Postnatal depression is relatively rare, according to a University of Queensland study.
Sociology, Anthropology and Archaeology Department head Professor Jake Najman says while the short-term hormone-driven "baby blues" affect many new mothers, severe and lasting depression was most likely to be a recurrence or reactivation of a previous mental illness.
Professor Najman's study showed the period after the birth was one of "optimal mental health" for the mother, and that women were more likely to become depressed as their children grew up.
Data was taken from the Mater Hospital-University of Queensland Study of Pregnancy, a study of 8556 pregnant women which began in 1981.
Women were assessed during pregnancy, three to five days after giving birth, and at six-month and five-year follow-ups. The results have been published in the prestigious international journal Social Psychiatry and Psychiatric Epidemiology.
"The more severe forms of depression are not characteristic of the period after childbirth," Professor Najman said. "When you look at clinically-relevant symptoms of major depression, the period after the birth of the baby is one of optimal mental health."
"I think a lot of women will look at this research and say, ?I experienced a depression after the birth of my baby and any suggestion that it doesn't happen is silly'. And they're right - they did experience it and two-thirds of women do.
"But the vast majority of those women get over that depression in a relatively short period of time. It's likely the depression relates to hormonal changes associated with giving birth and after a time it just disappears."
The study showed only 3.4 percent of women were depressed six weeks after the birth of their babies, compared with 6.5 percent five years after the birth.
"I think it is a mistake to see these depressions as occasioned by childbirth when, for many women, the evidence indicates that the first occurrence was well before the birth. We ought to be thinking of this not as an event caused by the birth, but as a problem of mental illness that the mother should probably have had help with a long time before."
Professor Najman said the study indicated a "switch in emphasis" was needed to recognise that raising a small child could be associated with more severe forms of mental illness.
"I think we've probably overstated the mental health effect of giving birth and understated the mental health consequences of rearing a child. The proportion of women with severe depression when the child is five is about twice as high as it is shortly after the birth," he said.
"Articles in women's magazines and newspapers talk about the desperate consequences of postnatal depression and see it as a major problem that isn't being addressed. But our data suggest there are other problems in relation to women's mental health that should be addressed before this one; times when women's mental health is more likely to be compromised."
Also involved in the study were Margaret Andersen of UQ's Obstetrics and Gynaecology Department, Dr William Bor of the Children's Health Sector, Brisbane North Regional Health Authority, Dr Michael O'Callaghan of the Mater Misericordiae Hospital, and Associate Professor Gail Williams of the Australian Centre for International and Tropical Health and Nutrition.
For more information, contact Professor Jake Najman (telephone 3365 3152 or email j.najman@mailbox.uq.edu.au) or the Communications Office (telephone 3365 2619)
