Social relationships are important determinants of well-being, health, and quality of life.

There are conflicting findings regarding the association between preterm birth or low birth weight and experiences of social relationships in adulthood.

systematically investigate the association between preterm birth or low birth weight and social outcomes in adulthood.

PubMed, PsycINFO, Web of Science, and Embase were searched for peer-reviewed articles published through August 5, 2018.

Prospective longitudinal and registry studies reporting on selected social outcomes in adults who were born preterm or with low birth weight (mean sample age ≥18 years) compared with control individuals born at term.

The meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

The data were collected and extracted by 2 independent reviewers. Pooled analyses were based on odds ratios (ORs) with 95% confidence intervals and Hedges g, which were meta-analyzed using random-effects models.