Continued cannabis use beyond the first trimester was associated with higher odds of depressive symptoms later in pregnancy, while any-use overall was not significantly linked.
Pregnant individuals considering cannabis use, prenatal care providers, perinatal mental health researchers.
60% higher depression odds with ongoing use (aOR 1.6)
What the researchers found
Among 8,424 pregnant women in the nuMoM2b study, any cannabis exposure was not significantly associated with later depressive symptoms (aOR 1.3, 95% CI 0.97-1.6). However, ongoing exposure beyond the first trimester was significantly associated with depressive symptoms at 22-29 weeks (aOR 1.6, 95% CI 1.2-2.2). Higher urine THC metabolite levels correlated with greater odds of depression.
Why it matters
This is one of the largest studies to use objective biomarker-confirmed cannabis exposure (urine testing rather than self-report) to examine the timing and dose relationship between prenatal cannabis use and depression. The finding that timing matters, with ongoing use being the key risk factor rather than any use, adds important nuance.
The numbers in context
8,424 participants included. 6.4% (535) had cannabis exposure. 32.1% (172) had first-trimester-only exposure. 67.9% (363) had ongoing exposure. Ongoing use aOR 1.6 (95% CI 1.2-2.2) for depressive symptoms.
How the study worked
Secondary analysis of the nuMoM2b prospective cohort study (2010-2013) across eight academic centers. Cannabis exposure was verified by urine immunoassay for THC-COOH with LC-MS/MS confirmation at three timepoints. Depression was measured using the Edinburgh Postnatal Depression Scale (EPDS > 10). Multivariable logistic regression adjusted for confounders.
What this study cannot tell us
Observational design cannot establish causation. Direction of association is unclear: depression may drive continued cannabis use rather than the reverse. Study enrolled participants 2010-2013, before more potent products became widespread. THC-COOH detection reflects recent use but does not capture frequency precisely.
How to read the evidence
Moderate: large prospective cohort (N=8,424) with biomarker-verified exposure and validated depression measure, though observational design limits causal inference.
When this study was published
2025 study (data from 2010-2013)
The bigger picture
The distinction between any exposure and ongoing exposure is clinically meaningful. Women who stopped cannabis use after the first trimester did not show elevated depression risk, while those who continued did. However, the study design cannot determine whether cannabis caused depression or whether worsening depression drove continued use.
Questions still open
- Does continued cannabis use during pregnancy worsen depression, or do women with worsening depression continue using cannabis for symptom relief? Would results differ with today's higher-potency products?
Common questions
Does any cannabis use during pregnancy cause depression?
How was cannabis use measured in this study?
Read the original research
Prenatal Cannabis Use and Depressive Symptoms.
Obstetrics and gynecology, 145(4), 417-425
Citation
Pitt, Taylor L; Allshouse, Amanda A; Kim, Pilyoung; McMillin, Gwen; Silver, Robert M; Chung, Judith H; Grobman, William A; Haas, David M; Mercer, Brian M; Parry, Samuel; Reddy, Uma M; Saade, George R; Simhan, Hyagriv N; Metz, Torri D. (2025). Prenatal Cannabis Use and Depressive Symptoms.. Obstetrics and gynecology, 145(4), 417-425. https://doi.org/10.1097/AOG.0000000000005860
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