Objective Offspring of parents with bipolar disorder (BD) are at increased risk for developing a range of psychiatric disorders. Although genetic factors clearly confer risk to offspring, environmental factors also play a role in increasing vulnerability. Such environmental factors may occur at the initial stages of development in the form of obstetric complications (OCs). The current investigation examined the relationship between OCs and the development of psychopathology in offspring at risk for BD and the influence of parental psychopathology in this relationship. Methods This cross‐sectional study included 206 offspring of 119 parents with BD. Probit regression analyses examined associations between: (1) OC history and offspring psychopathology; and (2) maternal lifetime comorbid anxiety diagnoses and OCs in pregnancy/delivery with their offspring. Path analyses then tested whether OCs mediate the relationship between maternal comorbid anxiety disorders and offspring lifetime psychopathology. Results Results indicated a specific association between OCs, particularly delivery complications, and increased risk for offspring anxiety disorders. Data also showed a significant relationship between maternal anxiety disorder comorbidity and OCs. Finally, path analyses suggested that delivery complications act as a mediator in the relationship between comorbid maternal anxiety disorder and offspring anxiety disorder. Conclusions Our findings lend support to the importance of identifying and reducing anxiety in pregnant woman with BD. The identification of OCs as early vulnerability factors for psychopathology in offspring at familial risk may also lead to earlier detection and intervention in these offspring.