A recent study suggests that postpartum depression and her little sister, the Baby Blues, may be caused by an elevated level of the enzyme monoamine oxidase A (MAO-A). This means that treatments that lower MAO-A might improve mood during early motherhood.
MAO-A is an enzyme that inactivates many neurotransmitters that affect mood, such as serotonin and dopamine.
If the Baby Blues really are nothing more than a chemical imbalance, they could become as much a thing of the past as smallpox.
Up to 13% of new mothers suffer from postpartum depression, defined as a major depressive episode occurring within four weeks of giving birth. And up to 70% of new mothers experience less severe but still unpleasant mood problems informally called postpartum blues or Baby Blues. These can include sadness, mood swings, anxiety, loss of appetite and irritability. Until now, this has pretty much been accepted as a fact of life.
In the first few days after birth, a new mother's estrogen levels drop from 100 to1000 fold. Estrogen is known to have an inverse relationship with MAO-A; when estrogen drops, MAO-A rises.
MAO-A levels had never been measured in women in the first few days after birth. A research team set out to do so and found that overall brain MAO-A levels were up 43%. And they peaked on day five postpartum, a day other studies have found that the mood of new mothers often hits a low.
This suggests that treatments that lower MAO-A could restore mood. It would also be possible to try to boost the levels of mood elevating neurotransmitters, but that would likely be a more complicated process. Right now nobody knows, because neither approach has been tried yet.
The researchers used positron emission tomography (PET) to compare brain MAO-A levels in 15 healthy women 4-6 days postpartum to 15 healthy women who had not recently given birth. Measurement was of a tiny amount of radioactively-labeled substance injected into the subjects that specifically binds to MAO-A.
An article on the study was published in the May issue of the Archives of General Psychiatry.