Detecting Postpartum Depression Requires Two-Phase Screening

Screening women once for postpartum depression in the first couple of weeks after childbirth may yield false-positive scores and may not be sufficient to confirm a diagnosis of postpartum depression, researchers report in the April Canadian Journal of Psychiatry.

Initial positive results on a screening instrument such as the Edinburgh Postnatal Depression Scale should be followed by a second screening a week or two later, as well as a thorough assessment of whether new mothers have the risk factors associated with postpartum depression, according to the study's researchers.

Cindy-Lee Dennis, Ph.D., and colleagues recruited 594 new mothers receiving health services near Vancouver, British Columbia, between April 2001 and January 2002 to participate in the study.

The women were recruited through a large group of family physician, obstetrician, and midwifery offices that agreed to be part of the study.

Dennis is an assistant professor of nursing at the University of Toronto and an investigator at the Canadian Institutes of Health Research.

Each of the mothers received a postpartum questionnaire at one, four, and eight weeks after giving birth.

Dennis assessed her subjects for postpartum depression using the Edinburgh Postnatal Depression Scale (EPDS), in which scores range from 0 to 30.

In the study, women who had a score greater than 9 were defined as exhibiting depressive symptoms.

The first questionnaire at the one-week mark also assessed risk factors for postpartum depression, including psychiatric, sociodemographic, biological, psychological, and items related to life stressors.

After getting those data, Dennis compared two groups of women—those who tested positive for depression at one week and remained symptomatic at the eight-week mark, and those who tested positive for depression at one week but were not symptomatic at eight weeks.

At one week after giving birth, 175 women (29.5 percent) exhibited depressive symptoms. Of those, 54.8 percent, or 80 women, exhibited depressive symptoms as measured by the EPDS at eight weeks postpartum.

“Mothers who continued to exhibit depressive symptomatology at eight weeks postpartum had significantly higher levels of perceived stress in the past year, were more likely to have a partner with a drug or alcohol problem, and were more likely to have been sexually abused as a child,” the authors wrote.

Women who were depressed at eight weeks were also more likely to have immigrated to Canada recently and perceived having less emotional support from others, including close family members.

Eight weeks after giving birth, 101 of 498 mothers who returned a follow-up survey (20.3 percent) were depressed, according to the findings. Of those 101 women, about 80 percent were also depressed at one week postpartum.

Mothers who exhibited depressive symptoms at one week and at eight weeks had higher levels of perceived stress and a number of stressful life events in the past year as compared with those who were not depressed at one week postpartum. In addition, they had higher reported levels of conflict with their partners.

According to Dennis, asking the women about certain risk factors is one way for physicians to predict more reliably whether mothers who report depressive symptoms at one week will go on to have symptoms months later.

“If the mother's first EPDS score is over 9 and she says she is fighting with her husband, feeling lonely, and perhaps one of her parents recently passed away, her depression will probably continue” if she is not treated, Dennis told Psychiatric News.

Dennis suggested that if physicians screen new mothers early in the postpartum period, they “implement a two-phase screening process” in which they screen new mothers twice using the EPDS.

“Based on the results of the second test, you'd implement some type of treatment protocol” appropriate for the severity of the new mother's depression, ranging from support groups to psychotherapy and medications. Dennis said. Screening without treatment is pointless, she noted.

“You must have appropriate and timely treatment in place” for women with postpartum depression.

An abstract of “Depressive Symptomatology in the Immediate Postnatal Period: Identifying Maternal Characteristics Related to True- and False-Positive Screening Scores” is posted at<www.cpa-apc.org/Publications/cjpHome.asp>.▪