Developmental characteristics of late preterm infants at six and twelve months: A prospective study

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Highlights

  • The present study is the first to prospectively assess a large cohort of LPI from birth to the end of their first year of life.

  • The present study suggests that that LPI do not complete their neurodevelopmental maturation by the first year of life.

  • Males and those born after emergent cesarean section (CS) are at increased risk for lower achievements.

Abstract

Aim

To longitudinally assess the neurodevelopmental outcomes of late preterm infants (LPI) through the first year of life and to investigate for perinatal conditions that may affect developmental outcomes.

Methods

The study population comprised of 124 LPI, born in a single Israeli inborn center over an eight months period. Thirty-three term infants (TI) were recruited for comparison. Alberta Infant Motor Scale (AIMS) for gross motor evaluation was performed at 6 months of age and the Griffiths Mental Development Scales (GMDS) were performed at 12 months (chronological age). Maternal and neonatal covariates, potentially associated with low developmental scores, were analyzed by multivariate logistic regression models.

Results

At chronological age of 6 and 12 months, LPI performed significantly lower than TI on all subscales, but when scores were corrected for post conception age, developmental scores were similar in the two groups. In a multivariate model of logistic regression, male gender, emergent cesarean section and higher maternal education (>14 years) were found to be associated with increased risk for lower developmental scores at 12 month of age in LPI.

Conclusions

LPI do not complete their neurodevelopmental maturation by the first year of life. Males and those born after emergent cesarean section (CS) are at increased risk for lower developmental scores. Correction of age to term birth in LPI may still be needed at this age.

Introduction

Late preterm infants (LPI) have been defined as infants born at 34 0/7 to 36 6/7 weeks (239–259 days) of gestation (Engle, 2006). This group comprises of 71% of all preterm births and has been increasing at a greater rate than all other preterm birth subgroups over the last two decades (Davidoff et al., 2006, Martin et al., 2006). In September 2006, the National Institute of Child Health and Human Development set a research agenda to better understand the short and long-term morbidities that may be associated with late-preterm births (Raju, Higgins, Stark, & Leveno, 2006). They pointed out the paucity of available data regarding long-term neuro-developmental outcome of LPI and expressed the need for studies that will estimate prevalence and risk factors for such morbidities. Following studies have shown that LPI are at higher risk for neonatal morbidities compared to infants born at term, but only few studies, mainly retrospective ones, assessed preschool and early school age outcome of LPI and found increased risk of developmental disabilities, emotional regulation difficulties and poorer academic achievements compared to infants born at term (Chyi et al., 2008, Morse et al., 2009, Tomashek et al., 2007, van Baar et al., 2009, Young et al., 2007). A major limitation of these studies is related to insufficient information (when provided) regarding the infants’ perinatal course and as such, inclusion of additional independent risk factors for developmental disabilities. Gurka et al. who compared healthy late-preterm infants with their full term counterparts from ages 4 through 15 years for a variety of cognitive, socioemotional, and behavioral outcomes, found that healthy LPI seem to have no real burdens regarding cognition, achievement, behavior, and socioemotional development throughout childhood (Gurka & Blackman, 2010).

The present study prospectively followed and assessed the developmental outcome of a cohort of LPI, from birth to the end of their first year of life.

Section snippets

Participants

The study population consisted of 124 LPI of 34 0/7 to 35 6/7 weeks, born at Sheba Medical Center between January 1 and August 31, 2008 whose parents agreed to participate and who had complete developmental assessments at 6 and 12 months’ chronological age. One hundred and ten LPI who were eligible for the study were not included: 93 due to parental refusal, 15 did not complete follow up and two were excluded due to diagnoses of genetic disorders. Participants and non-participants were

Results

Maternal and infant medical and demographic characteristics of LPI and TI that participated in the study are shown in Table 1. Mothers of LPI were more likely to be married and had less education years but did not differ in their age or use of assisted reproduction. LPI gestations were more commonly multiple, complicated by hypertension or diabetes and delivered by emergent cesarean section. Respiratory distress that required oxygen treatment as well as phototherapy was more likely to occur in

Discussion

The present data suggests that complete developmental maturation does not occur by the end of the first year of life in LPI; however LPI functioned as expected by their corrected age. Among LPI infants low Griffith scores were associated with male gender, birth by emergent cesarean section and maternal education >14 years.

An increased risk for poor early school achievements has been reported in LPI. Morse et al. (2009) assessed healthy singleton LPI born in Florida. They found a 36% increased

References (18)

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