From The Quarterly, Summer 2010
Notwithstanding the joy most women feel about having a baby, about three-quarters of all women experience a lowering in mood shortly after giving birth, and some 13 percent of new mothers go on to full-scale postpartum depression. New NARSAD-funded research by 2008 Young Investigator Julia Sacher, M.D., Ph.D., has provided the first biological explanation for this seeming paradox. It has also opened an avenue to possible intervention and prevention.
In the first few days after giving birth, women experience a 100- to 1,000-fold drop in their levels of estrogen, the primary female sex hormone. Changes in estrogen have an inverse effect on levels of an enzyme called mono-amine-A. MAO-A, as it is called, spurs the activity of neurotransmitters including serotonin, norepinephrine, and dopamine, which are involved in transmitting nerve signals from cell to cell. Elevated MAO-A levels in brain areas important in regulating mood have previously been associated with major depressive disorder.
Remarkably, prior to Dr. Sacher’s research, MAO-A activity levels in the early postpartum period had never been measured in vivo in any species. To do so, she and the team of her NARSAD mentor Jeffrey H. Meyer, M.D., Ph.D., and head of the neurochemical imaging program of mood disorders at the Centre for Addiction and Mental Health (CAMH), University of Toronto, applied the brain-imaging technique of positron emission tomography — more commonly known as PET scanning — to observe areas where MAO-A binding was elevated in the brains of research subjects. The researchers found that MAO-A activity levels were 43 percent higher throughout the brains of women who had just given birth, as compared with levels in women who were neither pregnant nor postpartum. The effect was strongest on the fifth day following birth, the day when, on average, postpartum blues symptoms are most pronounced.
Dr. Sacher believes that these findings point to exciting potential therapies. Her hope is that the information may be used in the future to create dietary supplements that could lower the risk for postpartum depression — in essence, by giving rise to molecules that are knocked out of commission when MAO-A
levels are high. In this way, she theorizes, it would be possible to minimize the impact of naturally high MAO-A levels upon mood in the period just after childbirth.
Currently at Max-Planck Institute for Human Cognitive and Brain Sciences, in Leipzig, Germany, Dr. Sacher began this research as a NARSAD Investigator with colleagues at the University of Toronto Centre for Addiction and Mental Health. They reported their results this past June in the journal Archives of General Psychiatry (“Elevated Brain Monoamine Oxidase A Binding in the Early Postpartum Period”).