Causes of Postpartum Depression

Although researchers don’t know the exact causes of perinatal depression, the following factors may contribute. 

Biological Risk Factors

hormonal changes during pregnancy, delivery, and lactation, or hormonal changes in response to other stress
genetic factors
prior history of a mood disorder, including previous PPD (parents with a history of PPD have a 25-50% chance of having PPD again)
family history of mental illness
discontinuation of medications for mental illnesses (especially if taking medication for depression)
significant medical or pregnancy-related problems, e.g. gestational diabetes or hypertension during pregnancy (preeclampsia)
severe lack of sleep

Psychosocial Risk Factors of PPD

unplanned pregnancy
lack of partner, family, and social support
stressful life event, including adverse childhood experiences
first time being pregnant or giving birth
being pregnant with or giving birth to multiple babies
lactation difficulties
colicky babies (babies who cry for longer than expected at one time) or infant health problems
low socio-economic status
history of abuse including child abuse, gender-based violence, and intimate partner violence
cultural (more info for specific populations below)
geographical location

Note: Additional Risk Factors

It’s important to know that some individuals, communities, and populations may experience increased or additional risk factors due to various societal factors. See the Additional Considerations section for more details.

Risk Factors for Partners

Partners can experience postpartum depression too. Here are some of the possible causes of depression for partners after baby arrives:

history of depression
partner currently has postpartum depression
marital tension
financial/life stressors
feeling excluded from the maternal-newborn bonding
changes in testosterone and cortisol (hormone) levels

Risk Factors for Indigenous Populations

Indigenous parents are at greater risk for postpartum depression. Here are some possible additional causes of PPD for these parents:

social and mental distress due to colonization and forced assimilation
experiences of racism
intergenerational trauma stemming from residential school experiences (by oneself or family member), which may include physical, psychological, sexual, and spiritual abuse
losing or feeling disconnected from language, culture, beliefs, traditions, and other important parts of identity
social determinants of health, which include living in poverty, being unemployed, lacking housing and being food food insecure, along with social exclusion and discrimination
lack of community resources, such as access to services and support

Risk Factors for Newcomers to Canada

Newcomers to Canada often face unique and complex challenges that can affect mental health and the healthcare they receive. Here are some possible causes of depression that newcomers may face:

stress due to moving to a new country, especially to a place of a different culture
not having friends and family for support when facing problems
not being able to understand or speak the local language
earning little money or having none
being of an ethnicity that is different from the majority of the population
having refugee or asylum-seeking status

Factors that Reduce the Chance of Developing Postpartum Depression

healthy and supportive relationship with your partner and family members
partner’s help in caring for the baby
caregiver support for you during the perinatal period
social support during the perinatal period
lactation (especially for parents who experience depression during pregnancy)
note: public health nurses often assist with the development of an infant feeding plan, which includes support for lactation challenges (link to resources)

Who Should Be Screened for PPD?

All parents who gave birth between 28-32 weeks of pregnancy and 6-16 weeks postpartum should be screened for symptoms of depression and anxiety. However, you can be screened at any time between three days and two years postpartum. If one parent is depressed, it’s very important that the other parent (if applicable) is also screened.