An estimated 12 percent of women develop major depression within a year of giving birth, and about 19 percent get minor forms of the illness. Postpartum depression disrupts maternal-infant bonding and retards infant behavioral and cognitive development. Yet many at-risk mothers go undiagnosed until the disease is well established.
Now a simple screening test has been used to identify mothers at risk for postpartum depression. In a small prospective study, 91 percent of mothers who scored 6 or above on the Modified Fatigue Symptom Checklist 14 days postpartum were found to be at increased risk of postpartum depression.
“We found that fatigue and not a history of stress or depression is the best indicator of which women will go on to develop postpartum depression,” the lead author of the study told Psychiatric News. She is Elizabeth Corwin, Ph.D., an associate professor of nursing at Ohio State University.
A report of her study appears in the September/October 2005 Journal of Obstetric, Gynecological, and Neonatal Nursing.
Corwin's group gave 31 women between 36 and 38 weeks gestation questionnaires on fatigue, stress, and both symptoms and history of depression; they also measured the women's cortisol levels. This procedure was repeated at one, two, and four weeks after delivery. All women had uneventful vaginal deliveries.
By the end of the fourth week, 11 of the 31 women were reported to have symptoms of depression. Seven had a family history of depression, four of whom also had a personal history of depression.
The most significant result was that 10 of the 11 women (91 percent) who showed symptoms of postpartum depression during the fourth and final week of the study had also reported higher-than-normal levels of fatigue two weeks earlier. Only one of the 11 women who went on to demonstrate symptoms of depression had not reported excessive fatigue at that visit.
“A personal history of depression is an excellent way to predict which women are at risk for postpartum depression,” Corwin said.“ Still, using that as the sole screening tool would have left seven of the women undiagnosed.
“Likewise, a family history of depression is a risk factor,” she went on. “But by using family history alone, we would have missed four women who went on to develop signs of depression.”
While these women reported that they also felt more stressed than normal, elevated stress levels based on the women's answers to the stress questionnaire weren't sufficient to predict which women would ultimately develop postpartum depression. Most of the women in the study reported higher-than-usual levels of stress during the first month after having their babies.
Also, cortisol levels were highest for all of the women in the study at the end of their pregnancies and steadily declined during the month after they gave birth. This ruled out using cortisol level as an indicator of differences in stress between women who went on to develop depression and those who did not.
“All mothers are tired after having a baby, but for some women the fatigue is relentless, and it is very hard to try to be a good mother and take on the new role when you are so exhausted, Corwin went on. “Little by little I think these moms don't respond to their babies because they are so tired, and eventually the babies won't respond to the mothers. Even if the mom does begin to respond later, she is out of sync with the baby from symptoms of depression.”
Other researchers have suggested that fatigue is an initiating factor or contributor to postpartum depression, and Corwin said she is not the first to suggest that. But their data were from retrospective studies. Corwin is believed to be the first to conduct studies that followed mothers prospectively.
Corwin conducted the study with colleagues from Pennsylvania State University. Support for the work came from a grant from the Association of Women's Health, Obstetric, and Neonatal Nurses and the Pennsylvania State General Clinical Research Center, which is funded by the National Institutes of Health.
J Obstet Gynecol Neonatal Nurs 2005 34 577