My admittedly nonprofessional understanding of the relationship between onset of Bipolar I and postpartum psychosis is that it’s only associated with
primiparity, or first pregnancy/childbirth. But maybe I’m misreading these studies:
Mood disorders and parity – A clue to the aetiology of the postpartum trigger
From this study: “The results of our study indicate that in women with BD-I, episodes of postpartum psychosis are associated with first pregnancies.”
Birth order and postpartum psychiatric disorders
From this study: “The highest risk was found in primiparous mothers 10-19 days postpartum [relative risk (RR) = 8.65; 95% confidence interval (CI): 6.89-10.85]. After the second birth, the highest risk was at 60-89 days postpartum (RR = 2.01; 95% CI: 1.52-2.65),
and there was no increased risk after the third birth.”
Callan was LC’s third child, so these studies seem to indicate her case wouldn’t be one of first onset of Bipolar Disorder I and associated psychosis. But again, maybe I’m reading them incorrectly or missing something.