Genes May Boost Woman's Risk of Postpartum Depression05/21/13
TUESDAY, May 21 (HealthDay News) -- Pregnant women with specific
alterations in two genes may be at increased risk of suffering
depression after giving birth, a small new study suggests.
The researchers hope they can use the findings to develop a
blood test that could help spot pregnant women who are vulnerable
to postpartum depression, which affects around 15 percent of new
Their study, reported in the May 21 issue of the journal
Molecular Psychiatry, uncovered specific chemical changes in
two genes that predicted which women would develop postpartum
depression with 85 percent accuracy.
Little is known about the genes, called TTC9B and HP1BP3, but
they are somehow involved in activity in the brain's hippocampus,
which regulates mood. Based on animal research, both genes seem to
be "reactive to estrogen," said Zachary Kaminsky, a researcher at
Johns Hopkins University School of Medicine in Baltimore who worked
on the study.
The findings offer clues as to what makes some women susceptible
to postpartum depression. But there is still a lot of work to be
done before a screening test becomes available, according to an
expert not involved in the research.
"This is a first step, but I think we're pretty far off from having a blood test," said Dr. Kimberly Yonkers, a professor of psychiatry and obstetrics and gynecology at Yale School of Medicine in New Haven, Conn.
She said the study was small -- involving only 51 women, about a
dozen of whom developed depression within a month of giving birth
-- so the results need to be validated in larger studies.
But beyond that, Yonkers said, there's the larger, "dicey" issue
of how much benefit there would be from telling pregnant women
their genes put them at heightened risk of postpartum
"You may unnecessarily worry some women," Yonkers said.
"Information is power," Kaminsky said, and for some women, knowing they are at risk of postpartum depression can offer a chance to minimize that risk: Their partner, family or friends could be especially attentive and step in to ease some of the stress of being a new mom, for example.
Kaminsky acknowledged that if a blood test result actually
caused distress for an expectant mom, it would not be good. But, he
said, having a blood test as an option for women who want an idea
of their risk could be valuable.
Kaminsky and two of his co-researchers have filed for a patent
on testing for the genetic markers.
The findings are based on 51 pregnant women with a history of
depression or bipolar disorder, which raises the risk of suffering
depression during or after pregnancy. One group of 19 women had
major depression during their pregnancies, and 12 continued to have
symptoms in the first month after giving birth.
Another 32 women were depression-free during pregnancy, but 11
developed postpartum depression.
Based on research with mice, Kaminsky's team suspected that
estrogen triggers so-called epigenetic changes in genes in the
brain's hippocampus. With epigenetic changes, there is no defect in
the underlying DNA, but a gene's activity is altered. The results
of research conducted in mice, however, often are not able to be
replicated in humans.
The researchers found that epigenetic changes in the TTC9B and
HP1BP3 genes were predictive of a woman's risk of postpartum
Yonkers said one theory has been that women who develop
postpartum depression may respond differently to the big shifts in
estrogen and other hormones that happen during pregnancy and after
Kaminsky said the new findings give some insight into that
hormonal response. But he said more research is needed to really
understand what's going on.
The results also need to be confirmed in a larger, more diverse
group of women, Kaminsky said. "The women in this study all had
been previously diagnosed with depression or bipolar disorder," he
said. "We really need to look at this in a general population of
In general, experts suspect that many factors come together to
cause postpartum depression, including a woman's particular
circumstances, such as whether she has a good "support network," if
she has other major stressors in her life or whether the pregnancy
was planned or not.
So no blood test would tell the whole story.
Right now, doctors may diagnose postpartum depression either
because a woman complains of symptoms, or through a screening
questionnaire. Yonkers said experts differ on whether new mothers
should be routinely screened; the American Academy of Pediatrics,
for example, says pediatricians should screen moms for depression
during newborn checkups.
Other groups, including the American College of Obstetricians
and Gynecologists, do not advise routine screening, but say doctors
and women should consider it.
Learn more about
postpartum depressionfrom the American
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