Risk of postpartum depression may last months

NEW YORK (Reuters Health) - First-time mothers remain at risk of postpartum mental illness 4 or 6 weeks or longer after the length of time suggested in reference manuals, a research team in Denmark reports in the Journal of the American Medical Association.

Furthermore, although new fathers are exposed to some of the same stressors as mothers -- lifestyle changes, sleep deprivation -- their risk of psychiatric illness does not increase during this time, Trine Munk-Olsen from the University of Aarhus and colleagues observe.

Previous studies of postpartum mental disorders have limited their focus to specific disorders, and generally excluded fathers, the investigators note.

To identify a first onset of psychiatric illness during the 12 months after becoming a parent, the team linked data from two Danish registries. Between 1973 and 2005, a total of 630,000 women and 547,000 men became parents for the first time.

Results showed that 1171 mothers were admitted to a psychiatric hospital within the first 12 months after delivery, and 1369 were treated on an outpatient basis. Among fathers, 658 were treated as in-patients and 664 as out-patients.

"Compared with women who had given birth 11 to 12 months prior, (first-time mothers) had an increased risk of incident hospitalization with any mental disorder through the first 3 months after childbirth," the researchers found. The pattern was similar for outpatient psychiatric visits.

Among women, inpatient treatment for schizophrenia-like disorders was most likely during the first month postpartum. The risks for manic depression and depressive disorder were higher through 2 months and 5 months, respectively.

Fathers, on the other hand, exhibited no trends between childbirth and treatment for mental disorders.

"This may indicate that the causes of postpartum mental disorders are more strongly linked to an altered physiological process related to pregnancy and childbirth than psychosocial aspects of motherhood," the investigators maintain.

Of course, Munk-Olsen and colleagues add, it's possible that fathers are simply less likely to seek psychiatric care than women.

In a related editorial, Dr. Katherine L. Wisner, from the University of Pittsburgh, and colleagues describe this research as "the first large-scale epidemiologic investigation of psychiatric illness during childbearing" to take place over the last two decades.

Wisner and her associates recommend that "screening should be implemented as early as 2 weeks after delivery and no later than 12 weeks postpartum to identify episodes of major mood disorder and other mental illnesses" among first-time mothers.

SOURCE: Journal of the American Medical Association, December 6, 2006.