Abstract Body: Background: Prenatal vaping and cannabis use are steadily increasing, with unknown epidemiological consequences. Unfortunately, the measurement of stigmatized health behaviors such as prenatal tobacco smoking, vaping, and cannabis use can be difficult. In the absence of biochemical testing, self-report via self-administered validated surveys may offer the best available estimates. Data from electronic health records (EHR) are a pragmatic alternative assessment method to research surveys, but the accuracy of EHR-reported prenatal vaping and cannabis use is unknown.

Methods: The Mountain Mama & Baby Study is a prospective pregnancy cohort seeking to establish the epidemiology and health outcomes associated with prenatal vaping and cannabis use in central Appalachia. Participants were recruited by nurse navigators from six West Virginia University Medicine obstetric clinics between January-June 2025 at their first prenatal encounter in their first trimester (N=417, 44% enrollment). Upon enrollment, participants completed self-administered surveys adapted from national validated instruments querying their first-trimester tobacco smoking, vaping, and cannabis use. EHR data on substance use reported during the initial prenatal visit were also abstracted. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated using survey data as the criterion standard.

Results: Among the 374 participants who completed all relevant surveys, self-reported substance use was consistently lower in the EHR than in the survey responses: 5.6% vs 6.1% for tobacco smoking, 11.7% vs. 13.3% for vaping, and 4.8% vs 9.4% for cannabis use. When identifying current smokers, the EHR had a sensitivity of 0.74, a specificity of 0.99, a PPV of 0.81, and an NPV of 0.98. When identifying current vapers, the EHR had a sensitivity of 0.76, a specificity of 0.98, a PPV of 0.86, and an NPV of 0.96. When identifying current cannabis users, the EHR had a sensitivity of 0.40, a specificity of 0.99, a PPV of 0.78, and an NPV of 0.94.

Conclusion: During the first trimester of pregnancy, the EHR was moderately concordant with self-administered surveys for tobacco smoking and vaping but had lower fidelity for cannabis use. Future research should compare EHR and survey-measured prenatal tobacco smoking, vaping, and cannabis use to biochemical assessments.