More than 70% of women with mood disorders who become pregnant experience at least one episode of their disorder in association with the birth or, less often, the pregnancy, according to a report published online Dec. 17 in Archives of General Psychiatry.
Given that approximately 40% of all pregnancies are unplanned, the risk of perinatal episodes of mania, hypomania, psychotic depression, and nonpsychotic major depression should be discussed with all women of childbearing age who have mood disorders, even those who are not planning a pregnancy, said Dr. Ian Jones of the Institute of Psychological Medicine and Clinical Neurosciences at Cardiff (Wales) University and his associates.
In addition, "it is important that all professionals providing health care for pregnant women, including midwives, family physicians, and obstetricians, are aware of this increased risk," they wrote.
Dr. Jones and his colleagues assessed the occurrence of a range of psychological disorders associated with childbirth using data from two clinical and genetic studies of mood disorders. One study cohort included 573 women with recurrent major depression occurring in 1998-2004, and the other included 980 women with bipolar I disorder and 232 with bipolar II disorder occurring in 1991-2010.
Data were available regarding 3,017 pregnancies in 1,410 of these women. The prevalence of episodes of mania, hypomania, depression with psychosis, or nonpsychotic major depression either during pregnancy or within 1 year of childbirth was similar across the spectrum of mood disorders: 70.8% for bipolar I disorder, 70.9% for bipolar II disorder, and 73.7% for recurrent major depression.
"The importance of pregnancy and childbirth for women with mood disorders should therefore not be underestimated," the investigators said (Arch. Gen. Psychiatry 2012 Dec. 17 [doi:10.1001/jamapsychiatry.2013.279]).
In this sample, 94% of the episodes of mania or psychotic depression occurred within 4 weeks postpartum.
For women with bipolar I disorder, approximately 20% of deliveries were associated with a postpartum episode of mania or psychotic depression and an additional 25% were associated with an episode of nonpsychotic major depression. Altogether, nearly half of the deliveries in women with bipolar I disorder were associated with "an episode of a major mood disorder of some description," Dr. Jones and his associates reported.
Although the rate of such episodes was lower for both bipolar II disorder and recurrent major depression, "it would be wrong to underestimate the importance" of such episodes in these patient populations, they said. Approximately 40% of deliveries among women with bipolar II disorder or major recurrent depression were associated with episodes of these disorders.
Only a small proportion of psychotic or depressive episodes occurred during pregnancy rather than postpartum in this sample. The rate, however, was roughly twice as high in women with bipolar II disorder (18.4%) than in those with bipolar I disorder (8.6%) or recurrent major depression (11%).
The relatively few episodes of psychosis or depression that developed during pregnancy were equally distributed across the three trimesters.
Similarly, less than 4% of all episodes of psychosis or depression occurred after 6 months postpartum, and the rates were similar across the three types of mood disorder, Dr. Jones and his associates said.
This study was supported by the Wellcome Trust, the Stanley Medical Research Institute, and the Welsh Assembly Government Health Studentship. No financial conflicts were reported.