Does puerperal illness distinguish a subgroup of bipolar patients?

Puerperal psychosis was found to be the 1st illness for 13 (36%) of a series of 36 mothers with bipolar affective disorder. The risk of recurrence with childbirth in those with established bipolar disorder was found to be 25-40%. Those women who survived childbirth without illness but then became ill at a later time reported a worse illness course. Recent fatherhood was not a precipitant of 1st affective illness for any of the 28 bipolar men.