The 9-item Cannabis Exposure in Pregnancy Tool (CEPT) showed 100% sensitivity and 82% specificity when validated against urine THC testing, offering a standardized way to measure prenatal cannabis use for research.
People interested in prenatal cannabis exposure research and standardized measurement of cannabis use during pregnancy.
100% sensitivity against urine THC testing
What the researchers found
The CEPT demonstrated excellent psychometric properties: convergent validity (kappa=0.72-1.0), high internal consistency (alpha=0.92), very good 3-month test-retest reliability (weighted kappa=0.92), and 100% sensitivity with 82% specificity against urine THC bioassay.
Why it matters
Research on prenatal cannabis effects has been limited by inconsistent measurement. Without a standardized tool, studies measure cannabis use differently, making it hard to compare findings. CEPT addresses this by capturing frequency, timing, dose, and mode of use.
The numbers in context
254 pregnant women participated. 9-item tool. Sensitivity: 100%. Specificity: 82%. Internal consistency: alpha=0.92. Test-retest reliability: weighted kappa=0.92 (95% CI: 0.86-0.97). Convergent validity kappa: 0.72-1.0.
How the study worked
Mixed-methods tool development study with 254 pregnant women in Alberta, Canada. Included environmental scan of existing tools, in-depth interviews, cognitive interviewing, and psychometric validation including convergent/discriminant validity, internal consistency, test-retest reliability, and external validation against urine THC testing.
What this study cannot tell us
Validated in an Alberta, Canada sample that may not represent other populations. Self-reported tool, even though validated against bioassay. The 82% specificity means some false positives. Cultural and legal context may affect disclosure willingness.
How to read the evidence
Rigorous validation study with multiple psychometric assessments and biological validation. Limited by single-population validation and self-report nature of the tool.
When this study was published
Published in 2024 in BMC Pregnancy and Childbirth.
The bigger picture
Cannabis use during pregnancy is a growing research topic, but crude measurement (e.g., "any use vs. no use") limits the field. CEPT captures multiple dimensions of exposure, which could help researchers identify more precisely which patterns of use carry the most risk.
Questions still open
- Will CEPT perform similarly in populations where cannabis is illegal? Can the tool be adapted for postpartum/lactation use measurement? Would widespread adoption of CEPT improve the quality of prenatal cannabis research?
Common questions
Why do researchers need a special tool for measuring cannabis use in pregnancy?
How accurate is the CEPT?
Read the original research
Development and validation of the Cannabis Exposure in Pregnancy Tool (CEPT): a mixed methods study.
BMC pregnancy and childbirth, 24(1), 280
Citation
Chaput, Kathleen H; McMorris, Carly A; Metcalfe, Amy; Ringham, Catherine; McNeil, Deborah; Konschuh, Shaelen; Sycuro, Laura J; McDonald, Sheila W. (2024). Development and validation of the Cannabis Exposure in Pregnancy Tool (CEPT): a mixed methods study.. BMC pregnancy and childbirth, 24(1), 280. https://doi.org/10.1186/s12884-024-06485-0
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