Figure 1.

Validity of Self-Reported Prenatal Cannabis Use Versus Urine Toxicology Results Among 281,025 Pregnancies in Kaiser Permanente Northern California, 2009–2017

Notes. The sample included women screened for prenatal cannabis use by self-report with a urine toxicology test within ± two weeks. Sensitivity was calculated as the proportion of patients with a positive urine toxicology test for cannabis who self-reported prenatal cannabis use. Specificity was calculated as the proportion of patients with a negative urine toxicology test who self-reported no prenatal cannabis use. Positive predictive value was calculated as the proportion of patients who self-reported prenatal cannabis use who had a positive urine toxicology test. Negative predictive value was calculated as the proportion of patients who self-reported no prenatal cannabis use who had a negative urine toxicology test.