Postmaturity in a genetic subtype of schizophrenia

Objective: To determine whether postmaturity (gestation > 41 weeks), small for gestational age (SGA), and other pregnancy and birth complications that may elevate risk for neurodevelopmental disorders, are associated with elevated risk for schizophrenia in 22q11 Deletion Syndrome (22qDS), a genetic subtype of schizophrenia. Method: Antepartum and intrapartum features were examined in 20 adults with 22qDS‐schizophrenia and three comparison groups: newborn encephalopathy ( n  = 164) and healthy newborn controls ( n  = 400) from Badawi et al.'s (Br Med J 1998, 317 : 1549) study, and 16 non‐psychotic 22qDS adults (22qDS‐NP). Results: Postmaturity (OR 13.0, 95% CI 3.95, 42.77; P  < 0.001) and SGA (OR 3.59, 95% CI 1.23, 10.5; P  = 0.03) were more prevalent in 22qDS‐SZ than controls. Postmaturity was non‐significantly more prevalent in 22qDS‐SZ than in newborn encephalopathy ( P  = 0.06) or 22qDS‐NP ( P  = 0.2). SGA showed similar rates in the two 22qDS groups and newborn encephalopathy, but was more prevalent in 22qDS‐NP than controls ( P  = 0.05). Conclusion: The results suggest that postmaturity may be associated with expression of schizophrenia in a 22qDS subtype of schizophrenia. SGA may be a non‐specific marker of neurodevelopmental disturbance.