Psychotic disorders are complex and caused by interplay of genetic and environmental factors.
Influenza (the flu) is a common infectious disease in humans, and it has been suggested that maternal influenza is an estimated risk factor for psychotic disorders, especially for schizophrenia.
… results showed that gestational influenza could increase mental disorders risks in adult offspring besides its established harms for gravidas (during pregnancy).
Results suggest it might be effective to increase attention to gravidas (women during pregnancy) to protect them from influenza infection through encouragement of vaccinations.
Important Note: It has been suggested by researchers that its important to get the flu vaccine before becoming pregnant. Flu vaccines generally become available in the fall (September, October) - so in an ideal world women would get the vaccine in the fall, then get pregnant in December.