Postpartum Psych Episode Predicts Bipolar Disorder
Published: December 08, 2011
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
In a large Danish cohort, women who had such an episode within 14 days of delivery were more than four times as likely to be diagnosed later with bipolar disorder than women whose first psychiatric episode came more than a year after childbirth, according to Trine Munk-Olsen, PhD, of Arhus University in Arhus, Denmark, and colleagues.
And women with first-time psychiatric contacts in the first month after delivery were more than three times as likely to convert to bipolar disorder as those whose first psychiatric contact was not related to childbirth, Munk-Olsen and colleagues reported online in Archives of General Psychiatry.
The findings suggest that mental illness in the postpartum period may be a marker of underlying bipolarity, even if the initial diagnosis is something else, the researchers argued.
One clinical implication, Munk-Olsen and colleagues argued, is that doctors should pay close attention to any signs of hypomania or mixed episode during a postpartum episode.
"Misdiagnosis of a bipolar spectrum disorder can have serious consequences," they noted, including incorrect prescription of antidepressants.
The researchers used comprehensive Danish medical records to identify some 120,378 women born in Denmark from 1950 to 1991 who were alive in 2006 and had at least one psychiatric contact – either inpatient or outpatient -- with any diagnosis except bipolar affective disorder.
The women were followed from the day of initial discharge, and the outcome of interest was a diagnosis of bipolar disorder in subsequent years.
All told, the researchers found, 2,870 of the women had their first psychiatric contact within the first year of giving birth to their first child.
And during follow-up, they found, 3,062 of the 120,378 women were diagnosed with bipolar affective disorder, including 132 who had their initial psychiatric episode in the first year after giving birth.
• Fifteen years after the first psychiatric episode, 13.87% of women with onset in the first month after childbirth had converted to bipolar disorder.
• In contrast, 4.69% of women with onset from 31 to 365 days postpartum and 4.04% of women with later onset had converted.
• 39 women had their first episode within 14 days of delivery and later converted to bipolar disorder. The relative risk, compared with those whose first episode was a year or more after childbirth, was 4.26, with a 95% confidence interval from 3.11 to 5.85.
• 21 women who later converted to bipolar had their first episode in the second two weeks after delivery; the relative risk was 2.65, with a 95% confidence interval from 1.72 to 4.07, compared with those whose first episode was a year or more after childbirth.
The study "confirms the well-established link between childbirth and bipolar affective disorder," the researchers concluded. But it also demonstrates that "initial psychiatric contact within the first 30 days postpartum significantly predicted conversion to bipolar affective disorder."
The researchers cautioned that the study only includes women who sought psychiatric care, so that less severe illness is not included.
It was also not possible to tell if women diagnosed later with bipolar disorder were simply misdiagnosed at their original contact or developed the illness in the following years.
Either way, Munk-Olsen and colleagues argued, the main clinical point stands: "A postpartum onset should raise the suspicion of an underlying bipolar disorder."