August 20, 2009 — Healthy, educated, middle-class women who are in stable relationships and who give birth to healthy, full-term babies experience disturbing rates of postpartum depression, according to a new study.
"Even in women who are as low risk as you can get in a community cohort, we find approximately 20% of women reporting symptoms of postpartum depression high enough to merit some clinical attention," said the study's lead author, Ruth Feldman, PhD, professor of psychology and neuroscience, and director, community-based infant clinic, Bar-Ilan University, Ramat-Gan, Israel.
This is important because, as the study suggests, postpartum depression can have a negative effect on infant development in terms of fear response and social interaction, Dr. Feldman told Medscape Psychiatry.
The study found that the rate of severe depressive symptoms among healthy educated women was 3.6%, and the rate of anxiety was 12.2%.
The study is published in the August issue of the Journal of the American Academy of Child and Adolescent Psychiatry.
Early Symptoms
The researchers started with a sample of 971 new mothers who reported symptoms of depression and anxiety on the second day after giving birth. At 6 months postpartum, the researchers mailed questionnaires on anxiety and depression to 360 women representing both the top and bottom of the depressive symptom continuum.
Of the 215 mothers who returned these questionnaires, the researchers contacted 150 at the upper and lower ends of the depressive symptom continuum for follow-up.
The final sample at 9 months included 100 women, 45% of whom were first-time mothers. Their average age was 30.7 years, and they had completed an average of 15.8 years of education.
Of the 41 mothers composing the clinical group, 22 had a major depressive disorder, and 19 had an anxiety disorder. Seven mothers in the major depressive disorder group and 3 in the anxiety group were treated with medication. Very few were undergoing psychotherapy.
Control Group
The sample also included a control group of 59 mothers who were matched to the clinical group in age, education, parenting experience, and infant birth weight and sex.
The 9-month assessment included 2 home visits. During the first visit, mothers were assessed for Diagnostic and Statistical Manual of Mental Disorders, 4th edition, disorders and completed self-report measures. During the second visit, investigators videotaped mothers and infants while they engaged in free play. They also monitored fear reactions in infants while showing them increasingly scary masks and took saliva samples to test for cortisol levels in both mothers and infants.
The study showed that infants of mothers who were depressed at 9 months scored the poorest on relational behavior measures including sensitivity, intrusiveness, social engagement, and withdrawal, as well as fear regulation and cortisol reactivity. These 3 measures are central to the social-emotional growth of infants.
Social Engagement
A new mother's depression might diminish her sensitivity, which in turn could stall the development of her infant's social skills. "We learn social engagement through modeling," said Dr. Feldman, adding that babies learn nonverbal "scripts" starting from about 3 months of age.
In the study, babies of depressed mothers cried and fussed more than other babies during the scary mask test. Fear response is a good indicator of how well a baby adapts to changes in his environment, explained Dr. Feldman.
"Normally, mothers would be able to provide some kind of a buffer between the child and the environment through their sensitive approach. They know when to stimulate, they know when the child needs rest, they know how to organize the child's environment and how to interact socially. When this is the case, the novelty in the world is not so scary for the child," he said.
Fear Response
Children who do not learn how to regulate their fear response become anxiety-prone later on, said Dr. Feldman. "Studies have found that those kids who show negative reaction on the same things that we measured at 9 months go on to become much more anxious and shy children in adolescence."
Babies of anxious mothers also show developmental problems. In the current study, offspring of anxious women did less well than children of control participants on infant social engagement, and the anxious mothers did worse than control participants on testing for maternal sensitivity. Mothers with anxiety scored the highest in intrusiveness, but fear regulation among their children was similar to that of children of control patients.
Anxiety in new mothers had the same negative effect on infant cortisol levels as maternal depression. These levels were highest at baseline among depressed women, followed by anxious moms, and rose still higher during testing.
It is important to know that a mother's mood is affecting the infant's physiology, said Dr. Feldman. Previous animal studies and studies that followed up children from birth to adolescence have shown that if the stress hormone, which is the body's stress management system, is altered, it is usually for life, she said.
Greater Expectations
The incidence of postpartum depression appears to be on the rise. Just a few years ago, researchers estimated the prevalence rate to be 12% to 15% but more recent research puts the figure at closer to 18% to 20% in developed countries, said Dr. Feldman.
There are likely many reasons for this rise. The problem is being studied more, and women are waiting longer to bear children (research shows depression may be related to maternal age).
In addition, women today face many more expectations than their mothers and grandmothers. "In modern society, women are expected to be thin and pretty and active right away after birth," said Dr. Feldman. They are also expected to have "this fabulous interesting career and to be this fabulous mom."
Dr. Feldman believes postpartum depression is not getting the attention it merits "Think about how much attention is being paid to autism now, and we're talking about — at most — 1.5% prevalence," she said.
Fits Clinical Experience
Asked by Medscape Psychiatry to comment on the study, Gail A. Bernstein, MD, professor and head, Division of Child and Adolescent Psychiatry, University of Minnesota Medical School, Minneapolis, said the study results fit her clinical experience, "but it was very nice to see this demonstrated with a prospective study using measures and observation that were scientifically based."
Dr. Bernstein said she and colleague Kathryn Cullen, MD, assistant professor in the same division, were very impressed with the study. "We thought it had a nice prospective study design, and we liked the fact it was a community sample. It seemed pretty clear that the study demonstrated the effects of maternal postpartum anxiety and depression on early infant development, that there were negative sequelae for infants, especially of depressed moms."
It was interesting to see a study on the effect of maternal depression and anxiety on very young babies because specialists do not see these children until they are older, added Dr. Cullen. "We don't see the children until they're perhaps 8 or 10 years old, or teenagers, so we wouldn't know what's happening in neurobiology at the early developmental stages," she said.
The authors have disclosed no relevant financial relationships.
J Am Acad Child Adolesc Psychiatry. 2009;48:919–927.
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Cite this: Postpartum Depression, Anxiety, May Affect Infant Development - Medscape - Aug 20, 2009.
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