Postpartum depression can be debilitating for many women.
Postpartum depression can be debilitating for many women. New research sheds light on the possible biological cause of this devastating illness.

Odds are if you have not suffered from postpartum depression personally, you know someone who has. After all, nearly one in five women are impacted by the disease, which can cause sadness, severe fatigue, anxiety, inability to bond with their baby, and, in rare cases, suicidal ideations. Mothers are not the only ones who are impacted by the illness. Studies have linked PPD to developmental difficulties in children.

Although postpartum depression is widely recognized, the cause of the disorder has been poorly understood. However, researchers from Tufts University School of Medicine may have identified one biological cause for PPD in some patients.

Related Study: Taking Probiotics During Pregnancy Reduces Risk of PPD and Depression

All living creatures experience stress. In humans, stress activates a pathway called the hypothalamic pituitary adrenal (HPA) axis. This complex stress system, responsible for the fight or flight response, regulates the body's levels of cortisol and other important stress-related hormones. During pregnancy, activation of the HPA axis is suppressed to protect the fetus from stress.

According to the new study, an imbalance of the HPA axis may cause mothers to be more susceptible to postpartum depression. Neuroscientists conducted a study on mice examining the connection between postpartum depression and a deficit of the brain protein, KCC2. KCC2 is responsible for regulating the amount of corticotrophin releasing hormone (CRH) that the brain releases in response to stress.

"Using a mouse model that we developed, our new study provides the first empirical evidence supporting the clinical observations of HPA axis dysfunction in patients with postpartum depression and shows for the first time that dysregulation of the HPA axis and a specific protein in the brain, KCC2, can be enough to induce postpartum depression-like behaviors and deficits in maternal care," Jamie Maguire, Ph.D., corresponding author on the new study and assistant professor in the Department of Neuroscience at Tufts University School of Medicine said in a press release.

Related: Understanding Postpartum Depression And Anxiety: What I Wish I Had Known As a New Mom

The authors do not believe that the HPA axis dysfunction is the only mechanism that impacts postpartum depression, as several factors may influence the disease. However, they hope that continued work will help them to identify women who may be vulnerable to postpartum depression due to the imbalance of the HPA axis.

"There is much more we need to learn, but we believe our model will be useful for testing novel therapeutic compounds for postpartum depression," said Maguire.