To systematically review and perform meta-analyses on the long-term neurodevelopmental outcomes of adults born moderate and late preterm (MLPT) in relation to cognitive functioning and psychiatric disorders.

A search was conducted to identify any studies that involved prematurity in adulthood. From these studies, reports that included a group of MLPT adults and included description of cognitive and/or mental health domains (including specific long-term outcomes) were selected.

In total, 155 publications were identified, but only 16 papers met the inclusion criteria. A small effect size (g = 0.38) was found in MLPT to demonstrate poorer intellectual performance compared with those born at term. Moreover, MLPT adults exhibited greater odds for any psychiatric (OR 1.14), substance use (OR 1.16), mood (OR 1.06), and psychotic disorders (OR 1.40).

Despite inconsistency due to the methodologic differences between the selected studies, MLPT showed minor long-term effects into adulthood. However, more studies are needed, because prematurity seems to confer some vulnerability to biological and environmental factors that enhance susceptibility to adverse neurodevelopment outcomes.