting stress score than parent characteristics; mothers however attempted to normalise the late preterm infant in order to minimise the parenting stress. Evidence-informed brief interventions tailored based on late preterm infant and parent characteristics may improve maternal confidence over time. Healthcare professional should provide education and anticipatory guidance prior to discharge, consistent care in hospital and postdischarge as this may impact maternal level of confidence. Future research needs to examine standards of care for discharge of LPIs and adherence to these standards.

Breastfeeding Characteristics of Late-Preterm Infants in a Kangaroo Mother Care Unit

OBJECTIVE

To describe the breastfeeding characteristics of late-preterm infants (LPIs) in a kangaroo mother care (KMC) unit.

MATERIALS AND METHODS

In a 20-bed KMC unit, the breastfeeding of 73 purposively-selected LPIs' (mean gestational age: 34.8 weeks) was observed once-off, using the Preterm Infant Breastfeeding Behavior Scale. Participants' mean age was 9.5 days, mean number of days in the unit was 3.1 days, and mean number of days breastfeeding was 7.5 on observation.

RESULTS

Only 13.7% of participants were directly breastfeeding without supplementary naso- or orogastric feeding/cup-feeding and 86.3% received supplementary cup-feeding of expressed breast milk. Most participants did not exhibit obvious rooting (83.5%) and although most latched-on (97.3%), those who did, latched shallowly (93%). The mean longest sucking burst was 18.8 (standard deviation: 10.5) and approximately half the participants swallowed repeatedly (53.4%). The mean breastfeeding session duration was 17.8 minutes, but most participants breastfed for less than 10 minutes (76.7%). No statistically significant differences in breastfeeding characteristics were detected between participants of different chronological ages. A general trend toward more mature behaviors in participants' breastfeeding for more days was present for many breastfeeding characteristics. More infants exhibited the most mature behavior for each breastfeeding characteristic when the environment was quiet, rather than noisy and disturbing, except for depth of latching (quiet: 0%, disturbance: 15.2%).

CONCLUSION

LPIs in this sample presented with subtle breastfeeding difficulties, highlighting their need for breastfeeding support. Further research is required to examine the effect of KMC on breastfeeding in LPIs.

Obstetrical, pregnancy and socio-economic predictors for new-onset severe postpartum psychiatric disorders in primiparous women

BACKGROUND

Childbirth is a potent trigger for the onset of psychiatric illness in women including postpartum depression (PPD) and postpartum psychosis (PP). Medical complications occurring during pregnancy and/or childbirth have been linked to postpartum psychiatric illness and sociodemographic factors. We evaluated if pregnancy and obstetrical predictors have similar effects on different types of postpartum psychiatric disorders.

METHOD

A population-based cohort study using Danish registers was conducted in 392 458 primiparous women with a singleton delivery between 1995 and 2012 and no previous psychiatric history. The main outcome was first-onset postpartum psychiatric episodes. Incidence rate ratios (IRRs) were calculated for any psychiatric contact in four quarters for the first year postpartum.

RESULTS

PPD and postpartum acute stress reactions were associated with pregnancy and obstetrical complications. For PPD, hyperemesis gravidarum [IRR 2.69, 95% confidence interval (CI) 1.93-3.73], gestational hypertension (IRR 1.84, 95% CI 1.33-2.55), pre-eclampsia (IRR 1.45, 95% CI 1.14-1.84) and Cesarean section (C-section) (IRR 1.32, 95% CI 1.13-1.53) were associated with increased risk. For postpartum acute stress, hyperemesis gravidarum (IRR 1.93, 95% CI 1.38-2.71), preterm birth (IRR 1.51, 95% CI 1.30-1.75), gestational diabetes (IRR 1.42, 95% CI 1.03-1.97) and C-section (IRR 1.36, 95% CI 1.20-1.55) were associated with increased risk. In contrast, risk of PP was not associated with pregnancy or obstetrical complications.

CONCLUSIONS

Pregnancy and obstetrical complications can increase the risk for PPD and acute stress reactions but not PP. Identification of postpartum women requiring secondary care is needed to develop targeted approaches for screening and treatment. Future work should focus on understanding the contributions of psychological stressors and underlying biology on the development of postpartum psychiatric illness.

Quantifying Neonatal Sucking Performance: Promise of New Methods

Neonatal feeding has been traditionally understudied so guidelines and evidence-based support for common feeding practices are limited. A major contributing factor to the paucity of evidence-based practice in this area has been the lack of simple-to-use, low-cost tools for monitoring sucking performance. We describe new methods for quantifying neonatal sucking performance that hold significant clinical and research promise. We present early results from an ongoing study investigating neonatal sucking as a marker of risk for adverse neurodevelopmental outcomes. We include quantitative measures of sucking performance to better understand how movement variability evolves during skill acquisition. Results showed the coefficient of variation of suck duration was significantly different between preterm neonates at high risk for developmental concerns (HRPT) and preterm neonates at low risk for developmental concerns (LRPT). For HRPT, results indicated the coefficient of variation of suck smoothness increased from initial feeding to discharge and remained significantly greater than healthy full-term newborns (FT) at discharge. There was no significant difference in our measures between FT and LRPT at discharge. Our findings highlight the need to include neonatal sucking assessment as part of routine clinical care in order to capture the relative risk of adverse neurodevelopmental outcomes at discharge.

Safe Sleep and Skin-to-Skin Care in the Neonatal Period for Healthy Term Newborns

Skin-to-skin care (SSC) and rooming-in have become common practice in the newborn period for healthy newborns with the implementation of maternity care practices that support breastfeeding as delineated in the World Health Organization's "Ten Steps to Successful Breastfeeding." SSC and rooming-in are supported by evidence that indicates that the implementation of these practices increases overall and exclusive breastfeeding, safer and healthier transitions, and improved maternal-infant bonding. In some cases, however, the practice of SSC and rooming-in may pose safety concerns, particularly with regard to sleep. There have been several recent case reports and case series of severe and sudden unexpected postnatal collapse in the neonatal period among otherwise healthy newborns and near fatal or fatal events related to sleep, suffocation, and falls from adult hospital beds. Although these are largely case reports, there are potential dangers of unobserved SSC immediately after birth and throughout the postpartum hospital period as well as with unobserved rooming-in for at-risk situations. Moreover, behaviors that are modeled in the hospital after birth, such as sleep position, are likely to influence sleeping practices after discharge. Hospitals and birthing centers have found it difficult to develop policies that will allow SSC and rooming-in to continue in a safe manner. This clinical report is intended for birthing centers and delivery hospitals caring for healthy newborns to assist in the establishment of appropriate SSC and safe sleep policies.

Blood Pressure Profile in the 7th and 11th Year of Life in Children Born Prematurely

Background

Several research trials have analyzed the impact of prematurity on the prevalence of hypertension (HT). However, prospective long-term studies are lacking.

Objectives

The aim of this study was to evaluate the prevalence of HT at the age of 7 and 11 years in a regional cohort of preterm infants with a birth weight of ≤ 1000 g.

Patients and Methods

This study included 67 children with a birth weight of ≤ 1000 g who were born in Malopolska between September 2002 and August 2004. The control group consisted of 38 children born at term, matched for age. Each child underwent 24-h ambulatory blood pressure measurement (ABPM) twice, once at the age of 7 and again at 11 years. The presence of HT was estimated according to the mean arterial pressure (MAP) and a number of individual measurements.

Results

At aged 7 years, preterm infants had a significantly higher incidence of HT, defined on the basis of MAP (15% vs. 0%; P < 0.02) and on the percent of individual measurements (56% vs. 33%, P < 0.036). After taking into account the group of patients who received anti-HT treatment after the first part of the study, the incidence of HT at the age of 11 years based on MAP was 19% vs. 10%. Based on the individual measurements, it was 36.5% in the preterm infants vs. 24% in the control group. The differences were not statistically significant. At both time points, the preterm group had a higher mean heart rate (HR) than the control group.

Conclusions

Children born prematurely are predisposed to HT in later life, in addition to the persistence of an increased HR.

[Newborn of mother with HELLP syndrome: characteristics and role of prematurity, low birth-weight and leukopenia in evolution]

BACKGROUND

HELLP syndrome is a serious hypertensive disorder of pregnancy with important neonatal problems in the newborn. The objective of this work was to determine the characteristics of these infants and its neonatal evolution.

METHODS

A retrospective observational study of all newborns of mothers with HELLP syndrome born in a university hospital between January 1, 2008 and December 31, 2013 was carried out. Thirty-three infants from 28 pregnancies (five twin gestations) were studied. A descriptive and comparative analysis between groups and a multivariate analysis of factors associated with mortality in the series took place.

RESULTS

Of 33 newborns studied (2.2 newborns/1,000 infants total), two were stillbirths (6.1% of the total) and four died after birth (12.9% of live neonates) with overall perinatal mortality of 18.2%. Pregnancies in 28 infants ended before 37 weeks (84.8%) and 11 pregnancies ended before week 32 (33.3%). Seven infants weighed<1500g (four weighed <1000g). Of the 31 live births, 13 infants were in a <10th percentile weight for gestational age (41.9%), 20 needed neonatal resuscitation (64.5%) and 14 had leukopenia at birth (45.2%). In the final logistic regression, neonatal mortality was associated with extreme prematurity regardless of underweight, leukopenia and/or need for neonatal resuscitation.

CONCLUSIONS

Children of mothers with HELLP syndrome have a high mortality associated with extreme prematurity, independent of the presence of leukopenia, low weight for gestational age and need for neonatal resuscitation.

The case of late preterm birth: sliding forwards the critical window for cognitive outcome risk

Many survivors of preterm birth experience neurodevelopmental disabilities, such as cerebral palsy, visual and hearing problems. However, even in the absence of major neurological complications, premature babies show significant neuropsychological and behavioural deficits during childhood and beyond. While the clinical tools routinely used to assess neurocognitive development in those infants have been useful in detecting major clinical complications in early infancy, they have not been equally sensitive in identifying subtle cognitive impairments emerging during childhood. These methodological concerns become even more relevant when considering the case of late preterm children (born between 34 and 36 gestational weeks). Although these children have been traditionally considered as having similar risks for developmental problems as neonates born at term, a recent line of research has provided growing evidence that even late preterm children display altered structural and functional brain maturation, with potential life-long implications for neurocognitive functioning. A recent study by Heinonen put forward the hypothesis that environmental factors, in this case educational attainment, could moderate the association between late preterm birth (LPT) and neuropsychological impairments commonly associated with aging. In this paper we bring together clinical literature and recent neuroimaging evidence in order to provide two different but complementary approaches for a better understanding of the "nature-nurture" interplay underlying the lifespan neurocognitive development of preterm babies.