Postpartum depression is usually defined as a woman’s depressive episodes that occur during the first year following childbirth. Hormonal changes, social and psychological adjustments for motherhood, and physical exhaustion are thought to be factors that promote maternal depression. The risk doesn’t stop after just 12 months, though, according to a recent study from Australia. Researchers there say the fourth year after delivering a baby are when the risk of maternal depression is highest of all.

The study “provide(s) a compelling case for re-thinking current policy frameworks for maternal mental health surveillance,” according to study co-author Dr. Hannah Woolhouse. Woolhouse is a senior research officer and psychologist at the Murdock Children’s Research Institute in Victoria. She suggests the mental health systems in Australia and the United Kingdom “miss more than half the women experiencing depression in the early years of parenting.”

When circumstances that could trigger depression in the most vulnerable women are identified and understood better, primary care services could be focused on helping them maintain quality of life for themselves and their children. Woolhouse says social relationships, especially with one’s intimate partner, are key elements to maternal mental health.

The Woolhouse research team enlisted 1,507 women getting maternity care at six public hospitals in Melbourne. Upon enrollment to the study, the women were an average of 15 weeks into pregnancy.

Each woman started the study by completing a mood-assessment questionnaire based on the Edinburgh Postnatal Depression Scale.  Partner relationship quality was assessed using the Composite Abuse Scale.

The same questionnaires were completed again at 3, 6, 12, and 18 months after childbirth and at four years after delivery. Evaluation of the assessments indicated:

  • One in three women experienced depressive symptoms during the first four years.
  • At the 4-year mark, 14.5% experienced depression.
  • This 14.5% rate at four years is higher than in the first year after childbirth.
  • 22.9% is the rate of depression at four years for mothers of one child.
  • 11.3% is the rate of depression at four years for mothers with multiple children.

Women who experienced symptoms of depression in the early stages of pregnancy or within 12 months after delivery were more likely to be depressed at four years than mothers not depressed earlier. Other factors that contributed to depression after four years included:

  • Age, with 18- to 24-year-old mothers being the most vulnerable
  • Stressful life events in year 3
  • Social adversity in year 3
  • Intimate partner violence
  • Low income

Women who experienced intimate partner abuse were four times more likely to be depressed in year 4 if the abuse occurred in the first year after childbirth or during year 3 after childbirth.

The research team recommends primary care services for new mothers be enhanced to include mental health services alongside routine healthcare services during the first few years after having children.

Source: Woolhouse, H, et al. “Maternal depression from early pregnancy to 4 years postpartum in a prospective pregnancy cohort study: implications for primary health care.” BJOG: An International Journal of Obstetrics and Gynaecology. John Wiley & Sons, Inc. May 21, 2014. Web. Jun 6, 2014.