Rates of hypothyroidism in postpartum women are high and peak at about five months postpartum. While the initial risk for a postpartum depression is one in ten, if a woman has had a previous history of depressive disorder the risk increases to one in four. Thus, having a prior history makes a woman more vulnerable to an episode in the postpartum. Further, if a woman has had a postpartum depression, she has a 50 percent chance of having another postpartum episode with her next baby. A recent study demonstrated that antidepressant prophylaxis, started in the last trimester or soon after delivery markedly reduced the likelihood of a recurrence of postpartum depression.
Postpartum psychosis is a rapidly changing state of confusion, agitation, and affective lability.
Up to 80 percent of these patients, upon long term follow up, will be diagnosed with bipolar disorder. As the age of onset of bipolar disorder often overlaps with the age of many women's first postpartum experiences, a postpartum psychosis may represent the first affective episode. The onset is often 3 to 14 days postpartum. While the incidence is one in 1000, the risk of infanticide has been reported as high as 4 percent. In general, the symptomatology of postpartum and major depressive episodes do not differ symptomatically from non-postpartum mood episodes.