May 21, 2014 10:37 AM EDT By Jaleesa Baulkman, UniversityHerald Reporter

More mental health surveillance is needed for mothers who have recently given birth, according to a recent study.

Australian researchers say that maternal depression is more common at four years following childbirth.

For the study, researchers used data from more than 1,500 women from six public hospitals in Melbourne, Australia to examine the prevalence of maternal depression from early pregnancy to four years postpartum. The researchers identified the possible risk factors for depressive symptoms at four years postpartum, including previous depression, relationship transitions, intimate partner violence and social adversity.

Study participants completed questionnaires at 3, 6, 12, 18 months postpartum and four years postpartum. The Edinburgh Postnatal Depression Scale was used in the questionnaire and intimate partner abuse was assessed at 12 months postpartum and at four years using the Composite Abuse Scale.

They found that almost one in three women reported depressive symptoms in the first four years after birth. The prevalence of depressive symptoms at four years postpartum was 14.5 percent, and was higher than at any time-point in the first 12 months postpartum.

Furthermore, women with one child at four years postpartum were more than twice as likely to report depressive symptoms at this time compared to women with subsequent children, 22.9 and 11.3 percent respectively.

Based on their findings, researchers suggest there is a need for current services to extend surveillance of maternal mental health to cover the early years of parenting and recommend the integration of core mental health services within routine primary healthcare (antenatal and postnatal visits).

"These findings provide a compelling case for re-thinking current policy frameworks for maternal mental health surveillance," Dr. Hannah Woolhouse, co-author of the study and psychologist and Senior Research Officer at the Murdoch Children's Research Institute in Australia said in a statement.

The findings were recently published in BJOG: An International Journal of Obstetrics and Gynecology.

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