Postpartum depression (PPD) is a mood disorder that affects women during pregnancy or within the first year after giving birth. Characterized by persistent feelings of sadness, anxiety and fatigue, this condition has a serious impact on a mother’s ability to care for herself and her newborn. This is significantly different from the ‘baby blues’, which usually resolve within a few weeks of giving birth.
The root causes of PPD are varied. Hormonal changes during and after pregnancy play an important role. Estrogen and progesterone levels increase rapidly during pregnancy and fall rapidly after birth. This hormonal roller coaster will eventually affect your mood and emotional stability.
Genetic factors also make some women more susceptible to PPD. Environmental factors such as stress, lack of sleep, and the physical demands of caring for a newborn also contribute to the development of this condition. These factors create a perfect storm that leads to PPD.
When these underlying causes converge, the normal functioning of the brain is disrupted. Hormonal imbalances affect the neurotransmitter systems responsible for regulating mood and emotions. Now researchers are trying to understand how the human brain changes and adapts during this period to help new mothers better manage their condition.
Brain structure of women with peripartum depression
The study, published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, aimed to uncover neurobiological differences between women who experience PPD and those who do not. The authors particularly focused on the effects of the basal ganglia and estradiol polygenic risk score (PRS), a group of structures in the brain involved in emotion, reward and decision-making processes, on brain morphology.1
The study involved 64 mothers diagnosed with major depressive disorder (MDD). Thirty had a history of PPD and 34 did not. They were recruited from a large cohort of 219 patients in Milan. To compare brain structure between the two groups, the team utilized voxel-based morphometric analysis to study gray matter volume within specific regions of the basal ganglia.
The group with a history of PPD showed significantly greater gray matter volume in bilateral clusters including the putamen, globus pallidus, caudate, and thalamus compared to the group without PPD. These structural differences indicate that the basal ganglia play an important role in the pathophysiology of PPD and contain high concentrations of estrogen receptors that are sensitive to hormonal changes.2
Additionally, this study showed that estradiol PRS interacts differently with brain volume based on PPD history.3 Specifically, in women with PPD, higher estradiol PRS was associated with increased gray matter volume in basal ganglia clusters. In contrast, women without PPD showed a negative association between estradiol PRS and gray matter volume in this region.4
How Estradiol Affects Brain Function
The study also examined how estradiol levels affect the structure and function of the basal ganglia. In context, estradiol affects gene expression, dendritic spine density, and neurotransmitter function within these brain regions.5 These pathways contribute to the observed structural differences, indicating that hormonal fluctuations during the peripartum period trigger or exacerbate depressive symptoms in vulnerable women.
Moreover, the involvement of the basal ganglia in emotion regulation and decision making provides a functional context for the observed structural differences. Altered basal ganglia structure and function have been associated with MDD in previously published studies, indicating that these regions play a role in the progression of depression.6
Overall, this study sheds new light on how hormonal and genetic factors interact to influence brain structure and function in the context of PPD. The identification of larger gray matter volumes in specific basal ganglia regions in women with PPD highlights the importance of considering both hormonal sensitivity and genetic predisposition in the diagnosis and treatment of this condition.7
Further neurobiological changes occur during the peripartum period.
In a meta-analysis published in Social Cognitive and Affective Neuroscience, researchers examined important changes that occur in women’s brains during pregnancy and after childbirth. In particular, they focused on understanding how hormonal changes, immune system adjustments, sleep disturbances and increased stress levels affect women’s mental health and brain structure.8
A comparison of pregnant and postpartum women with non-pregnant women found that more than a quarter of women experienced symptoms of depression during this period. Symptoms are also associated with significant changes in brain structure and function. This is caused by fluctuations in hormonal and immune systems, sleep disturbances, and increased care responsibilities after birth.9
Researchers found that during the peripartum period (the period just before, during, and immediately after birth):10), women experience significant structural changes in their brains. Gray matter volume decreases, especially in the hippocampus, an area important for memory and learning.
Changes also occur in the amygdala, which is involved in emotional processing. These changes are not temporary and continue beyond the postpartum period.11
Hormonal fluctuations play a role in these brain changes. When estrogen and progesterone levels drop after childbirth, a series of chemical reactions occur in the brain, increasing vulnerability to mood swings and depression. These hormones are essential for maintaining pregnancy, and their rapid decline subsequently affects various brain regions responsible for emotional regulation and cognitive function.12
Additionally, the immune system is greatly adjusted during pregnancy to protect both mother and fetus. This balance affects the brain by altering immune cell function, which influences neurodevelopmental processes. Impaired immune function affects structural changes in the brain and increases the risk of developing symptoms of depression.13
Sleep disturbances are another major factor contributing to neurobiological changes. Many new mothers experience poor sleep quality or insufficient sleep, which affects the amygdala, making it more reactive and heightening emotional responses. This increased reactivity increases emotional intensity and volatility, further worsening symptoms of depression and anxiety.14
Psychosocial stress that arises during the process of adjusting to care and motherhood also affects brain structure. Chronic stress leads to changes in brain regions associated with reward processing and decision-making, such as the striatum and prefrontal cortex. These changes impair cognitive functions such as memory and information processing, making it difficult for mothers to cope with their daily responsibilities.15
Structural Brain Abnormalities Found in Postpartum Depression
In another study published in Behavioral Brain Research, a team examined differences in brain structure between women who experience PPD and those who do not. The study focused on examining cortical and subcortical regions of the brain, including 29 women diagnosed with PPD and 23 healthy postpartum women as controls. All participants were right-handed, aged 20–40 years, and 1–2 months postpartum.16
Studies have shown that women with PPD have increased thickness in several specific areas of the brain. Specifically, compared to the healthy postpartum female group, the cortical thickness of the left superior frontal gyrus, sphenoid gyrus, right lingual gyrus, and fusiform gyrus was found to be significantly increased.17 Additionally, these women showed regional swelling in the right pallidum, a subcortical structure associated with emotion regulation and reward processing.
Looking more closely at the study results, we found that depression scores were significantly higher in the PPD group compared to the healthy group, indicating more severe depression symptoms.18 Interestingly, there was no significant difference in local gyrification index, another tool to measure cortical morphology, between the two groups. This suggests that certain aspects of brain folding were not affected by PPD.19
Increased cortical thickness in the affected area highlights important changes in areas responsible for cognitive control, emotional regulation, and visual processing. For example, the left superior frontal gyrus is central to executive functions, including decision-making and emotion management.
Meanwhile, the cuneiform and fusiform gyri are essential for processing visual information and recognizing facial emotions, which are essential for social interaction and bonding with infants.20
Moreover, this study highlighted that regional expansion of the right globus pallidus is associated with the limbic cortico-striatal pallidum thalamic (LCSPT) circuit. This circuit plays an important role in regulating emotions and processing rewards. Dysfunction of the globus pallidus causes symptoms such as lack of motivation, inability to feel pleasure, and persistent negative thoughts. All of these symptoms are common in PPD.
In essence, the hypertrophy of the globus pallidus observed in women with postpartum depression is associated with difficulties in responding positively to stimuli in the infant, which has a negative impact on maternal behavior.21
Four ways to help mothers manage postpartum depression
Dramatic hormonal changes and the combined stresses of pregnancy and postpartum inevitably lead to significant changes in the structure and function of the mother’s brain. Understanding and preparing for these changes will help you maintain your mental health during this important time. Here are some practical strategies I recommend for managing your symptoms:
1. Prioritize sleep and recovery — Sleep deprivation has a significant impact not only on brain regions involved in emotional regulation, but also on overall cognitive function. Make sleep a priority by working with your family to ensure they get 7 to 8 hours of rest while caring for their baby. Read “How Sleep Deficiency Impairs Cognitive Performance and Learning” for tips on how to improve your sleep quality.
2. Get regular, moderate-intensity exercise — If possible, take regular walks outdoors. Once you start moving again, your body experiences dose-dependent reductions in depression, sarcopenia, and overall mortality. Exercising with a friend or group class is better than exercising alone because it adds an element of social support.
3. Nourish yourself with brain-boosting foods — Reduce your intake of inflammatory foods like processed sugar and vegetable oils, which affect brain function. Focus on foods rich in B vitamins. That’s because this group of nutrients is important for brain health and emotional regulation.
4. Optimize your hormonal balance — It focuses on supporting progesterone production to counteract the rapid decline in hormones after childbirth. Adequate sunlight exposure supports vitamin D production, which works synergistically with progesterone for optimal brain function. Please read the detailed instructions below to properly administer progesterone.
