Children born preterm are at increased risk of deviation from the typical developmental trajectory. The probability of adverse developmental sequelae is increased in those with history of major perinatal complications. Retinopathy of prematurity (ROP) is a pathological disordered growth of retinal blood vessels occurring in very preterm neonates who require supplemental oxygen. ROP has been linked to intermittent hypoxemic events and blood gas derangements occurring in the Neonatal Intensive Care Unit (NICU), particularly in ventilated infants. Though presence and severity of ROP have been linked to neurodevelopmental impairment, little is known about the relationship between ROP severity and motor development in the preschool age. Because the same hypoxemic events and blood gas changes that lead to severe ROP may also lead to greater developmental deficits in motor control, we hypothesized that ROP severity will be inversely linked to the quality of motor functioning even in NICU graduates without neurological impairments.

We included 95 preterm (23.6 - 33.6 weeks gestation) preschoolers (49 females, 44 members of twin pairs or triplets). The participants' age ranged from 3.3 - 4.1 years (adjusted for prematurity). ROP screening was conducted during NICU stay and rated from immature retina (0) to grade 4. Motor abilities were assessed with the Peabody Developmental Motor Scales (PDMS-2). Cases with diagnosed perinatal brain pathology (moderate to severe) or cerebral palsy were excluded from analyses.

We used linear mixed regression analyses with multiple gestation as a random factor. Severity of ROP was our predictor of interest, whereas socioeconomic status, sex, gestational age, and birth-weight SD served as covariates. Separate analyses were conducted using the PDMS-2 Total Motor, Fine Motor, and Gross Motor Quotients as dependent variables. ROP severity explained a unique portion of the variance in the Total Motor Quotient (F[1, 89] = 5.59, p = .02). Examination of the relationship between ROP severity and motor skill domains yielded a significant association for the Fine Motor Quotient (F[1, 89] = 6.19, p = .015) and a trend for the Gross Motor Quotient (F[1, 89] = 3.64, p = .06).

The results of this study reveal that increase in ROP severity is linked to poorer motor skills in preterm-born preschoolers without major disabilities or perinatal diagnosis of moderate to severe brain pathology. This association was evident for both fine and gross motor skills, though only the relationship between ROP severity and the former motor index reached conventional statistical significance. Importantly, ROP severity accounted for a unique portion of the variance in motor performance, over and above the variance explained by other perinatal risk factors. This result is consistent with previous research findings indicating that ROP is linked to the occurrence of multiple, subtle hypoxemic events and 'exposure' to blood gas derangements during NICU stay in very preterm neonates who require respiratory support.