The Neurodevelopment of Preterm Infants: A Longitudinal Study from 0 to 24 Months

Preterm birth is defined as birth occurring before 37 weeks of gestational age, and is a major cause of neurodevelopment disability. Advances in neonatal care, including the development of Neonatal Intensive Care Units (NICUs), more aggressive delivery room management and antenatal steroids have led to substantial improvements in the survival rates of infants born preterm. Between 1990 and 2006, the rate of preterm birth rose 20% in the United States. Moreover, as of 2006, infants born premature accounted for 12.8% of all live births and infants weighing less than 1000 grams accounted for 1% of all live births (Bassan et al., 2006; Guyer, Freedman, Strobino, & Sondik, 1999; Martin et al., 2009; Saigal & Doyle, 2008). This increase in survival has placed significantly more demands on primary care providers serving this population as the costs associated with preterm birth, including the NICU, and life-long medical, education, and social services, are considerable. (Behrman, et al., 2007).

The aim of the present study was to gain a better understanding of the neurodevelopment of premature infants during the first 24 months of life. The Mullen Scales of Early Learning (Mullen, 1995) were used to examine the overall neurodevelopment, receptive language, expressive language, gross motor, fine motor, and visual reception development over time using a trend analysis.

The participants of this study were 219 premature infants horn at or below 32 weeks gestational age between the years 1999-2011, who were treated in the NICUs of New York University Langone Medical Center's (NYULMC) Tisch Hospital or Bellevue hospital, and who also received developmental follow-up care at the Neonatal Comprehensive Care Program (NCCP) of NYU Langone Medical Center. NCCP follow-up appointments were conducted at four to six-month intervals following discharge from the NICU.

For each of the areas assessed with the Mullen Scales of Early Learning (Mullen, 1995), the mean T scores and standard scores were found to be within the Average range throughout the first 24 months of life. Trend analysis of theses scores indicated that there were significant trend patterns for all of the areas assessed except for gross motor. In particular, overall neurodevelopment, fine motor, and visual reception initially improved before becoming relatively worse between 12 and 18 months of age. Moreover, receptive and expressive language were found to become relatively worse at least through the first 18 months of life. In addition, it was also found that as gestational age increases the trend pattern for receptive language becomes less negative.