Postpartum depression can continue beyond the first few months after giving birth

New mothers are most often assessed for postpartum depression in the first 12 weeks after giving birth. However, new research shows that for a significant number of women, postpartum depression can last throughout the first year and beyond.

“For some mothers postpartum depression will resolve on its own,” says the study’s lead author, Dr. Cindy-Lee Dennis, senior scientist at Women’s College Research Institute and Shirley Brown Chair in Women’s Mental Health Research at Women’s College Hospital. “However, this research suggests that for about eight per cent of mothers the depression continues and professional treatment is necessary.”

The study, which was published in the Canadian Journal of Psychiatry, used data from a national sample of 6,421 women who participated in the Maternity Experiences Survey of the Canadian Perinatal Surveillance System. The participants completed the survey between five and 14 months after giving birth.

Identifying risks

In addition to finding that eight per cent of Canadian women had symptoms of depression past 12 weeks postpartum, the study also identified several factors associated with increased risk of postpartum depression:

• low postpartum social support was linked to an almost four-fold risk of postpartum depression
• having several stressful life events in the year preceding childbirth was associated with an almost 2.5-fold risk
• a previous history of depression was associated with an 87 per cent increased risk of postpartum depression
• low household income was associated with a 64 per cent increased risk
• interpersonal violence was linked to a 40 per cent increased risk of postpartum depression

“Psychosocial variables are highly significant, even when we adjusted for other covariates, such as parity,” Dr. Dennis says. “Interpersonal violence, a significant number of stressful life events in the year preceding childbirth, low postpartum support and low income – these are all psychosocial variables.”

Continuing symptoms

Dr. Dennis believes that the depression affecting women later in the postpartum period is probably depression that is continuing, rather than postpartum depression that is beginning later.

“For the majority of mothers, if they’re going to develop postpartum depression, they usually develop it within the first 12 weeks,” Dr. Dennis says, adding that many women with postpartum depression report their depressive symptoms started within the first four weeks after giving birth.

“So we know postpartum depression often begins early in the postpartum period for many mothers and for about eight per cent of these women their depression will continue past the first year postpartum,” Dr. Dennis explains. “It is also important to note postpartum depression can actually be a continuation of depression that started during the pregnancy which was not detected or treated.”

Family impact

This information is crucial because of the significant impact a mother’s depression can have on the first year of a child’s life. Because maternal depression affects a mother’s behaviour and cognitions, it also affects the child’s development. Maternal depression is also a significant risk factor for paternal depression, placing infants and children at even greater risk for poorer developmental trajectories and a very stressful home environment.

The study results highlight a need for depression screening beyond the first 12 weeks after childbirth.