CHICAGO — A surprisingly high number of women have postpartum depressive symptoms, according to a new, large-scale study by a Northwestern Medicine® researcher.

This is the largest scale depression screening of postpartum women and the first time a full psychiatric assessment has been done in a study of postpartum women who screened positive for depression.

The study, which included a depression screening of 10,000 women who had recently delivered infants at single obstetrical hospital, revealed a large percentage of women who suffered recurrent episodes of major depression.

The study underscored the importance of prenatal as well as postpartum screening. Mothers’ and infants’ health and lives hang in the balance. The lives of several women who were suicidal when staff members called them for the screening were saved likely as a result of the study’s screening and immediate intervention.

“In the U.S., the vast majority of postpartum women with depression are not identified or treated even though they are at higher risk for psychiatric disorders,” said Northwestern Medicine lead study author Katherine L. Wisner, M.D. “It’s a huge public health problem. A woman’s mental health has a profound effect on fetal development as well as her child’s physical and emotional development.”

Wisner is director of Northwestern’s Asher Center for the Study and Treatment of Depressive Disorders and the Norman and Helen Asher Professor of Psychiatry and Behavioral Sciences and professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine. She’s also a physician at Northwestern Memorial Hospital.

“A lot of women do not understand what is happening to them,” Wisner said. “They think they’re just stressed or they believe it is how having a baby is supposed to feel.”

The paper was be published in JAMA Psychiatry March 13. Wisner conducted the research when she was at the University of Pittsburgh.

In the study, 14 percent of the women screened positive for depression. Of that group, 826 received full psychiatric assessments during at-home visits. Some of the key findings from those assessments:

– In women who screened positive for depression, 19.3 percent thought of harming themselves.

“Most of these women would not have been screened and therefore would not have been identified as seriously at risk,” Wisner said. “We believe screening will save lives.”

Suicide accounts for about 20 percent of postpartum deaths and is the second most common cause of mortality in postpartum women.

– Many women who screened positive for major depression postpartum had already experienced at least one episode of depression previously and, in addition, had an anxiety disorder. The study found 30 percent of women had depression onset prior to pregnancy, 40 percent postpartum and 30 percent during pregnancy. More than two-thirds of these women also had an anxiety disorder.

“Clinicians need to know that the most common clinical presentation in the post-birth period is more complex than a single episode of depression,” Wisner said. “The depression is recurrent and superimposed on an anxiety disorder.“

– Of the women who screened positive for major depression, 22 percent had bipolar disorder, the majority of whom had not been diagnosed by their physicians. There is often a delay in correctly diagnosing bipolar disorder, which depends on identifying not only the depressed phase but the manic or hypomanic phase as well. But postpartum is the highest risk period for new episodes of mania in a woman’s life.

“That’s a very high rate of bipolar disorder that has never been reported in a population screened for postpartum depression before,” said Wisner. “It is significant because antidepressant drug treatment alone can worsen the course of bipolar disorder.”

In addition, women who have been pregnant in the past year are less likely to seek treatment for depression than women who have not been pregnant, previous research has shown.

Maximizing a woman’s overall mental and physical health in pregnancy and after childbirth is critically important.

“Depression during pregnancy increases the risk to a woman and her fetus,” Wisner said. “Depression is a physiological dysregulation disorder of the entire body.”

Maternal prenatal stress and depression is linked to preterm birth and low infant birth weight, which increases the risk of cardiovascular disease. Depression also affects a woman’s appetite, nutrition and prenatal care and is associated with increased alcohol and drug use. Women with untreated depression have a higher body mass index preconception, which carries additional risks.

When a new mother is depressed, her emotional state can interfere with child development and increases the rate of insecure attachment and poor cognitive performance of her child, Wisner said.

Screening prenatal and postpartum are essential (Illinois requires mandatory screening for perinatal mental health disorders), but the health care field must develop cost effective and accessible treatment, Wisner emphasized.

“If we identify patients we must have treatment to offer them,” Wisner said.

The study was funded by grant RO1 MH 071825 from the National Institute of Mental Health of the National Institutes of Health.

Surprising Rate of Women Have Depression After Childbirth