To determine associations between sociodemographic and medical factors and odds of readmission after discharge from the neonatal intensive care unit for infants with very low birth weight (<1500g).

Cohort study using linked data from the California Perinatal Quality Care Collaborative, California Vital Statistics, and the Child Opportunity Index (COI) 2.0. Infants with very low birth weight born from 2009 through 2018 in California were considered. Odds ratios of readmission within 30 days of discharge adjusting for infant medical factors, maternal sociodemographic factors, and birth hospital were calculated via multivariable logistic regression and fixed-effect logistic regression models.

A total of 42 411 infants met inclusion criteria. Also, 8.5% of all infants were readmitted within 30 days of discharge. In addition to traditional medical risk factors, two sociodemographic factors were significantly associated with increased odds of readmission in adjusted models: payor other than private insurance for delivery [aOR = 1.25 (95% CI 1.14-1.36)] and maternal education of less than high school degree [aOR = 1.19 (95% CI 1.06-1.33)]. Neighborhood Child Opportunity Index was not associated with odds of readmission.

Sociodemographic factors, including lack of private insurance and lower maternal educational attainment, are significantly and independently associated with increased odds of readmission after neonatal intensive care unit discharge, in addition to traditional medical risk factors. Socioeconomic deprivation and health literacy may contribute to risk of readmission. Targeted discharge interventions focused on addressing social drivers of health warrant exploration.