A study of more than two million women and girls has found that major depression peaks around two weeks after childbirth, underscoring the need for earlier screening and stronger support systems.

The research, led by the University of Queensland and published in The Lancet Psychiatry, analysed data from 780 studies across 90 countries, tracking mental health from conception to one year after birth.

Researchers found that while major depression affects about 4.3% of women globally, the rate rises to 6.2% during pregnancy and 6.8% in the year following childbirth. The highest prevalence – 8.3% – occurs at around two weeks postpartum.

This timing is significant. The first few weeks after delivery are often when mothers are discharged from hospital and expected to settle into new routines, sometimes with limited follow-up care.

Experts say this gap may allow symptoms to go unnoticed or be dismissed as normal “baby blues”.

Unlike the temporary mood swings many mothers experience shortly after birth, major depression is more persistent and can affect daily functioning, bonding, and overall wellbeing.

Alize Ferrari, who led the study, said the findings highlight the need for mental health support to be integrated more consistently into maternal care.

“The results highlight the need for including early screening and intervention for depression during the entire peripartum period”,, particularly during antenatal visits and postnatal health checks, she said.

The study also revealed significant regional differences. Rates of major depression were highest in southern sub-Saharan Africa and South Asia, while the lowest were recorded in high-income Asia-Pacific regions.

In Australasia, prevalence was slightly below the global average.

Co-author Dr Paul Miller said these variations are likely shaped by differences in healthcare access, cultural attitudes, and the level of support available to new mothers.

“How families, communities and health systems support women during pregnancy and after birth plays a role in their mental health,” he said.

The findings add to growing evidence that maternal mental health needs to be treated as a core part of healthcare, rather than an afterthought.

Experts say recognising this critical two-week window could help ensure timely intervention – offering support when women may need it most, but are least likely to ask for it.