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

Abstract

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.

Keywords: Neonatology; Neurodevelopment.

Figure 1

Recruitment, follow-up rates and ascertainment of 2-year outcome data for late and moderately preterm infants and term-born controls.

Figure 2

Mean difference (95% CI) in Parent Report of Children's Abilities-Revised (PARCA-R) z scores between late and moderately preterm (32–36 weeks gestation) and term-born (37–42 weeks gestation) infants. z Scores were calculated using the mean (SD) of the term reference group. Solid lines represent crude differences and dashed lines represent differences adjusted for sex, socio-economic status and small for gestational age (SGA) status. PRC, parent report composite.