Purpose: Contradictory studies suggest that some neonatal factors may be associated with a pervasive developmental disorder (PDD) diagnosis, but limited data is available from longitudinal, prospective medical record assessments.Materials and methods: The present hypothesis-testing longitudinal, case-control study evaluated birth characteristics among cases diagnosed with a PDD in comparison to controls by examining prospectively collected automated medical records within the Vaccine Safety Datalink (VSD) database.Results: Cases were Health Maintenance Organization (HMO)-enrolled from birth until diagnosed with International Classification of Disease, 9th revision (ICD-9) PDD (299.xx) and controls were HMO-enrolled from birth for at least 4.75 years without a PDD diagnosis. The birth characteristics examined included: gender, gestational age in weeks at birth, mean birth weight in grams, Appearance-Pulse-Grimace-Activity-Respiration (APGAR) scores at 1 minute and 5 minutes, and maternal age in years at birth. Cases had a significantly increased male/female ratio relative to controls. By contrast, mean gestational age at birth, mean birth weight, mean maternal age at birth, and mean APGAR scores at 1 minute and 5 minutes were not statistically different among cases compared to controls.Conclusions: This study indicates that cases diagnosed with a PDD as compared to controls do not have significant differences in neonatal factors.