While any cannabis use during pregnancy was not associated with hypertensive disorders, frequent use (2+ times weekly to daily) was linked to 3.44 times higher odds compared to minimal use.
Obstetricians, midwives, prenatal care providers, pregnant individuals who use cannabis.
Frequent cannabis use (2+ times/week) linked to 3.44x higher odds of pregnancy hypertension
What the researchers found
Cannabis use as a binary variable (yes/no) was not associated with higher odds of hypertension during pregnancy (OR 0.86). However, among those who used cannabis, frequent use (2-6 times per week to daily) was associated with 3.44 times higher odds of hypertensive disorders compared to minimal use (once per month or less, OR 3.44, 95% CI 1.40-8.43).
Why it matters
This study may explain why prior research on cannabis and pregnancy hypertension has been mixed: looking at any use versus no use masks a dose-response relationship. The finding that frequency matters has practical implications for prenatal screening and counseling.
The numbers in context
n=10,911 (weighted 587,486); binary cannabis use OR 0.86 (95% CI 0.54-1.35, not significant); frequent vs minimal use OR 3.44 (95% CI 1.40-8.43); frequency categories: minimal (1x/month or less), moderate (2x/month to 1 day/week), frequent (2-6x/week to daily).
How the study worked
Retrospective cohort study using 2017-2018 Pregnancy Risk Assessment Monitoring System (PRAMS) data (n=10,911, weighted n=587,486). Cannabis use frequency was categorized as no use, minimal (1x/month or less), moderate (2x/month to 1 day/week), and frequent (2-6x/week to daily). Multivariable logistic regression examined dose-response.
What this study cannot tell us
Self-reported cannabis use may underestimate true frequency. PRAMS data are cross-sectional and cannot establish causation. Relatively small numbers in the frequent use category. Cannot account for cannabis potency, method of consumption, or specific cannabinoid profiles. Potential for residual confounding.
How to read the evidence
Moderate: Large nationally representative sample with dose-response analysis, though self-reported exposure and retrospective design are limitations.
When this study was published
Published in 2025 using 2017-2018 PRAMS data.
The bigger picture
Hypertensive disorders of pregnancy (including preeclampsia) are a leading cause of maternal and fetal morbidity. As cannabis use during pregnancy increases, understanding dose-response relationships is critical for clinical guidance beyond simple "use vs. no use" recommendations.
Questions still open
- What biological mechanism links frequent cannabis use to pregnancy hypertension? Does the type of cannabis product (smoking vs. edible) matter? Would these results hold in a prospective study with biomarker-verified exposure?
Common questions
Why was overall cannabis use not linked to hypertension, but frequent use was?
What are hypertensive disorders of pregnancy?
Read the original research
The Impact of Frequency of Cannabis Use on Hypertensive Disorders During Pregnancy.
Journal of addiction medicine, 19(5), 611-614
Citation
Nidey, Nichole; Raff, Erica; Ferdous Khan, Md Tareq; Watkins, Shannon Lea; McAllister, Jennifer M Jm; Kair, Laura; Terplan, Mishka; Greiner, Andrea. (2025). The Impact of Frequency of Cannabis Use on Hypertensive Disorders During Pregnancy.. Journal of addiction medicine, 19(5), 611-614. https://doi.org/10.1097/ADM.0000000000001454
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