Purpose-While women with a history of major depressive disorder (MDD) have higher chances for postpartum depressive and manic episodes, little is known about their chance for postpartum psychosis (PPP). We prospectively assessed the frequency of perinatal psychotic symptoms among primiparous women with a history of MDD only (structured clinical interview was used to exclude women with pre-existing histories of mania or psychosis), and explored whether sex of the baby influenced these symptoms.Methods-The presence of symptoms of psychosis was defined using previously established cutoff scores on five key items from the Positive and Negative Syndrome Scale (PANSS), which was administered during pregnancy, at 1 week, 1 month, and 3 months postpartum.Results-Fourteen of 60 women (23%) scored above threshold for psychosis at one or more time-points, with six experiencing postpartum onset. There was a non-significant trend (p = 0.073) towards higher frequency of these symptoms among mothers of girls.Conclusions-If controlled studies using diagnostic interviews confirm that psychotic symptoms are relatively common among women with MDD, monitoring for psychosis during the perinatal period may be indicated in this population. The potential effect of sex of the baby on mothers' chance for PPP requires further study.