School outcome in late preterm infants: a cause for concern

Risk and protective factors in early child development: Results from the All Our Babies (AOB) pregnancy cohort

BACKGROUND

Understanding factors that protect against early developmental delay among children who are experiencing adversity can inform prevention and early intervention strategies.

AIMS

To identify risk factors for development delay at one year and protective factors for developmental delay in 'at risk' environments (poor maternal mental health and socio-demographic risk).

METHODS AND PROCEDURES

Data was analyzed from 3360 mother-child dyads who participated in the All Our Babies (AOB) pregnancy cohort. Participants completed four questionnaires spanning pregnancy to one year postpartum and provided access to medical records. Risk factors for developmental delay at age one were identified using bivariate methods and multivariable modeling. Protective factors for child development in 'at risk' family environments were identified using bivariate analyses.

OUTCOMES AND RESULTS

At one year, 17% of children were developmentally delayed, defined as scoring in the monitoring zone on at least 2 of the 5 developmental domains of the Ages and Stages Questionnaire. Prenatal depression, preterm birth, low community engagement, and non-daily parent-child interaction increased the risk of delay. Protective factors for children in 'at risk' environments included relationship happiness, parenting self-efficacy, community engagement, higher social support, and daily parent-child interaction.

CONCLUSIONS AND IMPLICATIONS

The study results suggest that maternal and infant outcomes would be improved, even for vulnerable women, through identification and intervention to address poor mental health and through normalizing engagement with low cost, accessible community resources that can also support parent-child interaction.

Developmental Outcomes of Late Preterm Infants From Infancy to Kindergarten

OBJECTIVE

To compare developmental outcomes of late preterm infants (34-36 weeks' gestation) with infants born at early term (37-38 weeks' gestation) and term (39-41 weeks' gestation), from infancy through kindergarten.

METHODS

Sample included 1000 late preterm, 1800 early term, and 3200 term infants ascertained from the Early Childhood Longitudinal Study, Birth Cohort. Direct assessments of development were performed at 9 and 24 months by using the Bayley Short Form-Research Edition T-scores and at preschool and kindergarten using the Early Childhood Longitudinal Study, Birth Cohort reading and mathematics θ scores. Maternal and infant characteristics were obtained from birth certificate data and parent questionnaires. After controlling for covariates, we compared mean developmental outcomes between late preterm and full-term groups in serial cross-sectional analyses at each timepoint using multilinear regression, with pairwise comparisons testing for group differences by gestational age categories.

RESULTS

With covariates controlled at all timepoints, at 9 months late preterm infants demonstrated less optimal developmental outcomes (T = 47.31) compared with infants born early term (T = 49.12) and term (T = 50.09) (P < .0001). This association was not seen at 24 months, (P = .66) but reemerged at preschool. Late preterm infants demonstrated less optimal scores in preschool reading (P = .0006), preschool mathematics (P = .0014), and kindergarten reading (P = .0007) compared with infants born at term gestation.

CONCLUSIONS

Although late preterm infants demonstrate comparable developmental outcomes to full-term infants (early term and full-term gestation) at 24 months, they demonstrate less optimal reading outcomes at preschool and kindergarten timepoints. Ongoing developmental surveillance for late preterm infants is warranted into preschool and kindergarten.

Neuro-developmental outcome of a large cohort of growth discordant twins

Our aims were to study the effect of birthweight growth discordance (≥20%) on neuro-developmental outcome of monochorionic and dichorionic twins and to compare the relative effects of foetal growth discordance and prematurity on cognitive outcome. We performed a cross-sectional multicentre prospective follow-up study from a cohort of 948 twin pregnancies. One hundred nineteen birthweight-discordant twin pairs were examined (24 monochorionic pairs) and were matched for gestational age at delivery with 111 concordant control pairs. Participants were assessed with the Bayley Scales between 24 and 42 months of age. Analysis was by paired t test for intra-twin pair differences and by multiple linear regression. Compared to the larger twin of a discordant pair, the smaller twin performed significantly worse in cognition (mean composite cognitive score difference = -1.7, 95% confidence interval (CI) = 0.3-3.1, p = 0.01) and also in language and motor skills. Prematurity prior to 33 weeks' gestation, however, had a far greater impact on cognitive outcomes (mean cognitive composite score difference = -5.8, 95% CI = 1.2-10.5, p = 0.008).

CONCLUSION

Birthweight growth discordance of ≥20% confers an independent adverse effect on long-term neuro-development of the smaller twin. However, prior to 33 weeks' gestation, gestational age at birth adversely affects cognitive development to a greater extent than foetal growth discordance.

Proposal for mechanisms of protection of supine sleep against sudden infant death syndrome: an integrated mechanism review

Supine sleep decreases sudden infant death syndrome (SIDS) incidence, however the mechanisms for this are unclear. The triple risk model for SIDS requires that one or more underlying abnormalities of breathing or autonomic control are present; these are rare, but brainstem defects are found in most SIDS cases. Supine sleep increases sympathetic nervous system tone, and level of state organization, and may therefore act as a stressor. This is evidenced by physiological arousal, and by delayed neurodevelopment in supine compared to prone sleepers. It is argued here that prone sleep position is the biological normative standard in healthy infants, supporting autonomic regulation. During rapid eye movement (REM) sleep (and other circumstances), a parasympathetic-mediated adverse autonomic event (AAE) may be spontaneously triggered. In healthy infants, gasping initiates autoresuscitation and recovery.

HYPOTHESIS

The underlying vulnerability to SIDS is specific to autoresuscitation from an AAE, the initial serotonin-dependent gasp is commonly compromised. Serotonin metabolism defects also influence sleep architecture, increasing the likelihood of AAE. The mechanism whereby supine sleep decreases SIDS may therefore be a stressor effect, disturbing sleep architecture to decrease REM and AAEs, and increasing sympathetic tone, which may prevent and counteract the purely parasympathetic-mediated AAE, thereby decreasing the risk of SIDS.

A comparison between late preterm and term infants on breastfeeding and maternal mental health

The objective of this study was to compare breastfeeding, postpartum mental health, and health service utilization between a group of late preterm (LP) maternal infant pairs and term counterparts. Data was drawn from a prospective community-based cohort in Calgary, Alberta. Bivariate and multivariable analyses were performed. LP infants were more likely to have had a longer median length of stay after birth (P < 0.001) and a higher re-hospitalization rate at 4-months (P < 0.001) compared to term infants. Mothers of LP infants were more likely to report immediate breastfeeding difficulties (P < 0.001) and earlier cessation of breastfeeding at 4-months postpartum (P = 0.008). Multivariable analyses revealed that LP status was an independent risk factor for excessive symptoms of maternal anxiety (OR = 2.07; 95 % CI = 1.08,3.98), but not for depression, stress, or low parenting morale. LP infants and their families are a vulnerable population with unique developmental trajectories. Further longitudinal research is required.

Maternal and pregnancy-related factors associated with developmental delay in moderately preterm-born children

OBJECTIVE

To estimate the association between pre-existing maternal and pregnancy-related factors and developmental delay in early childhood in moderately preterm-born children.

METHODS

We measured development with the Ages and Stages Questionnaire at age 43-49 months in 834 moderately preterm-born (between 32 0/7 and 35 6/7 weeks of gestation) children born in 2002-2003. We obtained data on preexisting maternal, maternal pregnancy-related, fetal, and delivery-related factors. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) and attributable risks for developmental delay adjusted for sociodemographic and lifestyle variables.

RESULTS

Attributable risk for developmental delay for small-for-gestational-age (SGA, as a proxy for intrauterine growth restriction [IUGR]) was 14.2% (SGA 21.9%, no SGA 7.7%, P<.05, adjusted OR 2.75, CI 1.25-6.08), for preexisting maternal obesity 10.5% (obesity 18.0%, no obesity 7.5%, P<.01, adjusted OR 2.73, CI 1.35-5.52), for multiple pregnancy 4.2% (multiple 12.0%, singleton 7.8%, P<.05, adjusted OR 1.86, CI 1.02-3.42), and for male sex 9.3% (male 13.0%, female 3.8%, P<.001, adjusted OR 4.20, CI 2.09-8.46). No other preexisting or pregnancy-related maternal factors or any delivery-related factors were associated with increased risk of developmental delay.

CONCLUSIONS

Of all preexisting maternal and pregnancy-related factors studied, SGA, maternal prepregnancy obesity, being one of a multiple, and male sex were associated with the risk of developmental delay in early childhood after moderately preterm birth. Reinforced focus on prevention of IUGR, preconception lifestyle interventions aiming at weight reduction in fertile women, and reinforced efforts to reduce rates of multiple pregnancies in assisted reproduction may all contribute toward more favorable developmental outcomes in moderately preterm-born children.

LEVEL OF EVIDENCE

II.

Perinatal origins of first-grade academic failure: role of prematurity and maternal factors

OBJECTIVE

We examined the relationships among gestational age at birth, maternal characteristics, and standardized test performance in Georgia first-grade students.

METHODS

Live births to Georgia-resident mothers aged 11 to 53 years from 1998 through 2003 were deterministically linked with standardized test results for first-grade attendees of Georgia public schools from 2005 through 2009. Logistic models were used to estimate the odds of failure of the 3 components of the first-grade Criterion-Referenced Competency Test (CRCT).

RESULTS

The strongest risk factor for failure of each of the 3 components of the first-grade CRCT was level of maternal education. Child race/ethnicity and maternal age at birth were also associated with first-grade CRCT failure irrespective of the severity of preterm birth, but these factors were more important among children born moderately preterm than for those born on the margins of the prematurity distribution. Adjusting for maternal and child characteristics, there was an increased odds of failure of each component of the CRCT for children born late preterm versus term, including for math (adjusted odds ratio [aOR]: 1.17, 95% confidence interval [CI]: 1.13-1.22), reading (aOR: 1.13, 95% CI: 1.08-1.18), and English/language arts, for which there was an important interaction with being born small for gestational age (aOR: 1.17, 95% CI: 1.07-1.29).

CONCLUSIONS

Preterm birth and low maternal education increase children's risk of failure of first-grade standardized tests. Promoting women's academic achievement and reduce rates of preterm birth may be important to achieving gains in elementary school performance.

Gray matter volumetric MRI differences late-preterm and term infants

Gray matter develops rapidly during the third trimester of pregnancy, which is a critical period for lipid deposition. We measured brain volume in term and late-preterm infants to determine if it is related to disabilities in late-preterm infants. In addition, we measured serum lipid concentrations to investigate the relationship between brain volume and lipid nutrition. Magnetic resonance imaging scans were obtained in 16 late-preterm and 13 term infants. We measured cerebrum, gray matter, and white matter volumes. We performed serum cholesterol, triglyceride (TG), and lipoprotein analyses in cord blood by high-performance liquid chromatography using gel permeation columns to assess lipid nutritional levels. The gray matter volume and percent cerebrum volume of gray matter were significantly smaller in late-preterm infants (p<0.001). Head circumference and cerebrum and white matter volume did not differ between the two groups. Gray matter volume correlated positively with gestational age (r=0.647, p<0.001), head circumference (r=0.688, p<0.001), and high-density lipoprotein (HDL)-TG levels (r=0.496, p=0.006). Late-preterm infants had a normal head circumference and a lower gray matter volume than term infants. Gestational age and head circumference were significantly associated with gray matter volume. Only HDL-TG levels were significantly associated with gray matter volume. HDL-TG might contribute to the transport of fatty acids and gray matter development during the postnatal period. Thus, delayed gray matter development may partly contribute to neurodevelopmental disabilities in late-preterm infants.

Neonatal morbidities and developmental delay in moderately preterm-born children

BACKGROUND AND OBJECTIVE

Children born moderately preterm (32-35(6/7) weeks' gestation) are at increased risk of both neonatal morbidities and developmental delays in early childhood. It is unknown whether neonatal morbidities contribute to the increased risk of developmental delay. The objective of this study was to determine the effect of neonatal morbidities after moderately preterm birth on development at preschool age.

METHODS

In a community-based, stratified cohort, parents of 832 moderately preterm children born in 2002 or 2003 completed the Ages and Stage Questionnaire when their child was 43 to 49 months old. Data on Apgar scores, asphyxia, tertiary NICU admission, hospital transfer, circulatory insufficiency, hypoglycemia, septicemia, mechanical ventilation, continuous positive airway pressure, apneas, caffeine treatment, and hyperbilirubinemia were obtained from medical records. We assessed associations of neonatal characteristics with developmental delay, adjusted for gender, small-for-gestational-age status, gestational age, and maternal education.

RESULTS

Hypoglycemia and asphyxia were associated with developmental delay; odds ratios (ORs) were 2.42 (95% confidence interval [CI]: 1.23-4.77) and 3.18 (95% CI: 1.01-10.0), respectively. Tertiary NICU admission and hyperbilirubinemia had positive but statistically borderline nonsignificant associations with developmental delay: ORs were 1.74 (95% CI: 0.96-3.15) and 1.52 (95% CI: 0.94-2.46), respectively. No other neonatal morbidities were associated with developmental delay. In multivariate analyses, only hypoglycemia was associated with developmental delay (OR: 2.19; 95% CI: 1.08-4.46).

CONCLUSIONS

In moderately preterm-born children, only hypoglycemia increased the risk of developmental delay at preschool age. A concerted effort to prevent hypoglycemia might enhance developmental outcome in this group.

Motor system development of the preterm and low birthweight infant

Despite advances in knowledge and technology, accurate prediction of later neuromotor outcomes for infants born preterm remains somewhat elusive. Here we review some of the most recent findings regarding the differential effects of preterm birth and suboptimal fetal growth on neurodevelopment. Evidence from transcranial magnetic stimulation studies is presented that suggests neuromotor development may more directly influence cognitive outcomes than previously recognised. We discuss the role of neuroplasticity in both exacerbating and improving these postnatal outcomes, and possible therapeutic targets for manipulating this. Finally, some developmental care practices that might affect long-term outcomes for these children are discussed.

Term pregnancy: time for a redefinition

The designation term pregnancy and the distinction between term, preterm, and postterm pregnancy carry with them significant clinical implications with respect to the management of pregnancy complications. Although the potential hazards of both preterm birth and postterm pregnancy have been long recognized, little attention has, until recently, been given to the differential morbidity experienced by neonates born at different times within the 5-week interval classically considered term gestation. This article is a reevaluation of the concept of term pregnancy in light of current data.

Developmental delay in moderately preterm-born children at school entry

OBJECTIVE

To determine the prevalence and nature of developmental delay at preschool age in infants born moderately preterm compared with those born full-term and early preterm.

STUDY DESIGN

Parents of 927 moderate preterm infants (32-35(+6) weeks gestation), 512 early preterm infants (<32 weeks gestation) and 544 full-term infants (38-41(+6) weeks gestation) completed the Ages and Stages Questionnaire (ASQ) when the child was aged 43-49 months. We analyzed rates of abnormal ASQ scores and odds ratios for abnormal ASQ scores in both preterm groups compared with the full-term group. We repeated the analyses after adjustment for socioeconomic status, sex, being part of a multiple birth, and small for gestational age status.

RESULTS

Abnormal (ie, >2 SDs below the mean) ASQ total scores were noted in 8.3% of moderate preterm infants, in 4.2% of full-term infants, and in 14.9% of early preterm infants. ORs of abnormal ASQ total scores were 2.1 (95% CI, 1.3-3.4) for moderate preterm infants and 4.0 (95% CI, 2.4-6.5) for early preterm infants. Both moderate and early preterm infants had more frequent problems with fine motor, communication, and personal-social functioning compared with full-term infants. Compared with full-term infants, moderate preterm infants did not have a greater prevalence of problems with gross motor functioning and problem solving, whereas early preterms did. Socioeconomic status, small for gestational age status, and sex were associated with abnormal ASQ scores in moderate preterm infants.

CONCLUSIONS

At preschool age, the prevalence of developmental delay in moderate preterm infants was 2-fold of that in full-term infants and one-half of that in early preterm infants.

Visuospatial and verbal fluency relative deficits in 'complicated' late-preterm preschool children

BACKGROUND

Late-preterm children constitute a majority of all preterm deliveries (75%). Their immature brain development at birth has been associated with an increased risk for morbidities. Data have been sparse regarding neuropsychological outcomes in the preschool years.

AIM

To examine general cognition, attention/working memory, language, manual coordination/motor dexterity, visuomotor, visuospatial, and executive functions in preschoolers born late-preterm (LPT; 34-36 gestational weeks) who required NICU admission compared to term-born participants.

DESIGN

Single-center retrospective cohort study of 95 three-year-old children; 60 born LPT in 2004-2005 and admitted to the NICU compared to 35 healthy term-born participants born > or =37 gestational weeks and > or =2500 g.

RESULTS

LPT birth was associated with visuospatial (p=.005), visuomotor (p=.012), and executive function (noun [p=.018] and action-verb [p=.026] fluency) relative deficits, but not attention/working memory, receptive or expressive language, nonverbal reasoning, or manual coordination/dexterity deficit.

CONCLUSIONS

Late-preterm birth is likely to be associated with negative neuropsychological sequelae, although subtle and selective compared to effects reported for children born at an earlier gestational age. Visuospatial function appears to be especially vulnerable to disruption even at preschool age, and verbal fluency may be useful as an early predictor of executive dysfunction in childhood. Routine preschool neuropsychological evaluation is recommended to identify delay or deficit in LPT children preparing for school entry, and may highlight underlying vulnerable neural networks in LPT children.