Neurodevelopmental outcome at 12 and 18 months in late preterm infants

Quantitative Magnetic Resonance Imaging for Neurodevelopmental Outcome Prediction in Neonates Born Extremely Premature-An Exploratory Study

PURPOSE

Neonates born at < 28 weeks of gestation are at risk for neurodevelopmental delay. The aim of this study was to identify quantitative MR-based metrics for the prediction of neurodevelopmental outcomes in extremely preterm neonates.

METHODS

T1-/T2-relaxation times (T1R/T2R), ADC, and fractional anisotropy (FA) of the left/right posterior limb of the internal capsule (PLIC) and the brainstem were determined at term-equivalent ages in a sample of extremely preterm infants (n = 33). Scores for cognitive, language, and motor outcomes were collected at one year corrected-age. Pearson's correlation analyses detected relationships between quantitative measures and outcome data. Stepwise regression procedures identified imaging metrics to estimate neurodevelopmental outcomes.

RESULTS

Cognitive outcomes correlated significantly with T2R (r = 0.412; p = 0.017) and ADC (r = -0.401; p = 0.021) (medulla oblongata). Furthermore, there were significant correlations between motor outcomes and T1R (pontine tegmentum (r = 0.346; p = 0.049), midbrain (r = 0.415; p = 0.016), right PLIC (r = 0.513; p = 0.002), and left PLIC (r = 0.504; p = 0.003)); T2R (right PLIC (r = 0.405; p = 0.019)); ADC (medulla oblongata (r = -0.408; p = 0.018) and pontine tegmentum (r = -0.414; p = 0.017)); and FA (pontine tegmentum (r = -0.352; p = 0.045)). T2R/ADC (medulla oblongata) (cognitive outcomes (R2 = 0.296; p = 0.037)) and T1R (right PLIC)/ADC (medulla oblongata) (motor outcomes (R2 = 0.405; p = 0.009)) revealed predictive potential for neurodevelopmental outcomes.

CONCLUSION

There are relationships between relaxometry‑/DTI-based metrics determined by neuroimaging near term and neurodevelopmental outcomes collected at one year of age. Both modalities bear prognostic potential for the prediction of cognitive and motor outcomes. Thus, quantitative MRI at term-equivalent ages represents a promising approach with which to estimate neurologic development in extremely preterm infants.

Increased white matter fibre dispersion and lower IQ scores in adults born preterm

Preterm birth has been associated with altered microstructural properties of the white matter and lower cognitive ability in childhood and adulthood. Due to methodological limitations of the diffusion tensor model, it is not clear whether alterations in myelination or variation in fibre orientation are driving these differences. Novel models applied to multi-shell diffusion imaging have been used to disentangle these effects, but to date this has not been used to study the preterm brain in adulthood. This study investigated whether novel advanced diffusion MRI metrics such as microscopic anisotropy and orientation dispersion are altered in adults born preterm, and whether this was associated with cognitive performance. Seventy-two preterm born participants (<37 weeks gestational age) were recruited from a 1982-1984 cohort (33 males, mean age 33.5 ± 1.0 years). Seventy-two term born (>37 weeks gestational age) controls (34 males, mean age 30.9 ± 4.0 years) were recruited from the general population. Tensor FA was calculated with FSL, while microscopic FA and orientation dispersion entropy (ODE) were estimated using the Spherical Mean Technique (SMT). Estimated Full Scale IQ (FSIQ), Verbal Comprehension Index (VCI) and Perceptual Reasoning Index (PRI) were obtained from the WASI-II (abbreviated) IQ test. Voxel-wise comparisons using FSL's tract-based spatial statistics were performed to test between-group differences in diffusion MRI metrics as well as within-group associations of diffusion MRI metrics and IQ outcomes. The preterm group had significantly lower FSIQ, VCI and PRI scores. Preterm subjects demonstrated widespread decreases in ODE reflecting increased fibre dispersion, but no differences in microscopic FA. Tensor FA was increased in a small area in the anterior corona radiata. Lower FA values in the preterm population were associated with lower FSIQ and PRI scores. An increase in fibre dispersion in white matter and lower IQ scores after preterm birth exist in adulthood. Advanced diffusion MRI metrics such as the orientation dispersion entropy can be used to monitor white matter alterations across the lifespan in preterm born individuals. Although not significantly different between preterm and term groups, tensor FA values in the preterm group were associated with cognitive outcome.

Identification and prediction model of placenta-brain axis genes associated with neurodevelopmental delay in moderate and late preterm children

BACKGROUND

Moderate and late preterm (MLPT) birth accounts for the vast majority of preterm births, which is a global public health problem. The association between MLPT and neurobehavioral developmental delays in children and the underlying biological mechanisms need to be further revealed. The "placenta-brain axis" (PBA) provides a new perspective for gene regulation and risk prediction of neurodevelopmental delays in MLPT children.

METHODS

The authors performed multivariate logistic regression models between MLPT and children's neurodevelopmental outcomes, using data from 129 MLPT infants and 3136 full-term controls from the Ma'anshan Birth Cohort (MABC). Furthermore, the authors identified the abnormally regulated PBA-related genes in MLPT placenta by bioinformatics analysis of RNA-seq data and RT-qPCR verification on independent samples. Finally, the authors established the prediction model of neurodevelopmental delay in children with MLPT using multiple machine learning models.

RESULTS

The authors found an increased risk of neurodevelopmental delay in children with MLPT at 6 months, 18 months, and 48 months, especially in boys. Further verification showed that APOE and CST3 genes were significantly correlated with the developmental levels of gross-motor domain, fine-motor domain, and personal social domain in 6-month-old male MLPT children.

CONCLUSIONS

These findings suggested that there was a sex-specific association between MLPT and neurodevelopmental delays. Moreover, APOE and CST3 were identified as placental biomarkers. The results provided guidance for the etiology investigation, risk prediction, and early intervention of neurodevelopmental delays in children with MLPT.

Neurodevelopment outcome of late prematurity: a retrospective cohort study from a developing country

The late preterm infants (34 0/7 to 36 6/7 weeks of gestation) account for at least 70% of all preterm birth. Our aim was to detect growth and neurodevelopment outcome, incidence of neurodevelopmental disability, and its association with maternal and neonatal risk factors among sick late preterm population. Two hundred and ninety-nine late preterm infants were followed up till corrected 2 years of age in this retrospective cohort study. Assessment was done by anthropometry and Developmental Assessment Scale for Indian Infants (DASII) scale at corrected 2 years of age. Presence of visual and hearing impairment, cerebral palsy, and overall neurodevelopmental impairment were also recorded. At 2 years of corrected age, average motor development quotient (DMoQ) was 93.55 (95% CI 90.9 to 96.20) and average mental development quotient (DMeQ) was 89.59 (95% CI 87.13 to 92.04). The incidence of bilateral severe to profound hearing loss and visual loss were found in 6 (2%) and 4 (1.33%) infants, respectively. Severe neurodevelopmental impairment was found in 19 (6.35%) infants. Central nervous system disease and sepsis were found as independent predictors of moderate to severe neurodevelopmental disability.   Conclusion: Late preterm infants admitted in neonatal units were at risk of growth and neurodevelopmental impairment requiring close neurodevelopmental follow-up. In a resource limited setting, this may best be achieved by using DASII in follow-up clinic. What is Known: • Late preterm infants are at a high risk of prematurity-related morbidities. • There is increased risk of cognitive defect, learning difficulties, and behavior problems found at school age for sick late preterm infants. What is New: • Central nervous system disease and sepsis were found as independent predictors of early moderate to severe neurodevelopmental impairment for sick late preterm infants in developing countries like India.

Impact of Suspected Preterm Labor during Pregnancy on Cardiometabolic Profile and Neurodevelopment during Childhood: A Prospective Cohort Study Protocol

Introduction: Suspected preterm labor (SPL), defined as the presence of regular and painful uterine contractions and cervical shortening, represents a prenatal insult with potential long-term consequences. However, despite recent evidence demonstrating suboptimal neurodevelopment at 2 years in this population, it remains underestimated as a significant risk factor for neurodevelopmental disorders or other chronic diseases. The aim of this study is to assess the impact of suspected preterm labor during pregnancy on cardiometabolic profile and neurodevelopment during childhood (6–8 years). Methods and analysis: Prospective cohort study including children whose mothers suffered suspected preterm labour during pregnancy and paired controls. Neurodevelopmental, cardiovascular, and metabolic assessments will be performed at 6–8 years of age. A trained psychologist will carry out the neurodevelopment assessment including intelligence, visual perception, and behavioral assessment. Body composition and physical fitness assessment will be performed by one trained pediatrician and nurse. Finally, cardiovascular evaluation, including echocardiography and blood pressure, will be performed by two pediatric cardiologists. Data regarding perinatal and postnatal characteristics, diet, lifestyle, and weekly screen time of the child will be obtained from medical history and direct interviews with families. Primary outcome measures will include body mass index and adiposity, percentage of fat mass and total and regional lean mass, bone mineral content and density, cardiorespiratory resistance, isometric muscle strength, dynamic lower body strength, systolic and diastolic blood pressure, left ventricle (LV) systolic and diastolic function, general intelligence index, visuospatial working memory span, oculomotor control test, index of emotional, and behavioral problems.

Associations between sociodemographic and behavioural parameters and child development depending on age and sex: a cross-sectional analysis

OBJECTIVES

To explore environmental and individual factors that are associated with child development and to investigate whether the strength of these associations differs according to the age of the children.

DESIGN

Cross-sectional study.

SETTING

This study was part of the LIFE Child study, a large cohort study conducted in Leipzig, Germany.

PARTICIPANTS

778 children aged between 0.5 and 6 years (48.6% girls, mean age=2.67 years).

OUTCOME MEASURES

The outcomes were cognitive development, language development, body and hand motor skills, social-emotional development, and tracing skills, measured with a standardised development test. We analysed the associations between development and gestational age, socioeconomic status (SES), sex, behavioural difficulties, siblings, sleep duration, breastfeeding duration and overweight/obesity. We also tested for interactions between these variables and child age or sex.

RESULTS

Higher gestational age (b ranging between 0.12 and 0.26) and higher SES (b ranging between 0.08 and 0.21) were associated with better outcomes in almost all developmental domains (all p<0.019). Children with older siblings had improved body and hand motor skills compared with children without older siblings (both b=0.55, all p<0.029). Boys had poorer scores than girls in body and hand motor skills and tracing (b=-0.45, -0.68 and -1.5, all p<0.019). Children with behavioural difficulties had significantly poorer outcomes in most developmental domains. Some of the associations with SES and sex were stronger in older than in younger children. Associations between gestational age and motor development were weaker in older children. We did not find significant associations between child development and sleep duration, breastfeeding duration or overweight/obesity.

CONCLUSION

Some factors had a protective, others an adverse effect on development of children under 6 years of age. The effect of SES and sex increased, while the effect of gestational age decreased with age.

TRIAL REGISTRATION NUMBER

NCT02550236.

Longitudinal Cognitive Assessment in Low-Risk Very Preterm Infants

Background and Objectives: Preterm infants are at higher risk of neurodevelopmental impairment both at preschool and school ages, even in the absence of major neurological deficits. The early identification of children at risk is essential for early intervention with rehabilitation to optimize potential outcomes during school years. The aim of our study is to assess cognitive outcomes at preschool age in a cohort of low-risk very preterm infants, previously studied at 12 and 24 months using the Griffiths scales. Materials and Methods: Sixty-six low-risk very preterm infants born at a gestational age of <32 weeks were assessed at 12 and 24 months corrected age using the Griffiths Mental Development Scales (second edition) and at preschool age with the Wechsler Preschool and Primary Scales of Intelligence (third edition) (WPPSI-III). Results: At 12 and 24 months and at preschool age, low-risk very preterm infants showed scores within normal ranges with similar scores in males and females. A statistically significant correlation was observed in the general developmental quotient between 12 and 24 months; a further significant correlation was observed between the early cognitive assessments and those performed at preschool age, with a better correlation using the assessments at 24 months. Conclusion: The present study showed a favourable trajectory of cognitive development in low-risk very preterm infants, from 12 months to preschool age.

Cognitive flexibility in 12-month-old preterm and term infants is associated with neurobehavioural development in 18-month-olds

There is growing evidence that preterm children are at an increased risk of poor executive functioning, which underlies behavioural and attention problems. Previous studies have suggested that early cognitive flexibility is a possible predictor of later executive function; however, how it develops in infancy and relates to the later neurobehavioural outcomes is still unclear in the preterm population. Here, we conducted a longitudinal study to investigate oculomotor response shifting in 27 preterm and 25 term infants at 12 months and its relationship with general cognitive development and effortful control, which is a temperamental aspect closely associated with executive function, at 18 months. We found that moderate to late preterm and term infants significantly inhibited previously rewarded look responses, while very preterm infants did not show significant inhibition of perseverative looking at 12 months. Moreover, lower inhibition of perseverative looking was significantly associated with lower general cognitive development and attentional shifting at 18 months. These findings suggest that the early atypical patterns of oculomotor response shifting may be a behavioural marker for predicting a higher risk of negative neurobehavioural outcomes, including attention-related problems in preterm children.

Neurodevelopmental outcome of late-preterm infants: Literature review

Late-preterm infants are characterized by a birth term from 34^0/7 to 36^6/7 weeks of gestation. A foetal brain at 34^0/7 weeks of gestation weighs only 65% of the full-term newborn brain, which suggests a particular cerebral vulnerability to injury during this 6-week period. Epidemiological studies reporting the neurological outcomes of late-preterm infants exhibit large methodological heterogeneity that inhibits clarity on this issue. However, contradictory results and odds ratio values near neutral reveal probable moderate neurodevelopmental delay in late-preterm infants. This observation reflects the variable neurological outcomes of this population according to multiple perinatal factors. Therefore, the current challenge is to define efficient screening strategies to determine infants requiring specific follow-up.

Reduced Neurosteroid Exposure Following Preterm Birth and Its' Contribution to Neurological Impairment: A Novel Avenue for Preventative Therapies

Children born preterm are at an increased risk of developing cognitive problems and neuro-behavioral disorders such as attention deficit hyperactivity disorder (ADHD) and anxiety. Whilst neonates born at all gestational ages, even at term, can experience poor cognitive outcomes due to birth-complications such as birth asphyxia, it is becoming widely known that children born preterm in particular are at significant risk for learning difficulties with an increased utilization of special education resources, when compared to their healthy term-born peers. Additionally, those born preterm have evidence of altered cerebral myelination with reductions in white matter volumes of the frontal cortex, hippocampus and cerebellum evident on magnetic resonance imaging (MRI). This disruption to myelination may underlie some of the pathophysiology of preterm-associated brain injury. Compared to a fetus of the same post-conceptional age, the preterm newborn loses access to in utero factors that support and promote healthy brain development. Furthermore, the preterm ex utero environment is hostile to the developing brain with a myriad of environmental, biochemical and excitotoxic stressors. Allopregnanolone is a key neuroprotective fetal neurosteroid which has promyelinating effects in the developing brain. Preterm birth leads to an abrupt loss of the protective effects of allopregnanolone, with a dramatic drop in allopregnanolone concentrations in the preterm neonatal brain compared to the fetal brain. This occurs in conjunction with reduced myelination of the hippocampus, subcortical white matter and cerebellum; thus, damage to neurons, astrocytes and especially oligodendrocytes of the developing nervous system can occur in the vulnerable developmental window prior to term as a consequence reduced allopregnanolone. In an effort to prevent preterm-associated brain injury a number of therapies have been considered, but to date, other than antenatal magnesium sulfate and corticosteroid therapy, none have become part of standard clinical care for vulnerable infants. Therefore, there remains an urgent need for improved therapeutic options to prevent brain injury in preterm neonates. The actions of the placentally derived neurosteroid allopregnanolone on GABAA receptor signaling has a major role in late gestation neurodevelopment. The early loss of this intrauterine neurotrophic support following preterm birth may be pivotal to development of neurodevelopmental morbidity. Thus, restoring the in utero neurosteroid environment for preterm neonates may represent a new and clinically feasible treatment option for promoting better trajectories of myelination and brain development, and therefore reducing neurodevelopmental disorders in children born preterm.

Neurodevelopmental outcomes of the late preterm infant

Late preterm infants (born at 34^0/7-36^6/7 weeks gestation) have been found to have increased morbidity and mortality compared to full term infants. Research has also been done to explore longer-term neurodevelopmental outcomes. This review details neurodevelopmental outcomes from birth to adulthood for late preterm infants. Outcome studies indicate that they are at increased risk of developmental disability, school failure, behavior problems, social and medical disabilities, and death. Many questions still remain regarding late preterm infant neurodevelopmental outcomes and future research should be done into this topic. Given the high prevalence of late preterm births, even small differences in abilities, special education, and length of education may have broader consequences.

Late preterms: are they all the same?

Very preterm infants (VPT) and, especially extreme low gestational age (ELGA) preterms, often on the threshold of viability, make the headlines of both, the scientific as well as the popular press. However, all together they represent between 1 and 2% of all livebirths. Late preterms (LPT) those born between 34/07 and 36/06 weeks, on the other hand, may account for up to 80% of all preterms and for some 5-8% of all births. Although mortality is low they are prone to increasing neonatal morbidities posing a considerable medical, financial and psychosocial burden. In the last years, for many reasons, LPT appear to have increased considerably throughout the western world. But are LPT neonates all the same? In spite of overlapping gestational ages (GA) LPT may behave quite differently depending on circumstances surrounding their pre- and postnatal events. We can identify three different classes of LPT neonates: spontaneous late preterms (SpLPT) born in the absence of previous maternal illnesses and/or pregnancy related disorders; Induced LPT (IdLPT) due to maternal/fetal complications and those babies being born after 34-week gestation from postponed delivery at an earlier GA (PtLPT) - and they are quite different babies, with different behavior, despite a common and same gestational age.

Neurodevelopmental outcome of late preterm infants in Johannesburg, South Africa

Background

Late preterm infants, previously considered low risk, have been identified to be at risk of developmental problems in infancy and early childhood. There is limited information on the outcome of these infants in low and middle income countries.

Methods

Bayley scales of infant and toddler development, version III, were done on a group of late preterm infants in Johannesburg, South Africa. The mean composite cognitive, language and motor sub-scales were compared to those obtained from a group of typically developed control infants. Infants were considered to be “at risk” if the composite subscale score was below 85 and “disabled” if the composite subscale score was below 70. Infants identified with cerebral palsy were also reported.

Results

56 of 73 (76.7%) late preterm infants enrolled in the study had at least one Bayley assessment at a mean age of 16.5 months (95% CI 15.2–17.6). The mean birth weight was 1.9 kg (95%CI 1.8–2.0) and mean gestational age 33.0 weeks (95% CI 32.56–33.51). There was no difference in the mean cognitive subscales between late preterm infants and controls (95.4 9, 95% CI 91.2–99.5 vs 91.9.95% CI 87.7–96.0). There was similarly no difference in mean language subscales (94.5, 95% CI 91.3–97.7 vs 95.9, 95% CI 92.9–99.0) or motor subscales (96.2, 95% CI 91.8–100.7 vs 97.6, 95% CI 94.7–100.5). There were four late preterm infants who were classified as disabled, two of whom had cerebral palsy. None of the control group was disabled.

Conclusions

This study demonstrates that overall developmental outcome, as assessed by the Bayley scales of infant and toddler development, was not different between late preterm infants and a group of normal controls. However, 7.1% of the late preterm infants, had evidence of developmental disability. Thus late preterm infants in low and middle income countries require long term follow up to monitor developmental outcome. In a resource limited setting, this may best be achieved by including a parental screening questionnaire, such as the Ages and Stages Questionnaire, in the routine well baby clinic visits.

Association Between Temporal Changes in Neonatal Mortality and Spontaneous and Clinician-Initiated Deliveries in the United States, 2006-2013

IMPORTANCE

Preterm and postterm deliveries have declined since 2005 in the United States, but the association between these changes and neonatal mortality remains unknown.

OBJECTIVE

To estimate changes in the gestational age distribution among spontaneous and clinician-initiated deliveries between 2006 and 2013 and associated changes in neonatal mortality.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort analysis was conducted of 22 million singleton live births without major malformations in the United States from 2006 to 2013. Data analysis was performed from August to October 2017.

MAIN OUTCOMES AND MEASURES

Changes in gestational age distribution among spontaneous and clinician-initiated deliveries at extremely preterm (20-27 weeks), very preterm (28-31 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), term (39-40), late term (41 weeks), and postterm (42-44 weeks) gestations and changes in neonatal mortality rates at less than 28 days between 2006 and 2013. These changes were estimated from log-linear Poisson regression models with robust variance, adjusted for confounders.

RESULTS

Among 22 million births, 12 493 531 (56.7%) were spontaneous and 9 557 815 (43.3%) were clinician-initiated deliveries. Among spontaneous deliveries, the proportion of births at 20 to 27, 28 to 31, 32 to 33, 34 to 36, and 37 to 38 weeks declined. Among clinician-initiated deliveries, the proportion of births at 34 to 36 and 37 to 38 weeks declined and the proportion at 39 to 40 weeks increased. Among spontaneous deliveries, overall neonatal mortality rates declined from 1.8 to 1.3 per 1000 live births, mainly at 20 to 27 weeks (adjusted annual decline, 1%; 95% CI, -2% to -1%) and 28 to 31 weeks (adjusted annual decline, 6%; 95% CI, -8% to -5%). Among clinician-initiated deliveries, overall mortality rates remained unchanged (2.1 to 2.2 per 1000 live births). However, mortality rates declined (0.6 to 0.5 per 1000 live births) at 39 to 40 weeks by 1% (95% CI, -3% to -0.4%) annually, adjusted for confounders.

CONCLUSIONS AND RELEVANCE

In the United States, there was a decline in spontaneous deliveries associated with an overall decline in neonatal mortality. Although clinician-initiated deliveries increased at 39 to 40 weeks, neonatal mortality at that gestation declined.

Age correction in cognitive, linguistic, and motor domains for infants born preterm: an analysis of the Bayley Scales of Infant and Toddler Development, Third Edition developmental patterns

AIM

To verify whether it is appropriate to use age correction for infants born preterm in all the developmental domains (cognitive, linguistic, and motor) considered by the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).

METHOD

Seventy-three infants born preterm (26-35wks) without major neurological sequelae and 67 infants born at term were assessed at 12 months (corrected age for infants born preterm). The performance of the infants born preterm was assessed with two different evaluations: scores based on uncorrected age and scores based on corrected age.

RESULTS

The developmental trends of infants born at term and infants born preterm differ across domains. Statistical analysis shows that age correction produces an overrated estimate of motor performance (12.5 points [95% confidence interval 9.05-16.01]) but not of cognitive performance.

INTERPRETATION

Given the broad use of the Bayley-III by psychologists and paediatricians, these results are important in the early diagnosis of developmental difficulties for children born preterm. Correction for gestational age should be applied for the cognitive domain only; whereas for the motor domain, chronological age should be used. No clear data emerged for language.

WHAT THIS PAPER ADDS

Age correction with Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) for infants born preterm should be applied differently in cognitive, language, and motor domains. Using corrected age with Bayley-III, the motor skills are overrated. Correction for preterm births adequately measures cognitive skills. No clear indication emerged about language skills.

Neurological outcome at 6 and 12 months corrected age in hospitalised late preterm infants -a prospective study

Late preterm infants (34-0/7 to 36-6/7 weeks" gestation) account for 10-20% of NICU admissions and are at increased risk for morbidity and mortality. Although they are prone to developmental delays, reports on neurological outcome during the first 2 years of life are scarce. The aim of the study was to assess neurological/neuromotor outcome in high risk late preterm infants at 6 and 12 months corrected age and the change in neurological scores over time, and to identify factors associated with the neurological outcome. The Hammersmith Infant Neurological Examination was performed in a cohort of 157 late preterm infants admitted in the NICU. The infants were examined at 6 and 12 months corrected age respectively and scored with the optimality score system including 26 items assessing cranial nerve function, posture, movements, tone and reflexes. Also parents reported neurological milestones in the follow up visit. Infants at 6 months had a global score of 59 (47-76) and optimal scores achieved in 25.4%. At 12 months they had a global score of 70 (58-78) and achieved optimal scores in 63.2%. The subscores of posture, tone and reflexes gradually increased from 6 to 12 months corrected age. Being born small for gestational age was the only factor that adversely influenced HINE score at 6 and 12 months. At 12 months 58.5% achieved independent walking. High risk late preterm infants have suboptimal HINE scores at 6 and 12 months of age, suggesting a need for closer follow up and early intervention programs.

Association of Temporal Changes in Gestational Age With Perinatal Mortality in the United States, 2007-2015

Importance

Whether the changing gestational age distribution in the United States since 2005 has affected perinatal mortality remains unknown.

Objective

To examine changes in gestational age distribution and gestational age-specific perinatal mortality.

Design, Setting, and Participants

This retrospective cohort study examined trends in US perinatal mortality by linking live birth and infant death data among more than 35 million singleton births from January 1, 2007, through December 31, 2015.

Exposures

Year of birth and changes in gestational age distribution.

Main Outcomes and Measures

Changes in the proportion of births at gestational ages 20 to 27, 28 to 31, 32 to 33, 34 to 36, 37 to 38, 39 to 40, 41, and 42 to 44 weeks; changes in perinatal mortality (stillbirth at ≥20 weeks, and neonatal deaths at <28 days) rates; and contribution of gestational age changes to perinatal mortality. Trends were estimated from log-linear regression models adjusted for confounders.

Results

Among the 34 236 577 singleton live births during the study period, the proportion of births at all gestational ages declined, except at 39 to 40 weeks, which increased (54.5% in 2007 to 60.2% in 2015). Overall perinatal mortality declined from 9.0 to 8.6 per 1000 births (P < .001). Stillbirths declined from 5.7 to 5.6 per 1000 births (P < .001), and neonatal mortality declined from 3.3 to 3.0 per 1000 births (P < .001). Although the proportion of births at gestational ages 34 to 36, 37 to 38, and 42 to 44 weeks declined, perinatal mortality rates at these gestational ages showed annual adjusted relative increases of 1.0% (95% CI, 0.6%-1.4%), 2.3% (95% CI, 1.9%-2.8%), and 4.2% (95% CI, 1.5%-7.0%), respectively. Neonatal mortality rates at gestational ages 34 to 36 and 37 to 38 weeks showed a relative adjusted annual increase of 0.9% (95% CI, 0.2%-1.6%) and 3.1% (95% CI, 2.1%-4.1%), respectively. Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality showed an annual relative adjusted decline of -1.3% (95% CI, -1.8% to -0.9%). The decline in neonatal mortality rate was largely attributable to changes in the gestational age distribution than to gestational age-specific mortality.

Conclusions and Relevance

Although the proportion of births at gestational age 39 to 40 weeks increased, perinatal mortality at this gestational age declined. This finding may be owing to pregnancies delivered at 39 to 40 weeks that previously would have been unnecessarily delivered earlier, leaving fetuses at higher risk for mortality at other gestational ages.

Longitudinal patterns of early development in Canadian late preterm infants: A prospective cohort study

This prospective, longitudinal cohort study examined longitudinal patterns of early development in Canadian children born late preterm. A convenience sample of 82 mothers and their healthy, singleton, late preterm children participated. Mothers completed the Ages and Stages Questionnaires at 4, 8, and 18 months corrected age. Concerns were most commonly reported in the communication and gross motor domains, especially early in development. The proportion of children scoring below the referral cut-off in at least one domain at 4, 8, and 18 months was, respectively, 25.6, 25.6, and 14.6%. Only two children (2.4%) scored below referral cut-off in at least one domain at all three time points. At ages four and eight months, the late preterm sample had significantly lower communication and gross motor scores than the Ages and Stages Questionnaires normative sample. At age four months, there was also a significant difference on the fine motor domain. There were no significant differences at age 18 months. Healthy late preterm children appear to catch up to population norms by age 18 months corrected age. Longer term studies are needed to further clarify early indicators of delay in late preterm children and identity those who require close developmental monitoring.

Outcomes of infants born near term

Most research on outcomes of preterm birth has centred on babies born at <32 weeks gestation and at highest risk of mortality and serious morbidity. Recent years have seen a dramatic increase in studies focusing on late preterm infants (34-36 weeks gestation). Early epidemiological studies demonstrated increased risks of mortality and adverse neonatal outcomes in this group, prompting further investigations. These increased risks have been confirmed and more recent studies have also included babies born at 37-38 weeks, now defined as 'early-term' births. It now seems that it is inappropriate to consider term and preterm as a dichotomy; gestational age rather represents a continuum in which risk and severity of adverse outcomes increase with decreasing gestational age, but where measurable effects can be detected even very close to full term. In this review, we summarise current evidence for the outcomes of infants born at late preterm and early-term gestations.

Threatened preterm labor is a risk factor for impaired cognitive development in early childhood

BACKGROUND

Threatened preterm labor is a leading cause of hospital admission during pregnancy. Patients with an episode of threatened preterm labor who deliver at term are considered to have false preterm labor. However, threatened preterm labor has been proposed as a pathologic insult that is not always sufficient to induce irreversible spontaneous preterm birth but that could alter the normal course of pregnancy.

OBJECTIVE

The aim of this study was to evaluate threatened preterm labor during pregnancy as a risk factor of neurodevelopmental deficits of children at 2 years of age.

STUDY DESIGN

Two-year-old children who were born late preterm (n=22) or at term after threatened preterm labor (n=23) were compared with at-term control children (n=42). Neurodevelopment was evaluated at a corrected age of 24-29 months with the use of the Merrill-Palmer-Revised Scales of Development.

RESULTS

Children who were born at term after threatened preterm labor had lower scores than control children on global cognitive index (95.4 vs 104.2; P=.011), cognition (95.1 vs 103.1; P=.021), fine motor (95.2 vs 103.4; P=.003), gross motor (84.7 vs 99.8; P=.001), memory (92.9 vs 100.4; P=.015), receptive language (93.9 vs 102.9; P=.03), speed of processing (105.7 vs 113.3; P=.011), and visual motor coordination (98.8 vs 106.7; P=.003) subtests. Children born at term after threatened preterm labor had an increased risk of mild neurodevelopmental delay compared with control children (odds ratio for global cognitive index, 2.06; 95% confidence interval, 1.09-3.88; P=.033). There were no significant differences in any cognitive domain between children who were born late preterm and children who were born at term after threatened preterm labor.

CONCLUSIONS

Threatened preterm labor is a risk factor for impaired cognitive development at 2 years of age, even if birth occurred at term.

Longitudinal Growth and Neuropsychological Functioning at Age 7 in Moderate and Late Preterms

OBJECTIVE

To determine the association between longitudinal growth measures (height, weight, head circumference, and extent of catch-up growth) and neuropsychological functioning at 7 years in moderately and late preterm children.

METHODS

This study was part of a prospective, community-based cohort study. Data on growth were obtained from records on routine assessments in well-child centers until age 4 years and in a research setting at 7 years. Neuropsychological functioning was assessed at age 7 years. We assessed associations of growth with neuropsychological functioning and determined odds ratios for impaired neuropsychological functioning. All analyses were corrected for maternal education.

RESULTS

We included 234 children. Median gestational age was 34 weeks (P25-75: 33-35 weeks), and mean birth weight was 2.2 kg (± 0.5 kg). Short stature at all ages was associated with poorer motor, IQ, and attention scores and led to increased risks of impaired motor skills and low IQ. Lower weight at 1 and 4 years was associated with poorer IQ scores. Increased weight gain between age 4 and 7 years was, however, associated with poorer motor, IQ, and attention scores. Decreased head circumference gain in the first year of life was associated with poorer motor and attention scores and led to an increased risk of impaired motor and attention skills.

CONCLUSIONS

In moderately and late preterm children, poorer growth in the first 7 years is associated with poorer neuropsychological functioning. Regarding height, short stature was also associated with a higher likelihood of clinically relevant impaired neuropsychological functioning.

Risk of developmental delay: Comparison of late preterm and full term Canadian infants at age 12 months

BACKGROUND

Late preterm (34(0/7) to 36(6/7)weeks gestation) infants may experience developmental delays greater than those found in term (≥ 37(0/7)weeks gestation) infants.

AIM

The aim of this study was to compare the risk of developmental delay between late preterm and full-term Canadian born infants at age 12months, and to determine infant and maternal factors associated with risk of delay.

METHODS

A descriptive comparative study was conducted from data available from the All Our Babies community-based, prospective, pregnancy cohort in Calgary, Alberta. Participants were a sample of mothers of 52 infants born late preterm and 156 randomly selected mothers of term infants, matched for infant sex; eligible infants were singleton births. Mothers completed a developmental screening tool, the Ages and Stages Questionnaire, version 3 (ASQ-3), when their infant was age 12months. Corrected age (CA) was used for preterm infants.

RESULTS

Both late preterm and term infants who required neonatal intensive care (NICU) were more likely to demonstrate risk of developmental delay. Compared to term infants, there was a trend for late preterm infants to be at risk of communication and gross motor delay at age 12months CA that was attenuated to the null when adjustments were made for NICU admission and other covariates.

CONCLUSIONS

Infants born between 34 and 41weeks who are admitted to NICU are at increased risk of developmental delay. Early identification of risk provides an opportunity for referral for developmental assessment and early intervention programming.

Sex differences in cerebral palsy on neuromotor outcome: a critical review

Sex differences have been reported in children with cerebral palsy (CP), with males having a higher risk of developing CP, but it is not entirely clear whether sex may also affect the severity of motor impairment. The aim of the present study was to critically review the existing literature on sex influence on neuromotor outcome in children with CP. The published papers confirm that CP occurs more frequently in males than in females. Within different types of CP or individual level of impairment, however, there was limited evidence that sex also had an effect on their performance.

Early psychomotor development of low-risk preterm infants: Influence of gestational age and gender

BACKGROUND

The influence of gestational age and gender in the neurodevelopment of infants during the first year of age is not yet fully elucidated.

AIMS

The purpose of this study was to identify the early occurrence of neurodevelopmental differences, between very preterm, late preterm and term born infants and the possible influence of the gender on the neurodevelopment in early infancy.

METHODS

A total of 188 low-risk infants, 69 very preterms, 71 late-preterms, and 48 term infants were assessed at 3, 6, 9, 12 months corrected age using the Hammersmith Infant Neurological Examination (HINE). At two years of age infants performed the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development.

RESULTS

The main results indicate that both very preterms and late-preterms showed significant lower global scores than term born infants at each evaluation (p < 0.001) at HINE and namely, at 3 months for the subsections "cranial nerve" and "posture" and at every age for "tone"; no gender differences has been evidenced in neurological performances. At the MDI, very preterms showed significant lower scores (p < 0.01) than both late-preterm and term born infants; gender differences were observed for preterms only (very and late), with best performances for females.

CONCLUSIONS

Our results point out the presence of gestational age and gender-dependent differences in the development of infants assessed during the first 2 years of life.

Small-for-gestation birth exerts a minor additional effect on functional impairment of the auditory brainstem in high-risk babies born at late preterm

OBJECTIVE

To address if small-for-gestational-age (SGA) significantly affects the developing auditory brainstem in late preterm babies with perinatal problems (i.e. high-risk), providing valuable information for management of such babies.

METHODS

SGA and appropriate-for-gestational age (AGA) babies born at 33-36weeks of gestation were studied at term using maximum length sequence brainstem auditory evoked response in response to 91-910/s clicks.

RESULTS

Compared with AGA late preterm babies without perinatal problems (i.e. low-risk), the high-risk SGA babies manifested a significant increase in wave V latency and I-V interval at all 91-910/s clicks, and III-V interval at 455 and 910/s. The amplitude was smaller for wave I at 227 and 910/s, wave III at 910/s and wave V at 227 and 910/s. Compared with low-risk SGA babies, the high-risk SGA babies showed similarly abnormalities. Compared with high-risk AGA babies, the high-risk SGA babies manifested slightly different abnormalities.

CONCLUSIONS

Brainstem auditory response was abnormal in high-risk SGA late preterm babies. The abnormalities, suggesting brainstem auditory impairment, were slightly different from high-risk AGA late preterm babies.

SIGNIFICANCE

SGA birth exerts a minor additional effect on the impaired auditory brainstem in high-risk babies born at late preterm. For these babies, neuroprotective measures should mainly target at associated perinatal problems, although the relatively minor adverse SGA effect cannot be ignored.

Correcting for prematurity affects developmental test scores in infants born late and moderately preterm

BACKGROUND

Corrected age is typically applied when assessing the development of children born <32 weeks of gestation. There is no consensus as to whether corrected age should be applied when assessing children born late/moderately preterm (LMPT; 32-36 weeks of gestation).

AIMS

This study explored the impact of corrected age on developmental test scores in infants born LMPT.

STUDY DESIGN

221 LMPT infants were assessed at two years corrected age using the Bayley-III cognitive and language scales, from which cognitive and language composite scores were derived (Normative Mean 100; SD 15). Assessments were then re-scored using chronological age. Bayley-III composite scores <80 were used to define developmental delay. Paired sample t-tests were used to assess the difference in mean test scores derived using corrected versus chronological age, and McNemar's tests to assess the difference in the proportion of infants with developmental delay using corrected versus chronological age.

RESULTS

Mean corrected age scores were significantly higher than chronological age scores (cognitive: 2.1 points; 95% CI 1.6, 2.5; language 2.5; 95% CI 2.1, 2.8). Overall, significantly more LMPT infants were classified with developmental delay when chronological (18.3%) versus corrected (15.0%) age was used (p=0.016).

CONCLUSIONS

Correcting for prematurity results in significantly higher developmental test scores and a significantly lower prevalence of developmental delay in LMPT infants and may affect eligibility for intervention services. Researchers and clinicians should be aware that the use of corrected age may impact on developmental test scores at both an individual and population level among infants born LMPT.

Neonatal outcomes and delivery of care for infants born late preterm or moderately preterm: a prospective population-based study

OBJECTIVE

To describe neonatal outcomes and explore variation in delivery of care for infants born late (34-36  weeks) and moderately (32-33 weeks) preterm (LMPT).

DESIGN/SETTING

Prospective population-based study comprising births in four major maternity centres, one midwifery-led unit and at home between September 2009 and December 2010. Data were obtained from maternal and neonatal records.

PARTICIPANTS

All LMPT infants were eligible. A random sample of term-born infants (≥37 weeks) acted as controls.

OUTCOME MEASURES

Neonatal unit (NNU) admission, respiratory and nutritional support, neonatal morbidities, investigations, length of stay and postnatal ward care were measured. Differences between centres were explored.

RESULTS

1146 (83%) LMPT and 1258 (79% of eligible) term-born infants were recruited. LMPT infants were significantly more likely to receive resuscitation at birth (17.5% vs 7.4%), respiratory (11.8% vs 0.9%) and nutritional support (3.5% vs 0.3%) and were less likely to be fed breast milk (64.2% vs 72.2%) than term infants. For all interventions and morbidities, a gradient of increasing risk with decreasing gestation was evident. Although 60% of late preterm infants were never admitted to a NNU, 83% required medical input on postnatal wards. Clinical management differed significantly between services.

CONCLUSIONS

LMPT infants place high demands on specialist neonatal services. A substantial amount of previously unreported specialist input is provided in postnatal wards, beyond normal newborn care. Appropriate expertise and planning of early care are essential if such infants are managed away from specialised neonatal settings. Further research is required to clarify optimal and cost-effective postnatal management for LMPT babies.

Late Preterm Infants and Neurodevelopmental Outcomes at Kindergarten

BACKGROUND AND OBJECTIVE

Late preterm infants (LPIs) (gestation 34 weeks and 0 days to 36 weeks and 6 days) compared with full-term infants (FTIs) are at increased risk for mortality and short- and long-term morbidity. The objective of this study was to assess the neurodevelopmental outcomes in a longitudinal cohort study of LPIs from infancy to school age and determine predictive values of earlier developmental testing compared with school-age testing.

METHODS

We used general estimating equations to calculate the odds of school readiness in a nationally representative cohort of 4900 full-term and 950 late preterm infants. We generated positive and negative predictive values of the ability of the 24-month Mental Developmental Index (MDI) scores of the Bayley Short Form, Research Edition, to predict Total School Readiness Score (TSRS) at kindergarten age.

RESULTS

In multivariable analysis, late preterm infants had higher odds of worse TSRSs (adjusted odds ratio 1.52 [95% confidence interval 1.06-2.18], P = .0215). The positive predictive value of a child having an MDI of <70 at 24 months and a TSRS <5% at kindergarten was 10.4%. The negative predictive value of having an MDI of >70 at 24 months and a TSRS >5% was 96.8%. Most infants improved score ranking over the study interval.

CONCLUSIONS

LPIs continue to be delayed at kindergarten compared with FTIs. The predictive validity of having a TSRS in the bottom 5% given a MDI <70 at 24 months was poor. A child who tested within the normal range (>85) at 24 months had an excellent chance of testing in the normal range at kindergarten.

Neurodevelopmental outcomes following late and moderate prematurity: a population-based cohort study

OBJECTIVE

There is a paucity of data relating to neurodevelopmental outcomes in infants born late and moderately preterm (LMPT; 32(+0)-36(+6) weeks). This paper present the results of a prospective, population-based study of 2-year outcomes following LMPT birth.

DESIGN

1130 LMPT and 1255 term-born children were recruited at birth. At 2 years corrected age, parents completed a questionnaire to assess neurosensory (vision, hearing, motor) impairments and the Parent Report of Children's Abilities-Revised to identify cognitive impairment. Relative risks for adverse outcomes were adjusted for sex, socio-economic status and small for gestational age, and weighted to account for over-sampling of term-born multiples. Risk factors for cognitive impairment were explored using multivariable analyses.

RESULTS

Parents of 638 (57%) LMPT infants and 765 (62%) controls completed questionnaires. Among LMPT infants, 1.6% had neurosensory impairment compared with 0.3% of controls (RR 4.89, 95% CI 1.07 to 22.25). Cognitive impairments were the most common adverse outcome: LMPT 6.3%; controls 2.4% (RR 2.09, 95% CI 1.19 to 3.64). LMPT infants were at twice the risk for neurodevelopmental disability (RR 2.19, 95% CI 1.27 to 3.75). Independent risk factors for cognitive impairment in LMPT infants were male sex, socio-economic disadvantage, non-white ethnicity, preeclampsia and not receiving breast milk at discharge.

CONCLUSIONS

Compared with term-born peers, LMPT infants are at double the risk for neurodevelopmental disability at 2 years of age, with the majority of impairments observed in the cognitive domain. Male sex, socio-economic disadvantage and preeclampsia are independent predictors of low cognitive scores following LMPT birth.

Behaviour and development in 24-month-old moderately preterm toddlers

OBJECTIVE

Moderately preterm children (gestational age 32-36+6 weeks) are at risk of cognitive and behaviour problems at school age. The aim of this study was to investigate if these problems are already present at the age of 2 years.

STUDY DESIGN

Developmental outcome was assessed at 24-months (corrected age) with the Bayley-III-NL in 116 moderately preterm (M=34.66 ± 1.35 weeks gestation) and 99 term born children (M=39.45 ± 0.98 weeks gestation). Behaviour problems were assessed with the Child Behaviour Checklist.

RESULTS

With age corrected for prematurity, moderately preterm children scored below term peers on Receptive Communication skills (11.05 ± 2.58 vs 12.02 ± 2.74, p=0.02). Without correcting age for prematurity, moderately preterm children scored below term born peers on Cognition (8.97 ± 2.11 vs 10.68 ± 2.35, p<0.001), Fine Motor (10.33 ± 2.15 vs 11.96 ± 2.15, p<0.001), Gross Motor (8.47 ± 2.55 vs 9.39±2.80, p=0.05), Receptive Communication (10.09 ± 2.48 vs 12.02 ± 2.74, p<0.001) and Expressive Communication (10.33 ± 2.43 vs 11.49 ± 2.51, p=0.005) skills. Compared with term peers, more moderately preterm children showed a (mild) delay (ie, scaled score <7) in gross motor skills with age uncorrected for prematurity (20.7% vs 11.2%, p=0.04). Moderately preterm children had more internalising behaviour problems than term children (44.76 ± 8.94 vs 41.54 ± 8.56, p=0.03). No group differences were found in percentages of (sub)clinical scores.

CONCLUSIONS

At the age of 2 years, uncorrected for prematurity, differences in cognition, communication, and motor development were present in moderately preterm children compared with term born peers. After correcting age for prematurity, a difference was only found for receptive communication skills. In addition, moderately preterm children show more internalising behaviour problems.

Gestational age and developmental risk in moderately and late preterm and early term infants

OBJECTIVES

The objective of this study was to evaluate the association between gestational age (GA) at birth and risk of developmental delay at 8 and 18 months of corrected postnatal age.

METHODS

During 2008 to 2011, infants at a corrected postnatal age of 8 or 18 months attending health centers in Santiago, Chile, were recruited. Participants completed a form on biographical and demographic characteristics and the Chilean validated version of the Ages and Stages Questionnaires, Third Edition (ASQ). Logistic regression was used to detect the capacity of GA to predict scores < -2 SDs on the basis of the Chilean ASQ reference group, in at least 1 ASQ domain, adjusted by different control variables.

RESULTS

A total of 1667 infants were included in the analysis. An inverse "dose response" relationship between developmental delay risk and GA at birth was found, both in the crude and adjusted models. Compared with those born full term, the odds ratio for developmental delay risk was 1.56 for those born early term (95% confidence interval [CI]: 1.19-2.06), 2.58 for infants born late preterm (95%CI: 1.66-4.01), and 3.01 for those born moderately preterm (95%CI: 1.59-5.71).

CONCLUSIONS

An inverse dose-response relationship between GA and risk of developmental delay was found in the tested population. Future prospective studies and predictive models are needed to understand whether this higher developmental risk in moderately and late preterm infants is transient and modifiable or persists throughout life, allowing for better targeting of early-intervention strategies.

Mild maturational delay of the brainstem at term in late preterm small-for-gestation age babies

AIMS

To detect any functional abnormality in the brainstem auditory pathway in late preterm babies born of small-for-gestational age (SGA) using maximum length sequence brainstem evoked response.

STUDY DESIGN

The response was recorded and analyzed at term in 38 SGA (birthweight <3rd centile) babies born at 33-36 week gestation. The results were compared with 40 age-matched babies born of appropriate-for-gestational age (AGA) (birthweight >10th centile). None of the subjects had major perinatal problems.

RESULTS

All wave latencies and interpeak intervals in the SGA group were slightly longer than those in the AGA group at most click rates. Wave III latency was significantly longer than that in the AGA group at 227/s (P < 0.05), and wave V latency was at 227 and 910/s (P < 0.05 and 0.05). Of the interpeak intervals, only the I-V interval in the SGA group was significantly longer than that in the AGA group at the highest rate 910/s (P < 0.05). The amplitudes of waves I, III and V in the SGA group all tended to be smaller than those in the AGA group at all click rates 91-910/s. The wave V amplitude was significantly smaller at most click rates (227-910/s, all P < 0.05). The slopes of all wave latency-, interval-, and amplitude-rate functions were similar in SGA and AGA groups.

CONCLUSIONS

There were marginal abnormalities in MLS BAER of low-risk late preterm SGA babies, suggesting a mild degree of maturational delay in the brainstem. Intrauterine growth retardation occurring in late preterm babies has a minor effect on neural maturation of the immature brainstem.

Cognitive development in 7- to 24-month-old extremely/very-to-moderately/late preterm and full-term born infants: The mediating role of focused attention

The present study analyzed the links between prematurity, attention, and global cognitive performance in infancy and early childhood. At 7 months, focused attention (FA) was examined with an object examination task in 93 preterm infants (39 of them born extremely/very preterm, 54 born moderately/late preterm, and 38 infants born full-term). Global cognition was assessed at 7 and 24 months with the Bayley-II cognitive scale. Groups did not differ with respect to global cognitive performance but FA of infants born extremely/very preterm was significantly lower than in infants born moderately/late preterm. FA correlated significantly with both prematurity and cognitive performance at 7 months of age but not with global cognition in childhood. Findings point to a subtle adverse effect of prematurity on early attention and reveal evidence for the mediating role of FA on the effect of prematurity on cognition.

Influence of holding practice on preterm infant development

PURPOSE

The purpose of this randomized, controlled trial was to determine if nurse-supported kangaroo holding of healthy preterm infants in the first 8 weeks of the infant's life facilitates early behavioral organization and development.

METHODS

We randomized 87 infants born between 32 and 35 weeks gestation and their mothers to one of three holding groups: kangaroo (skin-to-skin between mother's breasts), blanket (held in mother's arms), or control (no holding restrictions). Nurse-supported groups (kangaroo and blanket) received 8 weekly visits from a registered nurse who encouraged holding and provided education about infant development. The control group received brief social visits. Mothers recorded time held in a daily diary. The Assessment of Preterm Infant Behavior was administered when infants were 40 to 44 weeks postconceptional age.

RESULTS

Total holding time averaged 4 to 5 hr/day and did not differ among groups. Mothers held kangaroo style an average of 59 min/day in the kangaroo group, and 5 and 9 min/day in the blanket and control groups, respectively (p < .001). Infants in the kangaroo and blanket groups had more optimal scores than the control group in Robust Crying (p = .015) indicating that they could arouse to vigorous crying and calm. Scores, except for Attention and State Regulation, were at least as high as those of full-term infants.

CLINICAL IMPLICATIONS

When kangaroo holding is compared to blanket holding, both methods may provide equal early behavioral organization and developmental benefit to the infant.

Premature infants with birth weights of 1500-1999 g exhibit considerable delays in several developmental areas

AIM

To establish the prevalence and factors associated with developmental scores and delays in premature infants.

METHODS

A cross-sectional study was conducted on 100 premature infants with corrected ages of 18-24 months (actual ages 19.9 ± 2.0 months) and birth weights of 1500-1999 g. Bayley III scales were used to assess developmental scores, percentage of children with developmental scores <85, factors associated with developmental scores and delays in at least one developmental domain.

RESULTS

The percentages and 95% confidence intervals of those children with developmental delays were as follows: cognitive (2.0%; 0.6-7.0%), language (5.0%; 2.2-11.2%), motor (3.0%; 1.0-8.5%), socio-emotional (13.0%; 7.8-20.1%), general adaptive (26.0%; 18.4-35.4%), conceptual (17.0%; 10.9-25.6%), social (46.0%; 36.6-55.7%) and practical (21.0%; 14.2-30.0%). Factors associated with delay in at least one developmental domain were as follows: caesarean delivery, low per capita income and peri-intraventricular haemorrhage. Factors associated with a reduction in developmental scores were as follows: non-white ethnicity, lower social class, caesarean delivery, male gender, peri-intraventricular haemorrhage, mechanical ventilation and length of hospitalisation.

CONCLUSION

Premature infants with birth weights of 1500-1999 g exhibited considerable delays in several developmental areas. In addition to biological factors, environmental factors contributed to the reduced scores and/or developmental delays.

Long-term outcomes of moderately preterm, late preterm, and early term infants

At present, moderate preterm (MPT) infants born at 32 to 33 weeks' gestation and late preterm (LPT) infants born at 34 to 36 weeks' gestation make up the largest subgroup of preterm infants and contribute to more than 80% of premature births in the United States. There is increasing evidence that both MPT and LPT infants are at increased risk of neurologic impairments, developmental disabilities, school failure, and behavior and psychiatric problems. Population studies suggest that for each 1 week decrease in gestational age below 39 weeks, there are stepwise increases in adverse outcomes after adjusting for confounders.

ADHD and learning disabilities in former late preterm infants: a population-based birth cohort

BACKGROUND AND OBJECTIVE

Previous studies suggest that former late preterm infants are at increased risk for learning and behavioral problems compared with term infants. These studies have primarily used referred clinical samples of children followed only until early school age. Our objective was to determine the cumulative incidence of attention deficit/hyperactivity disorder (ADHD) and learning disabilities (LD) in former late preterm versus term infants in a population-based birth cohort.

METHODS

Subjects included all children born 1976 to 1982 in Rochester, MN who remained in the community after 5 years. This study focused on the comparison of subjects in 2 subgroups, late preterm (34 to <37 weeks) and term (37 to <42 weeks). School and medical records were available to identify individuals who met research criteria for ADHD and LD in reading, written language, and math. The Kaplan-Meier method was used to estimate the cumulative incidence of each condition by 19 years of age. Cox models were fit to evaluate the association between gestational age group and condition, after adjusting for maternal education and perinatal complications.

RESULTS

We found no statistically significant differences in the cumulative incidence of ADHD or LD between the late preterm (N = 256) versus term (N = 4419) groups: ADHD (cumulative incidence by age 19 years, 7.7% vs 7.2%; P = .84); reading LD (14.2% vs 13.1%; P = .57); written language LD (13.5% vs 15.7%; P = .36), and math LD (16.1% vs 15.5%; P = .89).

CONCLUSIONS

These data from a population-based birth cohort indicate that former late preterm infants have similar rates of LD and ADHD as term infants.

Neural conduction abnormality in the brain stem and prevalence of the abnormality in late preterm infants with perinatal problems

Neurodevelopment in late preterm infants has recently attracted considerable interest. The prevalence of brain stem conduction abnormality remains unknown. We examined maximum length sequence brain stem auditory evoked response in 163 infants, born at 33-36 weeks gestation, who had various perinatal problems. Compared with 49 normal term infants without problems, the late preterm infants showed a significant increase in III-V and I-V interpeak intervals at all 91-910/s clicks, particularly at 455 and 910/s (p < 0.01-0.001). The I-III interval was slightly increased, without statistically significant difference from the controls at any click rates. These results suggest that neural conduction along the, mainly more central or rostral part of, auditory brain stem is abnormal in late preterm infants with perinatal problems. Of the 163 late preterm infant, the number (and percentage rate) of infants with abnormal I-V interval at 91, 227, 455, and 910/s clicks was, respectively, 11 (6.5%), 17 (10.2%), 37 (22.3%), and 31 (18.7%). The number (and percentage rate) of infants with abnormal III-V interval at these rates was, respectively, 10 (6.0%), 17 (10.2%), 28 (16.9), and 36 (21.2%). Apparently, the abnormal rates were much higher at 455 and 910/s clicks than at lower rates 91 and 227/s. In total, 42 (25.8%) infants showed abnormal I-V and/or III-V intervals.

CONCLUSION

Conduction in, mainly in the more central part, the brain stem is abnormal in late preterm infants with perinatal problems. The abnormality is more detectable at high- than at low-rate sensory stimulation. A quarter of late preterm infants with perinatal problems have brain stem conduction abnormality.

Comparison of the developmental tests Bayley-III and Bayley-II in 7-month-old infants born preterm

The study aims on comparing Bayley Scales of infant development third (Bayley-III) and Bayley second (Bayley-II) edition with special focus on patterns in the first year of life. Fifty-five premature infants (43 with low birth weight/LBW >1,499 g and 12 with very/extremely low birth weight/VLBW/ELBW <1,500 g) aged 7 months (corrected for prematurity) were assessed with the complete Bayley-III. From this assessment, Bayley-II results were retrospectively estimated. Bayley-III results were compared to the expected mean with one-sample t-tests. The mean scores of both editions were compared with the aid of paired-sample t-tests. Pearson correlations between subscales and editions were analysed. The Bayley-III cognitive score of the study group was significantly higher than the expected mean of the standardization sample. VLBW/ELBW had significantly lower motor scores than LBW in both editions. When compared to estimated Bayley-II scores, all relevant Bayley-III scores were significantly higher (all p < .01) with highest difference (ten points) between the motor scales of both editions. There were significant correlations not only between Bayley-III cognitive and language scales but also between language and motor scales. Given the strong association between motor and cognitive behaviour in early infancy, this age-specific pattern is heightening the risk of failure to identify infants at risk for both cognitive and motor delay. Therefore, assessment of infants should comprise all subscales. Since Bayley-III probably overestimates especially motor performance in young infants, when interpreting Bayley-III scores in this age, comparison groups are highly recommended until further validation of normative data are outstanding.

Neonatal outcomes are associated with latency after preterm premature rupture of membranes

OBJECTIVE

To determine factors associated with latency time to birth after preterm premature rupture of membranes (PPROM) and the impact on neonatal outcomes.

STUDY DESIGN

Data on singleton pregnancies with PPROM (n=1535 infants) were prospectively collected in a computerized perinatal/neonatal database at a tertiary care perinatal center. Latency was characterized as ≤72h versus >72 h after PPROM.

RESULT

The percentage of women with latency to birth >72 h decreased from 67% in very preterm (gestational age (GA) 25 to 28 weeks) to 10% in late preterm women (GA 33 to 36 weeks). PPROM women with latency ≤72 h were more likely to have pregnancy-induced hypertension and birth weight <3%; PPROM women with latency >72 h were more likely to have received steroids and develop clinical chorioamnionitis. PPROM <32 weeks GA with latency ≤72 h was associated with a two-fold higher incidence of severe neonatal morbidity, while PPROM between 29 to 34 weeks GA and latency ≤72 h was associated with a higher incidence of moderate neonatal morbidity.

CONCLUSION

A latency period >72 h was associated with a decreased incidence of adverse neonatal outcomes up to 32 weeks GA for severe and 34 weeks GA for moderate morbidity indices.

An overview of risk factors for poor neurodevelopmental outcome associated with prematurity

BACKGROUND

Preterm birth is a major cause of neonatal mortality and morbidity. While advances in medical care have improved the survival of preterm infants, neurodevelopmental problems persist in this population. This article aims to review factors associated with their neurodevelopmental outcomes.

DATA SOURCES

English language studies of neurodevelopmental outcomes in preterm infants were retrieved from PubMed. A total of 100 related publications were included.

RESULTS

Early gestational age and birth weight are the most significant predictors of poor long-term neurological outcome. Structural changes of the brain, infection, male gender and neonatal intensive care unit course are also important factors affecting eventual outcome. Other complex biological and socio-economic factors, which extend from prenatal through postnatal periods, up through and including adulthood, also affect the trajectory of brain development in preterm infants.

CONCLUSIONS

Neurodevelopmental problems continue to affect the preterm population. There is a critical need for collaboration among geneticists, obstetricians, pediatricians, and neuroimaging and rehabilitation experts to determine early predictive factors and neuroprotective therapies to properly treat or prevent poor neurodevelopmental outcomes in these infants.

Functioning of 7-year-old children born at 32 to 35 weeks' gestational age

OBJECTIVE

To compare neuropsychological functions in moderately preterm (32-35 weeks' gestation) and full-term children at the age of 7 years and identify gender differences.

METHODS

Community-based prospective cohort study of 248 moderately preterm children (138 boys) and 130 full-term children (58 boys). Neuropsychological tests included IQ, memory, attention, visual perception, motor skills, visuomotor skills, and parental report of executive functioning.

RESULTS

The moderately preterm group performed significantly worse on total and performance IQ, visuospatial reasoning, attention control, inhibition, and executive functioning. No differences were found in verbal IQ, verbal memory, and visuomotor and motor skills. Preterm children were at higher risk for scores <10th percentile on intelligence, visuospatial reasoning (relative risk ratio both: 1.69 [95% confidence interval: 1.29-2.28]), and executive functioning problems (relative risk: 1.94 [95% confidence interval: 1.51-2.57]). Using gender-specific norms, preterm boys performed significantly worse than full-term boys on visuospatial reasoning (P < .01); preterm girls performed significantly worse than full-term girls on visuospatial reasoning, intelligence, attention, and executive functioning (P < .05).

CONCLUSIONS

Moderately preterm birth is associated with lower intelligence and poorer neuropsychological functioning at early school age. No differences in motor skills and verbal memory were found. Using gender-specific norms, our data suggest that moderately preterm boys catch up, whereas moderately preterm girls lag behind their peers on various neuropsychological functions by the age of 7 years.

Late preterm birth: a review of medical and neuropsychological childhood outcomes

Late preterm (LP) birth (34 0/7 - 36 6/7 weeks' gestation) accounts for nearly three-fourths of all preterm births, making this population a sizeable public health concern. The immature fetal development associated with LP delivery increases the risk of mortality and short-term medical complications. Which combination of maternal, fetal, or neonatal risk factors may be most critical has only recently begun to be addressed, and whether LP birth's disruptive impact on brain development will exert adverse effects on neuropsychological functioning in childhood and adolescence has been understudied. Early data have shown a graded response, with LP children often functioning better than very preterm children but worse than term children, and with subtle intellectual and neuropsychological deficits in LP children compared with healthy children born at term gestational age. Further characterization of the neuropsychological profile is required and would be best accomplished through prospective longitudinal studies. Moreover, since moderate and LP births result in disparate medical and psychological outcomes, the common methodology of combining these participants into a single research cohort to assess risk and outcome should be reconsidered. The rapidly growing LP outcomes literature reinforces a critical principle: fetal development occurs along a dynamic maturational continuum from conception to birth, with each successive gestational day likely to improve overall outcome.

School outcome, cognitive functioning, and behaviour problems in moderate and late preterm children and adults: a review

A large number of children (6 to 11% of all births) are born at a gestational age between 32 and 36 weeks. Little is known of long term outcomes for these moderate and late preterm children. In this review, results of 28 studies on school outcome, cognitive functioning, behaviour problems, and psychiatric disorders are presented. Overall, more school problems, less advanced cognitive functioning, more behaviour problems, and higher prevalence of psychiatric disorders were found in moderate and late preterm born infants, children, and adults compared with full term peers. Suggestions for future research are discussed.

Epidemiology of late and moderate preterm birth

Preterm birth affects 12.5% of all births in the USA. Infants of Black mothers are disproportionately affected, with 1.5 times the risk of preterm birth and 3.4 times the risk of preterm-related mortality. The preterm birth rate has increased by 33% in the last 25 years, almost entirely due to the rise in late preterm births (34-36 weeks' gestation). Recently attention has been given to uncovering the often subtle morbidity and mortality risks associated with moderate (32-33 weeks' gestation) and late preterm delivery, including respiratory, infectious, and neurocognitive complications and infant mortality. This section summarizes the epidemiology of moderate and late preterm birth, case definitions, risk factors, recent trends, and the emerging body of knowledge of morbidity and mortality associated with moderate and late preterm birth.

Longitudinal cognitive assessment in healthy late preterm infants

BACKGROUND

Longitudinal cognitive development in late preterm (LP) infants has not been previously evaluated, using structured assessments.

AIM

To assess longitudinally cognitive development in a population of healthy LP infants from 12 months to preschool age.

METHODS

Sixty-two low-risk LP infants (33-36 weeks gestation) with normal or only minor findings on their cranial ultrasound scans were included in the study. They were assessed at 12 and 18 months corrected age using the Bayley Scales of Infant Development II to obtain the mental development index (MDI) and then at preschool age (mean age 62 ± 7 months) using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-R).

RESULTS

The MDI scores obtained at both 12 and 18 months corrected age were within the reported normative range. Using uncorrected ages, their scores were lower at both ages than those obtained using CA (p < 0.01). Full-scale IQ scores within the reported normal range were obtained at 5 years using the WPPSI-R for all but 6 children. Females had significantly higher scores than males (p < 0.001) for the MDI at both 12 and 18 months corrected and uncorrected age. No gender differences were found at preschool age using the WPPSI-R.

CONCLUSIONS

Our results suggest that over 90% of the low-risk late preterms reach an MDI and IQ at preschool age within normal range.

Cognitive development in very vs. moderately to late preterm and full-term children: can effortful control account for group differences in toddlerhood?

BACKGROUND

Preterm birth is thought to have an adverse impact on cognitive development and self-regulation.

AIM

Examining the effect of very vs. moderately to late premature birth on cognitive development and effortful control, as well as evaluating whether effortful control explains the link between preterm birth and poorer cognitive development.

SUBJECTS

Fifty-eight very preterm children (<32 weeks gestation or <1500 g birth weight), 88 moderately to late preterm children (≥32 weeks gestation and ≥1500 birth weight) and 86 full-term children (≥38 weeks gestation and ≥2500 g birth weight) were examined at the corrected age of 24 months.

OUTCOME MEASURES

Observational and parent-report measures of effortful control as well as the Bayley Scales of Infant Development II (BSID II, Mental Scale) as a measurement of cognitive development were analyzed.

RESULTS

Very preterm and moderately to late preterm children showed significantly lower cognitive performance compared to full-term children. Lower effortful control scores (on observational measures, but not on parent-reports) were merely found for very preterm children compared to full-term children. Observational measures of effortful control partially mediated the effects of very preterm birth on cognitive performance, but did not explain the effects of moderately to late preterm birth on cognitive performance.

CONCLUSION

Preterm birth in general is related to poorer cognitive performance in toddlerhood. In addition, effortful control mediates the effects of very preterm birth on cognitive development. Findings suggest that different mechanisms link moderately to late premature birth to poor cognitive development.