Why Am I So Tired After Having a Baby? The Overlooked Science of Postnatal Depletion
- Amy Simpson
- May 1
- 5 min read
Updated: 7 days ago
Motherhood is both transformative and depleting. If you're months, or even years, postpartum and still feeling exhausted, foggy, anxious or unlike yourself, you're not alone. The neurological and hormonal shifts of becoming a mother are immense. Yet many women are unaware that what they’re experiencing may be part of a recognised clinical pattern: postnatal depletion.
This blog unpacks the science behind postnatal depletion, why it's more common than ever, and what can be done to support long-term maternal wellbeing.
What is Postnatal Depletion?
Postnatal depletion is not just about being tired. It's a prolonged state of physical, emotional, and neurological exhaustion that can linger for years after giving birth. Coined by Australian integrative GP Dr Oscar Serrallach, the term reflects a constellation of symptoms including:
Persistent fatigue
Brain fog and memory issues
Anxiety or low mood
Nutrient depletion (iron, zinc, B12, omega-3s, choline)
Feeling "not like yourself" despite time passing
This condition is driven by a combination of nutritional demands, hormonal shifts, sleep deprivation, and the relentless nature of modern parenting. Left unaddressed, it can lead to burnout, depression, or even autoimmune dysfunction.
The Biological Demands of Early Motherhood
From a neuroendocrine perspective, motherhood is not just a social role, it's a full-body physiological transformation.
During pregnancy and postpartum, the maternal brain undergoes rapid structural changes. Brain regions responsible for emotional regulation, memory, and empathy are rewired through a process known as synaptic pruning. These changes help mothers respond to their baby's needs—but they also make the brain more sensitive to stress, sleep loss, and nutrient deficits.
Breastfeeding intensifies these demands. It draws heavily on maternal nutrient stores, especially iron, iodine, DHA, and choline, prioritising breastmilk quality over the mother's reserves. Without adequate replenishment, this can drive long-term depletion.
What is Postpartum Brain Fog?
You might feel like you're constantly walking into rooms and forgetting why, or rereading the same sentence multiple times. While often brushed off as "baby brain", this is a sign of real neurological and hormonal adaptation. Interestingly, research shows that motherhood can improve long-term cognitive health, but only when the mother is supported.
Cognitive symptoms in the postpartum period are usually temporary and reversible with:
Adequate sleep and circadian support
Targeted nutrient repletion
Emotional validation and reduction of invisible labour
Recognising and treating hormonal imbalances
Why Is Postnatal Depletion More Common Today?
Maternal age is one key factor. In Australia, nearly 60% of births are now to women aged 30–39. By age 35, many women are entering Stage -2 of the reproductive ageing process, known as early perimenopause.
This is a time of fluctuating oestrogen, disrupted sleep, and mood instability even before periods begin to change. In other words, a growing number of mothers are experiencing matrescence and perimenopause at the same time. This intersection of hormonal milestones increases vulnerability to depletion, anxiety, and cognitive overload.
Postpartum Hormones and Mental Health
The hormonal environment of early motherhood is unique. For the first 6–12 weeks, women are supported by elevated prolactin and oxytocin, which promote sleep, bonding, and stress buffering. But after the 4–6-month mark, these hormones start to decline. At the same time, cortisol sensitivity returns to normal. This hormonal shift can coincide with sleep regression, weaning, returning to work, or reduced social support. This is often when women first experience:
Anxiety or panic
Feelings of being overwhelmed
Sleep disturbances
Resurfacing symptoms of ADHD or mood disorders
What Does Science Say About Mother-Infant Bonding and Mental Load?
The early postpartum period is biologically designed for close contact between mother and baby. Skin-to-skin contact regulates infant heart rate, body temperature, blood sugar, and even gene expression. But in modern life, the burden often falls solely on mothers. They are expected to co-regulate, breastfeed, maintain a household, and “bounce back”—all while navigating a society that offers little structural support.
This mismatch between biological expectation and social reality is one of the root causes of depletion and mental distress in postpartum women.
What Is the Link Between Sleep and Postnatal Depletion?
Both postpartum and perimenopausal women experience disrupted sleep due to hormonal changes. In the early months, the maternal circadian rhythm becomes temporarily desynchronised to support 24-hour caregiving. Sleep deprivation alone increases risk for:
Depression and anxiety
Blood sugar instability
Poor cognitive function
Increased inflammatory markers
Safe co-sleeping, shared care, exposure to morning light, and avoiding screens at night can help restore circadian health in mothers without compromising infant attachment.
Postnatal Depletion Treatment?
There is no single treatment for postnatal depletion, but the approach must be multi-layered and individualised. Key areas to address include:
Preconception planning: improve your nutrient status, be physically and emotionally prepared for parenting.
Birth planning: nothing rail-roads good intentions faster than birth trauma
Nutrient repletion: iron, iodine, choline, omega-3s, magnesium, B vitamins
Nervous system support: adaptogens, nervines, circadian rhythm support
Structural support: help with meals, baby care, household tasks
Psychological support: validation, boundaries, trauma-informed care
Hormonal support: especially during breastfeeding weaning or return of menstrual cycles
Naturopathy can play a powerful role in restoring energy, mood, and cognitive function. Especially if your blood tests "come back normal".
When Should You Seek Extra Help?
If you're experiencing any of the following, it’s time to seek additional support:
Ongoing fatigue that doesn’t improve with sleep
Intrusive thoughts or persistent low mood
Difficulty bonding with your baby
Feeling constantly on edge or overwhelmed
Loss of joy or interest in things you once enjoyed
You do not need to wait for a crisis. Early intervention is key to recovery.
You’re Not Failing. You’re Depleted.
The modern mother is up against a world that does not reflect her biology. Postnatal depletion is not a personal weakness; it’s a natural response to an unnatural load.
With the right care, recovery is not only possible but likely.
If you're ready to begin healing, I invite you to learn more about how naturopathic care can support your postpartum health.
Amy is a degree-qualified naturopath dedicated to helping busy, tired clients regain their energy and vitality.
She combines evidence-based naturopathic medicine, nutrition, and lifestyle interventions to empower clients on their journey to optimal health. Whether it’s reclaiming energy, balancing hormones, resolving digestive issues, or enhancing overall well-being and longevity, her personalised approach focuses on identifying and addressing the root cause of health concerns. With a Bachelor of Health Science, ongoing studies in a Master of Advanced Practice, and full membership in the Naturopaths and Herbalists Association of Australia, Amy offers a unique blend of traditional wisdom and science to support individuals and families at every stage of life.
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