(616) Association between Cotinine Exposure and Outcomes in Patients with Prenatal Cannabis Use: A Secondary Analysis

Existing data regarding p</span>renatal cannabis use (PCU) and adverse outcomes are often confounded by tobacco use. We initially sought to assess maternal and neonatal outcomes in patients with isolated PCU, and performed a prospective cohort study with negative verbal tobacco use screening as criteria for enrollment. Interestingly, a large percent of enrolled patients were excluded from primary analysis due to urine drug screening (UDS) demonstrating exposure to cotinine, a tobacco metabolite. We sought to evaluate differences in outcomes between this excluded group and the larger PCU positive cohort.

Study Design: We performed a secondary analysis of a prospective cohort study of patients with pre-pregnancy cannabis use who were enrolled in the first trimester. The primary outcomes were a preeclampsia and small for gestational age (SGA). Secondary outcomes included gestational hypertension, gestational diabetes, fetal growth restriction, preterm birth, mode of delivery, large for gestational age (LGA)and APGARs. Descriptive statistics were used to compare baseline characteristics. Backwards stepwise logistic regression was used to control for potential confounders.

Results: 235 patients were enrolled in the PCU arm of the initial study. After crossover between PCU arms and cotinine testing, 96 PCU patients were positive for cotinine (Cpos) and 131 were negative (Cneg) . Baseline characteristics were similar in between groups, though the categorical distribution of income in the Cpos group was lower (p=0.006) and more Cpos patients had hypertensive disorders in prior pregnancies (23% Cpos vs 17% Cneg, p=0.03).  Cpos patients had greater risk of SGA < 5^th and 10^th percentiles in unadjusted analysis, but after controlling for confounds this finding only persisted for SGA< 10^th% (32% Cpos vs. 15% Cneg; aRR 2.16; 95% CI 1.21-3.42).

Conclusion: In patients with PCU, cotinine exposure was associated with a 2-fold increased risk of SGA < 10^th percentile, underscoring the differing contributions of PCU and tobacco to the risk of adverse pregnancy outcomes.