Frequency of Preconception and Prenatal Cannabis Use and Nausea and Vomiting in Pregnancy.

This cross-sectional study analyzed associations between preconception and prenatal cannabis use and first-trimester nausea and vomiting in pregnancy (NVP) using data from 356,343 pregnancies in a large health care system (2011-2022). Prevalence of preconception and prenatal cannabis use was 11.3% (2.7% daily, 2.4% weekly, 6.3% monthly or less) and 6.5% (0.7% daily, 0.7% weekly, 1.4% monthly or less, 3.7% positive toxicology with no self-reported use), respectively. Based on International Classification of Diseases diagnostic codes, 3.6% of patients were diagnosed with severe NVP and 16.0% with mild NVP. Self-reported preconception daily cannabis use was associated with greater odds of mild (adjusted odds ratio [aOR] 1.68, 95% CI, 1.59-1.77) and severe (aOR 2.61, 95% CI, 2.40-2.84) NVP when compared with individuals without preconception use. Self-reported weekly cannabis use was associated with greater odds of mild (aOR 1.26, 95% CI, 1.19-1.34) and severe (aOR 1.73, 95% CI, 1.57-1.90) NVP compared with no preconception use. Similarly, self-reported prenatal daily cannabis use was associated with greater odds of mild (aOR 1.97, 95% CI, 1.79-2.17) and severe (aOR 3.80, 95% CI, 3.28-4.39) NVP compared with no prenatal use. Self-reported weekly cannabis use was associated with greater odds of mild (aOR 1.85, 95% CI, 1.68-2.03) and severe (aOR 2.87, 95% CI, 2.47-3.34) NVP compared with individuals without prenatal use. This study found that preconception and prenatal cannabis use were associated with increased odds of both mild and severe NVP during the first trimester, with the highest odds observed among individuals using cannabis daily before or during early pregnancy. Findings underscore the need for patient education and medically appropriate therapies for NVP management.