Postpartum Depression: An Evolutionary Signal, Not a Failure
Postpartum depression (PPD) affects 10–20% of new mothers globally. It is characterised by persistent low mood, anxiety, difficulty bonding, and in severe cases, thoughts of self-harm. It is typically framed as a hormonal or psychological disorder — something that has gone wrong.
Evolutionary medicine offers a different framing — one that neither minimises the suffering nor locates the problem solely within the mother.
Why Would Depression After Birth Evolve?
At first glance, postpartum depression seems paradoxical from an evolutionary perspective. A state that reduces maternal investment in a new infant should be strongly selected against. Why has it persisted?
Evolutionary psychiatrist Randolph Nesse and others have proposed the “insufficient support” hypothesis. In ancestral human environments, infant care was never a solo enterprise. New mothers were embedded in extended kin networks — mothers, grandmothers, sisters, experienced community members — who provided food, infant care, rest, and social support continuously in the early postpartum months.
When sufficient support was absent, postpartum mood alteration may have functioned as a signal — one that would elicit support from the social group, alter partner behaviour, and potentially delay further reproductive investment in conditions where infant survival was compromised. The depression may have evolved to generate a response from the community, not to harm the mother or infant.
The Modern Amplifier
The problem is that modern industrialised societies have largely removed the social infrastructure that the signal was designed to activate. New mothers in nuclear families, far from extended kin, in cultures that celebrate independence and rapid “bouncing back,” find that the signal activates but the evolved response doesn’t come.
Research consistently shows that the strongest predictors of PPD are not hormonal but social: inadequate partner support, low social support, and isolation — all related to the ancestral “support deficit” framework.
OQ’s Support
Dr. Sakata works with many postpartum women — often from the early weeks after birth. The postpartum body is undergoing significant structural and neurological recalibration: hormonal shifts, pelvic floor changes, sleep deprivation, changed load distribution from caregiving.
Osteopathic support in this period addresses the physical dimension of postpartum recovery — reducing pain, supporting the autonomic nervous system, and creating the physical conditions in which emotional recovery is possible. For PPD specifically, Dr. Sakata takes seriously the importance of referring to appropriate psychological and social support alongside osteopathic care.
FAQ
Is postpartum depression caused by hormones?
Hormonal shifts (particularly the rapid oestrogen and progesterone drop) contribute, but are not sufficient explanation — many women have the same hormonal changes without developing PPD. Social and psychological factors appear to be more predictive.
Can the baby’s health be affected by postpartum depression?
Yes. PPD affects mother-infant bonding, which has documented effects on infant neurological and emotional development. Early intervention — for the mother — protects the infant as well.
How can osteopathy help in the postpartum period?
By supporting physical recovery (pelvic floor, sacral mechanics, postural changes from breastfeeding), improving sleep quality, and addressing the autonomic dysregulation that accompanies the whole postpartum transition. The body matters for the mind.
Postpartum and struggling? Physical and emotional wellbeing are deeply connected. Early support makes a difference. Book →